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	<title>antibiotic exposure &#8211; Science</title>
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	<title>antibiotic exposure &#8211; Science</title>
	<link>https://scienmag.com</link>
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		<title>H2 antagonists linked to lower C. difficile risk than PPIs in intensive care</title>
		<link>https://scienmag.com/h2-antagonists-linked-to-lower-c-difficile-risk-than-ppis-in-intensive-care/</link>
		
		<dc:creator><![CDATA[Ophelia Keating]]></dc:creator>
		<pubDate>Mon, 26 Oct 2026 01:14:28 +0000</pubDate>
				<category><![CDATA[Medicine]]></category>
		<category><![CDATA[antibiotic exposure]]></category>
		<category><![CDATA[C. difficile infection]]></category>
		<category><![CDATA[Comparison]]></category>
		<category><![CDATA[Critical illness]]></category>
		<category><![CDATA[histamine H2 antagonists]]></category>
		<category><![CDATA[hospital-acquired infection]]></category>
		<category><![CDATA[intensive care]]></category>
		<category><![CDATA[odds ratio]]></category>
		<category><![CDATA[propensity score matching]]></category>
		<category><![CDATA[proton pump inhibitors]]></category>
		<category><![CDATA[retrospective cohort study]]></category>
		<category><![CDATA[Risk]]></category>
		<guid isPermaLink="false">https://scienmag.com/?p=340927</guid>

					<description><![CDATA[A retrospective study of 15,462 intensive-care patients found that H2 receptor antagonists were associated with lower hospital-acquired C. difficile infection risk than proton pump inhibitors.]]></description>
										<content:encoded><![CDATA[<p>In a retrospective analysis of 15,462 critically ill patients, the use of histamine H2 receptor antagonists was associated with a lower risk of hospital-acquired Clostridioides difficile infection than the use of proton pump inhibitors. Among patients treated with H2 receptor antagonists, 2.6% developed C. difficile infection, compared with 3.4% among those treated with proton pump inhibitors. The matched odds ratio was 0.77, with a 95% confidence interval of 0.64–0.93 and a p-value of 0.006.</p>
<p>The investigators extracted data from the eICU Collaborative Research Database and MIMIC-IV for the study, which was published in BMC Infectious Diseases on 10 September 2026. Proton pump inhibitors and H2 receptor antagonists are commonly used in critically ill patients to prevent stress ulcers, but the relative risk of C. difficile infection associated with the two classes has been debated. The analysis specifically compared hospital-acquired C. difficile infection among intensive-care patients receiving the two treatments.</p>
<p>To improve comparability between the treatment groups, the researchers used propensity score matching to balance covariates. They compared clinical outcomes in the matched groups with chi-square tests and used multivariable logistic regression to identify factors associated with C. difficile infection, reporting odds ratios and 95% confidence intervals. Because this was an observational analysis, the results show an association rather than demonstrating that H2 receptor antagonists caused the lower infection risk.</p>
<p>Matching can also leave potential confounding from factors that were not adequately measured, recorded or represented in the matching process. The association between H2 receptor antagonist use and lower C. difficile infection risk was consistent across every subgroup evaluated: men and women; patients younger than 65 years and those aged 65 years or older; and patients with a body-mass index below 28 kg/m² and those with a body-mass index of at least 28 kg/m². The analysis also found that obesity, defined in the study by a body-mass index of at least 28 kg/m², was associated with a higher risk of infection.</p>
<p>Diabetes mellitus, kidney disease and the use of high-risk antibiotics were likewise associated with increased C. difficile infection risk. The findings provide additional evidence that the two classes of stress-ulcer treatments may have different associations with hospital-acquired C. difficile infection in critically ill patients. The analysis was limited to the population and data represented in the two databases and to the infection outcome examined.</p>
<p>Within those bounds, H2 receptor antagonist use was associated with a modestly lower risk of hospital-acquired C. difficile infection than proton pump inhibitor use among critically ill patients.</p>
<p><strong>Subject of Research:</strong> Comparative observational risk of hospital-acquired C. difficile infection with H2 receptor antagonists and proton pump inhibitors in critically ill patients</p>
<p><strong>Article Title:</strong> A comparison of the risk of hospital-acquired clostridioides difficile infection among critically ill patients treated with proton pump inhibitors and histamine H2 receptor antagonists</p>
<p><strong>Article References:</strong> Guan, C., Chen, J., &amp; Fang, L. (2026). A comparison of the risk of hospital-acquired clostridioides difficile infection among critically ill patients treated with proton pump inhibitors and histamine H2 receptor antagonists. <em>BMC Infectious Diseases</em>. <a href="https://doi.org/10.1186/s12879-026-14387-z" rel="noopener noreferrer">https://doi.org/10.1186/s12879-026-14387-z</a></p>
<p><strong>Image Credits:</strong> AI Generated</p>
<p><strong>DOI:</strong> <a href="https://doi.org/10.1186/s12879-026-14387-z" rel="noopener noreferrer">10.1186/s12879-026-14387-z</a></p>
<p><strong>Keywords:</strong> C. difficile infection, histamine H2 antagonists, proton pump inhibitors, intensive care, hospital-acquired infection, retrospective cohort study, propensity score matching, antibiotic exposure, odds ratio, critical illness, comparison, risk</p>
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		<post-id xmlns="com-wordpress:feed-additions:1">340927</post-id>	</item>
		<item>
		<title>Ward Colonisation Pressure Scores Add Little Power to Predict Hospital-Onset Infections</title>
		<link>https://scienmag.com/ward-colonisation-pressure-scores-add-little-power-to-predict-hospital-onset-infections/</link>
		
		<dc:creator><![CDATA[Ophelia Keating]]></dc:creator>
		<pubDate>Sun, 25 Oct 2026 00:59:32 +0000</pubDate>
				<category><![CDATA[Medicine]]></category>
		<category><![CDATA[antibiotic exposure]]></category>
		<category><![CDATA[antibiotic exposure history]]></category>
		<category><![CDATA[BMC Infectious Diseases]]></category>
		<category><![CDATA[case-control study]]></category>
		<category><![CDATA[case-control study design]]></category>
		<category><![CDATA[clinical risk assessment]]></category>
		<category><![CDATA[colonisation pressure]]></category>
		<category><![CDATA[cross-validation in machine learning]]></category>
		<category><![CDATA[data quality in infection studies]]></category>
		<category><![CDATA[drug-resistant pathogens]]></category>
		<category><![CDATA[hospital-onset infection]]></category>
		<category><![CDATA[hospital-onset infections]]></category>
		<category><![CDATA[infection control data analysis]]></category>
		<category><![CDATA[infection prevention]]></category>
		<category><![CDATA[logistic regression analysis]]></category>
		<category><![CDATA[Machine learning]]></category>
		<category><![CDATA[Mass General Brigham]]></category>
		<category><![CDATA[predictive modeling in infectious diseases]]></category>
		<category><![CDATA[predictive modelling]]></category>
		<category><![CDATA[random forest classifier]]></category>
		<category><![CDATA[risk factors for hospital-acquired infections]]></category>
		<category><![CDATA[Ward]]></category>
		<category><![CDATA[ward colonisation-pressure scores]]></category>
		<guid isPermaLink="false">https://scienmag.com/?p=338791</guid>

					<description><![CDATA[A reanalysis of eleven pathogen-specific matched cohorts from Mass General Brigham found that ward colonisation-pressure scores and antibiotic exposure added only marginal discrimination for hospital-onset target-pathogen cases, with area under the curve values between 0.54 and 0.57.]]></description>
										<content:encoded><![CDATA[<p>A large secondary analysis published in BMC Infectious Diseases has found that ward colonisation-pressure scores and antibiotic exposure histories, two variables long suspected of carrying signal about hospital-onset pathogen acquisition, added only marginal discriminatory power when tested against matched controls. The research team, led by Xiaoqing Gan and Qingjiang Lyu, took an unusually rigorous approach to the underlying data. Before any modelling, they audited the source code, exposure definitions, repeated records and matching identifiers in the released matched sample.</p>
<p>After data-quality exclusions, the final dataset comprised 54,934 records representing 34,444 patients and 16,650 matched case-control sets. This careful cleaning matters because matched case-control designs, while useful for comparing cases with similar controls, do not by themselves establish absolute clinical risk, and errors in exposure reconstruction can silently distort results. The authors evaluated four logistic regression models and one random forest classifier using five-fold cross-validation that deliberately kept connected patients and entire matched sets together, preventing information leakage across the training and testing splits.</p>
<p>Uncertainty was estimated by resampling these components. The baseline model using patient variables alone achieved an area under the receiver operating characteristic curve of 0.542, with a 95 percent confidence interval of 0.537 to 0.549, barely above the 0.5 expected from chance. Adding antibiotic courses and colonisation-pressure scores raised the area under the curve to 0.563, and the random forest reached 0.568.</p>
<p>Within-set concordance for the full logistic model was 0.544, meaning the model correctly identified which member of a matched pair was the case only slightly more often than a coin flip. The exploratory association analyses told a similarly restrained story. Using conditional logistic regression with component-robust confidence intervals, the researchers found that the pooled conditional odds ratio for drug-susceptible Enterobacterales colonisation pressure was 0.993 per score unit, with a confidence interval of 0.982 to 1.004, a range that includes the null value of 1.</p>
<p>Several antibiotic associations remained inverse, and pathogen-specific pressure associations differed markedly between the two matching branches examined in design sensitivity analyses. The results stayed weak even when colonisation pressure was omitted entirely, reduced to a simple presence indicator, or represented by training-fold ranks, indicating that no particular operationalisation of the score rescued its performance. One notable technical contribution of the paper is its numerical auditing of the colonisation-pressure implementation.</p>
<p>The authors found that the archived 90-day colonisation-pressure calculation was supported by their checks, lending credibility to the released scores. However, raw exposure reconstruction remained unavailable, meaning the team could not independently verify how antibiotic exposure histories had been generated from the source records. This limitation is important, because the authors are careful to state that their conclusions apply to the released scores as distributed, not to any conceivable version of these measures.</p>
<p>The study&#x27;s conclusions are deliberately cautious. The authors write that the variables added limited discrimination in the matched sample and that the results do not establish absolute infection risk, causal protection, or usefulness for clinical triage, including low-burden interventions. This last point addresses a tempting but unsupported inference: an inverse antibiotic association in matched data cannot be read as evidence that antibiotics protect against infection, since matching and confounding structures can produce such patterns without any causal mechanism.</p>
<p>For infection prevention teams, the message is that ward colonisation-pressure scores, at least as currently implemented and released, are not ready to serve as triage tools for hospital-onset target-pathogen infections. The authors note that prospective clinical prediction would require fully verified exposure generation and evaluation in an appropriate population cohort, rather than a matched case-control sample. Until such cohorts exist and the exposure pipelines are independently validated, the modest area-under-the-curve values reported here, hovering between 0.54 and 0.57, stand as a reminder that plausible ward-level and medication variables can look compelling in theory yet deliver nearly chance-level discrimination in carefully validated matched data.</p>
<p><strong>Subject of Research:</strong> Hospital-onset pathogen prediction using ward colonisation pressure and antibiotic exposure</p>
<p><strong>Article Title:</strong> Ward colonisation-pressure scores and antibiotic exposure for distinguishing hospital-onset target-pathogen cases from matched controls: a secondary analysis with grouped internal validation and exploratory conditional associations</p>
<p><strong>Article References:</strong> Gan, X., &amp; Lyu, Q. (2026). Ward colonisation-pressure scores and antibiotic exposure for distinguishing hospital-onset target-pathogen cases from matched controls: a secondary analysis with grouped internal validation and exploratory conditional associations. <em>BMC Infectious Diseases</em>. <a href="https://doi.org/10.1186/s12879-026-14701-9" rel="noopener noreferrer">https://doi.org/10.1186/s12879-026-14701-9</a></p>
<p><strong>Image Credits:</strong> AI Generated</p>
<p><strong>DOI:</strong> <a href="https://doi.org/10.1186/s12879-026-14701-9" rel="noopener noreferrer">10.1186/s12879-026-14701-9</a></p>
<p><strong>Keywords:</strong> colonisation pressure, hospital-onset infection, antibiotic exposure, case-control study, machine learning, infection prevention, drug-resistant pathogens, predictive modelling, BMC Infectious Diseases, Mass General Brigham, Ward, colonisation-pressure</p>
]]></content:encoded>
					
		
		
		<post-id xmlns="com-wordpress:feed-additions:1">338791</post-id>	</item>
		<item>
		<title>Finding the Goldilocks zone of antibiotic prescribing in preterm infants</title>
		<link>https://scienmag.com/finding-the-goldilocks-zone-of-antibiotic-prescribing-in-preterm-infants/</link>
		
		<dc:creator><![CDATA[Harold Sullivan]]></dc:creator>
		<pubDate>Fri, 16 Oct 2026 14:00:30 +0000</pubDate>
				<category><![CDATA[Technology and Engineering]]></category>
		<category><![CDATA[antibiotic exposure]]></category>
		<category><![CDATA[antimicrobial]]></category>
		<category><![CDATA[antimicrobial resistance in newborns]]></category>
		<category><![CDATA[antimicrobial stewardship]]></category>
		<category><![CDATA[balancing infection treatment and antibiotic overuse]]></category>
		<category><![CDATA[early antibiotic treatment risks]]></category>
		<category><![CDATA[Goldilocks]]></category>
		<category><![CDATA[Goldilocks zone in neonatology]]></category>
		<category><![CDATA[microbiome]]></category>
		<category><![CDATA[microbiome development in preterm infants]]></category>
		<category><![CDATA[necrotizing enterocolitis]]></category>
		<category><![CDATA[neonatal antibiotic stewardship]]></category>
		<category><![CDATA[neonatal blood culture limitations]]></category>
		<category><![CDATA[neonatal intensive care antibiotic protocols]]></category>
		<category><![CDATA[neonatal sepsis]]></category>
		<category><![CDATA[neonatal sepsis diagnosis challenges]]></category>
		<category><![CDATA[neonatology]]></category>
		<category><![CDATA[neurodevelopmental outcomes of neonatal infections]]></category>
		<category><![CDATA[optimal]]></category>
		<category><![CDATA[optimizing antibiotic dosing in preterm neonates]]></category>
		<category><![CDATA[precision prescribing]]></category>
		<category><![CDATA[preterm infant infection management]]></category>
		<category><![CDATA[preterm infants]]></category>
		<category><![CDATA[zone]]></category>
		<guid isPermaLink="false">https://scienmag.com/?p=285602</guid>

					<description><![CDATA[A new commentary in Pediatric Research argues that neonatal antibiotic prescribing must move toward precision stewardship, balancing the risks of undertreated sepsis against microbiome disruption and antimicrobial resistance in preterm infants.]]></description>
										<content:encoded><![CDATA[<p>In the fairy tale, Goldilocks tastes three bowls of porridge before finding one that is just right. A team of neonatal researchers writing in Pediatric Research argues that the same logic should govern one of the most consequential decisions in intensive care: how much antibiotic to give a preterm infant in the first days of life. Too little treatment risks a missed or undertreated infection that can kill within hours. Too much exposes a fragile newborn to disrupted microbiome development, antimicrobial resistance and avoidable harm. Between those extremes, the authors contend, lies a Goldilocks zone of optimal antimicrobial stewardship, and finding it has become one of the defining challenges of modern neonatology.</p>
<p>The analogy, borrowed from astronomy, where the Goldilocks zone describes the orbital band around a star in which liquid water can survive, is more than a catchy framing device. It captures a genuine clinical dilemma. Neonatal sepsis, defined as life-threatening organ dysfunction caused by bacterial, viral or fungal infection, remains a leading cause of neonatal mortality worldwide and can leave survivors with serious neurodevelopmental sequelae. Yet the clinical presentation of sepsis in a newborn is notoriously nonspecific, and blood culture, the diagnostic cornerstone, has well-recognised limitations, particularly for early-onset sepsis. Antibiotics therefore remain the mainstay of treatment, and clinicians frequently must decide whether to start them in infants whose risk of infection is uncertain.</p>
<p>The stakes of that decision are amplified in preterm infants. These babies are immunologically immature, have thin skin and invasive lines, and are frequently exposed to maternal and neonatal risk factors that make infection plausible. Empiric antibiotics are started liberally, often within the first hours of life, and are continued for days in many infants who never have a positive culture. Recent studies quantifying this practice have found substantial variation in antibiotic exposure among culture-negative preterm infants, both within single centres over a decade and across international cohorts of late-preterm and term newborns. The question is no longer whether antibiotics are overused in this population, but how to measure the exposure precisely and what the consequences of that exposure actually are.</p>
<p>Those consequences have been examined in a growing body of observational research. Several large cohort studies have reported associations between prolonged duration of initial empiric antibiotic therapy and increased rates of necrotising enterocolitis and death in extremely low birth weight infants. Other analyses have linked extended early antibiotic exposure to subsequent development of late-onset sepsis, and to bronchopulmonary dysplasia in very preterm infants at low risk of early-onset sepsis. Multicentre cohort work has also associated longer empiric courses with necrotising enterocolitis and late-onset sepsis in preterm infants. These findings have fuelled calls for shorter empiric courses and more rapid discontinuation when cultures remain negative.</p>
<p>Yet the picture is not straightforward. Not every study points in the same direction. Some analyses, including a large international cohort of very low birth weight infants, have reported that early antibiotic use was associated with a lower incidence of necrotising enterocolitis, while a single-centre retrospective study found no association between early antibiotic exposure and short-term adverse outcomes in very preterm infants. Additional population-based and single-centre cohort analyses have produced mixed results regarding early empiric antibiotics and adverse clinical outcomes. The authors of the Pediatric Research commentary emphasise that this heterogeneity reflects real methodological complexity: confounding by indication, differences in gestational age, centre-level prescribing culture, and the difficulty of measuring what antibiotics are actually being given, at what dose, for how long, and against which suspected organisms.</p>
<p>Quantifying antibiotic use is itself a technical problem. A systematic review and international multidisciplinary consensus procedure has produced metrics for measuring antibiotic consumption in the hospital setting, recognising that simple days-of-therapy counts may obscure differences in spectrum, dose intensity and route. In neonatal intensive care, where weight-based dosing changes daily and renal clearance matures rapidly, the same number of days may represent very different cumulative exposures in different infants. The commentary argues that stewardship programmes must therefore move beyond crude consumption metrics toward precision prescribing, in which treatment is given to infants likely to benefit while unnecessary exposure is avoided in infants unlikely to have infection.</p>
<p>Achieving that precision requires better diagnostics as much as better prescribing habits. Inflammatory markers such as C-reactive protein and procalcitonin have been proposed as adjuncts to guide antibiotic decisions in early-onset sepsis, but their performance remains debated, with some experts questioning whether they are game changers or gimmicks. The absence of an accepted consensus definition of neonatal sepsis further hinders standardisation of registries, outcome measures, clinical trials and the evaluation of new diagnostics and therapeutics. Progress in developing advanced diagnostics and therapeutics for neonatal sepsis has been slow, which is precisely why antibiotics continue to carry such a heavy clinical load.</p>
<p>Where diagnostics fall short, pharmacology may help. Population pharmacokinetic models and simulation studies are being used to optimise vancomycin dosing in neonates, and a digital twin framework has been proposed for optimal aminoglycoside dosing in neonates with suspected sepsis, allowing clinicians to model individual drug exposure before administering it. Rapid point-of-care genotyping has been deployed in neonatal intensive care to identify infants at risk of aminoglycoside-induced ototoxicity, offering a way to personalise therapy at the genetic level. Best-evidence dosing recommendations for term and preterm neonates have been developed through dedicated projects, and considerations for drug dosing in premature infants continue to evolve as understanding of developmental pharmacology matures. Neonatal drug formularies are also being catalogued on a global scale to support safer prescribing.</p>
<p>The commentary also highlights the NANO trial, a randomised multicentre clinical trial assessing empiric antibiotics and clinical outcomes in newborn preterm infants, as an example of the kind of prospective evidence needed to move the field beyond observational associations. Randomised data are scarce in this population, partly because of ethical and logistical constraints, but without them the field risks perpetuating prescribing patterns based on weak evidence. The authors call for multidisciplinary antimicrobial stewardship programmes that bring together neonatologists, pharmacists, infectious disease specialists and microbiologists to define the optimal duration, spectrum and intensity of antibiotic exposure for preterm infants.</p>
<p>The goal, the authors stress, is not simply less antibiotic use. It is the right antibiotic, for the right infant, for the right duration, guided by evidence rather than habit or fear. In an era of rising antimicrobial resistance and growing recognition of the long-term consequences of early-life microbiome disruption, the Goldilocks zone of neonatal antibiotic prescribing is not a metaphorical luxury. It is a clinical target with measurable outcomes, and the tools to reach it, from precision metrics to pharmacokinetic modelling to point-of-care genotyping, are finally coming within grasp. What remains is the will to test them rigorously in the infants who need them most.</p>
<p><strong>Subject of Research:</strong> Antimicrobial stewardship in preterm infants</p>
<p><strong>Article Title:</strong> The Goldilocks zone of optimal antimicrobial stewardship in preterm infants</p>
<p><strong>Article References:</strong> Molloy, E. J., Johnson, L., Klebanoff, M., Tingay, D., &amp; Wynn, J. L. (2026). The Goldilocks zone of optimal antimicrobial stewardship in preterm infants. <em>Pediatric Research</em>. <a href="https://doi.org/10.1038/s41390-026-05558-4" rel="noopener noreferrer">https://doi.org/10.1038/s41390-026-05558-4</a></p>
<p><strong>Image Credits:</strong> AI Generated</p>
<p><strong>DOI:</strong> <a href="https://doi.org/10.1038/s41390-026-05558-4" rel="noopener noreferrer">10.1038/s41390-026-05558-4</a></p>
<p><strong>Keywords:</strong> neonatology, antimicrobial stewardship, preterm infants, neonatal sepsis, antibiotic exposure, microbiome, necrotizing enterocolitis, precision prescribing, Goldilocks, zone, optimal, antimicrobial</p>
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		<post-id xmlns="com-wordpress:feed-additions:1">285602</post-id>	</item>
		<item>
		<title>AI Model Flags Which Food-Allergic Babies Will Develop Asthma by School Age</title>
		<link>https://scienmag.com/ai-model-flags-which-food-allergic-babies-will-develop-asthma-by-school-age/</link>
		
		<dc:creator><![CDATA[Harold Sullivan]]></dc:creator>
		<pubDate>Mon, 12 Oct 2026 13:53:28 +0000</pubDate>
				<category><![CDATA[Technology and Engineering]]></category>
		<category><![CDATA[antibiotic exposure]]></category>
		<category><![CDATA[asthma development in food-allergic children]]></category>
		<category><![CDATA[asthma prediction]]></category>
		<category><![CDATA[childhood asthma prediction]]></category>
		<category><![CDATA[clinical predictors of asthma]]></category>
		<category><![CDATA[cost-sensitive learning]]></category>
		<category><![CDATA[early childhood health monitoring]]></category>
		<category><![CDATA[early identification of asthma risk]]></category>
		<category><![CDATA[early screening]]></category>
		<category><![CDATA[ensemble model]]></category>
		<category><![CDATA[food allergy]]></category>
		<category><![CDATA[food allergy and respiratory health]]></category>
		<category><![CDATA[infant health risk assessment]]></category>
		<category><![CDATA[Machine learning]]></category>
		<category><![CDATA[machine learning in pediatric health]]></category>
		<category><![CDATA[non-invasive asthma screening]]></category>
		<category><![CDATA[pediatric cohort studies]]></category>
		<category><![CDATA[pediatrics]]></category>
		<category><![CDATA[predictive modeling in pediatric medicine]]></category>
		<category><![CDATA[prospective cohort]]></category>
		<category><![CDATA[RSV infection]]></category>
		<category><![CDATA[SHAP]]></category>
		<category><![CDATA[wheezing]]></category>
		<guid isPermaLink="false">https://scienmag.com/?p=264859</guid>

					<description><![CDATA[A prospective study of 447 food-allergic infants reports a cost-sensitive ensemble model that predicts school-age asthma with an AUC of 0.886 and zero missed cases using routine clinical data collected before age two.]]></description>
										<content:encoded><![CDATA[<p>For parents of a baby newly diagnosed with a food allergy, one of the most anxious unanswered questions is whether the child will go on to develop asthma a few years later. Food allergy in early life is one of the strongest known predictors of childhood asthma, yet clinicians have lacked a reliable, non-invasive way to identify, during infancy, which of these children are truly on the path to the disease. A new prospective cohort study published in Pediatric Research by a team at Wenzhou Medical University and collaborating institutions now reports a machine-learning model that attempts to close that gap, screening infants between birth and age two and predicting their asthma risk at school age using routine clinical data alone.</p>
<p>The study enrolled 447 infants with confirmed food allergy, all aged between zero and two years, and collected an unusually rich baseline dataset: 135 candidate predictors organized across seven clinical categories, spanning demographic details, allergic history, respiratory symptoms, infections, medication exposure, sleep patterns, and family background. The children were then followed for a median of 4.5 years, until they reached school age of six years or older, at which point asthma status was established. This prospective design matters, because most existing asthma prediction tools were built retrospectively or in general birth cohorts rather than in a population of food-allergic infants, a group whose risk profile differs substantially from that of the general pediatric population.</p>
<p>At the heart of the work is a two-stage, performance-weighted ensemble that combines four very different families of algorithms: Random Forest, XGBoost, LightGBM, and a deep residual network. Each base learner captures different structure in the data. Tree-based gradient boosting methods such as XGBoost and LightGBM excel at nonlinear interactions among tabular clinical variables, Random Forests provide variance reduction through bagging, and the deep residual network can model higher-order feature relationships. Rather than averaging their outputs naively, the researchers assigned fusion weights proportional to each model&#8217;s measured performance, allowing stronger learners to dominate the final risk score while weaker ones still contribute complementary signals.</p>
<p>The most distinctive technical choice, however, is the cost-sensitive optimization. In asthma screening, the two types of error are not equivalent: a false alarm means extra monitoring for a child who may never develop the disease, but a missed case means a high-risk infant slips through without preventive attention, potentially delaying diagnosis and treatment that studies have linked to worse lung function outcomes. The team therefore trained the ensemble with a missed-to-false-alarm cost ratio of 5:1, deliberately penalizing missed cases five times more heavily. The result, on an independent test set, was an area under the receiver operating characteristic curve of 0.886 and a recall of 1.00, meaning that not a single child who went on to develop asthma was missed by the model at the chosen threshold.</p>
<p>Sensitivity analyses added an important nuance: the zero-missed performance remained stable across cost ratios of 5:1 and above, suggesting that the 5:1 setting was not itself the key driver of the perfect recall. Instead, the ensemble&#8217;s underlying discrimination appears strong enough that a range of asymmetric cost settings yields the same reassuring property. The researchers also evaluated clinical utility beyond raw discrimination using decision-curve analysis, a method that quantifies the net benefit of acting on a model&#8217;s predictions across a range of threshold probabilities. The model showed superior net benefit across broad threshold ranges, with an optimal operating cutoff identified at a predicted probability of just 0.09, a low threshold consistent with the deliberately sensitive screening posture.</p>
<p>Interpretability was addressed through SHAP-based feature importance analysis, which ranked the predictors driving individual predictions. The top contributors were respiratory syncytial virus infection, the frequency of wheezing episodes, characteristics of nocturnal sleep, cumulative antibiotic exposure, and the duration of rhinitis. Several of these echo long-standing clinical intuition, particularly wheeze grading, which has anchored classical tools such as the asthma predictive index for two decades. Others are more provocative. The prominence of antibiotic exposure aligns with a growing body of literature linking early-life antibiotics, possibly through gut microbiome disruption, to later allergic disease, although the observational nature of the data means the model captures association rather than proven causation.</p>
<p>The team also engineered three clinically interpretable features from the raw variables before model training, a step intended to translate pediatric knowledge into representations the algorithms could exploit more efficiently. Interaction analysis of the top ten feature pairs, visualized alongside the SHAP results, suggests that combinations such as wheeze frequency with infection history carry predictive information beyond what either variable contributes alone. Radar charts comparing three threshold strategies and calibration curves assessing the agreement between predicted probabilities and observed outcomes round out a performance evaluation that is unusually thorough for a clinical prediction study of this size.</p>
<p>The clinical logic behind the effort is straightforward. Delayed asthma diagnosis has been associated with more frequent exacerbations and measurable decrements in pulmonary function, while early intervention with inhaled corticosteroids in persistent disease has documented benefits. A screening tool that works before age two, using nothing more than clinical history, could allow primary care providers to stratify food-allergic infants into intensive follow-up versus routine monitoring, individualizing surveillance long before symptoms become unmistakable. Because the model requires no blood tests, lung function measurements, or imaging, the barrier to deployment in community settings is comparatively low, at least in principle.</p>
<p>Important caveats remain. The cohort of 447 children came from a single Chinese hospital network, and the authors themselves describe the model as a preliminary predictor, noting that external validation in independent, geographically diverse populations will be essential before any clinical adoption. Individual-level data are not publicly available for privacy reasons, which limits independent scrutiny, although aggregated results and supplementary tables are provided. Calibration, threshold selection, and the stability of the top predictors all need to be confirmed in settings with different healthcare patterns, antibiotic prescribing habits, and RSV epidemiology. The 1.00 recall figure, while striking, will also need replication; perfect sensitivity on a single test set can reflect favorable data splits as well as genuine generalizable performance.</p>
<p>Even with those qualifications, the study represents a meaningful step toward proactive, data-driven allergy care. It demonstrates that a carefully engineered ensemble, tuned for the asymmetric costs that actually matter to families and clinicians, can extract a usable school-age asthma risk signal from information gathered in the first two years of life. If validated externally, the approach could shift the management of food-allergic infants from watchful waiting toward targeted prevention, giving the children at highest risk a head start on the interventions that preserve lung function and, ideally, change the trajectory of the allergic march before it hardens into chronic disease.</p>
<p><strong>Subject of Research:</strong> Machine-learning prediction of school-age asthma risk in infants with food allergy</p>
<p><strong>Article Title:</strong> Ensemble model–based prediction of school–age asthma risk in children with food allergy</p>
<p><strong>Article References:</strong> Jia, X., Ye, Y., Shi, C., Wang, J., Fu, Z., Wu, Y., Tao, Q., Hu, H., Ye, H., Ouyang, Z., Zhang, W., &amp; Wang, L. (2026). Ensemble model–based prediction of school–age asthma risk in children with food allergy. <em>Pediatric Research</em>. <a href="https://doi.org/10.1038/s41390-026-05553-9" rel="noopener noreferrer">https://doi.org/10.1038/s41390-026-05553-9</a></p>
<p><strong>Image Credits:</strong> AI Generated</p>
<p><strong>DOI:</strong> <a href="https://doi.org/10.1038/s41390-026-05553-9" rel="noopener noreferrer">10.1038/s41390-026-05553-9</a></p>
<p><strong>Keywords:</strong> food allergy, asthma prediction, machine learning, ensemble model, pediatrics, cost-sensitive learning, SHAP, RSV infection, wheezing, antibiotic exposure, prospective cohort, early screening</p>
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		<title>How COVID-19 May Open the Door to a Dangerous Gut Infection</title>
		<link>https://scienmag.com/how-covid-19-may-open-the-door-to-a-dangerous-gut-infection/</link>
		
		<dc:creator><![CDATA[Kristina Jarvis]]></dc:creator>
		<pubDate>Wed, 07 Oct 2026 08:21:27 +0000</pubDate>
				<category><![CDATA[Biology]]></category>
		<category><![CDATA[ACE2]]></category>
		<category><![CDATA[antibiotic exposure]]></category>
		<category><![CDATA[Antibiotic Stewardship]]></category>
		<category><![CDATA[antibiotic-associated diarrhea]]></category>
		<category><![CDATA[bile acid metabolism]]></category>
		<category><![CDATA[Clostridioides difficile]]></category>
		<category><![CDATA[colonization resistance]]></category>
		<category><![CDATA[corticosteroid use]]></category>
		<category><![CDATA[COVID-19]]></category>
		<category><![CDATA[COVID-19 treatment complications]]></category>
		<category><![CDATA[extracellular vesicles]]></category>
		<category><![CDATA[gut dysbiosis]]></category>
		<category><![CDATA[gut infections]]></category>
		<category><![CDATA[healthcare-associated colitis]]></category>
		<category><![CDATA[hospital-acquired infections]]></category>
		<category><![CDATA[hospitalization]]></category>
		<category><![CDATA[immune system effects]]></category>
		<category><![CDATA[inflammation]]></category>
		<category><![CDATA[pandemic impact on gut microbiota]]></category>
		<category><![CDATA[renin-angiotensin system]]></category>
		<category><![CDATA[risk factors for C. difficile]]></category>
		<category><![CDATA[SARS-CoV-2]]></category>
		<guid isPermaLink="false">https://scienmag.com/?p=243781</guid>

					<description><![CDATA[A new review in Gut Pathogens argues that SARS-CoV-2 infection and COVID-19 care pathways may create gut conditions permissive to Clostridioides difficile infection through dysbiosis, ACE2 disruption, and persistent inflammation.]]></description>
										<content:encoded><![CDATA[<p>When SARS-CoV-2 swept across the world in 2020, clinicians noticed that the pandemic was changing more than the epidemiology of respiratory disease. Hospital wards filled with older, medically fragile patients who received broad-spectrum antibiotics, prolonged courses of corticosteroids, intensive oxygen support, and long stays in overcrowded intensive care units. Each of these factors is also a classic risk condition for Clostridioides difficile infection, the leading cause of antibiotic-associated diarrhea and health care-associated colitis worldwide. A new narrative mini-review published in the journal Gut Pathogens by Renata Ferreira de Carvalho Leitão of the Federal University of Ceará and colleagues, including researchers at the University of Virginia&#8217;s Center for Global Health, brings these threads together. The authors synthesize clinical and mechanistic evidence suggesting that COVID-19 itself, and the pathways of care that surround it, may create a biological environment in which C. difficile can flourish in susceptible individuals.</p>
<p>The review is careful to separate what is established from what remains hypothetical, a distinction that matters in a field where observational data can easily be overinterpreted. The authors distinguish three clinical scenarios that are often conflated in the literature. The first is simultaneous co-infection, in which a patient harbors both SARS-CoV-2 and actively toxin-producing C. difficile at the same time. The second is CDI that develops during hospitalization for COVID-19, a situation in which antimicrobial exposure and disrupted infection-prevention practices during pandemic surges may play dominant roles. The third, and perhaps the most intriguing, is delayed or recurrent CDI after apparent recovery from acute infection, which points toward persistent alterations of the intestinal ecosystem rather than simple nosocomial exposure. Each scenario implies a different balance of contributing causes, and each demands a different study design to disentangle.</p>
<p>The most straightforward explanation for an association between the two diseases is iatrogenic. Patients hospitalized with severe COVID-19 frequently received broad-spectrum antibiotics, either because bacterial co-infection was suspected or as empirical coverage during the chaotic early phases of the pandemic, when distinguishing viral pneumonia from secondary bacterial infection was difficult. Antibiotic exposure is the single strongest risk factor for C. difficile infection because it dismantles colonization resistance, the collective ability of a diverse gut microbiota to suppress pathogen expansion through competition for nutrients, production of bacteriocins, and, critically, the metabolism of bile acids. Primary bile acids such as taurocholate stimulate germination of C. difficile spores, while secondary bile acids generated by commensal bacteria inhibit its growth. When antibiotics deplete the bile acid-metabolizing community, the gut becomes a permissive niche for the pathogen.</p>
<p>Yet the review argues that antibiotics and hospitalization alone cannot fully account for the observed patterns. SARS-CoV-2 is increasingly recognized as an agent capable of perturbing the gut directly. Viral RNA has been detected in intestinal tissue and stool, and the angiotensin-converting enzyme 2 receptor, the cellular entry gate for the virus, is abundantly expressed on intestinal epithelial cells, particularly mature enterocytes of the small intestine. The authors emphasize that ACE2 is not merely a viral docking site. In normal physiology, ACE2 participates in regulating amino acid homeostasis, antimicrobial peptide expression, and the composition of the gut microbiome. Loss or dysregulation of ACE2 function during infection could therefore weaken epithelial barrier integrity and shift the microbial community toward a dysbiotic state, independently of any antimicrobial exposure.</p>
<p>This leads to the renin-angiotensin system, one of the review&#8217;s central mechanistic themes. SARS-CoV-2 binding to ACE2 promotes internalization and degradation of the receptor, reducing its protective enzymatic activity. The consequence is an imbalance in the renin-angiotensin axis: less angiotensin II is converted into the vasoprotective angiotensin-(1-7), and unopposed angiotensin II signaling through the AT1 receptor increases. In the intestine, excessive angiotensin II/AT1R signaling is associated with inflammation, increased epithelial permeability, and impaired barrier repair. The authors propose that this signaling imbalance could amplify mucosal damage during COVID-19 and thereby lower the threshold at which residual C. difficile spores, persisting in the lumen after germination conditions improve, can establish infection and produce toxin.</p>
<p>Downstream of angiotensin signaling, the review highlights inflammatory cascades that connect viral injury to bacterial opportunity. Severe COVID-19 is characterized by activation of the transcription factors NF-κB and MAPK in epithelial and immune cells, driving robust production of interleukin-6 and other pro-inflammatory mediators. Persistent inflammatory signaling can disrupt epithelial tight junctions, alter mucus production, and change the metabolic landscape of the lumen in ways that favor pathogenic taxa over obligate anaerobes that maintain colonization resistance. The authors also draw attention to nutritional vulnerability, noting that malnutrition and micronutrient deficiencies, common in hospitalized and older patients, impair epithelial regeneration and immune defense. They further discuss apolipoprotein E-related immunometabolic pathways as a possible link between host lipid metabolism, inflammatory resolution, and susceptibility to intestinal injury, an area they flag as requiring direct experimental validation.</p>
<p>Among the more forward-looking elements of the review is its treatment of extracellular vesicles as a potential biomarker framework. Extracellular vesicles, small membrane-bound particles released by cells into circulation and bodily fluids, carry proteins, lipids, and nucleic acids that reflect the physiological state of their cell of origin. The authors suggest that vesicle cargo could eventually serve as a readout of the combined inflammatory, epithelial, and microbial perturbations that characterize patients at heightened risk of CDI during or after COVID-19. Such biomarkers could, in principle, allow clinicians to identify which recovered COVID-19 patients warrant closer surveillance for delayed intestinal complications, although this remains a hypothesis-generating proposal rather than a validated clinical tool.</p>
<p>The authors are explicit that direct longitudinal evidence linking SARS-CoV-2 infection to subsequent CDI remains limited. Much of the available data come from single-center cohorts, retrospective chart reviews, and studies with heterogeneous testing practices, which complicates interpretation. Distinguishing true C. difficile infection from colonization in patients with diarrhea of other causes is a persistent diagnostic challenge, and pandemic-era disruptions to infection-prevention bundles and testing algorithms further muddy the picture. What the review offers instead is convergence: multiple independent lines of clinical and experimental evidence that all point in the same direction, supporting what the authors describe as a cautious, testable hypothesis rather than a demonstrated causal relationship.</p>
<p>To move the field forward, the review calls for prospective studies with standardized CDI testing protocols, careful quantification of antimicrobial exposure, and integrated microbiome and metabolomic profiling of patients followed from acute COVID-19 through recovery. Such studies would need to track bile acid pools, inflammatory markers, and microbial community structure over time to determine whether SARS-CoV-2 infection produces a durable shift in colonization resistance, and whether that shift translates into elevated risk of primary or recurrent CDI. Mechanistic biomarker discovery, including the extracellular vesicle framework, would ideally proceed in parallel. The authors also underline the importance of clarifying prognosis and long-term consequences, since recurrent CDI carries substantial morbidity and mortality in the same older and medically complex populations that bore the heaviest burden of the pandemic.</p>
<p>The broader significance of the work lies in its reframing of COVID-19 as a condition with potential gastrointestinal sequelae mediated through the microbiome, rather than a purely respiratory illness. If the hypothesis holds, the implications extend beyond the acute pandemic: clinicians managing patients recovering from severe COVID-19 may need to weigh antibiotic stewardship more carefully, monitor for gastrointestinal symptoms after discharge, and consider gut-protective strategies such as targeted microbiome restoration. At the same time, the review&#8217;s disciplined separation of established observations from mechanistic speculation serves as a model for how the field should proceed. The interaction between a global respiratory pathogen and an opportunistic intestinal spore-former is almost certainly multifactorial, involving antimicrobial exposure, hospitalization dynamics, dysbiosis, barrier dysfunction, altered bile acid metabolism, and persistent inflammation. Untangling those threads will require exactly the kind of rigorous, longitudinal, mechanistically informed research that the authors advocate.</p>
<p><strong>Subject of Research:</strong> Potential mechanisms linking COVID-19 and Clostridioides difficile infection through gut dysbiosis</p>
<p><strong>Article Title:</strong> COVID-19 and clostridioides difficile infection: clinical overlap, gut dysbiosis, and mechanistic hypotheses</p>
<p><strong>Article References:</strong> de Carvalho Leitão, R. F., da Silva Costa, D. V., Nguyen, A., Vieira, L. L., Nunes, P. I. G., Warren, C. A., Oriá, R. B., &amp; de Castro Brito, G. A. (2026). COVID-19 and clostridioides difficile infection: clinical overlap, gut dysbiosis, and mechanistic hypotheses. <em>Gut Pathogens</em>. <a href="https://doi.org/10.1186/s13099-026-00862-0" rel="noopener noreferrer">https://doi.org/10.1186/s13099-026-00862-0</a></p>
<p><strong>Image Credits:</strong> AI Generated</p>
<p><strong>DOI:</strong> <a href="https://doi.org/10.1186/s13099-026-00862-0" rel="noopener noreferrer">10.1186/s13099-026-00862-0</a></p>
<p><strong>Keywords:</strong> COVID-19, Clostridioides difficile, SARS-CoV-2, ACE2, gut dysbiosis, renin-angiotensin system, bile acid metabolism, colonization resistance, inflammation, extracellular vesicles, hospitalization, antibiotic exposure</p>
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