The researchers collected 30 healthy A. dealbatum specimens at 2-meter intervals from a natural population in Doimukh, Arunachal Pradesh, during the flowering season in June 2023. Following authentication, the rhizomes were washed, shade-dried and divided into finely and coarsely ground portions for microscopy, physicochemical analysis, chromatographic fingerprinting and essential-oil extraction. The dried material was also tested for heavy metals, aflatoxins, pesticides, total microbial load, yeast and mould, and specified pathogens. A voucher specimen was deposited in the herbarium of the Central Ayurveda Research Institute in Kolkata under accession number 57,936.

Macroscopic and microscopic characterization established a set of features intended to support botanical identification. Dried rhizome fragments were approximately 3.5–7 cm in diameter, pale greyish brown and rough, with a pungent odor and bitter taste. Their transverse sections showed cork composed of elongated rectangular cells, covering trichomes, starch-bearing parenchyma, prismatic calcium oxalate crystals, secretory cells, xylem vessels and fibers. Powder microscopy revealed reticulate vessel fragments, starch grains, thick-walled pitted cork cells, lignified parenchyma, calcium oxalate crystals and aseptate fibers. Together with the high-performance thin-layer chromatography profile, these morpho-anatomical traits were proposed as tools for distinguishing A. dealbatum from a closely related species, A. sabutalum.

The quality-control analyses indicated that the sampled rhizome met the pharmacopoeial limits for the contaminants examined. Atomic absorption spectrometry found arsenic, cadmium, mercury and lead below the cited permissible limits, while high-performance liquid chromatography detected no reported aflatoxin residues. Gas chromatography–mass spectrometry also found no pesticides from the organophosphate, organochlorine or pyrethroid groups tested. No yeast or mould growth was observed in the dried material, and the tested specific pathogens were not reported. The authors described the sample as free of detected external contamination, while noting that more comprehensive toxicity testing would still be required before human consumption.

Physicochemical testing characterized the dried rhizome through loss on drying, ash values and extractive values in several solvents. Methanol produced the highest extractive value, whereas the comparatively low hexane value was interpreted as indicating that the rhizome contained abundant polar phytocompounds. A methanolic extract was also examined by high-performance thin-layer chromatography using a two-step gradient solvent system. The resulting qualitative profile showed bands at retention factors of 0.095, 0.212, 0.315, 0.428, 0.527, 0.604, 0.649, 0.759 and 0.838 under 254-nanometre viewing. Comparisons with standards and densitometric patterns indicated gallic acid and quercetin in the extract, while derivatization revealed blue and green bands attributed to terpenoids.

For chemical analysis, the team hydro-distilled 600 grams of coarsely powdered rhizome using a Clevenger apparatus. The distillation rate was maintained at 2–3 mL per minute for three hours, after which the oil was partitioned with diethyl ether and dried over anhydrous sodium sulfate. The resulting essential oil had a sweet aroma with a slightly pungent undertone, a faint brownish color, a density of 1.11 g/mL, a refractive index of 1.112 and a yield of 1.43 ± 0.07%. The oil also had a visible-light transmission of 65% at 565 nanometres. These measurements documented the physical characteristics of the particular extract used in the investigation.

Conventional gas chromatography coupled with mass spectrometry identified 19 compounds, whereas the comprehensive two-dimensional system detected 51 phytoconstituents. Assignments were based on mass-spectral matching, retention indices and chromatographic behavior; only library matches with similarity scores of at least 80% and retention-index deviations within ±10 units were carried forward for evaluation. The identified oil was dominated numerically by monoterpenes, with sesquiterpenes also forming a major group. Geraniol, linalool, pinocarvone, terpineol and ocimene appeared among notable monoterpenes, while the two-dimensional method also resolved hydrocarbons, esters and additional minor constituents more effectively than the conventional analysis.

The researchers observed substantial differences in relative peak areas assigned by the two chromatographic systems. For example, a compound identified as 2-methyl-4-(2,2,3-trimethylcyclopent-3-en-1-yl) butanol accounted for 14.25% of the conventional GC area but 4.56% in the two-dimensional analysis. The authors attributed the difference to improved separation of co-eluting constituents rather than a true reduction in concentration and cautioned against direct quantitative comparison between configurations using different integration procedures. They also noted uncertainty around the natural status of detected phthalates, including diamyl phthalate and diisooctyl phthalate, which may represent contamination from plastic containers or other laboratory materials rather than plant-derived compounds.

Antibacterial activity was tested in a 96-well micro-broth dilution assay against Enterococcus faecalis and Staphylococcus aureus as Gram-positive cocci, and Escherichia coli and Salmonella sp. as Gram-negative bacilli. Crude oil was prepared in aqueous dimethyl sulfoxide containing Tween-80 and tested across serial dilutions from 1:16 to 1:4,096. Each well received a bacterial suspension giving a final inoculum of 5 × 10⁴ CFU/mL, and the plates were incubated for 18 hours at 37 °C. Samples from the wells were then plated on Mueller–Hinton agar, allowing the researchers to distinguish inhibition in broth from bactericidal activity associated with no visible growth after subculture.

The essential oil was bactericidal against all four test organisms. For E. coli, Salmonella sp. and E. faecalis, the minimum bactericidal concentrations ranged from 1:16 to 1:64. S. aureus was the most sensitive organism: no growth was detected at any tested dilution, so its minimum bactericidal concentration was reported as no more than 1:4,096. Solvent-only and bacterial-only controls grew normally, while ciprofloxacin served as the positive control. The assay therefore measured laboratory bactericidal activity against only four strains, without testing the oil in animals or people. Taken together, the study presents A. dealbatum rhizome as a chemically distinct source of monoterpene-rich essential oil with measurable in vitro activity, alongside an anatomical and chromatographic profile intended to authenticate the plant material.

Subject of Research: Pharmacognostic, chromatographic and in vitro bactericidal evaluation of Amomum dealbatum rhizome essential oil

Article Title: Phytochemical evaluation of Amomum dealbatum Roxb. rhizome and correlating bactericidal activity with GC profiling of its essential oil

Article References: Dutta, S., Roy, S., Kumar, D., Singh, P., Narasimhaji, C. V., Prasad, S. B., Samadder, A., Bose, R., & Hazra, K. (2026). Phytochemical evaluation of Amomum dealbatum Roxb. rhizome and correlating bactericidal activity with GC profiling of its essential oil. Discover Chemistry, 3(1), Article 587. https://doi.org/10.1007/s44371-026-01041-5

Image Credits: AI Generated

DOI: 10.1007/s44371-026-01041-5

Keywords: Amomum dealbatum, essential oil, bactericidal activity, Staphylococcus aureus, Escherichia coli, Salmonella, Enterococcus faecalis, GC-MS, two-dimensional chromatography, plant phytochemistry, Phytochemical, evaluation

The species’ biological profile explains much of its ecological success. Red-eared sliders combine broad physiological tolerance with phenotypic plasticity and flexible behavioral strategies, allowing them to survive and reproduce across a remarkable range of climates and habitats. Once established, they compete directly with native turtles for basking sites, food, and nesting areas, and their presence can destabilize entire aquatic ecosystems. They also carry zoonotic pathogens, including Salmonella species, creating a public health dimension that extends the threat beyond biodiversity loss. These traits mean that every individual released into a novel water body carries the potential to seed a self-sustaining population.

The scale of trade in China is staggering. Hatchling production in Hainan Province alone reached nearly three million individuals in 2004, and breeding across provinces such as Hainan, Jiangsu, Zhejiang, Hunan, and Guangdong was estimated at 25 million animals in 2005. A decade later, a single major e-commerce platform recorded sales of approximately 3.36 million sliders in 2017. Offline pet markets are equally active: surveys conducted between 2019 and 2020 found that a single market stall could sell more than a thousand sliders per year. This massive, well-developed industrial chain, spanning large-scale breeding through market-oriented sales, has transformed the slider from a rare exotic curiosity into an easily accessible commodity.

That accessibility is precisely the problem. The trade creates a clear transmission mechanism: the greater the circulation volume, the higher the probability that unwanted individuals are released into natural environments, proportionally escalating ecological risk. Sliders are now found in all major Chinese river basins, with particularly dense populations in the Pearl and Yangtze systems, and they cluster in water bodies adjacent to dense urban areas, scenic spots, and parks. Their presence has even been documented inside protected areas such as the Lhalu Wetland National Nature Reserve, demonstrating that the invasion frontier has reached ecosystems nominally shielded from human pressure.

What makes the situation especially frustrating is that the law is already on the books. The species was added to China’s List of Alien Invasive Species in 2014, and legislation explicitly prohibits illegal introduction, release, and discarding. Yet intentional releases remain common, driven by two factors: the sheer availability of animals and a severe lack of public awareness. Merchants frequently advertise the recreational appeal of sliders while downplaying their invasive status and omitting information about release prohibitions. Many consumers buy them for ritual release, a Buddhist-influenced merit-making practice, as companions, or for a first pet-keeping experience, and remain unaware of the ecological harm that irresponsible release can cause.

The research proposes a tripartite management framework built on institutional improvement, consumption guidance, and sales regulation, forming a closed-loop model that targets supply, demand, and the transaction itself. The institutional pillar is the foundation. It calls for accelerating supporting regulations that clarify breeding and sale procedures for prohibited invasive species, establishing permitting and monitoring requirements for breeding facilities, refining penalty standards, and implementing full-chain licensing, unified labeling, and traceability so that supervision is verifiable and grounded in law. Crucially, the framework also anticipates market displacement: if slider supply shrinks, consumer demand may redirect toward other turtle species, including native taxa, potentially generating new risks.

To manage that displacement responsibly, the authors propose a government-led Local Turtle Breeding Transformation Service Platform to orchestrate a sector-wide transition. The platform would partner with research institutions to provide technical training, coordinate with financial institutions on transformation loans, connect breeders with compliant sales channels, and offer subsidies. But the authors are emphatic that such guidance must be approached with extreme caution. Many native Chinese turtles are severely threatened, and shifting demand without ironclad safeguards could inadvertently incentivize the illegal harvesting and laundering of wild-caught animals, worsening the very conservation crisis the policy aims to solve.

The benchmark for any legal alternative is deliberately high. China’s List of Artificial Breeding of National Key Protected Aquatic Wild Animals permits market entry only for species meeting five rigorous criteria: universally mature and standardized breeding technology; self-sustaining captive populations requiring no wild sourcing; breeding stock at the F3 generation or beyond with at least two stable captive populations; demonstrated contribution to wild-population conservation, such as channeling sales revenue toward critically endangered species like the big-headed turtle; and compliance with national law and social ethics. Eight turtle species, including Mauremys reevesii and Mauremys sinensis, currently satisfy these benchmarks, proving that a legal, traceable pathway is feasible. Because the vast majority of native species do not meet the criteria, the platform’s non-negotiable function is a fail-safe full-chain traceability system ensuring every market-bound individual is certified captive-bred.

The consumption pillar aims to dampen demand by steering cultural practice toward ecologically sound substitutes. For ritual release, the proposal favors meaningful non-organism alternatives, such as sponsoring wildlife habitat restoration or supporting the rehabilitation and scientifically justified reintroduction of injured native wildlife through accredited conservation centers, preserving the compassionate intent of the tradition while directly benefiting ecosystems. Where living animals are discussed, guidance would operate within strict institutional boundaries: short videos comparing care requirements and highlighting the dangers of genetic pollution and disease spread, educational zones in physical pet markets, e-commerce sections promoting sustainable native turtles with traffic support, and intelligent prompts suggesting legal alternatives when users browse sliders. Individual turtles would be photographically registered to buyers using unique scute patterns, linked to a central registry, and accompanied by signed no-release commitments with legal liability for intentional release.

The third pillar enforces accountability at the point of sale. Physical venues would display prominent warnings categorizing the animal as an invasive alien species, while e-commerce product pages would incorporate pop-up hazard reminders and slogans such as Illegal Release Prohibited in titles and images. Sellers who fail their disclosure duties would bear joint liability for ecological damages alongside the releaser, and platforms neglecting oversight would be held accountable for supervisory negligence. The authors frame the challenge as more than species control: it is an opportunity to re-evaluate the wildlife trade model itself. If the tripartite framework succeeds, it would erect a barrier against further invasion while building the public awareness and regulatory rigor needed for any sustainable future interaction between people, markets, and wildlife.

Subject of Research: Ecological risks and trade regulation of the invasive red-eared slider turtle in China

Article Title: Beyond commercial interests lies an ecological responsibility: The dilemma of red-eared slider sales

Article References: Liu, D., Xie, C., Guan, H., Hou, S., & Xue, X. (2026). Beyond commercial interests lies an ecological responsibility: The dilemma of red-eared slider sales. Nature Conservation, 61, 177-184. https://doi.org/10.3897/natureconservation.61.176927

Image Credits: AI Generated

DOI: 10.3897/natureconservation.61.176927

Keywords: red-eared slider, invasive alien species, China, pet trade, turtle conservation, ritual release, e-commerce regulation, traceability, captive breeding, biodiversity, Salmonella, consumption guidance

Salmonella is a genus of rod-shaped, Gram-negative bacteria encompassing more than 2,500 serotypes, traditionally divided into typhoidal and non-typhoidal varieties. Typhoidal serotypes, such as Salmonella Typhi, cause typhoid fever, while non-typhoidal Salmonella, often abbreviated NTS, typically trigger self-limiting gastroenteritis in healthy people. Yet in infants, the elderly, and the immunocompromised, NTS can turn invasive, spreading from the intestinal lining into the bloodstream and, far less commonly, crossing the blood-brain barrier to seed the meninges, the protective membranes surrounding the brain and spinal cord. Salmonella meningitis in children is genuinely rare, and the authors note that reports of sepsis and purulent meningitis caused by Salmonella in pediatric patients are very scarce in the literature. That rarity is precisely what makes the diagnosis so easy to miss on a first pass.

The girl’s illness followed a recurrent pattern that initially confounded her care team. She was hospitalized three times over the course of her disease, and the authors are candid that the first round of anti-infective treatment was insufficient in both intensity and duration. When invasive bacterial infections are treated with antibiotics that are too brief, too narrow, or inadequately dosed, the pathogen can persist at low levels within protected anatomical compartments, only to flare again once the drug pressure is removed. The meninges, with their restricted penetration by many antimicrobial agents, are a classic sanctuary site for surviving bacteria. Each relapse in this child’s course was a signal that the underlying infection had never been fully eradicated, a mistake the authors explicitly frame as a lesson for other clinicians managing similar presentations.

Getting to the correct etiologic answer required layering multiple diagnostic technologies. Cerebrospinal fluid, the clear liquid bathing the brain and spinal cord, was sampled via lumbar puncture and subjected to both traditional pathogen culture and metagenomic next-generation sequencing, abbreviated mNGS. Culture, the workhorse of clinical microbiology for more than a century, involves growing the organism on selective media and identifying it biochemically, but it can fail when bacterial loads are low, when the patient has already received antibiotics, or when the organism is fastidious. mNGS, by contrast, works by extracting all genetic material from a clinical sample, sequencing it in parallel, and computationally matching the resulting reads against reference databases of known pathogens. This approach can identify bacteria, viruses, fungi, and parasites directly from their DNA without needing to grow anything, making it especially powerful in cases where prior antimicrobial exposure has suppressed culturability.

The mNGS results from the child’s cerebrospinal fluid pointed to Salmonella group D, a serogroup that includes Salmonella Enteritidis and Salmonella Typhi among its members. Confirmatory culture from the same fluid grew the organism, and the clinicians added a serologic layer by performing a Widal test, a classic agglutination assay that detects antibodies against Salmonella O and H antigens in the patient’s serum. The H/O antibody titer came back at 1:320, a level the authors considered supportive of active Salmonella infection when interpreted alongside the molecular and cultural findings. The Widal test, developed in 1896, remains in widespread use in resource-limited settings, though its specificity is limited by cross-reactivity with other Enterobacteriaceae and by residual antibodies from prior exposure or vaccination. In this case, the convergence of three independent lines of evidence, molecular, cultural, and serologic, gave the team the confidence to commit to a targeted therapeutic strategy.

Treating Salmonella meningitis is pharmacologically tricky because the organism’s susceptibility profile varies by serotype and geography, and because the drugs must penetrate the blood-brain barrier in sufficient concentrations. The clinicians tried ceftriaxone, a third-generation cephalosporin that is often first-line for invasive Salmonella disease in children, then escalated to vancomycin, a glycopeptide active against Gram-positive organisms but sometimes added empirically when the pathogen remains unclear, and meropenem, a broad-spectrum carbapenem with excellent central nervous system penetration. When the infection proved stubborn, they added compound sulfamethoxazole, a combination of sulfamethoxazole and trimethoprim that achieves reliable intracellular and cerebrospinal fluid exposure. The authors emphasize that resistance assessment, meaning formal antimicrobial susceptibility testing of the isolated organism, should be a routine part of managing invasive Salmonella infections, since resistance patterns among non-typhoidal Salmonella have been rising globally and can render empiric choices ineffective.

Ultimately, what turned the tide was not a single new drug but a combination of extended anti-infective treatment courses and immune support. The authors argue that clinicians should monitor the immune status of children with invasive Salmonella disease, because an immature or dysregulated immune system can undermine even the most pharmacologically sound regimen. Infants have naturally lower levels of certain immunoglobulins and complement proteins, and their neutrophil function is not yet fully mature, which means that bacterial clearance depends heavily on adequate antibiotic exposure over a sufficiently long period. By prolonging the antimicrobial course and layering in immune-supportive measures, the team finally achieved durable control of the infection, and the child’s condition stabilized. The authors do not report long-term neurologic sequelae in the abstract, leaving that question open for follow-up, but the acute episode was resolved.

The case carries broader implications for how pediatric infectious disease is approached in the era of molecular diagnostics. The authors conclude that treatment plans should be dynamically adjusted as new information arrives, rather than locked into a fixed empiric protocol, and that mNGS should be combined with conventional techniques to accurately identify pathogens in complicated cases. This is a message that resonates well beyond Salmonella. As sequencing costs fall and turnaround times shrink, metagenomic approaches are increasingly being deployed as first-line tools in unexplained fevers, suspected central nervous system infections, and sepsis of unknown origin, particularly in children where the differential diagnosis is broad and the cost of a missed pathogen is high. The technology is not without limitations, including the risk of detecting contaminants, the difficulty of distinguishing colonization from infection, and the computational burden of analyzing millions of reads, but its ability to shortcut the diagnostic odyssey is transforming clinical practice.

For clinicians, the takeaway from this single child’s illness is a checklist of three technical priorities: perform rigorous drug resistance assessment on any invasive Salmonella isolate, ensure that anti-infective treatment courses are adequate in both duration and intensity rather than prematurely shortened, and monitor the patient’s immune status throughout the disease course. For the wider scientific community, the case is a vivid demonstration that rare pathogens can masquerade as common ones, that conventional diagnostics can fail in the very situations where they are needed most, and that molecular sequencing, when layered thoughtfully with culture and serology, can catch what would otherwise slip through. The authors thank the patient and her parents for permission to publish the case, and their candor about the initial treatment missteps is what gives the report its enduring value as a teaching document for pediatricians everywhere.

Subject of Research: Infectious Diseases

Article Title: Purulent meningitis caused by salmonella group D in a one-year-old child: lessons learned from mistakes

Article References: Li, W., Zhao, H., Zhou, Q., & Guo, X. (2026). Purulent meningitis caused by salmonella group D in a one-year-old child: lessons learned from mistakes. BMC Pediatrics. https://doi.org/10.1186/s12887-026-07620-w

Image Credits: AI Generated

DOI: 10.1186/s12887-026-07620-w

Keywords: Salmonella, meningitis, sepsis, mNGS, pediatrics, antibiotic resistance, case report, Purulent, caused, group, one-year-old, child

The research team, led by Adama Pamba Séré of the University Joseph KI-ZERBO in Ouagadougou, sampled 120 farms across three sites in the Northern Region of Burkina Faso, collecting 66 lettuce and 54 tomato samples. Each farm drew irrigation water from one of three sources: open reservoirs, shallow wells, or deep boreholes. The researchers scored each farm’s compliance with Good Agricultural Practices and Good Hygiene Practices through detailed field audits, then quantified two key pathogens, Escherichia coli and Salmonella, using ISO reference methods. What sets the study apart is its statistical rigor: rather than relying on a single test, the team applied five independent analytical methods, including analysis of variance, logistic regression, random forest modeling, principal component analysis, and k-means clustering, to determine which factor best predicts contamination.

The results were unambiguous. Irrigation water source explained roughly half of the variation in E. coli loads on the vegetables, with an effect size of 0.51, a value considered large in statistical terms. Vegetables irrigated with reservoir water carried an average of 3.00 log colony-forming units per gram of E. coli, those irrigated with well water averaged 2.25, and those irrigated with borehole water averaged just 1.19. Notably, no Salmonella was detected in any sample irrigated with borehole water, while reservoir water emerged as the primary risk factor for Salmonella presence, nearly quadrupling the odds of contamination compared with other sources.

Random forest modeling, a machine learning technique that ranks predictors by their importance, confirmed the pattern. Water source accounted for 41.1 percent of predictive importance, while hygiene practices contributed only 9.8 percent. This ranking held steady across all five analytical methods, giving the researchers high confidence that the result is not an artifact of any particular statistical approach. The convergence of multiple methods on the same conclusion is rare in food safety research and lends the finding considerable weight.

The study also translates its results into a practical tool. The researchers developed a Water-Security Risk Score that extension services can deploy in the field to help farmers and advisors quickly assess the contamination risk associated with their irrigation water. Rather than requiring laboratory analysis, the score is based on the water source itself, offering a simple decision rule: borehole water carries the lowest risk, wells carry moderate risk, and open reservoirs carry the highest.

The implications extend beyond Burkina Faso. The authors situate their findings within the broader Sahelian context, where smallholder vegetable production increasingly depends on irrigation as rainfall becomes less reliable. Open reservoirs, which collect runoff and are often shared with livestock, are common across the region. The study suggests that monitoring the microbial quality of these water sources, rather than focusing exclusively on post-harvest handling, should be a priority for food safety interventions across the Sahel.

The research also highlights the limits of hygiene-focused programs. While Good Agricultural and Hygiene Practices remain important for reducing contamination, the study shows that they cannot compensate for a heavily contaminated water source. A farmer who follows every recommended practice but irrigates with reservoir water still faces a substantially higher contamination risk than one who uses borehole water with mediocre hygiene. This does not mean hygiene practices are irrelevant, but it does mean that water quality is the dominant lever.

The study’s methodology is worth noting for its transparency. The authors used ISO 16649-2 for E. coli enumeration and ISO 6579-1 for Salmonella detection, both internationally recognized reference methods. The field audits scored compliance against Codex Alimentarius food hygiene principles. The dataset, comprising 120 observations, is not yet publicly deposited but is available upon reasonable request, and the authors commit to depositing it in a public repository upon acceptance.

For consumers of raw vegetables in the Sahel, the message is sobering but actionable. The path from reservoir to plate is not merely a metaphor: the water that touches the crop in the field is the strongest determinant of what reaches the consumer. As climate change intensifies pressure on water resources across the region, ensuring that irrigation water is safe may become one of the most effective public health interventions available.

Beyond the headline finding, the study’s design offers useful context for interpreting how strongly water source dominates. The three water sources represent a natural gradient of protection: open reservoirs are exposed to runoff, livestock, and direct human contact; shallow wells offer partial shielding from surface contamination; and boreholes tap deeper aquifers that are typically less vulnerable to fecal intrusion. The roughly 2.5-fold difference in mean E. coli loads between reservoir- and borehole-irrigated vegetables maps neatly onto this gradient, which strengthens the plausibility of a causal link rather than a mere statistical association. The absence of Salmonella in borehole-irrigated samples is particularly striking, since it suggests that a sufficiently protected water source may effectively eliminate one of the most serious foodborne pathogens from the raw vegetable pathway.

The choice of E. coli as an indicator organism deserves explanation for readers unfamiliar with microbiological monitoring. E. coli itself is not always pathogenic, but its presence signals recent fecal contamination and correlates with the likelihood that other enteric pathogens, including Salmonella, are also present. Enumeration in colony-forming units per gram, expressed here on a logarithmic scale, means that the difference between 3.00 and 1.19 log CFU/g is not a modest one: it represents roughly a sixty-fold reduction in bacterial load. Because many foodborne pathogens have low infectious doses, even order-of-magnitude reductions in contamination can translate into meaningful declines in public health risk.

The statistical framework the authors employed is also notable in a field where single-method analyses are common. Analysis of variance with an eta-squared of 0.51 indicates that water source alone accounts for about half of the variability in contamination, an unusually large effect for environmental health data, where many interacting factors typically dilute any single predictor. Logistic regression, which estimates the odds of Salmonella presence rather than its continuous load, independently identified reservoir water as the primary risk factor with an odds ratio of 3.82. Random forest modeling, a machine learning approach that grows many decision trees on resampled data, provided a third, methodologically distinct perspective and ranked water source at more than four times the importance of hygiene practices. Principal component analysis and k-means clustering, which make no assumptions about outcome relationships, allowed the team to check whether farms naturally grouped by water source and contamination profile. That all five approaches converged on the same hierarchy of predictors is the study’s strongest methodological asset.

The regional context amplifies the significance of these results. The World Health Organization has estimated the global burden of foodborne disease at hundreds of millions of illnesses annually, with the heaviest toll in low- and middle-income countries, and sub-Saharan Africa bears a disproportionate share. Prior research in Ouagadougou and elsewhere in Burkina Faso has documented Salmonella contamination of vegetables, street foods, and surface waters, and studies from neighboring Ghana and Ethiopia have similarly linked irrigation water quality to produce contamination. The present study adds value by quantifying the relative weight of water source against on-farm practices within a single coherent framework, something earlier descriptive surveys generally could not do.

The Water-Security Risk Score also reflects a pragmatic response to the realities of extension work in the Sahel. Laboratory capacity for routine microbiological testing of irrigation water is limited in many rural districts, and turnaround times can be long. A score based on water source requires no equipment, only knowledge of where a farm’s water comes from, which farmers themselves know. This makes the tool immediately deployable, though it should be understood as a screening heuristic rather than a substitute for periodic laboratory verification, since individual reservoirs and wells can vary considerably in quality depending on season, rainfall, and local sanitation conditions.

Several caveats temper the findings. The study covered three sites and 120 farms in one region of one country, and seasonal variation in water quality was not the central focus. Reservoir water quality can shift dramatically between wet and dry seasons as dilution, evaporation, and runoff patterns change, so contamination levels measured at one time may not represent the annual picture. The authors also note that the dataset is not yet publicly deposited, which limits independent reanalysis until the promised repository deposit occurs. Nonetheless, the consistency of the water-source effect across sites, crops, and analytical methods suggests a robust underlying pattern rather than a local artifact.

For policymakers, the practical implication is that investments in protected water infrastructure, such as boreholes or treated water points for irrigation, may yield larger food safety returns than hygiene training alone. This does not argue for abandoning hygiene programs, which remain essential for preventing contamination during harvesting, washing, and transport, but it reframes the hierarchy of interventions. Where farmers cannot switch water sources, intermediate measures such as sand filtration, storage settling, or drip irrigation that avoids direct water contact with edible plant parts could reduce the transfer of pathogens from water to crop. Testing these mitigation options in Sahelian field conditions would be a natural next step for this research program.

Subject of Research: Food Safety

Article Title: From reservoir to plate: monitoring irrigation water source as the dominant driver of vegetable microbial contamination risk in Sahelian smallholder systems

Article References: Séré, A. P., Sanou, A., Roamba, E. N., Ouattara, N., Dakuyo, R., Kaboré, K., Konaté, K., Kaboré, D., & Dicko, M. H. (2026). From reservoir to plate: monitoring irrigation water source as the dominant driver of vegetable microbial contamination risk in Sahelian smallholder systems. Environmental Monitoring and Assessment, 198(11), Article 1217. https://doi.org/10.1007/s10661-026-16056-9

Image Credits: AI Generated

DOI: 10.1007/s10661-026-16056-9

Keywords: food safety, irrigation water, Burkina Faso, Escherichia coli, Salmonella, smallholder farming, reservoir, plate, monitoring, irrigation, water, source

The new model, published in the Food Modelling Journal, estimates two key outputs: the number of illnesses per million servings of egg and the probability of illness when a random serving is ingested. It is adapted from the European Food Safety Authority’s 2014 Scientific Opinion on public health risks of table eggs, but sets new illustrative values for contamination prevalence and storage conditions. Crucially, the model is released in Food Safety Knowledge Markup Language, or FSK-ML, an open exchange format built on harmonised terms, metadata and controlled vocabulary that packages the model script, visualisation script and simulation settings together so that other risk assessors can reuse and adapt it with minimal friction.

Technically, the exposure assessment is structured as six process steps along the farm-to-household chain: on farm before collection, during grading, during transport to wholesale, during storage at wholesale, at retail, and finally at household. At each step, the model tracks the internal temperature of the egg, which starts at 41.2 degrees Celsius at laying and then decays progressively toward the ambient storage temperature. The decay follows an exponential cooling equation in which the internal temperature T equals the storage temperature plus the difference between the initial internal temperature and the storage temperature, multiplied by an exponential term governed by a cooling rate constant and the time spent in that stage. Storage temperatures and durations at each step are drawn from Pert distributions, capturing the variability introduced by ventilation systems, air humidity and handling practices.

The pivotal biological event in the model is the breakdown of the yolk membrane. While that membrane remains intact, growth of S. Enteritidis in the albumen is considered insignificant, because the albumen’s antimicrobial properties keep the bacterium in check. The membrane’s resistance, however, declines with time and temperature — and with physical vibrations during transport. The model calculates the time of yolk membrane breakdown, TRMV, through a linear relationship with temperature, using an intercept of 2.0872 hours and a slope of minus 0.042579 hours per degree Celsius. Because the temperature changes across stages, the calculation is performed hourly: the inverse of the TRMV at the prevailing temperature is cumulated across the egg’s life, and once that cumulative sum reaches or exceeds one, the membrane is deemed ruptured. From that point, yolk nutrients diffuse into the albumen and Salmonella growth becomes possible throughout the egg.

Once the membrane fails, the model switches to a Rosso-type growth rate equation to describe bacterial proliferation. The maximum growth rate is the product of the optimal growth rate, set at 1.6 log10 colony-forming units per gram per hour, and a gamma mitigation factor that depends on temperature. That factor drops to zero below the minimum growth temperature of 6.29 degrees Celsius and above the maximum of 43.46 degrees Celsius, peaking near the optimum of 40.11 degrees Celsius. Growth rates are reassessed hourly and cumulated until the end of storage, yielding a number of ten-fold increases, NCD, for each egg. The final Salmonella count per egg is then the initial concentration — drawn from a Poisson distribution with a mean of 7 and a minimum of 1 cell per egg — multiplied by ten raised to the power of NCD.

Cooking enters the model as a decisive reduction step. Three scenarios are defined: uncooked, lightly cooked and well cooked. Lightly cooked eggs experience a log10 reduction drawn from a normal distribution with a mean of 2 and a standard deviation of 0.5, while well-cooked eggs achieve a mean reduction of 12 log10 with a standard deviation of 1 — an enormous difference in surviving bacteria. The number of bacteria ingested is the pre-cooking count multiplied by ten raised to the negative reduction. A beta-Poisson dose-response model, parameterised from Thomas and colleagues’ 2006 work with coefficients alpha of 0.1345 and beta of 53.33, then converts the ingested dose into a probability of salmonellosis per contaminated serving, assuming variability in host-pathogen interaction is beta distributed.

Running the default simulation with 2,000 iterations to explore variability, and an illustrative contamination prevalence of 10 percent, the model produces striking numbers. Under the entered time-temperature conditions, lightly cooked eggs would generate 186 salmonellosis cases per million servings. The risk from well-cooked eggs is 1,690 times lower than for lightly cooked eggs, thanks to the near-sterilising effect of thorough cooking. Raw egg consumption carries roughly twice the risk of lightly cooked eggs. In the default settings, 90 percent of consumers are assumed to cook eggs well, which heavily weights the overall risk estimate toward the well-cooked scenario.

Perhaps the most practically relevant output is the relationship between egg age and risk. The model shows that the probability of illness per consumed egg rises sharply after nine days of storage, when the cumulative membrane damage under typical ambient conditions allows bacterial growth to accelerate. This gives regulators and retailers a quantitative basis for recommendations on refrigeration and shelf life: keeping eggs below the minimum growth temperature of 6.29 degrees Celsius effectively freezes the risk clock, while storage at ambient temperature rapidly advances it. The cumulative distribution of the log10 probability of illness for a random contaminated serving, weighted by the mix of lightly and well-cooked consumption practices, rounds out the risk characterisation.

The authors emphasise that the model is deliberately generic and adaptable. Prevalence, fixed at 10 percent for illustration, can be replaced with more realistic surveillance values, and the frequency of well-cooked egg consumption can be recalibrated against national dietary surveys. Time-temperature profiles for production, transport and storage can be swapped to reflect specific national supply chains. Because the model travels in FSK-ML format with its R script, visualisation script and simulation settings bundled together, a food safety authority in one country can execute it online with default parameters or upload new ones, making quantitative risk assessment for eggs a reusable, transparent and openly shared tool rather than a one-off analysis.

Subject of Research: Quantitative microbial risk assessment for Salmonella in eggs

Article Title: Quantitative microbial risk assessment for Salmonella in eggs

Article References: Desvignes, V., Buschhardt, T., Guillier, L., & Sanaa, M. (2019). Quantitative microbial risk assessment for Salmonella in eggs. Food Modelling Journal, 1, Article e39643. https://doi.org/10.3897/fmj.1.39643

Image Credits: AI Generated

DOI: 10.3897/fmj.1.39643

Keywords: Quantitative, microbial, risk, assessment, Salmonella, eggs, scientific research

The model itself is a descendant of the so-called Hald model, a Bayesian approach first developed in 2004 that uses microbial subtyping data to infer the sources of foodborne illness. In this implementation, Salmonella isolates from humans and from four animal sources—broilers, laying hens, pigs, and turkeys—are subtyped by serovar and, for the two dominant serovars Enteritidis and Typhimurium, additionally by phage type. The model considers more than thirty serovars in total, ranging from Salmonella Agama to Salmonella Virchow, along with rough strains and unspecified serotypes. Based on the distribution of these subtypes across sources and among human cases, the model estimates how many human salmonellosis cases can be attributed to each source, including an unknown category that captures infections the four animal reservoirs cannot explain.

Two datasets from Germany parameterize the model. The first, called baseline data, comes from four baseline studies conducted between 2004 and 2007 under European harmonized monitoring programs. The second, called monitoring data, was compiled from national Salmonella control programs during 2010 and 2011. Because national monitoring of Salmonella prevalence in pigs was carried out only in 2011, the pig data from that year were combined with the poultry data from 2010, under the assumption that serotype distributions in the animals were equal in both years. Human case data came from the Robert Koch Institute, with serotype distributions obtained from the SurvStat@RKI database and phage type information for Enteritidis and Typhimurium provided by the institute’s national Salmonella reference laboratory. Since only a subset of human isolates had been phage typed, the researchers assumed that the phage type distribution among typed strains was representative of the untyped ones.

Mathematically, the model assumes that the number of observed human cases for each Salmonella subtype is Poisson distributed, with the expected number of cases caused by subtype i in source j defined as the product of four factors: the amount of source j consumed, the prevalence of subtype i in source j, a subtype-dependent factor describing the ability of that subtype to cause illness, and a source-dependent factor describing the ability of that source to serve as a vector for Salmonella. Consumption is measured in tons of meat for broilers, pigs, and turkeys, and in number of eggs for laying hens. The subtype-dependent and source-dependent factors are unknown parameters estimated from the data, with uniform distributions assumed as priors.

The specific variant used here incorporates a reparameterization introduced by David and colleagues in 2013, which exploits so-called unique types—Salmonella subtypes found exclusively in one food source and in no other source under consideration. When unique types exist for a source, the corresponding subtype-dependent parameters are fixed according to a data-based formula, which improves the robustness of the source attribution estimates and addresses convergence difficulties reported with the original Hald model. For sources without unique types, the source-dependent parameter is instead defined directly from the total number of observed cases divided by the amount consumed. This reparameterization can only be applied when all serotypes are phage typed, which is why the two dominant serovars, Enteritidis and Typhimurium, were excluded from it in the original application.

Running the model requires the programming language R together with the open-source software OpenBUGS, linked through the R package R2OpenBUGS. The FSKX-compliant version bundles the model script, visualization script, simulation settings, and harmonized metadata annotated with controlled vocabulary, so that the model can be executed, modified, and adapted to new data. Two simulation scenarios are provided: a default scenario based on the baseline data and a second scenario based on the monitoring data. The transformation into the FSKX format took about one day of work for a person already familiar with the format, and the packaged model predicts the same source attribution as the original version because the R and OpenBUGS code is nearly identical to the code used in the original publication.

But packaging a Bayesian model is only half the story. The researchers also documented three technical pitfalls that can silently corrupt results when running Bayesian models based on Markov chain Monte Carlo (MCMC) calculations. The first concerns the completeness of posterior distributions. The limits of the uniform prior distributions have a strong influence on whether the posterior distributions are complete or trimmed. With the chosen limits—an upper bound of 0.2 for the source-dependent parameters and 1 for the subtype-dependent parameters—complete posteriors were obtained for both datasets. Reducing the upper limit of the subtype-dependent prior to 0.2 produced incomplete, trimmed posteriors, a problem that might affect only some but not all model parameters, making it easy to overlook.

The second pitfall involves the choice of initial values for the Markov chains. The model runs with five chains, and the researchers demonstrated three parameter scenarios using the baseline data. When the starting points were evenly spaced in the lower fifth of the plane of possible starting values, the chains converged successfully and the error bars on the source attribution results were small. When the starting points clustered near two distant points, convergence slowed for some parameters and the error bars grew much larger. When the starting points clustered near two other points, some chains failed to converge at all within 30,000 iterations, and the error bars became larger still. Because the error bars represent a 90 percent equal-tailed interval of the posterior distribution of the number of human cases, poor convergence directly inflates the apparent uncertainty of the source attribution estimates, potentially misleading anyone who reads the results without checking the diagnostics.

The third pitfall concerns the consumption data. Some authors have argued that the consumption parameter serves merely as a scaling factor and could be set to 1 or omitted altogether. For this model, that simplification caused serious problems. With all consumption parameters set to 1 and the original priors, OpenBUGS failed to execute the model, reporting a conjugate gamma updater error for one of the subtype-dependent parameters. Enlarging the subtype-dependent prior removed the numerical error, but the results remained inconsistent—the predicted number of human cases for certain subtypes was not in the same order of magnitude as the observed cases, with observed numbers up to a factor of 2000 larger than the model estimates. Only when the prior for the source-dependent parameters was enlarged to a uniform distribution between 0 and 30,000 did the model produce consistent results for both datasets. One interpretation is that when consumption data are simplified, the subtype-dependent and source-dependent parameters must compensate, effectively becoming complex prior distributions that combine the potential of each Salmonella subtype and each source to cause salmonellosis.

The source attribution results themselves are revealing. For the baseline period 2004 to 2007, laying hens caused the majority of salmonellosis cases among the considered sources, while turkeys caused the smallest burden. For the monitoring period 2010 to 2011, the majority of cases resulted from unknown sources, closely followed by laying hens and pigs, with a relatively low burden from turkeys. Although the two datasets were compiled in a comparable way and no significant difference was expected, the packaged model provides the basis for such comparisons. Beyond the specific findings, the researchers argue that the reproducibility challenge in computational science is real: models are often re-invented and re-implemented in time-consuming and error-prone processes because of limited documentation, versioning, and scope information. By providing an annotated, ready-to-use source attribution model in an open exchange format, the team hopes to facilitate model exchange, adjustment, and reuse by the international and multi-sectoral One Health community, saving future researchers much of the painstaking work that would otherwise be needed to rebuild such models from scratch.

Subject of Research: Epidemiology

Article Title: An FSKX compliant source attribution model for salmonellosis and a look at its major hidden pitfalls

Article References: Sundermann, E. M., Correia Carreira, G., & Käsbohrer, A. (2021). An FSKX compliant source attribution model for salmonellosis and a look at its major hidden pitfalls. Food Modelling Journal, 2, Article e70008. https://doi.org/10.3897/fmj.2.70008

Image Credits: AI Generated

DOI: 10.3897/fmj.2.70008

Keywords: Salmonella, source attribution, Bayesian model, food safety, FSKX, Markov chain Monte Carlo, zoonoses, One Health, microbial subtyping, Germany, OpenBUGS, reproducibility

The laboratory workflow used in the study reflects a layered confirmation strategy that is worth appreciating for what each step contributes. Selective enrichment in Selenite F broth increases the relative abundance of Salmonella against a background of competing enteric organisms, which is essential when the target bacterium may be present at low levels in fecal material. Culture on Salmonella-Shigella agar and Xylose Lysine Deoxycholate agar exploits characteristic biochemical reactions, notably the production of hydrogen sulfide, which produces the distinctive black-centered colonies that alert microbiologists to presumptive Salmonella. However, culture and biochemistry alone cannot always distinguish closely related species or detect atypical strains, which is why the study’s use of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry represents a meaningful methodological strength. This technique generates a protein fingerprint from each isolate and matches it against a reference database, providing rapid and highly accurate species-level identification, as reflected in the 99.9% confidence scores reported for all three isolates. The subsequent polymerase chain reaction targeting the invA gene adds a third, independent line of confirmation. The invA gene encodes a component of the type III secretion system needle complex that Salmonella uses to invade host cells, and it is highly conserved across Salmonella enterica serovars, making it a widely accepted molecular marker for confirming the genus and detecting false-negative culture results. The consistent 796 base pair amplicon obtained from all three isolates indicates that the genetic target was intact and detectable, reinforcing confidence that the cultured organisms were genuinely Salmonella enterica rather than biochemically similar commensals.

The antimicrobial susceptibility pattern observed in these isolates tells a coherent story about the selective pressures operating in poultry production. Tetracyclines and sulfonamide-potentiator combinations such as trimethoprim-sulfamethoxazole are among the oldest and most inexpensive antimicrobial classes, and they have historically been used extensively in Tanzanian poultry farming for growth promotion, prophylaxis, and treatment. Prolonged and widespread exposure to these drugs creates strong selection for resistance determinants, which often accumulate on mobile genetic elements such as plasmids, integrons, and transposons. These elements can carry multiple resistance genes simultaneously, which helps explain why resistance to tetracycline and trimethoprim-sulfamethoxazole appeared in every isolate. The finding that two-thirds of isolates were resistant to ampicillin and azithromycin is also notable. Ampicillin resistance is common in enteric bacteria from livestock settings and often reflects the dissemination of beta-lactamase enzymes, while reduced susceptibility to azithromycin is of particular concern because macrolides are increasingly important for treating invasive salmonellosis in settings where fluoroquinolone resistance limits other options. The observation that one isolate was resistant to ciprofloxacin, a fluoroquinolone that is frequently used to treat severe human salmonellosis, adds to a growing body of evidence that fluoroquinolone resistance is emerging in food animal reservoirs in sub-Saharan Africa, mirroring patterns documented in Asia and elsewhere where fluoroquinolone use in poultry has been widespread.

Equally significant is what did not appear in the susceptibility results. All three isolates remained susceptible to ceftriaxone, a third-generation cephalosporin that is a mainstay for treating invasive non-typhoidal Salmonella infections in children and immunocompromised patients. Cephalosporin resistance in Salmonella is typically mediated by extended-spectrum beta-lactamase enzymes or AmpC beta-lactamases, genes that have spread alarmingly through Enterobacteriaceae in many regions. The absence of ceftriaxone resistance in this small sample suggests that these particular determinants had not yet established themselves in the sampled population, though the very small number of isolates means this observation carries limited statistical weight and should not be interpreted as reassurance about the broader situation. Similarly, the complete susceptibility profile of any single isolate cannot be assumed from the aggregate data, and the study does not report minimum inhibitory concentrations, which would provide more precise quantification of resistance levels than disk diffusion zones alone.

The multidrug resistance observed in all three isolates, defined as non-susceptibility to at least one agent in three or more antimicrobial classes, is a pattern that public health authorities consider especially problematic. Multidrug-resistant Salmonella infections are associated with longer illness duration, higher rates of hospitalization, increased treatment failure, and greater healthcare costs compared with infections caused by susceptible strains. When resistance spans multiple drug classes, clinicians face progressively narrower treatment options, and in severe invasive disease the therapeutic margin can shrink to a handful of last-line agents. The mechanisms underlying multidrug resistance in Salmonella frequently involve the acquisition of resistance genes on conjugative plasmids, which can transfer horizontally not only between Salmonella strains but also across bacterial species and genera within the gut environment. This means that resistant organisms or their resistance genes circulating in poultry can potentially colonize or transfer determinants to human commensal and pathogenic bacteria through the food chain, direct contact with live birds, or environmental contamination in markets and households.

The live-bird market setting itself warrants attention as an ecological niche for antimicrobial resistance. Markets where birds from multiple sources are held together, often with shared cages, water sources, and handling equipment, create conditions for cross-contamination and for resistant organisms to spread between flocks. Fecal matter accumulates in market environments, and Salmonella can survive for extended periods in organic material, particularly when temperatures are moderate and moisture is retained. Workers, traders, and consumers who handle live birds or carcasses in these settings face direct exposure risks, and the practice of transporting birds home for slaughter can extend contamination into domestic kitchens. The cloacal swabbing approach used in this study captures intestinal carriage, which is the most relevant indicator of both food contamination risk and environmental shedding, but it does not distinguish between transient passage of organisms and persistent colonization, a distinction that would require repeated sampling or molecular typing to resolve.

The overall isolation rate of 1% in this study is low compared with prevalence figures reported in some other studies of poultry in low- and middle-income countries, where Salmonella detection rates in cloacal samples or carcasses have ranged from several percent to more than twenty percent depending on the production system, sampling strategy, and diagnostic methods. Several factors could contribute to the low recovery rate observed here. The sensitivity of culture-based detection depends heavily on sample handling, the interval between collection and laboratory processing, the adequacy of enrichment conditions, and the number of colonies examined per plate. Sampling from live birds at markets rather than from flocks on farms introduces additional variability, because stress during transport and holding can alter gut microbiology. It is also possible that the true prevalence in the source flocks was genuinely low at the time of sampling, or that the three positive samples represent a cluster from a single contaminated batch rather than three independent introductions. The authors’ transparent acknowledgment that logistical constraints reduced the sample size below the calculated minimum of 385, widening the margin of error to approximately 5.6%, is an important caveat for interpreting the precision of the prevalence estimate.

From a surveillance perspective, the study illustrates both the value and the limitations of cross-sectional market-based sampling. Such studies provide snapshots of what is circulating at the point of sale, which is directly relevant to consumer exposure, but they cannot trace resistant organisms back to specific farms, hatcheries, feed mills, or transport chains. Achieving that traceability would require integrated sampling along the production continuum, combined with molecular methods such as whole-genome sequencing, which can identify specific resistance genes, plasmid types, and phylogenetic relationships between isolates from animals, food, and humans. Whole-genome sequencing has become the reference standard for antimicrobial resistance surveillance in high-income settings because it reveals not only which resistance determinants are present but also how they are related to one another across time and geography. Building such capacity in Tanzania and neighboring countries would substantially strengthen the evidence base for targeted interventions.

The policy implications suggested by these findings align with the One Health framework, which recognizes that human, animal, and environmental health are interconnected and that antimicrobial resistance must be addressed across all three domains. In the poultry sector specifically, interventions with demonstrated potential include enforcing regulations on antimicrobial sales so that veterinary oversight precedes drug use, phasing out the use of medically important antimicrobials for growth promotion, improving biosecurity and vaccination to reduce the underlying disease burden that drives antibiotic demand, and training farmers and market traders in hygiene practices that limit pathogen transmission. Tanzania’s participation in regional and global antimicrobial resistance initiatives provides a foundation for such measures, but implementation at the level of smallholder and commercial poultry producers remains uneven. The detection of multidrug-resistant Salmonella enterica in a market serving urban consumers underscores that the consequences of antimicrobial practices on farms do not remain on farms; they travel with the birds, the meat, and the resistant bacteria themselves into kitchens, hospitals, and communities, making sustained surveillance and stewardship in food animal systems a matter of direct public health protection.

Subject of Research: Detection of AMR and identification of Salmonella enterica in indigenous, broiler and layers poultry in some major markets of Morogoro Municipal, Tanzania

Article Title: Detection of AMR and identification of Salmonella enterica in indigenous, broiler and layers poultry in some major markets of Morogoro Municipal, Tanzania

Article References: Peter, B., Mzula, A., & Hoza, A. S. (2026). Detection of AMR and identification of Salmonella enterica in indigenous, broiler and layers poultry in some major markets of Morogoro Municipal, Tanzania. Frontiers in Bacteriology, 5, Article 1815759. https://doi.org/10.3389/fbrio.2026.1815759

Image Credits: AI Generated

DOI: 10.3389/fbrio.2026.1815759

Keywords: Detection, identification, Salmonella, enterica, indigenous, broiler, layers, poultry, some, major, markets, Morogoro

The scale of the problem the review addresses is considerable. At least 2,463 Salmonella serotypes have been identified worldwide, and non-typhoidal Salmonella is estimated to cause roughly 94 million cases of gastroenteritis each year, resulting in approximately 155,000 deaths. In sub-Saharan Africa the burden is compounded by invasive disease: certain serovars are associated with bloodstream infections, particularly among children, and the strains circulating there often carry drug resistance and virulence genes. Humans typically acquire infection through foods of animal origin, with poultry products a dominant route of transmission.

After screening titles, abstracts and full texts independently, the team included 74 articles in its qualitative analysis, published between 2009 and 2025, with 2019 and 2021 the most represented years at 11 articles each. Ten West African countries were covered, although Nigeria dominated the literature with 40 publications. Of the 74 articles, 64 identified non-typhoidal Salmonella and 49 went further to identify specific serovars. A deeper quantitative analysis focused on 28 articles from five countries, again led by Nigeria with 18 studies, published between 2016 and 2025.

From those 28 studies the reviewers extracted 1,202 non-typhoidal Salmonella serovar records from animal, environmental, food and human sources. Animal sources, particularly poultry, yielded the most isolates, followed by environmental samples, with food and human samples contributing the remainder. Three serovars towered over the rest: Salmonella Kentucky, Salmonella Enteritidis and Salmonella Typhimurium, followed by Salmonella Derby and Salmonella Poona. The distribution was source-dependent. Kentucky was most frequently recovered from animal and environmental samples, whereas Enteritidis was mainly associated with food and human samples, a pattern consistent with poultry acting as the principal reservoir from which contaminated products carry the pathogen to consumers.

The antimicrobial resistance findings are among the most alarming in the review. Of the 1,202 isolates documented, 923 lacked phenotypic resistance data, but among the 279 with available profiles, 251, or 89.9 percent, were resistant to at least one antibiotic. Resistance to ciprofloxacin, tetracycline, nalidixic acid and ampicillin was most frequently observed, and resistance ranged from a single drug to as many as ten. Several isolates showed multidrug resistance to between 8 and 10 antimicrobial agents. Salmonella Kentucky exhibited the greatest diversity of resistance profiles.

Genotypic screening told a complementary story. Resistance gene data were available for 309 isolates, or 25.7 percent of the total. The most commonly detected genes belonged to the aac class, found in 66.02 percent of those isolates and conferring aminoglycoside resistance, followed by tet genes at 27.83 percent for tetracycline resistance and qnr genes at 23.94 percent, the principal determinants of quinolone resistance. Intriguingly, the review uncovered mismatches in both directions: some strains carried resistance genes such as aac or fos without showing phenotypic resistance, while others, particularly Kentucky isolates, were phenotypically resistant to quinolones without any detectable quinolone resistance gene, hinting at resistance mechanisms that current genotyping panels miss.

The diagnostic landscape the review maps is one of pragmatic compromise. Three primary approaches were used for serovar identification: molecular methods based on PCR assays or sequencing, including whole-genome sequencing and targeted sequencing; serological methods relying on antigen-antibody reactions such as slide agglutination with specific antisera under the Kauffmann-White scheme; and mass spectrometry, specifically MALDI-TOF MS. Molecular methods were the most commonly used overall, and some studies combined approaches. Serotyping remains valuable for differentiating strains within a species, but the sheer diversity of non-typhoidal Salmonella serovars limits its resolution, especially where comprehensive antisera panels are unavailable.

MALDI-TOF MS, although classified as a phenotypic technique, works by proteomic profiling and has become widely adopted in clinical microbiology because it cuts turnaround time from several days to under an hour while remaining fast, cost-effective and accurate. Its weakness is discrimination: closely related Salmonella isolates can be indistinguishable without complementary analysis. At the other end of the spectrum, whole-genome sequencing offers the highest resolution, enabling not only precise serovar identification but also analysis of genetic relationships, evolutionary patterns, and the determinants of pathogenicity and antimicrobial resistance through workflows that include sequence alignment, variant calling and genome annotation. Emerging innovations, such as coupling MALDI-TOF MS with machine learning algorithms and bacteriophage-based detection systems, promise further gains in speed and specificity.

Yet the review makes clear that advanced tools remain largely inaccessible for routine use in the subregion. The barriers are not only the prohibitive cost of reagents and platform maintenance but also energy instability, which compromises the preservation of DNA and enzyme reagents. Consequently, bacterial culture on selective media such as Salmonella-Shigella or Compass Salmonella agar, coupled with Kauffmann-White serotyping, remains the most viable strategy, ensuring continuity of epidemiological surveillance and the detection of serotypes of public health interest even where molecular platforms are absent. PCR-based assays, meanwhile, are particularly useful for detecting low-abundance pathogens in complex samples and for revealing virulence and resistance markers that phenotypic methods alone cannot assess.

Among the serovars of greatest concern, Enteritidis, Kentucky and Typhimurium stand out. Typhimurium, Enteritidis and Dublin are widely recognized as the serovars most commonly associated with invasive infections, including bloodstream disease and severe gastroenteritis in children in sub-Saharan Africa. Typhimurium is transmitted primarily via the fecal-oral route and has been detected in retail poultry products at prevalence rates reaching up to 44 percent in some settings. Enteritidis is a foodborne zoonotic pathogen whose transmission spans animal reservoirs, environmental contamination and water systems, a clear One Health interface. Most striking is the story of Salmonella Kentucky ST198: 29 strains were reported across the reviewed literature, and every one of them was resistant to gentamicin, tetracyclines and quinolones. Once considered an antibiotic-susceptible poultry-associated serovar, Kentucky ST198 acquired the SGI1 resistance island and has since spread at high prevalence across Africa, the Middle East and South and Southeast Asia, reaching Europe and North America through travel-related infections. Because quinolones are considered last-resort antibiotics, this clone represents a significant public health concern for patient management.

Perhaps the review’s most sobering structural finding is what was missing: not a single one of the reviewed studies employed a comprehensive One Health sampling framework. Each focused exclusively on an isolated component, whether human, animal, food or environmental, limiting any comprehensive understanding of transmission across interconnected systems. The authors also acknowledge substantial limitations, above all a geographic surveillance bias, with more than half of the included studies originating from Nigeria, whose surveillance systems, laboratory capacity and research output outpace those of many neighbors. Heterogeneous study designs, sampling strategies and laboratory methodologies further complicate comparisons, and countries with limited publication output may be underrepresented.

Looking forward, the authors argue that future research should operationalize the One Health framework through integrated multisectoral studies combining human, animal, food and environmental samples; the gradual implementation of genomic surveillance tools including whole-genome sequencing to track transmission routes and antimicrobial resistance; the establishment of regional data-sharing platforms and laboratory networks to harmonize methodologies and strengthen outbreak response; and attention to environmental and socioeconomic determinants such as antimicrobial use practices and food distribution systems. Strengthening interdisciplinary collaboration and investing in scalable, context-appropriate technologies, they conclude, will be essential to close current gaps, improve public health preparedness, and slow the spread of antimicrobial-resistant non-typhoidal Salmonella across West Africa and beyond.

Subject of Research: Diversity and identification methods of non-typhoidal Salmonella serovars in West Africa: a scoping review

Article Title: Diversity and identification methods of non-typhoidal Salmonella serovars in West Africa: a scoping review

Article References: Deguenon, E., Hougbenou, B.-G., Hounkanrin, M., Hounmanou, G., & Dougnon, V. (2026). Diversity and identification methods of non-typhoidal Salmonella serovars in West Africa: a scoping review. Frontiers in Bacteriology, 5, Article 1825225. https://doi.org/10.3389/fbrio.2026.1825225

Image Credits: AI Generated

DOI: 10.3389/fbrio.2026.1825225

Keywords: Salmonella, West Africa, antimicrobial resistance, One Health, poultry, food safety, whole-genome sequencing, MALDI-TOF, public health, zoonoses, Diversity, identification

The antigen selection in this nanovaccine also merits attention. Outer membrane proteins of Salmonella are surface-exposed and participate in host cell attachment and immune recognition, making them logical targets for antibodies that can interfere with the earliest steps of infection. Flagella antigens, meanwhile, are not merely structural components; flagellin, the monomeric building block of the bacterial flagellum, is recognized by innate immune receptors such as Toll-like receptor 5, which means that including flagellar material in a vaccine can simultaneously provide a protective antigen target and a built-in innate immune stimulus. Combining these two antigen classes in a single particle therefore offers both specificity and immunostimulatory potential, a design philosophy that contrasts with older subunit approaches relying on single purified proteins.

The timing of probiotic administration in this study is noteworthy from a developmental immunology perspective. In ovo delivery at embryonic day 18 means that Lactobacillus acidophilus is introduced just before hatching, a period when the chick’s gut is essentially sterile and the immune system is beginning to encounter the microbial world. Research on early-life microbial colonization has shown that the first microbial residents of the intestine can have lasting effects on immune system calibration, influencing the balance between inflammatory and regulatory responses for weeks afterward. By seeding the gut with a beneficial organism before the chick ever encounters environmental microbes, feed, or pathogens, the researchers aimed to establish a gut environment primed for mucosal immunity. The subsequent post-hatch doses at days 2, 4, and 6 reinforce this early colonization during the window when the intestinal epithelium and immune tissues are still maturing rapidly.

The immunological findings reported in the study align with established principles of mucosal vaccine design. Secretory IgA is the dominant antibody class at mucosal surfaces, where it functions by agglutinating bacteria, blocking their attachment to epithelial cells, and neutralizing toxins without triggering the inflammatory consequences associated with complement activation. The observation that the probiotic-nanovaccine combination increased specific secretory IgA in both the intestine and bile is significant because bile IgA reflects immune activity in the upper intestinal tract and liver-associated lymphoid tissues, providing a broader measure of mucosal immunity than intestinal secretions alone. The elevation of activated B cells suggests that the vaccine successfully engaged the germinal center reactions and T cell help needed to drive antibody class switching toward the IgA isotype, a process heavily influenced by the cytokine milieu in gut lymphoid tissues.

The cytokine profile observed in the cecal tonsils provides additional insight into the quality of the immune response generated. Interferon-gamma, a hallmark Th1 cytokine, promotes cell-mediated immunity and macrophage activation, both of which are important for controlling intracellular pathogens like Salmonella that can survive within host cells. Interleukin-17, produced by Th17 cells, recruits neutrophils and stimulates epithelial cells to produce antimicrobial peptides, strengthening the barrier function of the intestinal lining. The concurrent detection of interleukin-10, an anti-inflammatory cytokine, suggests that the immune response was not skewed toward uncontrolled inflammation but rather achieved a balance between pathogen clearance and tissue preservation. This balance is particularly relevant in the intestine, where excessive inflammation can damage the epithelial barrier and paradoxically facilitate bacterial translocation.

The microbiome data add an important dimension to the interpretation of vaccine efficacy. The finding that overall microbial diversity was not altered by the probiotic-nanovaccine combination is reassuring from an ecological standpoint, since dramatic disruptions of the gut microbiome can have unintended consequences for digestion, nutrient absorption, and pathogen resistance. However, the significant shift in community composition, with an R-squared value of 0.378, indicates that the treatment did meaningfully restructure which taxa were present and in what relative abundances. The enrichment of short-chain fatty acid-producing Clostridiales, including genera such as Blautia, Butyricicoccus, and members of the Christensenellaceae family, is consistent with a beneficial shift, as these organisms produce metabolites that nourish colonocytes, strengthen epithelial tight junctions, and modulate immune cell function. Short-chain fatty acids such as butyrate and acetate have been shown to promote regulatory T cell development and to create an intestinal environment less hospitable to facultative anaerobes like Salmonella.

By contrast, the commercial live-attenuated vaccine group showed an increase in Escherichia and Shigella alongside a reduction in Lactobacillus, a pattern that could reflect either direct effects of the live vaccine strain on the gut ecosystem or indirect consequences of the inflammatory environment it generates. Live-attenuated Salmonella vaccines replicate within the host and can transiently perturb the intestinal microbiota, potentially opening ecological niches that opportunistic organisms can fill. This distinction between the two vaccination strategies highlights a potential advantage of subunit nanovaccines combined with probiotics: they can confer protection without the ecological side effects associated with administering a replicating organism.

The reduction in cecal Salmonella Enteritidis colonization by 1.2 log10 units compared with the commercial vaccine represents a meaningful improvement in pathogen burden. In practical terms, each log10 reduction corresponds to a tenfold decrease in bacterial numbers, so a 1.2 log10 reduction means roughly a sixteenfold lower bacterial load in the cecum. Because the cecum is the primary reservoir for Salmonella in poultry and the source of fecal contamination that spreads the organism through flocks and onto carcasses during processing, reducing cecal colonization directly translates to lower contamination of meat products and, by extension, reduced risk to consumers. The measurement at four days post-challenge captures the peak of the acute colonization phase, when differences between vaccinated and unvaccinated birds are most pronounced.

The broader context of this work relates to ongoing efforts to reduce antimicrobial use in food animal production. As regulatory pressure and consumer demand drive the poultry industry away from routine antibiotic administration, alternative strategies for maintaining flock health and food safety have become increasingly urgent. Probiotics, prebiotics, organic acids, bacteriophages, and vaccines each play a role in this transition, but their combined application, as demonstrated in this study, may offer synergistic benefits that no single intervention can achieve alone. The concept of using a probiotic as a vaccine adjuvant rather than as a standalone intervention represents a refinement of both approaches, leveraging the immunomodulatory capacity of Lactobacillus acidophilus to amplify the response to a defined antigen payload delivered via nanoparticles.

Questions remain regarding the scalability and field applicability of this approach. In ovo vaccination requires specialized equipment and trained personnel, though it is already widely practiced in commercial hatcheries for other vaccines such as Marek’s disease, suggesting that the logistical infrastructure exists. The stability of chitosan nanoparticles under commercial storage and transport conditions, the cost of producing antigen-loaded particles at industrial scale, and the consistency of probiotic colonization across different genetic lines of broilers are all factors that would need to be addressed before this technology could move from the laboratory to the hatchery floor. Additionally, the study focused on Salmonella Enteritidis, and further research would be needed to determine whether the same platform provides cross-protection against other Salmonella serovars that circulate in poultry flocks, such as Salmonella Typhimurium or Salmonella Heidelberg.

The regulatory landscape for such combination products also warrants consideration. A product combining a live probiotic organism with a nanoparticle-encapsulated subunit vaccine may fall under multiple regulatory frameworks, and establishing safety and efficacy data sufficient for approval would require additional studies in larger numbers of birds across multiple farms and production cycles. Nevertheless, the conceptual framework demonstrated here, namely that probiotic priming of the gut can enhance the immunogenicity of an oral nanovaccine while simultaneously shaping the microbiome in ways that favor pathogen resistance, offers a template for future interventions targeting not only Salmonella but also other enteric pathogens of poultry, including Campylobacter, Clostridium perfringens, and pathogenic Escherichia coli. The integration of nanotechnology, probiotics, and mucosal immunology in a single intervention strategy reflects the multidisciplinary direction that veterinary vaccine research is increasingly taking as the industry seeks alternatives to antimicrobial growth promotion and responds to consumer expectations regarding food safety and animal welfare.

Subject of Research: Probiotic Lactobacillus acidophilus provides an adjuvant effect to an orally administered chitosan nanoparticle-based Salmonella subunit vaccine in broilers against Salmonella Enteritidis infection

Article Title: Probiotic Lactobacillus acidophilus provides an adjuvant effect to an orally administered chitosan nanoparticle-based Salmonella subunit vaccine in broilers against Salmonella Enteritidis infection

Article References: Dolatyabi, S., Sharma, S., Olaitan Shekoni, C., Suresh, R., Yadav, S., Schrock, J., Wood, R., Shivalingaiah, G. A., Dhakal, A., Tenney, M., Rahman, T., Sanko, J., Lagos, R. Z., Abdelaziz, K., & Renukaradhya, G. J. (2026). Probiotic Lactobacillus acidophilus provides an adjuvant effect to an orally administered chitosan nanoparticle-based Salmonella subunit vaccine in broilers against Salmonella Enteritidis infection. Frontiers in Microbiology, 17, Article 1898587. https://doi.org/10.3389/fmicb.2026.1898587

Image Credits: AI Generated

DOI: 10.3389/fmicb.2026.1898587

Keywords: Probiotic, Lactobacillus, acidophilus, provides, adjuvant, effect, orally, administered, chitosan, nanoparticle-based, Salmonella, subunit

The research team began with a large and clinically grounded collection: 373 Enterobacteriaceae isolates that had been recovered from routine diagnostic specimens and found to be resistant to third-generation cephalosporins. Because these isolates came from the clinical microbiology laboratory rather than from a targeted screening program, they represent the resistant organisms that clinicians actually encountered in practice. Every isolate was subjected to antimicrobial susceptibility testing and to polymerase chain reaction confirmation of bla_CTX-M-65, a deliberate step that guards against the false positives that can arise when sequence reads are assigned to closely related CTX-M alleles. Whole-genome sequencing followed, allowing the investigators to place each confirmed isolate within its species phylogeny, to characterize its full resistome and to extract and compare the plasmids carrying the resistance gene.

The headline finding from the local collection was one of relative rarity paired with striking breadth. Only 20 of the 373 isolates, or 5.4 percent, carried bla_CTX-M-65, confirming that this allele is a minority player among cephalosporin-resistant Enterobacteriaceae. Yet those 20 isolates were distributed across three distinct species: 14 Escherichia coli, 5 Salmonella enterica serovar Typhimurium and a single Klebsiella pneumoniae. That spread across genera is itself informative, because it suggests that bla_CTX-M-65 is not locked into a single bacterial lineage. Instead, the gene appears able to establish itself in genetically very different hosts, consistent with the idea that horizontal gene transfer, rather than clonal expansion alone, drives its dissemination.

The resistance phenotypes of these isolates added a sobering clinical dimension. All 20 were resistant to cefuroxime, an expected consequence of possessing an extended-spectrum beta-lactamase, but the co-resistance extended well beyond the beta-lactam class. Seventy percent were resistant to levofloxacin, a fluoroquinolone that is frequently used when cephalosporin therapy fails or when oral treatment is preferred. Multidrug resistance of this kind narrows therapeutic options significantly, particularly for pathogens such as Salmonella Typhimurium, where fluoroquinolones are a mainstay for invasive disease. The combination of a cephalosporin-hydrolyzing enzyme and fluoroquinolone resistance on the same bacterial background is a recurring pattern in Enterobacteriaceae, and this study confirms that bla_CTX-M-65-positive isolates fit squarely within it.

Phylogenetic analysis of the sequenced genomes revealed two episodes of likely within-hospital transmission hiding inside the otherwise diverse collection. Among the E. coli isolates, a pair belonging to sequence type ST155 differed by only 9 single nucleotide polymorphisms across their core genomes, despite having been recovered from different hospital departments. In genomic epidemiology, core-genome differences of that magnitude are generally interpreted as evidence of a very recent common ancestor, pointing to direct or indirect transmission of a single clone between wards. Similarly, the five Salmonella Typhimurium isolates formed a tight cluster belonging to ST34, with fewer than 20 core-genome SNPs separating members of the group, and the affected patients included children treated in pediatrics. Together these findings illustrate how genomic resolution can uncover transmission chains that routine susceptibility testing would never flag.

Perhaps the most clinically alarming single isolate was the K. pneumoniae strain, which belonged to ST11 and carried both bla_CTX-M-65 and bla_KPC-2. The ST11 lineage is already notorious as one of the principal vehicles for carbapenem resistance in K. pneumoniae worldwide, and bla_KPC-2 encodes a carbapenemase that inactivates the last-line beta-lactam antibiotics used against multidrug-resistant Gram-negative infections. The co-occurrence of a carbapenemase and an extended-spectrum cephalosporinase in the same genome means the organism carries enzymatic firepower against nearly the entire beta-lactam arsenal. Whether the two genes reside on the same plasmid or on separate elements was not the central question of the study, but their coexistence in a single ST11 background underscores how resistance determinants accumulate on successful lineages, creating organisms that are progressively harder to treat.

To place these local findings in a global context, the investigators compiled and analyzed 1,421 bla_CTX-M-65-positive plasmids from public sequence databases. This comparative step is where the study’s architecture becomes most distinctive. Rather than treating the plasmid as an accessory detail, the team asked which replicon types dominate the plasmids that carry this particular gene and how conserved their backbones are across geography and time. The answer was a small set of recurrent architectures. IncHI2 plasmids, large low-copy-number elements with a well-documented role in carrying multiple resistance genes, were prevalent, as were members of the IncF family, specifically IncFIA/IB combinations and IncFII/R plasmids. The prominence of IncF-type plasmids aligns with their established reputation as the workhorses of CTX-M dissemination in E. coli, while the frequent appearance of IncHI2 elements highlights that versatile, broad-host-range plasmids also serve as major carriers of this allele.

Backbone comparison delivered the study’s most geographically expansive insight. Representative plasmids sequenced in this study showed high backbone similarity to bla_CTX-M-65-carrying plasmids previously reported from China and South Korea, indicating that the same underlying plasmid frameworks, rather than merely the same gene, are circulating across the region. In other words, the dissemination of CTX-M-65 appears to follow a two-track model: diverse bacterial clones pick up the gene, but they pick it up on a limited set of shared plasmid scaffolds. This pattern matters for surveillance, because tracking the plasmid backbones, and not just the bacterial lineages, can reveal importation events and cross-border spread that host-based analysis alone would miss. It also matters mechanistically, since a conserved backbone implies conserved fitness properties, copy number and transfer machinery that may explain why these particular plasmids succeed.

The analysis of the DNA immediately surrounding bla_CTX-M-65 added a third layer to the picture. Insertion sequences are short mobile DNA elements that can shuttle genes between chromosomes and plasmids, and certain ones are known accomplices of CTX-M genes. ISEcp1 in particular is famous for its role in mobilizing bla_CTX-M alleles by providing promoter sequences and acting as a transposition vehicle, and IS26 has become synonymous with the assembly of multidrug-resistance regions through a replicative transposition mechanism. In this study, ISEcp1, IS26 and IS903 were the mobile elements most commonly identified within the bla_CTX-M-65-associated genetic contexts, painting a consistent picture of a gene that has been repeatedly captured, re-packaged and redeployed by the standard genetic toolkit of the Enterobacteriaceae resistome.

Taken together, the study delivers a message that is more nuanced than a simple alarm. On one hand, bla_CTX-M-65 is uncommon, appearing in only 5.4 percent of cephalosporin-resistant isolates in this collection, and its detection should not overshadow the dominant CTX-M lineages. On the other hand, its behavior is instructive: it colonizes multiple species, rides on a small number of successful plasmid backbones that span international boundaries, hitches its mobility to well-known insertion sequences and occasionally lands in the most dangerous possible hosts, such as carbapenemase-producing ST11 K. pneumoniae. The identification of a clonally related E. coli pair spanning hospital departments and an ST34 Salmonella cluster within pediatrics demonstrates that genomic surveillance can catch transmission events that conventional methods overlook. The authors’ conclusion, that the diversity of bacterial hosts combined with related plasmid backbones demands continued genomic monitoring, is a fitting one. As sequencing becomes cheaper and databases grow, the ability to distinguish a gene hitchhiking on a shared plasmid from an independently acquired allele will increasingly determine how effectively hospitals and public health agencies can interrupt the silent traffic in resistance genes that moves between wards, species and countries.

Subject of Research: Genomic epidemiology of CTX-M-65-producing multidrug-resistant Enterobacteriaceae and the plasmid backbones carrying the resistance gene

Article Title: Genomic epidemiology of blaCTX−M−65-positive clinical Enterobacteriaceae reveals clonal diversity and shared plasmid backbones

Article References: Chen, X., Zhang, X., Song, J., Zeng, S., Huang, Y., & Li, X. (2026). Genomic epidemiology of blaCTX−M−65-positive clinical Enterobacteriaceae reveals clonal diversity and shared plasmid backbones. BMC Genomics. https://doi.org/10.1186/s12864-026-13446-8

Image Credits: AI Generated

DOI: 10.1186/s12864-026-13446-8

Keywords: CTX-M-65, Enterobacteriaceae, antimicrobial resistance, extended-spectrum beta-lactamases, plasmids, whole-genome sequencing, Escherichia coli, Salmonella, Klebsiella pneumoniae, genomic epidemiology, mobile genetic elements, hospital transmission