MicrobiologyOpen[JOURNAL]
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200 papers
Decoding HIV-1 Next Move Through Matrix Protein p17 Quasi-Species.
Messali S, Bertelli A, Giovanetti M … +5 more , Sclavi L, Ciccozzi M, Slevin M, Caruso A, Caccuri F
Microbiologyopen · 2026 Apr · PMID 41932850 · Full text
Since the introduction of combined antiretroviral therapy, acquired immune deficiency syndrome (AIDS)-related lymphomas account for a growing proportion of deaths among people living with human immunodeficiency virus (PL...
Since the introduction of combined antiretroviral therapy, acquired immune deficiency syndrome (AIDS)-related lymphomas account for a growing proportion of deaths among people living with human immunodeficiency virus (PLWHIV). In addition to the immune deficiency caused by AIDS and other cofactors, it has been shown that circulating HIV-1 proteins play a critical role in lymphoma development. The HIV-1 matrix protein p17 (refp17) is released from infected cells and accumulates in lymph nodes of PLWHIV, even during effective pharmacological control of viral replication. Circulating refp17 deregulates the biological activity of different immune cells. Moreover, p17 variants (vp17s) characterized by peculiar amino acid insertions occurring in the C-terminal region of the protein, differently from the refp17, also induce B-cell growth and clonogenicity. Notably, vp17s were found at a significantly higher prevalence in PLWHIV with than without lymphoma. HIV-1 mutants expressing clonogenic vp17s are actively spreading, and their prevalence is globally increasing worldwide. RNA viruses exist as a population of quasi-species, transmitted from one host to another, which ultimately leads to viral evolution by generating new master sequences. Here, we developed a next-generation sequence approach to evaluate the frequency of vp17 quasi-species in PLWHIV upon time and demonstrated that the incidence of vp17s also increases at quasi-species levels. Additionally, we established a regression model capable of predicting the insertions with higher probability to be fixed, further highlighting the evolutionary relevance of the C-terminal region in the adaptation of p17 to the human host.
Meta-Analysis of COVID-19 Cluster Events Suggestive of Long-Distance Airborne Transmission/Inhalation.
Yagi M, Tasaki R, Komano J
Microbiologyopen · 2026 Apr · PMID 41928489 · Full text
SARS-CoV-2 spreads through both contact and airborne routes, the latter encompassing airborne transmission/inhalation as well as the direct deposition of infectious respiratory particles. During the early phase of the CO...
SARS-CoV-2 spreads through both contact and airborne routes, the latter encompassing airborne transmission/inhalation as well as the direct deposition of infectious respiratory particles. During the early phase of the COVID-19 pandemic, numerous cluster events were suspected to involve long-distance airborne transmission/inhalation. We conducted a comparative analysis of these cluster events to characterize outbreak settings and associated clinical parameters. Thirteen cluster events from 2020 attributed to the original SARS-CoV-2 strain were examined, including choral activities, indoor sports, and bus tours. Incubation periods and infection-hospitalization rates (IHRs) were compared across settings and against estimates from large-scale cohort studies that predominantly reflect transmission via direct deposition. Statistical analyses were performed using the Mann-Whitney U test, Student's t-test, and Fisher's exact test (p < 0.05). The mean incubation period in suspected long-distance airborne transmission/inhalation cases was 6.1 ± 3.9 days (median: 5 days; N = 176), with indoor sports and choral events showing significantly shorter incubation periods (p = 0.034). The average IHR was 6.7 ± 12.5%, with significantly higher rates in choral clusters (p = 0.013). Age-adjusted IHRs were lower in long-distance airborne transmission/inhalation-related clusters than those reported from contact-tracing datasets. This analysis provides an integrated evaluation of long-distance airborne transmission/inhalation settings and their associated clinical characteristics. Activities involving vigorous respiration may contribute to shorter incubation periods and higher disease severity, potentially reflecting increased viral inoculum at exposure.
Of Commensals and Opportunists: Genomics of Coagulase-Negative Staphylococci During Sequential Ear and Eye Infections in a Healthy Adult.
Lean SS, Yeo CC, Illyaaseen Z … +4 more , Kaur S, Ngeow YF, Clarke SC, Ng HF
Microbiologyopen · 2026 Apr · PMID 41917802 · Full text
Coagulase-negative staphylococci (CoNS) are ubiquitous skin commensals but can cause opportunistic infections and may serve as reservoirs for mobile genetic elements such as the staphylococcal cassette chromosome mec (SC...
Coagulase-negative staphylococci (CoNS) are ubiquitous skin commensals but can cause opportunistic infections and may serve as reservoirs for mobile genetic elements such as the staphylococcal cassette chromosome mec (SCCmec) associated with healthcare-adapted lineages. In this longitudinal, single-participant case study, we characterized CoNS isolates obtained over time from a healthy 32-year-old male who experienced two infection episodes 6 months apart (left ear, followed by the left eye), together with post-recovery sampling from additional body sites. Six CoNS isolates were recovered, tested for antimicrobial susceptibility and subjected to whole-genome sequencing. Genome-based identification showed that the ear and arm isolates were Staphylococcus capitis (subsp. urealyticus and subsp. capitis), whereas three isolates from the symptomatic left eye were Staphylococcus epidermidis. The three S. capitis isolates belonged to distinct sequence types (ST1, ST2, and ST10), while the three S. epidermidis isolates shared a novel sequence type, ST1284. A non-typable, mosaic SCCmec type IV element homologous to SCCmec IVa/IVn was identified in the multidrug-resistant S. capitis subsp. urealyticus ST1 isolate E_e2, recovered from the infected ear. Core-genome phylogeny and genomic signatures placed E_e2 within the proto-NRCS-A clade, indicating that a lineage closely related to hospital-associated outbreak strains can be encountered in a community-dwelling individual without known prior healthcare exposure. These findings provide a within-host genomic snapshot of CoNS dynamics across contiguous anatomical sites, and while the study does not establish causality for infection or permit population-level inference, it highlights the need for broader, systematic community surveillance of CoNS lineages and their mobile genetic elements.
A Simple and Label-Free Gold Nanoparticle Assay and Duplex PCR for Rapid Detection of Klebsiella pneumoniae K2.
Ahmadi S, Haddadi F, Kamaladini H
Microbiologyopen · 2026 Apr · PMID 41913079 · Full text
Rapid, accurate, and cost-effective diagnostic tools are crucial for the early detection of bacterial pathogens, particularly Klebsiella pneumoniae, a leading cause of multidrug-resistant infections. In this study, we de...
Rapid, accurate, and cost-effective diagnostic tools are crucial for the early detection of bacterial pathogens, particularly Klebsiella pneumoniae, a leading cause of multidrug-resistant infections. In this study, we developed two molecular detection approaches: a simplified, label-free colorimetric assay using unmodified gold nanoparticles (AuNPs) with direct DNA addition, and a duplex PCR assay targeting the K2A and orf10 genes, two key virulence and identification markers of K. pneumoniae. The unmodified AuNP assay, employing a 20 bp K2A gene probe, enabled visible color change detection within 60 min, without the need for complex instrumentation, achieving a sensitivity of 1.56 ng/μL. Duplex PCR successfully amplified fragments of 532 bp (K2A) and 309 bp (orf10), with high sensitivity levels of 1 pg/μL and 0.07 ng/μL, respectively. This integrated strategy offers both visual rapid screening and molecular confirmation in a single workflow, improving diagnostic reliability while maintaining low cost and simplicity. The use of unmodified AuNPs eliminates the need for chemical functionalization, significantly reducing assay preparation time and cost. Together, these features make the proposed method a promising platform for point-of-care molecular diagnostics and epidemiological monitoring of K. pneumoniae in resource-limited settings.
Imported Retail Beef and Chicken Meat Products Serve as Reservoirs for Emerging Antibiotic-Resistant Pathotypes of Escherichia coli in Pristine Areas Free From Agricultural Activity.
Yi S, Alexander KA, Bywater A … +5 more , Dintwe G, Sies AN, Haidl TH, Cameron ADS, Ponder MA
Microbiologyopen · 2026 Apr · PMID 41910070 · Full text
Increasing attention is being directed toward the role of retail meat in introducing pathogens and antibiotic-resistant bacteria into local food supplies. This study characterized the antibiotic resistance (AR) and virul...
Increasing attention is being directed toward the role of retail meat in introducing pathogens and antibiotic-resistant bacteria into local food supplies. This study characterized the antibiotic resistance (AR) and virulence of E. coli isolates from chicken and beef (n = 109) imported for retail sale in Kasane, Botswana. In this relatively pristine environment, commercial beef and chicken production is absent, resulting in reliance on imports, creating concerns that multidrug-resistant (MDR) and pathogenic E. coli may be introduced through the food supply sourced from distant regions. E. coli was isolated from 54.7% of samples (63/109). Antibiotic susceptibility testing against a panel of 12 antibiotics revealed resistance to 11 antibiotics, with multiple combinations of resistance phenotypes identified. Higher levels of MDR were found in chicken isolates (45.5%) compared to beef (13.3%), with the highest resistance rates observed for tetracycline, trimethoprim/sulfamethoxazole, and doxycycline. Genomic analysis of eight MDR isolates revealed diverse sequence types, including diarrheagenic and extraintestinal-associated serotypes. The latter has critical implications in health systems where this clinical presentation may not be investigated with foodborne pathogen exposures. Plasmid-borne AR genes with conjugation-associated genes were detected in most isolates, suggesting that some AR genes may be horizontally transferable by plasmid conjugation. Several isolates clustered with human and chicken isolates from around the globe, highlighting the high potential for retail beef and chicken products to harbor MDR pathogenic E. coli, including emerging pathogens, and to introduce those microbes and associated AR attributes into new ecosystems.
A Pilot Study on the Prevalence and Characterization of Multidrug-Resistant Gram-Negative Bacteria in Chicken and Pork Meat Around Kathmandu District, Nepal.
Paudel S, Tamang S, Singh P … +3 more , Das R, Paudel S, Shakya A
Microbiologyopen · 2026 Apr · PMID 41891294 · Full text
The increasing trend of multidrug resistance in Gram-negative bacteria (MDR-GNB) has been a major concern for the healthcare settings in Nepal and globally. In Nepal, previous studies on antimicrobial resistance (AMR) ha...
The increasing trend of multidrug resistance in Gram-negative bacteria (MDR-GNB) has been a major concern for the healthcare settings in Nepal and globally. In Nepal, previous studies on antimicrobial resistance (AMR) have received limited attention to animal-sourced food, which represents a significant route for the zoonotic transmission of antibiotic-resistant pathogens. This study aimed to assess antibiotic resistance and multidrug resistance patterns of Gram-negative bacteria isolated from intestinal and gizzard samples of chicken and pork meat collected from five municipalities in Kathmandu. From 13 samples (11 chicken and 2 pork), a robust collection of 136 Gram-negative bacteria was isolated and subjected to susceptibility testing against 16 different antibiotics. The bacterial isolates, representing 11 distinct types, were successfully identified: Escherichia coli (33.82%) and Shigella spp. (11.76%) were the predominant bacteria, followed by Yersinia (8.8%), Citrobacter (8.8%), Proteus (8.8%), Klebsiella (5.1%), and Plesiomonas (5.1%), among others. Notably, the prevalence of multidrug-resistant bacteria was notably high, with half (50%) of the isolates exhibiting resistance to multiple classes of antibiotics. Additionally, 73.9% of E. coli, 14.28% of Klebsiella, 58.33% of Yersinia, and 41.67% of Citrobacter are found to be multidrug resistant. Thus, this study showed that the meat samples exhibited a high burden of MDR-GNB, indicating a high risk of food-borne illness and zoonotic transmission, calling for AMR monitoring and mitigation strategies.
Bacillus cereus Induces Necroptosis in Microglia via the RIPK1/3-MLKL Pathway.
Yang J, Sun B, Xu H … +5 more , Shen Y, Ye H, Yuan Q, Chen S, Zheng M
Microbiologyopen · 2026 Apr · PMID 41887200 · Full text
Bacillus cereus endophthalmitis is a rapidly progressing intraocular infection that often results in poor visual outcomes due to extensive retinal damage. Microglia are resident innate immune cells in the brain and retin...
Bacillus cereus endophthalmitis is a rapidly progressing intraocular infection that often results in poor visual outcomes due to extensive retinal damage. Microglia are resident innate immune cells in the brain and retina that play critical roles in neurological and ocular diseases. To investigate the functional role and mechanisms of microglia during B. cereus infection, we established an in vitro microglial infection model using murine BV2 and human HMC3 cells. B. cereus infection reduced microglial viability and induced membrane rupture. Transcriptome analysis revealed enrichment of inflammatory and cell death. Flow cytometric screening identified that the RIPK1 inhibitor Nec-1 rescued cell death. Mechanistically, B. cereus increased phosphorylation of RIPK3 and MLKL, which was abolished by Nec-1. Moreover, Nec-1 suppressed B. cereus-induced secretion of IL-1β, IL-6, and TNF-α. In summary, this study demonstrates that B. cereus induces microglial necroptosis by activating the RIPK3/MLKL pathway, providing a new mechanism for neuroinflammation caused by related infections.
Emerging Antimicrobial Resistance in Klebsiella pneumoniae: A Molecular and Antibiogram Insight From the Beef Value Chain in Bangladesh.
Uddin MS, Fahim FJ, Rana S … +9 more , Kafi AA, Khanam J, Uddin MN, Rahman MM, Noor M, Hossain MM, Rahman MM, Uddin MB, Hossain FMA
Microbiologyopen · 2026 Apr · PMID 41878996 · Full text
Klebsiella pneumoniae is an opportunistic pathogen linked to rising antimicrobial resistance (AMR) globally. To assess the antimicrobial resistance pattern and biofilm-forming ability of K. pneumoniae, a total of 240 sam...
Klebsiella pneumoniae is an opportunistic pathogen linked to rising antimicrobial resistance (AMR) globally. To assess the antimicrobial resistance pattern and biofilm-forming ability of K. pneumoniae, a total of 240 samples were collected from slaughterhouses, open butcher shops, wet market selling points, and high-grade, medium-grade, and poor-grade restaurants in Dhaka City Corporation (DCC) and Gazipur City Corporation (GCC). Among the samples, 132 (55%) samples were positive for K. pneumoniae, with the highest prevalence (60%) in raw beef from GCC. The antibiogram profile depicted diverse resistance patterns with the highest resistance pattern to ampicillin (100%), amoxicillin (100%), and cefoxitin (87.12%). All isolates exhibited a multiple antibiotic resistance index (MARI) value greater than 0.2, indicating contamination from high-risk sources. The antimicrobial resistance encoding genes were bla and bla were 54% and 36%, respectively. Phenotypic characterization, utilizing Congo red agar and microtiter plate tests, identified 25 out of 132 (19%) isolates as biofilm producers, with 7 (28%) classified as strong producers, and 3 (12%) and 15 (60%) as intermediate and weak producers, respectively. This study addresses the alarming emergence of antimicrobial resistance within the beef value chain in Bangladesh, posing an alarming threat to food safety and public health associated with biofilm-producing foodborne pathogens, underscoring the necessity for improved hygiene practices to mitigate the public health risk posed by these pathogens.
NCY-1 β-Lactamase Activity Correlates With Antimicrobial Susceptibility of a Clinical Strain of Nocardia cyriacigeorgica.
Couston J, Le Marchand A, Hodille E … +6 more , Genestet C, Joannard B, Feuillard J, Benito Y, Dumitrescu O, Blaise M
Microbiologyopen · 2026 Apr · PMID 41860015 · Full text
Nocardiosis is an infectious disease caused by several Nocardia species, among which Nocardia cyriacigeorgica is one of the most frequently isolated species in the clinic. Albeit most isolates of this species are suscept...
Nocardiosis is an infectious disease caused by several Nocardia species, among which Nocardia cyriacigeorgica is one of the most frequently isolated species in the clinic. Albeit most isolates of this species are susceptible to standard treatment combining trimethoprim and sulfamethoxazole, resistance has been reported, necessitating alternative or combination therapies. β-lactam antibiotics are of particular interest in this context. In this study, we aimed to address the β-lactam susceptibility profile of a clinical strain of N. cyriacigeorgica and assessed whether it correlated with the enzymatic activity of purified β-lactamase of the strain. We herein established that the strain is highly susceptible to imipenem and ceftriaxone, moderately susceptible to meropenem and resistant to amoxicillin. The resistance could be counteracted by β-lactamase inhibitors from two distinct chemical classes: vaborbactam, and avibactam while clavulanate was less potent. We demonstrated that the β-lactam susceptibility of the strain is in direct line with the enzymatic activity of purified NCY-1, a class A β-lactamase. NCY-1 was indeed only active with amoxicillin but displayed poor activity towards other classes of β-lactams. The NCY-1 activity could be inhibited in vitro by vaborbactam, clavulanate, and avibactam. We consolidated these data by determining the high-resolution structure of NCY-1 bound to avibactam. The structural analysis supported a conserved inhibitor binding site among other Nocardia class A β-lactamases strongly suggesting a broad inhibition spectrum of avibactam across Nocardia species.
Whole-Genome Sequence Profiling of Listeria innocua From Different Sources: Implications for Public Health.
Tchatchouang CK, Ajose DJ, Amagliani G … +1 more , Ateba CN
Microbiologyopen · 2026 Apr · PMID 41858225 · Full text
Foodborne disease outbreaks, particularly those associated with antimicrobial-resistant (AMR) bacterial pathogens, have become an issue of severe public health concern owing to increased globalisation and active food tra...
Foodborne disease outbreaks, particularly those associated with antimicrobial-resistant (AMR) bacterial pathogens, have become an issue of severe public health concern owing to increased globalisation and active food trade among countries. These disease outbreaks include listeriosis, which can cause notable complications such as diarrhoea, headaches, and vomiting. The data generated during the South African foodborne outbreak caused by AMR Listeria monocytogenes led to the inclusion of listeriosis on the South African list of mandatory notifiable medical conditions. Prospective solution to managing the increasing threat caused by AMR foodborne pathogens to humans require frequent surveillance of food products using techniques with high throughput and discriminatory potential. Thus, this study assessed the virulome, resistome, and phylogenetics of two Listeria innocua strains (LIN_NWU_CNKT and LIN5_NWU_CNKT) previously isolated from food and water samples collected in the North-West Province, South Africa, using whole-genome sequencing (WGS). Based on WGS analysis, the isolates were confirmed as L. innocua, with genomes that are closely related to previously isolated human pathogens. The genomes of these two isolates harboured virulence genes, including those responsible for adherence (fbpA, inlJ), invasion (aut, inlA), and immune modulation (inlC, lntA). In addition, the genes encoding antibiotic resistance were found in the genomes. These genes confer resistance to antibiotics such as phosphonic acid (fosX), lincosamide (lin), tetracycline (tetM), and glycopeptide (vanT). These findings highlight a crucial need to enforce standard operating procedures in food processing to reduce the spread of AMR and foodborne outbreaks.
Glutathione Impacts Both Batrachochytrium dendrobatidis Virulence and Amphibian Cellular Defense in a Chytridiomycosis Model.
Webb RJ, Roberts AA, Berger L … +2 more , Robert J, Skerratt LF
Microbiologyopen · 2026 Apr · PMID 41858012 · Full text
Glutathione has important roles in diverse infections, yet its involvement in the interaction between the deadly fungal pathogen Batrachochytrium dendrobatidis (Bd) and its amphibian hosts is still unclear. Using in vitr...
Glutathione has important roles in diverse infections, yet its involvement in the interaction between the deadly fungal pathogen Batrachochytrium dendrobatidis (Bd) and its amphibian hosts is still unclear. Using in vitro assays and a cell infection model, we examined how glutathione influences Bd virulence traits and cellular host disease resistance. For Bd, inhibition of glutathione reductase rapidly killed zoospores, indicating that glutathione is essential for this pathogen. In addition, exposure to exogenous glutathione promoted the potential for virulence through accelerated and increased zoospore release. In host amphibian cells, Bd infection decreased intracellular glutathione content and increased reactive oxygen species, suggesting that chytridiomycosis pathogenesis involves oxidative stress. Depletion of host glutathione before exposure to Bd increased infection severity, whereas amphibian cells with slightly elevated glutathione levels were partially protected against Bd. However, manipulation of host glutathione levels after the establishment of Bd infection did not impact its intracellular growth, implying that the host glutathione-mediated resistance only occurs during the initial Bd invasion process. Importantly, this effect of glutathione on host resistance is not a general response to pathogens, as it was not observed in cells exposed to the viral pathogen FV3. As glutathione increased both infectious zoospore production and host resistance to zoospore infection, our study suggests that this antioxidant may play an important role in the host/pathogen interaction during chytridiomycosis. Thus, environmental conditions and therapeutic approaches that affect glutathione systems in the host and/or pathogen have the potential to alter chytridiomycosis dynamics and should be further explored.
Tn-seq of Thermus thermophilus Genome Reveals Unexpected Tolerance to Insertions in Bacterial Common Essential Genes.
Gómez-Campo CL, Gost M, de Sousa BFS … +4 more , Álvarez L, Berenguer J, Redrejo-Rodríguez M, Mencía M
Microbiologyopen · 2026 Apr · PMID 41853935 · Full text
A large library based on a Tn5 minitransposon carrying a thermostable kanamycin resistance gene was prepared using Thermus thermophilus HB27 genomic DNA as target. To increase the yield of transformants, DNA from the in...
A large library based on a Tn5 minitransposon carrying a thermostable kanamycin resistance gene was prepared using Thermus thermophilus HB27 genomic DNA as target. To increase the yield of transformants, DNA from the in vitro transposition reaction was amplified using isothermal multiple displacement amplification. The resulting product was first transformed into the high-transformation efficiency addAB/ppol strain and then into a wild-type HB27 strain. Tn-seq analysis of the libraries showed that almost all genes contained insertions and the distribution of the number of insertions per gene was unimodal, unlike the bimodal distribution reported in most Tn-seq analyzes, thus hindering the discrimination of required or essential genes. Upon comparing the Tn-seq results with gene conservation in pangenomic analysis from Thermus thermophilus to Deiococcota levels, as well as with available HB27 RNA-seq data, we observed a very low correlation between core genes or gene transcription levels and Tn-seq insertion frequency. Notably, many genes largely deemed part of the essential bacterial core, supporting critical cellular pathways, showed relatively high transposon insertion numbers. In the case of DNA repair routes, which are essential but somewhat redundant, our results align well with previously published essentiality data, indicating that many genes are dispensable and permissive to insertions. The analysis of these striking results in the context of Thermus biology suggests that the polyploidy of the Thermus genome and the differential stability of proteins may explain the apparent non-essentiality of key genes.
Ionomycin Exhibits Potent and Selective Bactericidal Activity Against Clostridioides difficile Through Calcium-Dependent Membrane Disruption.
Abouelkhair AA, Abutaleb NS, Seleem MN
Microbiologyopen · 2026 Apr · PMID 41846263 · Full text
Clostridioides difficile represents a critical global health concern due to its high morbidity, mortality, and recurrent infections associated with current therapeutic options. There is an urgent need for novel, selectiv...
Clostridioides difficile represents a critical global health concern due to its high morbidity, mortality, and recurrent infections associated with current therapeutic options. There is an urgent need for novel, selective anti-C. difficile therapeutic agents. Screening the microbial metabolite library against C. difficile identified ionomycin, a calcium ionophore produced by Streptomyces conglobatus, as a potent inhibitor for C. difficile. Ionomycin exhibited potent activity against 30 C. difficile isolates, with minimum inhibitory concentrations of 1 μg/mL and 2 μg/mL against 50% (MIC) and 90% (MIC) of isolates, respectively. Time-kill assays revealed rapid bactericidal activity, achieving a ≥ 3 log₁₀ reduction within 8 h, surpassing the efficacy of vancomycin and fidaxomicin. At subinhibitory concentrations, ionomycin markedly reduced toxin production (~20%) and spore formation (~3 log CFU/mL). Moreover, ionomycin exerted a potent activity against C. difficile spore germination and significantly prevented the toxin production from the germinating C. difficile cells. Importantly, ionomycin displayed limited activity against representative gut microbiota strains, indicating a favorable selectivity profile. Mechanistic investigations revealed a calcium-dependent mode of action, as exogenous calcium enhanced ionomycin-mediated bactericidal activity, whereas calcium chelation attenuated its effects. Consistent with this mechanism, ionomycin disrupted C. difficile membrane potential, an effect that was further potentiated by calcium supplementation. Collectively, these findings identify ionomycin as a potent and selective anti-C. difficile agent with a distinct calcium-dependent mechanism of action, supporting its potential as a promising therapeutic candidate warranting further investigation.
Quercetin: A Light in the Fight Against MRSA.
Galantini MPL, Gonçalves CV, Novaes AKS … +10 more , Magalhães COL, Muniz IPR, Ribeiro IS, Lima PHB, Flores MES, Carvalho AR, Santos LC, Lopes DS, Amaral JG, Silva RAAD
Microbiologyopen · 2026 Apr · PMID 41841172 · Full text
Antimicrobial photodynamic therapy (aPDT) for treating methicillin-resistant Staphylococcus aureus (MRSA) infections has gained increasing attention in recent years. This study aimed to evaluate the potential of querceti...
Antimicrobial photodynamic therapy (aPDT) for treating methicillin-resistant Staphylococcus aureus (MRSA) infections has gained increasing attention in recent years. This study aimed to evaluate the potential of quercetin as a photosensitizer for aPDT. In vitro assays were conducted to assess the cytotoxicity and the antibacterial activity of quercetin photoactivated with blue LED light. In in vivo assays, and intradermal infection model was conducted in mice to evaluate the quercetin antimicrobial activity and cytokine production. The in vitro experiments showed low compound toxicity and antimicrobial activity accompanied by the generation of singlet oxygen. BALB/c mice infected with MRSA and treated with quercetin exhibited a reduced bacterial load in the draining lymph nodes and decreased recruitment of polymorphonuclear cells at the infection site. In response to infection, a strong interaction between the cytokines IL-12 and TNF-α was observed in the groups treated with quercetin. These observations support quercetin's anti-inflammatory and antimicrobial potential in infections with resistant strains of MRSA.
Farm-Level Factors Associated With Multidrug-Resistant Escherichia coli and Klebsiella spp. in Bulk Tank Milk in Tigray, Northern Ethiopia.
Gebru GG, Muthupandian S, Kassaye E
Microbiologyopen · 2026 Apr · PMID 41839746 · Full text
Raw milk is widely consumed unpasteurized in Ethiopia, posing food safety risks when contaminated with multidrug-resistant (MDR) bacteria. This study investigated farm-level factors associated with the occurrence of MDR...
Raw milk is widely consumed unpasteurized in Ethiopia, posing food safety risks when contaminated with multidrug-resistant (MDR) bacteria. This study investigated farm-level factors associated with the occurrence of MDR Escherichia coli and Klebsiella spp. in bulk tank raw milk from dairy farms in the Tigray region, Northern Ethiopia. A cross-sectional study was conducted among 178 dairy farms, combining microbiological analysis of bulk tank milk with data on farm hygiene, animal health, and antimicrobial use (AMU) practices. A total of 119 isolates (70 E. coli and 49 Klebsiella spp.) were recovered, of which 32.8% were classified as MDR. Multivariable analysis showed that infrequent washing of milking utensils (once daily or less) was strongly associated with MDR-positive milk (adjusted odds ratio [AORs] = 7.41; 95% CI, 1.94-28.31). Self-administration of antimicrobials by farm owners (AOR = 3.73; 95% CI, 1.48-9.39) and a history of mastitis in the herd (AOR = 4.79; 95% CI, 1.39-16.52) were also independently associated with MDR occurrence, while herd size was not significantly associated. The presence of MDR E. coli and Klebsiella spp. in raw milk represents a significant food safety concern in smallholder dairy systems. Targeted interventions focusing on improved milking hygiene, responsible AMU under veterinary supervision, and effective mastitis management are essential to reduce the entry of resistant bacteria into the dairy value chain and limit consumer exposure.
Bridging the Cultivation Gap in Plant Microbiomes: A Comparative Study of Aerial Root Mucilage Microbiome Characterization by Conventional Isolation, Prospector High-Throughput Cultivation, and Molecular Profiling.
De la Vega-Camarillo E, Quattrone AC, Okumoto S … +4 more , Rajan N, Hernández-Rodríguez C, Bernal JS, Antony-Babu S
Microbiologyopen · 2026 Apr · PMID 41833567 · Full text
The "great plate count anomaly" represents a fundamental challenge in microbiome research, with vast microbial diversity remaining uncultivable. We systematically compared three methodological approaches for characterizi...
The "great plate count anomaly" represents a fundamental challenge in microbiome research, with vast microbial diversity remaining uncultivable. We systematically compared three methodological approaches for characterizing plant-associated bacterial communities: conventional plate cultivation, the high-throughput Prospector platform, and full-length 16S rRNA nanopore sequencing. Using mucilage-associated bacteria from teosinte and sorghum as model systems, we evaluated efficiency, taxonomic coverage, and inherent biases. The Prospector platform dramatically outperformed conventional cultivation, achieving 8x to 13.5x improvements in isolate recovery (342 vs. 43 isolates from sorghum; 379 vs. 28 from teosinte) and 1.5x to 1.8x improvements in genus-level detection. While metabarcoding detected 82 total genera, cultivation methods captured only 35.4% of this diversity, with Prospector recovering 16.9%-25.7% compared to 11.3%-14.3% for conventional methods. Each approach exhibited distinct taxonomic biases: conventional plating favored fast-growing taxa (Pseudomonas, Pantoea, Bacillus), Prospector accessed slower-growing bacteria (Sphingomonas, Curtobacterium), while metabarcoding exclusively detected 59-85 cultivation-resistant genera. We propose an integrated framework leveraging complementary strengths: metabarcoding for comprehensive profiling, Prospector for enhanced cultivation efficiency, and conventional isolation for targeted applications. Together, our findings establish quantitative benchmarks for method comparison and support an integrative framework that combines metabarcoding for comprehensive profiling, the Prospector platform for enhanced cultivation efficiency, and conventional isolation for targeted applications, highlighting how methodological choices fundamentally shape our understanding of microbial diversity.
Nasal Carriage Rate of Biofilm Producing Methicillin Resistant Staphylococcus aureus and Its Associated Factors Among Health Care Workers at Hospital of Central Ethiopia.
Mathewos W, Kumalo A, Teklu T … +3 more , Demisse T, Temesgen M, Chinasho T
Microbiologyopen · 2026 Apr · PMID 41833560 · Full text
Not susceptible to methicillin Staphylococcus aureus (MRSA), is a potentially harmful bacteria that is resistant to the most important antimicrobial agents. Because MRSA is so resistant to many antibiotics, it can cause...
Not susceptible to methicillin Staphylococcus aureus (MRSA), is a potentially harmful bacteria that is resistant to the most important antimicrobial agents. Because MRSA is so resistant to many antibiotics, it can cause illnesses by forming biofilms. The aim of this study was to assess the nasal carriage rate of biofilm-producing methicillin-resistant Staphylococcus aureus (MRSA) and its associated factors among HealthCare Workers at Wachemo University Nigist Ellen Mohammed Memorial Comprehensive Specialized Hospital, Central Ethiopia. This cross-sectional study, carried out at Wachemo University Nigist Ellen Mohammed Memorial Comprehensive Specialized Hospital, Central Ethiopia from August 1 to November 30, 2023. Nasal swab samples from 294 healthcare workers (HCWs) were obtained using sterile cotton swabs. Bacterial isolates were identified using standard culture methods on Mannitol Salt and Blood Agar, while antimicrobial susceptibility testing and biofilm formation assessments followed the CLSI 2023 (M100, 33rd edition) guidelines via the Kirby-Bauer disk diffusion methods. All laboratory analyses were performed in triplicate to ensure consistency. Data were double-entered into Epi Data version 4.6 and cross-checked for accuracy. Missing or inconsistent data were verified against original laboratory records and latterly then, exported to SPSS V25 for analysis. Descriptive statistics and logistic regression were applied for statistical evaluation, with a p-value of ≤ 0.05 regarded as statistically significant. In this study, the occurrence rates of S. aureus, MRSA, and biofilm-producing MRSA were 98 out of 294 isolated strains (33.4%), 41 out of 294 isolated strains (13.9%), and 28 out of 294 isolated strains (9.5%), respectively. The MRSA strains exhibited high sensitivity to linezolid, rifampicin, and vancomycin while showing resistance to cefoxitin, cotrimoxazole, and ciprofloxacin. A history of prior hospitalization (length of stay in the hospital) was statistically significant for the colonization of biofilm-producing MRSA, with an adjusted odds ratio of 10.00 (95% CI: 1.36-73.3; P = 0.024). MRSA and MRSA that produces biofilms were found to be 41.8% and 68.3% prevalent overall in the study area, respectively. Biofilm-producing MRSA is a potential cause of healthcare-associated diseases. Therefore, these findings emphasize the urgent need for improved infection-prevention practices and routine screening of healthcare workers to mitigate the risk of healthcare-associated infections.
Sequence-Based and Functional Analysis for the Discovery of N-Glycan Degrading Glycosidases From the Microbial Metagenome of the Infant Gut.
Boscá-Sánchez I, Rodríguez-Díaz J, Yebra MJ
Microbiologyopen · 2026 Apr · PMID 41810553 · Full text
The role of bacterial glycosyl hydrolases (GHs) in degrading free human milk oligosaccharides is well documented. However, their activity on glycoconjugates is less well known. Here, an in silico analysis of the metageno...
The role of bacterial glycosyl hydrolases (GHs) in degrading free human milk oligosaccharides is well documented. However, their activity on glycoconjugates is less well known. Here, an in silico analysis of the metagenome of the fecal microbiome of breastfed infants was employed to identify GH2 β-galactosidases, GH20 exo-N-acetylglucosaminidases and GH18 endo-N-acetylglucosaminidases active on N-glycans. A total of nine β-galactosidases were recombinantly expressed and two of them, Gal1b and Gal99, were able to remove galactose from the G2 peptide and asialofetuin. Gal1b, Gal25, Gal37c, Gal99 and Gal296 hydrolyzed lactose and N-acetyllactosamine, indicating specificity for galactose β1,4-linked to glucose or GlcNAc. All of the exo-β-N-acetylglucosaminidases studied here (Exo10a, Exo18, Exo38, Exo39b, Exo360 and Exo399) hydrolyzed the disaccharide N-acetylglucosaminyl-β1,2-mannose, which forms part of the N-glycan structures. Exo10a, Exo38 and Exo360 hydrolyzed N-acetylglucosamine (GlcNAc) from the G2 peptide pretreated with Gal1b. Notably, Exo360 hydrolyzed GlcNAc at both the α1,3 and α1,6 branches of the G2 peptide core mannose simultaneously, whereas Exo10a showed a preference for GlcNAc at one branch. Exo38 and Exo360 also release GlcNAc from asialofetuin once galactose has been removed. The whole structures of N-glycans were liberated from glycoproteins by the action of the endo-N-acetylglucosaminidases Endo38 and Endo358. These enzymes hydrolyze the N,N'-diacetylchitobiose core of N-linked glycans of the high-mannose and non-sialylated complex types, respectively. Overall, these results provide insight into the range of glycosyl hydrolases present in the infant gut microbiota that act on glycoconjugates, which may play a role in the establishment and composition of the newborn microbiota.
Therapeutic Impact of Caffeic Acid Phenethyl Ester and Acyclovir Combination on Human Gingival Fibroblasts (HGF-1) Infected With Herpes Simplex Type 1 ICP0.
Sen M, Celik S
Microbiologyopen · 2026 Apr · PMID 41808302 · Full text
Herpes simplex virus Type 1 (HSV-1) is a prevalent infectious agent globally, often causing oral infections like gingivostomatitis. The ICP0 protein of HSV-1 exacerbates infection severity by inhibiting antiviral respons...
Herpes simplex virus Type 1 (HSV-1) is a prevalent infectious agent globally, often causing oral infections like gingivostomatitis. The ICP0 protein of HSV-1 exacerbates infection severity by inhibiting antiviral responses. Our study explored how combinations of CAPE (caffeic acid phenethyl ester) and acyclovir influenced immune responses in gingival cells treated with ICP0 We applied ICP0 protein, CAPE, acyclovir, and their combinations to HGF-1 cells for 24 h. IC dose amounts were determined using the MTT cell viability test, gene expressions were assessed by RT-PCR, and protein levels were gauged by the ELISA method. No statistically significant changes were noted between the ICP0 applied groups and the control groups (p > 0.05). However, significant increases were observed in the IFN-β (p < 0.0001), IFN-γ (p < 0.0001), IRF3 (p < 0.0001), β-catenin (p < 0.0001), WNT-1 (p < 0.0001). protein levels of the ICP0 + CAPE applied groups. The increases in all groups administered ICP0 + acyclovir surpassed those administered ICP0 + CAPE (p < 0.0001). The combination of CAPE and acyclovir could potentially reduce both the adverse effects caused by the ICP0 protein and the undesirable side effects that may be caused by the acyclovir used in the treatment. This combination could serve as a potential therapy in the treatment of HSV-1.
Effects of Lactic Acid Bacteria on Fermentation Quality and Microbiome of Leymus chinensis Silage.
Jiang X, He L, Han Z … +4 more , Zong S, Du S, Wu H, Xiao Y
Microbiologyopen · 2026 Apr · PMID 41796087 · Full text
This study investigated the distinct effects of Lentilactobacillus buchneri (LB) and Lactiplantibacillus plantarum (LP) inoculants on the fermentation characteristics and bacterial community succession of Leymus chinensi...
This study investigated the distinct effects of Lentilactobacillus buchneri (LB) and Lactiplantibacillus plantarum (LP) inoculants on the fermentation characteristics and bacterial community succession of Leymus chinensis silage. Treatments included distilled water (CON), LB, and LP, applied at a concentration of 1 × 10 cfu/g of fresh matter (FM). Compared with the CON group, the fermentation quality was improved by the inoculations, the markedly (p < 0.05) lower pH and NH-N were found in the LB and LP treatments. The significantly (p < 0.05) highest LA and AA contents were detected in the LP and LB treatments, respectively. The bacterial diversity, reflected by Shannon and Chao1 indices, decreased throughout the ensiling process, with the LP group exhibiting the most pronounced reduction. Furthermore, beta-diversity analysis revealed distinct microbial community structures among the treatments. While fresh L. chinensis was dominated by Proteobacteria (48.03%), Firmicutes (26.23%), and Actinobacteriota (23.72%), the microbiome shifted dramatically after 60 days of ensiling to be predominantly Firmicutes (94.96%-99.79%), the genus Rhodococcus, Microbacterium, Enterococcus and Leuconostoc, Weissella, and Enterococcus were markedly (p < 0.05) enriched in the CK treatment during fermentation from 3 to 14 days, while from 30 days, the genus Lactobacillus as the dominant genus, especially in the LB and LP treatments. In conclusion, both additives facilitate L. chinensis ensiling by regulating the microbiome, yet L. plantarum demonstrates superior efficacy in optimizing fermentation quality.
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