The scale of the problem the review addresses is difficult to overstate. Candida species are the leading cause of opportunistic fungal infections, ranging from superficial mucosal disease such as thrush and vulvovaginal candidiasis to life-threatening bloodstream infections in intensive care patients, organ transplant recipients, and the immunocompromised. While Candida albicans remains the dominant pathogen, non-albicans species such as C. glabrata, C. tropicalis, C. parapsilosis, and C. krusei are increasingly prevalent, and C. auris has emerged over the past decade as a genuine global public health threat. Its ability to adhere tenaciously to environmental surfaces and persist in hospitals makes it extraordinarily difficult to eradicate once it takes hold in a healthcare setting.

Part of what makes Candida so formidable is its arsenal of resistance mechanisms. The fungus can mutate target genes, ramp up efflux pumps that expel drugs, alter the sterol composition of its membranes, activate stress responses, and—perhaps most troublingly—form biofilms. These structured communities of cells encased in protective matrix can tolerate antifungal drugs at concentrations up to 1,000 times higher than free-floating cells, which is why biofilms on catheters, prosthetic heart valves, dentures, and implants are such a clinical nightmare. The four existing drug classes—azoles, polyenes, echinocandins, and pyrimidine analogues—all suffer from limitations including toxicity, poor tissue penetration, harmful drug interactions, and the rapid emergence of resistance.

Zinc oxide nanoparticles attack the fungus in a fundamentally different way. Rather than targeting a single molecular pathway, they deploy a multi-pronged assault that the review identifies as the key to their promise. The primary mechanism is the generation of reactive oxygen species, which induces oxidative stress that damages DNA, oxidizes proteins, and disrupts mitochondrial function. Simultaneously, the nanoparticles physically compromise the fungal cell wall and plasma membrane, forming pores, rupturing membranes, and causing leakage of intracellular contents. Dissolution of the particles releases zinc ions that further interfere with intracellular enzyme systems and metabolic pathways. Because this attack hits multiple cellular targets at once, the likelihood of Candida evolving effective resistance is substantially reduced compared with single-target drugs.

Beyond outright killing, ZnO NPs also disarm the fungus’s virulence machinery. Studies included in the review showed that the nanoparticles reduce biofilm formation, inhibit the yeast-to-hypha transition that underpins tissue invasion, block quorum sensing, and downregulate key virulence genes including HWP1, ALS1, ALS3, ERG11, SAP, and RAS1. Electron microscopy evidence is particularly vivid: treated C. albicans cells exposed to nanoparticle concentrations of 80 and 160 micrograms per milliliter displayed hyphal breakdown, surface pitting, membrane invagination, and complete membrane rupture, while untreated cells retained their smooth, intact morphology. Spectroscopic analysis confirmed that zinc accumulated on the surface of treated fungal cells, supporting a model in which direct adhesion of nanoparticles triggers membrane disruption, oxidative stress, and lethal leakage.

How the nanoparticles are made matters enormously, and here the review highlights the rise of green synthesis. Conventional chemical and physical production of nanomaterials relies on toxic reducing agents, volatile organic solvents, high temperatures, and energy-intensive processes that generate hazardous waste. Green synthesis instead uses plant extracts, bacteria, fungi, and algae as natural reducing, capping, and stabilizing agents, converting zinc salts into nanoparticles under mild conditions. The review catalogs an impressive range of biological sources that have successfully yielded antifungal ZnO NPs, from fenugreek seeds and green tea leaves to sage, lemon peel, mango leaves, cashew apple juice, bay leaf, garden cress, egg albumin, and even lignin biotemplates, alongside microbes such as Lactobacillus gasseri, Pseudomonas putida, and Bacillus licheniformis.

The green route offers more than environmental credentials. Phytochemicals such as flavonoids, phenolics, alkaloids, and terpenoids remain adsorbed on the nanoparticle surface, adding antioxidant and antimicrobial activity of their own while reducing cytotoxicity to host cells. The review found that green-synthesized ZnO NPs met all but one of the traits required for biocompatibility, and several studies reported favorable therapeutic windows, excellent hemocompatibility with minimal hemolysis, and low toxicity toward mammalian cells at concentrations that effectively kill Candida. Doping strategies add another layer of tunability: calcium-doped ZnO nanoparticles showed strong activity against multidrug-resistant C. auris, while gadolinium and lanthanum doping have been shown to modify antimicrobial properties and defect states such as oxygen vacancies, potentially allowing researchers to optimize the balance between fungal killing and host safety.

Perhaps the most clinically exciting finding concerns synergy with existing drugs. Green-synthesized ZnO NPs significantly enhanced the activity of fluconazole against multiple Candida species, with especially strong effects against C. glabrata and C. parapsilosis, and moderate synergy against C. albicans and C. tropicalis. Amphotericin B conjugated onto ZnO nanoparticles outperformed unconjugated particles, suggesting the nanoparticles could double as drug delivery vehicles, and ZnO-based nanocomposites incorporating vancomycin, silver, or chitosan also showed enhanced antifungal activity. The mechanistic logic is compelling: by disrupting membrane integrity, the nanoparticles increase intracellular drug penetration, while their own oxidative stress and antibiofilm effects complement the drugs’ actions. In principle, such combinations could lower effective drug doses, reduce dose-dependent toxicity, and delay the emergence of resistance in multidrug-resistant and biofilm-associated infections.

The authors are careful, however, not to oversell the current state of evidence. Most of the 33 studies focused on synthesis, characterization, and susceptibility testing, while in-depth molecular investigations were rare; comprehensive transcriptomic, proteomic, and metabolomic analyses of how Candida responds to nanoparticle exposure are almost entirely lacking. Cytotoxicity data frequently came from immortalized or cancer-derived cell lines such as HepG2 rather than primary human cells, which may distort safety estimates in either direction. Not a single clinical trial has evaluated ZnO NPs for candidiasis, few studies progressed to animal models, and none comprehensively assessed the environmental fate or ecotoxicological impact of the nanoparticles after biomedical use. Heterogeneity in particle size, surface chemistry, synthesis methods, and testing protocols further complicates direct comparison between studies.

Those caveats frame the road ahead. The review calls for standardized synthesis and characterization protocols covering zeta potential, colloidal stability, hydrodynamic size, and dissolution kinetics; toxicity testing in normal human cell lines and repeated-dose animal studies; pharmacokinetic and biodistribution assessments; systematic evaluation of combinations across all major antifungal classes; and, ultimately, well-designed clinical trials. If those steps succeed, zinc oxide nanoparticles could move from the laboratory bench to catheter coatings, wound dressings, denture liners, implant surfaces, and systemic combination therapies—applications where their multimodal mechanism, green manufacturability, and synergy with existing drugs could make a decisive difference in an era when the fungi are winning ever more often.

Subject of Research: Antifungal activity and mechanisms of zinc oxide nanoparticles against drug-resistant Candida species

Article Title: Zinc oxide nanoparticles against Candida: mechanistic pathways, synergistic potentials, and biocompatibility challenges in the era of antimicrobial resistance

Article References: Sahu, B. K., Mohanta, T. K., Sahu, M. C., & Panda, S. K. (2026). Zinc oxide nanoparticles against Candida: mechanistic pathways, synergistic potentials, and biocompatibility challenges in the era of antimicrobial resistance. Frontiers in Antibiotics, 5, Article 1933663. https://doi.org/10.3389/frabi.2026.1933663

Image Credits: AI Generated

DOI: 10.3389/frabi.2026.1933663

Keywords: zinc oxide nanoparticles, Candida, antifungal resistance, green synthesis, biofilm inhibition, reactive oxygen species, Candida auris, fluconazole synergy, nanotechnology, biocompatibility, candidiasis, virulence genes

The study’s central innovation lies in its timing. Most previous research on infection and heart defects has focused on infections contracted during pregnancy, particularly in the first trimester when the embryonic heart is forming. This new analysis shifts the window backward, asking whether the state of a woman’s immune system and reproductive tract before she conceives might also shape her child’s cardiac risk. The investigators assessed two broad categories of preconception exposure. The first comprised active reproductive tract infections, specifically candidiasis and Chlamydia trachomatis infection, diagnosed at the preconception examination. The second comprised immunoglobulin G seropositivity to three well-known pathogens: cytomegalovirus, Toxoplasma gondii, and rubella virus. Immunoglobulin G antibodies indicate prior exposure to a pathogen and persist in the blood for years, so seropositivity serves as a marker of a woman’s immunological history rather than of an active acute illness at the time of testing.

The data came from China’s National Free Preconception Health Examination Project, a government program that offers voluntary health screening to couples planning marriage or pregnancy. All participants provided written informed consent, and the retrospective analysis of anonymized records was approved by the Institutional Review Board of Guangdong Women and Children Hospital. Because the screening program covers a defined population rather than a selected sample of hospital patients, the cohort reflects a broad cross-section of women of reproductive age in one of China’s most populous provinces, which strengthens the generalizability of the findings within similar settings.

Statistically, the team used multivariable modified Poisson regression with robust error variance, a modeling approach widely favored in epidemiology when the outcome of interest is relatively common and researchers want to estimate relative risks directly rather than odds ratios, which can overstate risk in such settings. The models adjusted for potential confounding factors, and the authors reported both adjusted relative risks and risk differences per 1,000 births, each accompanied by 95 percent confidence intervals. The primary outcome, congenital heart disease, was ascertained from the birth defects registry, providing a standardized and population-wide mechanism for capturing diagnoses rather than relying on self-report or single-hospital records.

The results were striking across the board. Chlamydia trachomatis infection detected before conception was associated with an adjusted relative risk of 1.89, meaning the risk of congenital heart disease in offspring was nearly doubled among exposed women, with a confidence interval of 1.14 to 3.15. Even more pronounced was the association with cytomegalovirus IgG seropositivity, which carried an adjusted relative risk of 2.70, with a confidence interval of 2.26 to 3.22. Candidiasis was linked to an adjusted relative risk of 1.50, rubella IgG seropositivity to 1.59, and Toxoplasma gondii IgG seropositivity to 1.32, all with confidence intervals excluding the null value of 1. In other words, every one of the five preconception infection-related exposures examined showed a statistically significant association with elevated offspring heart defect risk in the fully adjusted models.

Perhaps the most eye-catching numbers emerged when the researchers examined women exposed to more than one factor. Among women with both Chlamydia trachomatis infection and cytomegalovirus IgG seropositivity, the adjusted relative risk reached 5.14, with a confidence interval of 2.92 to 9.06. Women with candidiasis combined with cytomegalovirus IgG seropositivity showed an adjusted relative risk of 3.72, with a confidence interval of 2.53 to 5.49. These joint-exposure estimates suggest that women carrying multiple infection-related markers before conception may face substantially higher absolute risks than those with any single marker. However, the authors are careful to frame these findings appropriately: the elevated estimates in jointly exposed groups describe joint exposure patterns and should not be interpreted as evidence of biological interaction, meaning the study cannot establish that the two exposures amplify each other’s effects at a mechanistic level.

The biological plausibility of a link between maternal infection and fetal cardiac development has a long scientific pedigree. Congenital heart disease arises from disruptions in the intricate choreography of embryonic heart formation, which occurs largely within the first eight weeks of gestation. Maternal immune activation, whether triggered by active infection or by the lingering immunological landscape left by past pathogens, is thought in some contexts to influence early embryonic environments through inflammatory signaling, altered cytokine profiles, and effects on placental development. Rubella is a classic and well-established teratogen, capable of causing a constellation of congenital defects including cardiac anomalies when infection occurs in early pregnancy. Cytomegalovirus, the most common congenital infection worldwide, and Toxoplasma gondii, a parasite transmitted through undercooked meat or contact with cat feces, are both recognized causes of congenital disease, though their specific contribution to structural heart defects has been less clearly quantified. This study adds a preconception dimension to that picture, suggesting that the immunological terrain established before pregnancy may matter as much as events during gestation.

The methodological strengths of the study deserve emphasis. With more than 630,000 pregnancies and over 1,300 outcome cases, the analysis had the statistical power to detect associations of modest magnitude that smaller studies would miss. The prospective timing of the exposure assessment is another advantage: infection status and serology were measured at preconception examinations, before any pregnancy outcome was known, which reduces the risk of recall bias and reverse causation that plague studies relying on postnatal reporting. The use of a birth defects registry for outcome ascertainment provides systematic case identification across the province. Sensitivity analyses, in which the researchers re-ran their models under alternative assumptions, produced results consistent with the primary findings, adding confidence that the associations are not artifacts of particular modeling choices.

At the same time, the authors and readers alike must weigh the inherent limits of observational research. An association, however robust, does not prove causation. Seropositivity to cytomegalovirus, rubella, and Toxoplasma gondii reflects past exposure and may correlate with unmeasured characteristics, such as socioeconomic conditions, occupational exposures, dietary patterns, or broader immune profiles, that could themselves influence cardiac development risk. The study was conducted in a single province of China, and seroprevalence of these pathogens varies considerably across regions and income settings, so the absolute risks and even the magnitude of associations may differ elsewhere. The authors also note that the published version was shared early as a citable, peer-reviewed accepted manuscript subject to further editorial refinement, a reminder that details may be updated in the final version of record.

Even with those caveats, the public health implications are considerable. Congenital heart disease imposes a lifelong burden on affected children and families, often requiring surgery, ongoing cardiology care, and in severe cases resulting in early mortality. If preconception infection status genuinely contributes to risk, then the period before pregnancy becomes a critical and currently underused window for intervention. Screening and treating chlamydial infections and candidiasis before conception, counseling women on toxoplasmosis prevention, and ensuring rubella immunity through vaccination well ahead of pregnancy are all established, low-cost measures already embedded in many preconception care frameworks. The findings from Guangdong suggest that such measures may carry benefits beyond the infections themselves, potentially reducing the burden of the most common birth defect. For the millions of couples planning pregnancy each year, the message from this research is that the health of the next generation’s heart may begin taking shape long before the first heartbeat.

Subject of Research: Preconception maternal infection-related exposures and the risk of congenital heart disease in offspring

Article Title: Preconception maternal infection-related exposures and risk of congenital heart disease in offspring: evidence from a large population-based cohort in South China

Article References: Chen, Y., Xu, R., Wei, H., Gu, Q., Liu, Y., Zhu, J., Yang, L., Zhang, Y., & Tan, G. (2026). Preconception maternal infection-related exposures and risk of congenital heart disease in offspring: evidence from a large population-based cohort in South China. BMC Public Health. https://doi.org/10.1186/s12889-026-29782-z

Image Credits: AI Generated

DOI: 10.1186/s12889-026-29782-z

Keywords: congenital heart disease, preconception health, Chlamydia trachomatis, cytomegalovirus, rubella, Toxoplasma gondii, candidiasis, IgG seropositivity, population-based cohort, birth defects registry, maternal infection, Guangdong China

The research team, led by Ahmed Rezk, Heba S. Said, Sherin M. Elfeky, Mohammed El-Mowafy, and Ramadan Hassan of Mansoura University, began by surveying the local resistance landscape. They collected 64 clinical isolates of C. albicans from hospitals in Dakhlya governorate, drawn from urine samples, vaginal swabs, blood cultures, and other clinical sources between May and July 2022. Using standard disk diffusion and broth microdilution methods aligned with Clinical and Laboratory Standards Institute guidelines, they found that 16 isolates, a full 25 percent of the collection, were resistant to fluconazole. Minimum inhibitory concentrations among these resistant strains ranged from 64 to 2048 micrograms per milliliter, levels far above what fluconazole can achieve safely in patient tissue.

That resistance is not accidental. Fluconazole works by inhibiting the fungal enzyme lanosterol demethylase, encoded by the ERG11 gene, which is essential for building ergosterol, the structural backbone of the fungal cell membrane. Resistant fungi fight back in several ways: they mutate ERG11 so the drug binds poorly, they overproduce the target enzyme, and, most importantly for this study, they crank up expression of efflux pumps that simply eject the drug from the cell before it can do damage. The dominant player among these pumps is Cdr1, an ATP-binding cassette transporter embedded in the plasma membrane. Cdr1 operates like a molecular bilge pump: azole drugs drift into the cytoplasm, slip into a hydrophobic cavity in the transporter’s transmembrane domains, and are then expelled outward when ATP binding and hydrolysis at the nucleotide-binding domains drive a conformational flip from an inward-facing to an outward-facing state.

Disulfiram, chemically known as tetraethylthiuram disulfide, has a long and curious pharmacological history. Approved for aversion therapy in alcohol use disorder, it inhibits aldehyde dehydrogenase in the liver, causing acetaldehyde to accumulate and producing the flushing, nausea, and headaches that discourage drinking. But over the past two decades it has attracted attention as a repurposing candidate in oncology and infectious disease. Previous work had already hinted at antifungal potential: an earlier study showed disulfiram directly modulates Cdr1p, and a non-toxic concentration of the drug enhanced the sensitivity of yeast cells expressing the pump to fluconazole and miconazole. It has also shown activity against methicillin-resistant Staphylococcus aureus, Helicobacter pylori, and metallo-beta-lactamase enzymes.

To test whether that promise held up against real clinical resistance, the Mansoura team measured disulfiram’s own minimum inhibitory concentration against six representative fluconazole-resistant isolates, obtaining values between 10 and 20 micrograms per milliliter. They then repeated fluconazole susceptibility testing in the presence of a subinhibitory dose of disulfiram, one too low to inhibit fungal growth on its own. The results were striking: fluconazole’s MIC dropped by factors ranging from 2-fold to as much as 128-fold across the resistant isolates. In other words, a dose of disulfiram that by itself could not harm the fungus dramatically re-sensitized it to a drug it had previously shrugged off.

Checkerboard assays, in which both drugs are titrated in two dimensions across a microtiter plate, confirmed the synergy quantitatively. Using the fractional inhibitory concentration index, the team classified the combination as fully synergistic in three isolates, partially synergistic in two, and additive in one. No antagonism was observed. Under the conventional interpretation scheme, a FICI of 0.5 or below indicates synergy, meaning the drugs together accomplish more than the sum of their individual effects, a hallmark of a genuine resistance-reversing interaction rather than simple additive killing.

The molecular mechanism behind this synergy emerged from two complementary lines of evidence. First, quantitative reverse-transcription PCR on two resistant isolates, Ca15 and Ca39, showed that Cdr1 was overexpressed when the fungi were exposed to fluconazole alone, consistent with the pump being the engine of resistance. When disulfiram was added at subinhibitory concentrations, either alone or in combination with fluconazole, Cdr1 expression was downregulated relative to untreated controls. Second, molecular docking simulations using the recently solved cryo-EM structure of Cdr1 bound to fluconazole revealed that disulfiram can occupy two strategic positions on the transporter. At the hydrophobic substrate cavity in the transmembrane domain, disulfiram binds in a mode nearly identical to fluconazole, forming a hydrogen bond with Asn1240 and hydrophobic contacts with residues including Phe552, Leu555, Phe559, and Ile1237, with a calculated binding affinity of minus 6.46 kilocalories per mole, slightly stronger than fluconazole’s minus 6.07. At the ATP-binding site in the nucleotide-binding domain, disulfiram mimics ATP itself, hydrogen bonding with Thr195, Cys193, Gly190, Ser194, and Gly192, residues essential for ATP binding and hydrolysis. By competing at both sites simultaneously, disulfiram appears to jam the pump’s fuel supply and its cargo door at once, allowing fluconazole to accumulate in the cytoplasm and attack its target enzyme.

Beyond reversing resistance, disulfiram delivered a second blow to the fungus: it interfered with biofilm formation. Biofilms, the organized communities of cells encased in a protective matrix that adhere to catheters, mucosal surfaces, and medical devices, are notoriously tolerant of antifungals and a major driver of persistent infection. Using a tissue culture plate assay with crystal violet staining, the researchers showed that disulfiram reduced biofilm formation in a dose-dependent manner at sub-MIC concentrations of one-half, one-quarter, one-eighth, and one-sixteenth of its MIC. Remarkably, even at the weakest dose tested, one-sixteenth of the MIC, the drug still achieved roughly 14 to 37 percent inhibition of biofilm formation and significant eradication of mature, 24-hour-old biofilms. This dual activity, chemosensitization plus anti-biofilm action, suggests disulfiram could undermine two of the most stubborn survival strategies C. albicans deploys in the human host.

The study’s authors are careful to frame these results as a foundation rather than a finished therapy. All experiments were conducted in vitro, and the researchers explicitly call for follow-up work including site-directed mutagenesis, functional binding assays, and investigation of other resistance mechanisms such as ERG11 point mutations and the efflux genes Cdr2 and Mdr1. In vivo efficacy and pharmacodynamic studies will be essential before any clinical conclusions can be drawn. Still, the appeal of the strategy is considerable. Drug repurposing bypasses the years of safety profiling required for entirely new molecules, and combination therapy can lower effective doses of both agents, potentially reducing toxicity and slowing the further evolution of resistance. With fluconazole resistance rates in Egyptian bloodstream isolates recently reported as high as 58.3 percent, and with the researchers highlighting the infrequent use of routine antifungal susceptibility testing in the region, the need for such adjuvant approaches is urgent. If subsequent animal and clinical studies validate what the Mansoura team observed in the laboratory, a fifty-year-old sobriety drug could become an unexpected ally in preserving the usefulness of modern antifungal medicine.

Subject of Research: Reversal of fluconazole resistance in Candida albicans by disulfiram through Cdr1 efflux pump inhibition and biofilm disruption

Article Title: Disulfiram reverses fluconazole-resistance mediated by Cdr1 in Candida albicans and interferes with biofilm formation

Article References: Rezk, A., Said, H. S., Elfeky, S. M., El-Mowafy, M., & Hassan, R. (2026). Disulfiram reverses fluconazole-resistance mediated by Cdr1 in Candida albicans and interferes with biofilm formation. Applied Microbiology and Biotechnology, 110(1), Article 269. https://doi.org/10.1007/s00253-026-13977-w

Image Credits: AI Generated

DOI: 10.1007/s00253-026-13977-w

Keywords: Candida albicans, fluconazole resistance, disulfiram, Cdr1 efflux pump, drug repurposing, antifungal synergy, biofilm inhibition, ATP-binding cassette transporter, molecular docking, candidiasis, antimicrobial resistance, combination therapy