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Microbiology Research
Volume 17
Issue 3
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Microbiol. Res., Volume 17, Issue 3 (March 2026) – 19 articles

Cover Story (view full-size image): Semi-aquatic turtles are increasingly recognized as potential reservoirs of zoonotic bacteria with relevance to environmental and public health. In this study, Aeromonas spp. isolated from turtles were characterized with respect to their antimicrobial resistance and virulence profiles. The results revealed the presence of strains harboring clinically relevant resistance and virulence traits, thereby highlighting the role of aquatic wildlife in the maintenance and dissemination of potentially pathogenic bacteria. These findings underscore the importance of a One Health approach and the need for the surveillance of aquatic ecosystems to better understand the spread of antimicrobial resistance. View this paper
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13 pages, 445 KB  
Article
Chemical Treatment to Remove or Prevent Salmonella Contamination of Poultry Feed
by Shaun Cawthraw, Andrew Wales, Tom Huby and Rob Davies
Microbiol. Res. 2026, 17(3), 64; https://doi.org/10.3390/microbiolres17030064 - 20 Mar 2026
Viewed by 634
Abstract
Introduction: Salmonella may contaminate livestock feed at several stages of production, transport and storage. Formaldehyde is an effective anti-Salmonella feed treatment, but it is now banned for this use in Europe. Organic acid-based additives are an alternative. Gap Statement: The efficacy of [...] Read more.
Introduction: Salmonella may contaminate livestock feed at several stages of production, transport and storage. Formaldehyde is an effective anti-Salmonella feed treatment, but it is now banned for this use in Europe. Organic acid-based additives are an alternative. Gap Statement: The efficacy of organic acid feed additives against natural Salmonella feed contamination is uncertain due to a paucity of reported work investigating low levels of infection that may be relevant for real-world situations. Aim: To compare the anti-Salmonella effects of feed additives based on formaldehyde versus those based on organic acids. Methodology: Experimental contamination of poultry feed with one of three Salmonella serovars at moderate (between 10 and 200 CFU/g) or low (around 1 CFU/g) levels was preceded (‘prevention’ mode) or followed (‘decontamination’ mode) by application of commercial antimicrobial additives. Storage at room temperature for 24 h was followed by pre-enrichment then culture. Results: Organic acid-based products at recommended application rates only eliminated detectable Salmonella from samples with the lowest degree of contamination. The effect was partial, with a proportion of samples still yielding Salmonella in most experiments, and only one such product showed efficacy above 50% of samples for the decontamination mode. The two formaldehyde-based products showed partial efficacy against moderate contamination, and one was entirely effective against low-level contamination even at its lower inclusion rate. Conclusions: Organic acid-based feed additives have a lesser anti-Salmonella effect than formaldehyde-based products at their respective recommended inclusion rates. However, some non-formaldehyde products may be substantially effective against a low, natural degree of contamination. Impact Statement: Chemical suppression of Salmonella in animal feed is an important element of measures to safeguard livestock health and, consequentially, public health too. The European ban on using formaldehyde for this purpose has necessitated the use of alternative products. The present work includes very low levels of Salmonella in feed, possibly mimicking natural contamination, to show that under these circumstances some such alternatives may be as efficacious as formaldehyde products. Full article
(This article belongs to the Special Issue Zoonotic Bacteria: Infection, Pathogenesis and Drugs—Second Edition)
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20 pages, 1022 KB  
Article
Characterization, Virulent-Determinants, Antimicrobial Resistance, and MALDI-TOF MS Proteomic Profile of Nontyphoidal Salmonella Isolated from Chicken Meat in Fukuoka, Japan
by Khin Zar Linn, Su Zar Chi Lwin, Aye Thida Maung, Marwa Nabil Sayed Abdelaziz, Catherine Damaso Hofilena, Yuzhi Lin, Haomin Ye, Yoshimitsu Masuda, Takahisa Miyamoto and Ken-ichi Honjoh
Microbiol. Res. 2026, 17(3), 63; https://doi.org/10.3390/microbiolres17030063 - 20 Mar 2026
Viewed by 590
Abstract
Nontyphoidal Salmonella (NTS) is a zoonotic pathogen that threatens public health worldwide. This study investigated the prevalence, serotype, virulence, and antimicrobial resistance of NTS isolated from chicken meat in Fukuoka, Japan. Of 50 samples, 64% were positive for Salmonella spp., and 32 NTS [...] Read more.
Nontyphoidal Salmonella (NTS) is a zoonotic pathogen that threatens public health worldwide. This study investigated the prevalence, serotype, virulence, and antimicrobial resistance of NTS isolated from chicken meat in Fukuoka, Japan. Of 50 samples, 64% were positive for Salmonella spp., and 32 NTS strains were isolated from positive samples. Serotyping identified three serotypes: S. enterica ser. Schwarzengrund (78.1%), S. enterica ser. Thompson (15.6%), and S. enterica ser. Oranienburg (6.3%). Multilocus sequence typing revealed three sequence types (STs), and MALDI-TOF MS analysis revealed six distinct clusters, reflecting heterogeneity in protein expression among isolates with the same STs. All isolates harbored the virulence genes hilA, spiC, and ssrB, but not spvC. Microplate assays showed that all S. enterica ser. Schwarzengrund and S. enterica ser. Thompson strains formed biofilms with varying strengths. Antimicrobial susceptibility tests demonstrated that S. enterica ser. Thompson and S. enterica ser. Oranienburg strains were sensitive to all the antimicrobials tested. However, S. enterica ser. Schwarzengrund strains showed resistance to multiple antibiotic classes, and 36% of the isolates were multidrug resistant. These findings suggest a potential public health concern, particularly from S. enterica ser. Schwarzengrund, and underscore the importance of continuous surveillance that integrates both genotypic and phenotypic methods. Full article
(This article belongs to the Topic Multidrug Resistance Across Pathogens: Fungi, Bacteria, Parasites, and Viruses)
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15 pages, 344 KB  
Article
Prevalence and Risk Factors of Anal Human Papillomavirus and Anal–Cervical Concordance Among Women of Eastern Cape Province, South Africa
by Zizipho Z. A. Mbulawa, Laston Gonah, Lindiwe M. Faye and Charles B. Businge
Microbiol. Res. 2026, 17(3), 62; https://doi.org/10.3390/microbiolres17030062 - 20 Mar 2026
Viewed by 732
Abstract
Anal human papillomavirus (HPV) and cancer prevalence are increasing. Therefore, this study investigated the prevalence of anal HPV and associated risk factors, as well as HPV genotype-specific concordance at cervical and anal sites and associated risk factors among women of Eastern Cape Province, [...] Read more.
Anal human papillomavirus (HPV) and cancer prevalence are increasing. Therefore, this study investigated the prevalence of anal HPV and associated risk factors, as well as HPV genotype-specific concordance at cervical and anal sites and associated risk factors among women of Eastern Cape Province, South Africa. A total of 326 women aged 18–60 were recruited from an Eastern Cape community health facility. HPV DNA was detected in cervical and anal specimens using the Seegene Anyplex™ and Allplex™ II HPV28 assay (Seegene Inc., Seoul, Republic of Korea), respectively. Anal HPV was detected in 68.1% (95% CI: 62.9–72.9) and independent predictors were cervical HPV positivity (AOR: 2.40, 95% CI: 1.39–4.14, p = 0.002), abnormal cytology (AOR: 3.12, 95% CI: 1.29–7.55, p = 0.012), single marital status (AOR: 3.55, 95% CI: 1.24–10.17, p = 0.018), and having more than three lifetime sexual partners (AOR: 1.75, 95% CI: 1.03–2.98, p = 0.039). Anal high risk (HR)-HPV types were detected in 50.9%, with HPV-58 (13.2%), HPV-68 (11.0%) and HPV-52 (9.2%) being the most dominant types. HPV genotype-specific cervical and anal concordance was observed in 33.5% of cases, with HPV-58 (7.1%), HPV-68 (4.9%), and HPV-35 (4.6%) being the most dominant. Women who were positive for cervical HPV infection (AOR: 3.24, 95% CI: 2.36–4.45, p < 0.001), anal HPV infection (AOR: 2.70, 95% CI: 2.01–3.63, p < 0.001) and abnormal cervical cytology (AOR: 2.01, 95% CI: 1.36–2.96, p < 0.001) had substantially higher odds of anal–cervical HPV concordance compared to those who were negative. High anal HPV prevalence and HPV genotype-specific anal and cervical concordance were observed among Eastern Cape women. Understanding anal HPV, HPV genotype-specific anal–cervical concordance, and associated factors can contribute to strategies towards anal HPV and associated disease prevention. These findings warrant further longitudinal investigation in future studies. Full article
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12 pages, 3527 KB  
Case Report
Dermatofibrosarcoma Protuberans in a Patient Living with Human Immunodeficiency Virus Infection
by Vincenzo Verdura, Pasquale Bisceglia, Luigi Annacontini, Luigi Cagiano, Francesca Sanguedolce, Martina Miracapillo, Fabrizia Fusco, Sergio Lo Caputo, Francesco Drago, Gaetano Serviddio, Aurelio Portincasa and Giulia Ciccarese
Microbiol. Res. 2026, 17(3), 61; https://doi.org/10.3390/microbiolres17030061 - 19 Mar 2026
Viewed by 462
Abstract
Dermatofibrosarcoma protuberans (DFSP) is a rare tumor presenting as a slow-growing, plaque-like or multinodular, brownish lesion on the trunk in adult patients. Diagnosis is established by histological examination and surgical excision is the primary treatment. Typically, DFSP has an indolent course and local [...] Read more.
Dermatofibrosarcoma protuberans (DFSP) is a rare tumor presenting as a slow-growing, plaque-like or multinodular, brownish lesion on the trunk in adult patients. Diagnosis is established by histological examination and surgical excision is the primary treatment. Typically, DFSP has an indolent course and local spread. In the present work, we describe the clinical–histologic features, surgical treatment and follow-up of a case of DFSP in a patient living with HIV infection (PLWH). A 40-year-old man was referred to us with confluent lesions on the left shoulder, present for about 3 years. His medical history was positive for HIV-1 infection, for which he was taking antiretroviral therapy. Microscopic examination showed dermal and hypodermic proliferation of spindle cells in a storiform pattern, confirming the clinical diagnosis of DFSP. A wide excision was performed with 3 cm clinically healthy tissue margins, and the defect was repaired using an artificial bilaminar dermal matrix. The histological examination revealed tumor-free margins, and a split-thickness skin graft was harvested from the same arm. After 10 months, the patient was free from the disease. As observed with other skin cancers, DFSP may have a higher incidence and greater aggressiveness in immunosuppressed than in immunocompetent patients. DFSP has been reported only twice in PLWH. Our case constitutes a third report, adding to the evidence that there may be an over-representation of this cancer in immunosuppressed individuals. Full article
(This article belongs to the Special Issue Host–Microbe Interactions in Health and Disease)
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13 pages, 1867 KB  
Article
Screening and Culture Condition Optimization of a Catalpol-Producing Brevundimonas olei
by Jianmin Liu, Mingliang Geng, Yi Chen and Zhenhui Wang
Microbiol. Res. 2026, 17(3), 60; https://doi.org/10.3390/microbiolres17030060 - 19 Mar 2026
Viewed by 383
Abstract
Catalpol, one of the primary bioactive components in Rehmannia glutinosa, is an iridoid glycoside with significant pharmacological activities. To expand the microbial sources of catalpol, endophytic bacteria were isolated from R. glutinosa (cultivated in Jiaozuo, China) using the dilution plating method combined [...] Read more.
Catalpol, one of the primary bioactive components in Rehmannia glutinosa, is an iridoid glycoside with significant pharmacological activities. To expand the microbial sources of catalpol, endophytic bacteria were isolated from R. glutinosa (cultivated in Jiaozuo, China) using the dilution plating method combined with vanillin–sulfuric acid colorimetric assay. High-performance liquid chromatography (HPLC) and liquid chromatography–mass spectrometry (LC-MS) were employed for screening and identification. The isolated strain was identified through morphological characterization and 16S rDNA gene sequence analysis, while single-factor experiments coupled with response surface methodology were utilized to optimize its fermentation conditions. Results indicated that the strain DH14 formed circular, cream-white, opaque colonies and was Gram-negative. It was identified as Brevundimonas olei. The optimal fermentation conditions were determined to be 190 rpm, pH 7.6, 31 °C, and 0% NaCl. Meanwhile, the results revealed a positive correlation between the pH of the fermentation broth and catalpol production. Under the optimized conditions, the maximum catalpol yield reached 0.142 mg/mL after 3 days of cultivation. This study provides a promising microbial resource and optimized fermentation parameters for the microbial production of catalpol. Full article
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9 pages, 1619 KB  
Communication
Protective Effects of Laktera Nature Probiotic in Experimentally Induced Gastric Ulcers in Rats
by Kaloyan D. Georgiev, Deyan Dzhenkov, Marieta Georgieva and Antoaneta Tsvetkova
Microbiol. Res. 2026, 17(3), 59; https://doi.org/10.3390/microbiolres17030059 - 17 Mar 2026
Viewed by 1231
Abstract
Probiotics are live microorganisms that, when administered in adequate amounts, confer health benefits to the host. The present study aimed to evaluate the protective effects of a probiotic against experimentally induced gastric ulcers in rats. Male Wistar rats were allocated into five groups [...] Read more.
Probiotics are live microorganisms that, when administered in adequate amounts, confer health benefits to the host. The present study aimed to evaluate the protective effects of a probiotic against experimentally induced gastric ulcers in rats. Male Wistar rats were allocated into five groups (n = 6 per group): Control, Model (indomethacin-induced ulcers, IND), Positive control (IND + famotidine), IND + Laktera Nature (LN) probiotic (800 mg/kg), and IND + LN probiotic (1600 mg/kg). The study duration was 14 days. On day 15, rats in groups 2–5 received 1 mL of indomethacin (40 mg/kg) orally. All rats were euthanized four hours later via cervical dislocation under diethyl ether anesthesia. LN probiotics have demonstrated dose-dependent protection against indomethacin-induced gastric ulcers, as assessed by both macroscopic and microscopic evaluation. Therefore, LN probiotics may represent a valuable adjunctive strategy in the management of gastric ulcers. Full article
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15 pages, 7308 KB  
Article
Computational Insights into the Linker-Dependent Binding of Trehalose–Porphyrin Conjugates to Antigen 85B of Mycobacterium tuberculosis
by Christopher T. Piatnichouk, Joshua V. Ruppel and Nicole L. Snyder
Microbiol. Res. 2026, 17(3), 58; https://doi.org/10.3390/microbiolres17030058 - 9 Mar 2026
Viewed by 487
Abstract
Tuberculosis, caused by Mycobacterium tuberculosis, remains a global health challenge, particularly due to multidrug-resistant strains. Photodynamic therapy using porphyrin-based photosensitizers offers a promising alternative by targeting the trehalose-rich cell wall of the bacillus. Motivated by prior experimental observations that shorter linkers improve [...] Read more.
Tuberculosis, caused by Mycobacterium tuberculosis, remains a global health challenge, particularly due to multidrug-resistant strains. Photodynamic therapy using porphyrin-based photosensitizers offers a promising alternative by targeting the trehalose-rich cell wall of the bacillus. Motivated by prior experimental observations that shorter linkers improve efficacy, this study probes the molecular basis of linker-length-dependent activity in trehalose–porphyrin glycoconjugates. Here, we show that shorter linker lengths are consistent with improved activity in vitro and, in an Ag85B docking model, constrain conformational flexibility, reduce solvent exposure, and promote tighter packing consistent with stronger predicted interactions. Using computational docking, we analyzed binding scores, RMSD variability, steric clashes, and protein–ligand interactions for conjugates docked into Ag85B, a key enzyme in cell wall synthesis. Shorter linkers (0–2 carbons) were found to exhibit superior binding scores, lower RMSD variability, and stronger interactions with residues such as ARG 43, including unique π–cation interactions. In contrast, longer linkers displayed increased flexibility, reduced binding specificity, and greater solvent exposure. These findings, which support our experimental observations, suggest a molecular basis for linker-dependent efficacy and provide a framework for designing next-generation porphyrin-based therapeutics for tuberculosis treatment. Full article
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32 pages, 3225 KB  
Review
Life with Boron: Microbial Boron-Binding Siderophores, Adaptation, and Function
by Valery M. Dembitsky, Alexander O. Terent’ev and Sergey V. Baranin
Microbiol. Res. 2026, 17(3), 57; https://doi.org/10.3390/microbiolres17030057 - 9 Mar 2026
Cited by 4 | Viewed by 979
Abstract
Siderophores are classically understood as microbial iron-acquisition metabolites: low-molecular-weight ligands secreted by bacteria to solubilize and transport Fe(III) under iron-limited conditions. In this review, we expand that paradigm by highlighting an emerging and underappreciated chemical axis—boron coordination by siderophores—that links terrestrial (soil/rhizosphere) and [...] Read more.
Siderophores are classically understood as microbial iron-acquisition metabolites: low-molecular-weight ligands secreted by bacteria to solubilize and transport Fe(III) under iron-limited conditions. In this review, we expand that paradigm by highlighting an emerging and underappreciated chemical axis—boron coordination by siderophores—that links terrestrial (soil/rhizosphere) and marine microbiomes. Across diverse bacterial taxa, siderophore production is widespread and central to competitive fitness because Fe(III) is poorly soluble and frequently sequestered in environmental or host matrices. Yet in boron-rich settings (seawater and borate-enriched soils), the same oxygen-donor architectures that support Fe(III) chelation can also engage boron chemistry. We synthesize evidence that carboxylate/α-hydroxyacid (dicitrate-type) and catecholate siderophores can form tetrahedral borate/boronate complexes, whereas hydroxamate siderophores generally lack the vicinal dianionic O,O motif required for stable boron binding. Structurally characterized examples—including vibrioferrin, rhizoferrin, and petrobactin—demonstrate that boron complexation is experimentally observable by ESI-MS and multinuclear NMR and can be modulated by pH and microenvironment. Integrating these findings with datasets on boron-tolerant bacteria, we propose that when iron is scarce and boron is available, boron–siderophore complexation becomes chemically feasible and may influence microbial physiology by altering ligand conformation, metal selectivity, and potentially extracellular signaling behavior—especially in marine systems where borate is abundant at oceanic pH. Overall, this review frames boron-binding siderophores as a cross-ecosystem phenomenon and a promising conceptual bridge between environmental boron geochemistry, microbial metal economy, and metalloid-mediated signaling. Full article
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14 pages, 950 KB  
Article
Semi-Aquatic Turtles as Potential Reservoirs for Resistant and Virulent Aeromonas spp.
by Gonçalo Melo, Raquel Abreu, Gonçalo Pereira, Eva Cunha, Lélia Chambel, Luís Tavares and Manuela Oliveira
Microbiol. Res. 2026, 17(3), 56; https://doi.org/10.3390/microbiolres17030056 - 5 Mar 2026
Viewed by 633
Abstract
Semi-aquatic turtles are popular companion animals and represent an important One Health interface in Portugal due to their potential to harbour zoonotic pathogens. This study aimed to characterize the virulence and antimicrobial resistance (AMR) profiles of Aeromonas spp. isolated from captive semi-aquatic turtles [...] Read more.
Semi-aquatic turtles are popular companion animals and represent an important One Health interface in Portugal due to their potential to harbour zoonotic pathogens. This study aimed to characterize the virulence and antimicrobial resistance (AMR) profiles of Aeromonas spp. isolated from captive semi-aquatic turtles in Portugal. Cloacal swabs (n = 31) were collected from turtles under human care, and Aeromonas spp. were isolated using selective media and identified by multiplex PCR. Antimicrobial susceptibility was assessed by disk diffusion using eleven antibiotics, while the phenotypic virulence profile was evaluated by determining isolates’ ability to express five hydrolytic enzymes and to form biofilm. A total of 86 Aeromonas isolates were recovered, with A. hydrophila being the most prevalent (77.9%). Most isolates displayed high pathogenic potential: over 87% produced DNase, haemolysin, and lecithinase, while nearly all produced protease and gelatinase. Also, 44.2% of the isolates were resistant to at least one antibiotic, and 12 (14.0%) were multidrug resistant. Higher Multiple Antibiotic Resistance (MAR) indices were significantly associated with turtles housed in indoor aquariums (p < 0.05). These findings indicate that captive semi-aquatic turtles may act as reservoirs of virulent and antimicrobial-resistant Aeromonas spp., highlighting potential zoonotic risks and supporting the need for a One Health approach in their management. Full article
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16 pages, 618 KB  
Review
Navigating the Gut–Prostate Axis: The Gut Microbiome in Prostate Cancer Resistance and Targeted Interventions
by Zeyu Ai, Ping Dai, Kangnan He, Ruilong Nie, Shimin Zou and Liang Chen
Microbiol. Res. 2026, 17(3), 55; https://doi.org/10.3390/microbiolres17030055 - 5 Mar 2026
Viewed by 993
Abstract
In recent years, the gut microbiome has been increasingly recognized as an important factor in regulating treatment responses and disease progression in prostate cancer (PCa). We synthesized literature published over the past five years, focusing on preclinical and clinical studies linking the microbiome [...] Read more.
In recent years, the gut microbiome has been increasingly recognized as an important factor in regulating treatment responses and disease progression in prostate cancer (PCa). We synthesized literature published over the past five years, focusing on preclinical and clinical studies linking the microbiome to PCa treatment outcomes. There is accumulating evidence that gut microbiota dysbiosis and its associated metabolites can modulate key biological processes, such as androgen metabolism, inflammatory signaling pathways, and antitumor immune responses. These processes affect the sensitivity of PCa patients to androgen deprivation therapy (ADT) and other systemic treatments. The available evidence suggests that the gut microbiome has the potential to serve as a predictive biomarker for treatment response and could represent a novel target for interventional precision therapy in PCa. This narrative review summarizes the latest research on the “gut–prostate axis”, focusing on the role of the gut microbiome in regulating therapeutic responses in PCa and the underlying mechanisms. Finally, we address current limitations, including the predominance of preclinical evidence, methodological heterogeneity, and the critical need for longitudinal clinical validation to distinguish causality from association. Full article
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1 pages, 597 KB  
Correction
Correction: Reyes-Estebanez, M.; Mendoza-de Gives, P. The Genus Clonostachys (Bionectria) as a Potential Tool Against Agricultural Pest and Other Biotechnological Applications: A Review. Microbiol. Res. 2025, 16, 86
by Manuela Reyes-Estebanez and Pedro Mendoza-de Gives
Microbiol. Res. 2026, 17(3), 54; https://doi.org/10.3390/microbiolres17030054 - 4 Mar 2026
Viewed by 286
Abstract
In the original publication [...] Full article
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12 pages, 1823 KB  
Brief Report
Functional Characterization of CfRgs2 Reveals Its Critical Role in Growth, Conidiation, Stress Response, and Virulence of Colletotrichum fructicola
by Yadi Liu, Qiuyue Hu and He Li
Microbiol. Res. 2026, 17(3), 53; https://doi.org/10.3390/microbiolres17030053 - 2 Mar 2026
Viewed by 361
Abstract
Colletotrichum fructicola is the predominant pathogenic agent responsible for anthracnose in Camellia oleifera. RGS2 is a GTPase-activating protein that negatively regulates G-protein signaling by inactivating Gα subunits. In this study, we characterized the ortholog of CfRGS2 in C. fructicola to explore its [...] Read more.
Colletotrichum fructicola is the predominant pathogenic agent responsible for anthracnose in Camellia oleifera. RGS2 is a GTPase-activating protein that negatively regulates G-protein signaling by inactivating Gα subunits. In this study, we characterized the ortholog of CfRGS2 in C. fructicola to explore its pathogenic roles. Seven canonical RGS genes were identified through BLASTp and keyword searches. Conserved domains and subcellular localizations were predicted bioinformatically. A CfRGS2 knockout mutant was generated via overlap-PCR and PEG-mediated transformation, verified by PCR, and complemented by reintroducing the wild-type gene. Phenotypic characterization showed that the growth rates of mutants ΔCfrgs2-1 and ΔCfrgs2-2 were significantly reduced compared with those of the wild-type and complemented strains. On both PDA and minimal medium, the mutant strains exhibited significantly smaller colony diameters of 3.3 cm and 3.1 cm, respectively, relative to the control strains. Moreover, conidiation in the mutants was only 4% of that in the wild-type and complemented strains, and appressorium formation was reduced to 6%, with statistical analyses confirming high significance. Under cell wall stress induced by 400 μg/mL Congo red, the growth inhibition rates of ΔCfrgs2-1 and ΔCfrgs2-2 were 44% and 48%, respectively, significantly higher than those of the control strains. Pathogenicity assays demonstrated that the mutants failed to induce lesions on unwounded leaves and caused 47% and 30% smaller lesion areas on wounded apple fruits, respectively. In summary, C. fructicola possesses seven canonical RGS proteins that regulate G-protein signaling, among which CfRgs2 is implicated in growth, conidiation, the stress response to cell wall perturbation, and virulence. Full article
(This article belongs to the Special Issue Advances in Plant–Pathogen Interactions)
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33 pages, 1836 KB  
Systematic Review
Antimicrobial Effects of Quebrachitol: A Systematic Review
by Doris Evelyn Yah Hui Jong, Siang Yin Lee, Yun Khoon Liew, Phyu Synn Oo, Amar Harris Arifin, Zi Ni Ngai, Beek Yoke Chin, Shamala Salvamani and Rhun Yian Koh
Microbiol. Res. 2026, 17(3), 52; https://doi.org/10.3390/microbiolres17030052 - 27 Feb 2026
Cited by 1 | Viewed by 819 | Correction
Abstract
Quebrachitol, an optically active cyclitol derived from plants, has recently gained attention as a potential natural product with therapeutic properties, though its antimicrobial effects remain unclear. This systematic review aims to determine, appraise, and consolidate evidence of the antimicrobial potential of quebrachitol. PRISMA-guided [...] Read more.
Quebrachitol, an optically active cyclitol derived from plants, has recently gained attention as a potential natural product with therapeutic properties, though its antimicrobial effects remain unclear. This systematic review aims to determine, appraise, and consolidate evidence of the antimicrobial potential of quebrachitol. PRISMA-guided searches of PubMed, Scopus, and Google Scholar (2000–2024) identified English-language experimental in vitro, in vivo, and in ovo studies. Data on antimicrobial activity, dosage or treatment duration, and mechanisms were extracted, with study quality assessed using QUIN and SYRCLE tools. Of 866 studies screened, 11 met inclusion criteria: seven in vitro, one in vivo, one in ovo, and two combining both approaches. Quebrachitol demonstrated inhibitory effects against Salmonella sp., Candida albicans, infectious bursal disease virus (Avibirnavirus gumboroense), Newcastle disease virus, Plasmodium sp., and notably, biofilm formation by Staphylococcus epidermidis and methicillin-resistant Staphylococcus aureus (MRSA). Overall, quebrachitol exhibits promising antimicrobial potential, but rigorous in vivo studies are required to confirm its efficacy and safety in addressing antimicrobial resistance. Full article
(This article belongs to the Topic Multidrug Resistance Across Pathogens: Fungi, Bacteria, Parasites, and Viruses)
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23 pages, 1813 KB  
Article
Shifts in Straw-Associated Functional Microbiomes Under Long-Term Soil Management
by Alexandra Gheorghiță, Anca Pleșa, Bianca Pop, Vlad Stoian and Roxana Vidican
Microbiol. Res. 2026, 17(3), 51; https://doi.org/10.3390/microbiolres17030051 - 27 Feb 2026
Viewed by 509
Abstract
Long-term soil fertility is governed by the metabolic plasticity of microbial communities, particularly during the decomposition of crop residues. This study investigated the straw-associated functional microbial profile associated with straw decomposition under the influence of 62 years of continuous management with mineral fertilization [...] Read more.
Long-term soil fertility is governed by the metabolic plasticity of microbial communities, particularly during the decomposition of crop residues. This study investigated the straw-associated functional microbial profile associated with straw decomposition under the influence of 62 years of continuous management with mineral fertilization and liming. Using the Biolog EcoPlateTM approach combined with a modified litter-bag protocol, we assessed shifts in metabolic activity patterns of functional guilds and groups. PERMANOVA results revealed that the interaction between liming and fertilization (p < 0.05) was the primary driver of divergence in functional communities, rather than the individual effect of factors. Long-term treatments induced a significant reconfiguration of the functional niche, shifting from the native, generalist microbiome to specialized communities in treated variants, with carbohydrate (CH) guilds as dominant and indicators of community performance. Moderate levels of liming (L1) stimulated metabolic activity and maintained higher functional diversity across amino acid (AA) and polymers (Px) guilds. Intensive liming (L2), in contrast, restricted the activity of most microbial functional groups and favored amine (AM) and carboxylic acid (CX) guilds. Shifts from a generalist microbiome in native soil to specialized communities in treated soils show the capacity of microorganisms to adapt efficiently under agronomic management. Full article
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14 pages, 1647 KB  
Article
Effect of Pregnancy Gingivitis on Maternal Saliva Microbiota
by Ana K. Rocha-Viggiano, Saray Aranda-Romo, Edgar R. Rocha-Lara, Karla G. López-Macías, Sergio Casas-Flores, Nicolás Gómez-Hernández, Daniel E. Noyola, Cesaré Ovando-Vázquez and Mariana Salgado-Bustamante
Microbiol. Res. 2026, 17(3), 50; https://doi.org/10.3390/microbiolres17030050 - 26 Feb 2026
Cited by 1 | Viewed by 646
Abstract
Pregnant women undergo a myriad of physiological changes, including important hormonal variations. Pregnancy gingivitis is a condition that affects up to 30% to 100% of women, is related to hormonal modifications, and could play an important role in gestational gut colonization and immunological [...] Read more.
Pregnant women undergo a myriad of physiological changes, including important hormonal variations. Pregnancy gingivitis is a condition that affects up to 30% to 100% of women, is related to hormonal modifications, and could play an important role in gestational gut colonization and immunological training of the newborn. Nonetheless, oral health is not always included in routine prenatal care. In this study, we collected saliva samples of pregnant women with and without pregnancy gingivitis and analyzed the oral microbiota through 16S sequencing. In addition, meconium samples from the infants of participating women were analyzed. The oral microbiota of pregnant women with and without pregnancy gingivitis did not show significant differences in diversity. However, significant differences in microbiome composition were observed. Pathway analysis showed that, despite taxonomic similarity, the PG group had activated energy metabolism, bacterial growth, lipid metabolism, and virulence pathways with NOD-like receptor activation, indicating pro-inflammatory microbial activity. In contrast, the NPG group exhibited central metabolism and repair mechanisms, suggesting that PG could affect microbiome function rather than composition. In addition, it appears that the microbiome composition of offspring of mothers with gingivitis also differs from that of offspring from mothers without gingivitis, although the number of available samples did not allow for definite conclusions. As such, a larger cohort and deeper sequencing methods are needed to assess the oral microbiota of pregnant women with and without gingivitis and to explore the possibility of bacterial translocation from the maternal gingiva to the fetal gut. Full article
(This article belongs to the Special Issue Host–Microbe Interactions in Health and Disease)
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28 pages, 2221 KB  
Article
Phenotypic Characterization of Phosphofructokinase Variants in Escherichia coli
by Hemshikha Rajpurohit and Mark A. Eiteman
Microbiol. Res. 2026, 17(3), 49; https://doi.org/10.3390/microbiolres17030049 - 26 Feb 2026
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Abstract
Phosphofructokinase 1 (PfkA) mediates the ATP-dependent phosphorylation of fructose-6-phosphate and is a key, controlling enzyme in glycolysis for Escherichia coli and other organisms. In this study, 22 chromosomally expressed PfkA variants were constructed in E. coli C. These variants, the wild-type strain, and [...] Read more.
Phosphofructokinase 1 (PfkA) mediates the ATP-dependent phosphorylation of fructose-6-phosphate and is a key, controlling enzyme in glycolysis for Escherichia coli and other organisms. In this study, 22 chromosomally expressed PfkA variants were constructed in E. coli C. These variants, the wild-type strain, and the ∆pfkA strain were compared for growth rates using glucose as the sole carbon source. The majority of variants (14 of 22) attained a growth rate less than 20% of the growth rate of the wild-type strain (0.94 h−1) and thus similar to the knockout strain (0.12 h−1). Three variants (R171S, F76Y, and R77A), representing a range of growth phenotypes, and strains expressing the wild-type PfkA and the ∆pfkA deletion strain were additionally examined for key intracellular metabolites and gene expression under nitrogen-limited steady-state conditions. These five strains could be distinguished by two groupings: strains with relatively high growth rates under batch conditions (wild-type and R77A variant) showed the greatest glucose consumption rate and formed acetate, whereas strains with low growth rates (F76Y, R77A, and ∆pfkA) exhibited low glucose consumption and did not accumulate acetate. As the PfkA mutation severity increased, the intracellular concentrations of acetyl-CoA and fructose-1,6-bisphosphate and the sum of dihydroxyacetone and glyceraldehyde-3-phosphate greatly decreased. Although the mutation severity had a limited effect on the expression of maeB and icd genes expressing malic enzyme and isocitrate dehydrogenase, it correlated with reduced expression of zwf and pta genes expressing glucose-6P-dehydrogenase and phosphotransacetylase, respectively. The results highlight the great sensitivity of the enzyme to substitutions and the key role it plays in controlling glycolytic flux. Full article
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22 pages, 3513 KB  
Article
Evaluation of a Bivalent Hexon-L1 and Fiber-2 Subunit Vaccine Candidate Against Homologous Fowl Adenovirus Serotype 4 Challenge in Chickens
by Xiaoran Chu, Kaili Wang, Vincenzo Cuteri, Cheng Liu, Yubao Li and Zhenshu Si
Microbiol. Res. 2026, 17(3), 48; https://doi.org/10.3390/microbiolres17030048 - 26 Feb 2026
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Abstract
Fowl adenovirus serotype 4 (FAdV-4) is the major causative agent of hydropericardium-hepatitis syndrome (HHS), a disease responsible for considerable economic losses in poultry production. Although inactivated and live-attenuated vaccines reduce mortality, continued outbreaks highlight the need to optimize vaccination strategies. To address these [...] Read more.
Fowl adenovirus serotype 4 (FAdV-4) is the major causative agent of hydropericardium-hepatitis syndrome (HHS), a disease responsible for considerable economic losses in poultry production. Although inactivated and live-attenuated vaccines reduce mortality, continued outbreaks highlight the need to optimize vaccination strategies. To address these limitations, we developed and evaluated a bivalent subunit vaccine composed of recombinant hexon-L1 and fiber-2 proteins, two major antigenic determinants associated with neutralization and pathogenicity. The proteins were expressed in Escherichia coli, purified under native conditions, confirmed for purity and antigenicity, and emulsified into a water-in-oil formulation. Chickens were immunized with either 10 μg or 20 μg doses, boosted after 14 days, and challenged with the homologous virulent FAdV-4 strain SDLC202009. The 20 μg dose conferred complete survival, eliminated histopathological lesions, prevented viral detection in tissues by PCR and immunohistochemistry, and fully blocked viral shedding. Similarly, the 10 μg dose induced a good protection with only minor pathological differences compared to the group treated with 20 μg. These results demonstrate that a bivalent hexon-L1 and fiber-2 subunit formulation elicits strong, dose-dependent humoral and tissue-level protection against homologous FAdV-4 challenge under the conditions tested. The experimental design did not include a monovalent fiber-2 comparator; therefore, conclusions regarding the relative contribution of each antigen are not drawn. Full article
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16 pages, 3433 KB  
Article
Molecular Biodiversity and De Novo Transcriptomic Analysis of Boletus griseipurpureus: Investigating Associated Genes During Symbiosis with Specific Hosts
by Alisa Nakkaew and Kotchakorn Praopring
Microbiol. Res. 2026, 17(3), 47; https://doi.org/10.3390/microbiolres17030047 - 25 Feb 2026
Viewed by 425
Abstract
Boletus griseipurpureus is an ectomycorrhizal mushroom characterized by a bitter flavor. In this study, specimens were collected from three host plants—Acacia auriculiformis (BgAa), Melaleuca cajuputi (BgMc), and Eucalyptus camaldulensis (BgEc)—and initially classified based on pileus morphology. Molecular biodiversity was investigated using internal [...] Read more.
Boletus griseipurpureus is an ectomycorrhizal mushroom characterized by a bitter flavor. In this study, specimens were collected from three host plants—Acacia auriculiformis (BgAa), Melaleuca cajuputi (BgMc), and Eucalyptus camaldulensis (BgEc)—and initially classified based on pileus morphology. Molecular biodiversity was investigated using internal transcribed spacer (ITS) DNA barcoding, and comprehensive phylogenetic analysis revealed that B. griseipurpureus populations in southern Thailand clustered according to their symbiotic host species. De novo transcriptome assembly of B. griseipurpureus associated with different hosts was performed to generate unigene datasets, followed by functional gene annotation. A total of 1157 differentially expressed genes (DEGs) were identified and linked to ectomycorrhizal symbiosis. The genes involved in biosynthesis and metabolic processes exhibited host-dependent expression patterns. Furthermore, expression profiles of five selected genes—major facilitator superfamily (MFS) substrate transporter, phosphatase II, hexose transporter, terpenoid synthase, and fungal hydrophobin—were consistent between DEG analysis and semi-quantitative RT-PCR validation. These findings suggest that these genes play important roles in ectomycorrhizal symbiosis and the biosynthesis of bioactive compounds in B. griseipurpureus, with expression influenced by host association. This study provides valuable insights into the molecular biodiversity and gene regulation underlying ectomycorrhizal symbiosis, contributing to a better understanding of the biological processes in B. griseipurpureus. Full article
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17 pages, 1063 KB  
Article
Isolation and Molecular Identification of Potential Myo-Inositol-Utilizing Bacteria from the Gastrointestinal Tract of Laying Hens
by Harshita Naithani, Amélia Camarinha-Silva, Thilo M. Fuchs and Jana Seifert
Microbiol. Res. 2026, 17(3), 46; https://doi.org/10.3390/microbiolres17030046 - 25 Feb 2026
Cited by 1 | Viewed by 924
Abstract
Myo-inositol (MI) is an essential dietary polyol involved in host metabolism. However, the identity and diversity of MI-utilizing gut bacteria in poultry remain largely unknown. This study aimed to isolate anaerobically growing bacteria enriched under MI-based cultivation conditions from two commercial laying [...] Read more.
Myo-inositol (MI) is an essential dietary polyol involved in host metabolism. However, the identity and diversity of MI-utilizing gut bacteria in poultry remain largely unknown. This study aimed to isolate anaerobically growing bacteria enriched under MI-based cultivation conditions from two commercial laying hen breeds. Digesta samples were cultured on minimal growth media containing MI as the sole (Trial 1) or principal (Trial 2) carbon source. Isolates were purified, screened by amplified ribosomal DNA restriction analysis (ARDRA), and identified using 16S rRNA gene sequencing. Among 42 sequenced isolates, ten representative strains were classified within the phyla Pseudomonadota (n = 5), Bacillota (n = 4), and Bacteroidota (n = 1). Members of the Escherichia-Shigella clade were most frequently recovered, followed by Clostridium, Enterococcus, Pediococcus, and Bacteroides. Selected Escherichia-Shigella isolates were screened negative for ipah and ial virulence genes, except for three isolates that tested positive only for the ipah gene. These findings provide the first culture-based framework for investigating MI-responsive bacteria in the chicken gut. Full article
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