Microbiology Research

16 pages, 3467 KB

Open AccessArticle

Monoxenic Root Organ Culture Enables High-Yield Production of Viable Indigenous Rhizophagus irregularis Inoculum for Arid Oasis Agroecosystems

by Elmostafa Gagou, Hanae El Yeznasni, Wissame Chafai, Khadija Chakroune, Mahmoud Abbas, Touria Lamkami, Mondher El Jaziri and Abdelkader Hakkou

Microbiol. Res. 2026, 17(1), 28; https://doi.org/10.3390/microbiolres17010028 - 22 Jan 2026

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Abstract

Arbuscular mycorrhizal fungi (AMF) play a pivotal role in plant adaptation to arid ecosystems, yet their widespread agricultural use is constrained by the scarcity of high-quality, locally adapted inoculum. This study established a reliable monoxenic culture system for mass-producing an indigenous AMF isolate [...] Read more.

Arbuscular mycorrhizal fungi (AMF) play a pivotal role in plant adaptation to arid ecosystems, yet their widespread agricultural use is constrained by the scarcity of high-quality, locally adapted inoculum. This study established a reliable monoxenic culture system for mass-producing an indigenous AMF isolate from the date palm (Phoenix dactylifera L.) rhizosphere in the Figuig oasis, southeastern Morocco. The isolate was identified as Rhizophagus irregularis based on spore morphology and Large Subunit ribosomal DNA (LSU rDNA) phylogeny. Two propagule types, surface-sterilized spores and mycorrhizal root fragments of Plantago lanceolata L., were compared for initiation of in vitro cultures on Ri T-DNA-transformed carrot (Daucus carota L.) hairy roots. By week 16, cultures initiated from mycorrhizal root fragments produced 1414 ± 65 spores per plate and showed significantly higher performance than spore-derived cultures in terms of propagule viability, root colonization, and hairy root growth. Propagule viability reached 84% and 68%, root colonization frequencies were 95% and 72%, and hairy root lengths averaged 81 and 63 cm in root fragment- and spore-derived cultures, respectively (p < 0.01). In a subsequent whole-plant assay using P. lanceolata, in vitro-produced spores induced markedly higher mycorrhizal colonization frequency (91.0 ± 1.6% compared with 74.8 ± 1.9%) and intensity (70.0 ± 1.6% compared with 55.0 ± 1.6%) than spores obtained from conventional trap cultures (p < 0.001). These results demonstrate that monoxenic root-organ culture using root fragments is a robust, reproducible method for generating abundant, contaminant-free, and functionally superior inoculum of native R. irregularis. This advance provides a solid platform for developing tailored bio-inoculants to enhance crop resilience and sustainability in arid and semi-arid agroecosystems. Full article

(This article belongs to the Special Issue Advances in Plant–Pathogen Interactions)

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16 pages, 1577 KB

Open AccessArticle

Genomic Relationship Between High-Risk Pseudomonas aeruginosa Clone ST244 Serotypes O5 and O12 from Southeastern Brazil

by Kayo Bianco, Thereza Cristina da Costa Vianna, Samara Santanna de Oliveira, Kaylanne Montenegro, Claudia Flores, Ana Paula Alves do Nascimento, Alexander Machado Cardoso and Maysa Mandetta Clementino

Microbiol. Res. 2026, 17(1), 27; https://doi.org/10.3390/microbiolres17010027 - 21 Jan 2026

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Abstract

Pseudomonas aeruginosa is an opportunistic pathogen commonly associated with nosocomial infections and environmental dissemination. Among its high-risk clones, ST244 is notable for its global distribution and distinctive genomic traits. This study reports whole-genome sequencing of ten ST244 isolates from hospitalized patients and wastewater [...] Read more.

Pseudomonas aeruginosa is an opportunistic pathogen commonly associated with nosocomial infections and environmental dissemination. Among its high-risk clones, ST244 is notable for its global distribution and distinctive genomic traits. This study reports whole-genome sequencing of ten ST244 isolates from hospitalized patients and wastewater in a healthcare complex in Southeastern Brazil. Genomic comparisons revealed a highly conserved clonal group, with nine isolates forming a tight monophyletic cluster based on rMLST, SNP phylogeny, and average nucleotide identity (>99.5%). One isolate showed close phylogenetic proximity to strains from Asia and North America, suggesting international dissemination. Serotype analysis revealed both O5 and O12 variants, indicating intra-lineage antigenic diversity. Resistance profiling identified multidrug-resistant phenotypes carrying carbapenemase genes (bla_OXA-494, bla_OXA-396) and diverse insertion sequences (ISPa1, ISPa6, ISPa22, ISPa32, and ISPa37), facilitating horizontal gene transfer. Virulence gene analysis showed conserved elements related to adhesion, iron uptake, secretion systems, and quorum sensing, while the cytotoxin gene exoU was absent. These results highlight clonal persistence, possible intra-hospital transmission, and links to globally circulating ST244 sublineages. Our findings underscore the importance of genomic surveillance to track high-risk P. aeruginosa clones at the clinical–environmental interface. Full article

(This article belongs to the Special Issue Host–Microbe Interactions in Health and Disease)

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13 pages, 751 KB

Open AccessArticle

Cosmetic Wipe Sample Preparation for Microbiological Analysis—Single Laboratory Validation Study

by Nadine Yossa, Roma Adu Osei, Travis Canida, Anna Laasri, Qing Jin, Pascal Iraola, Thomas Hammack, Mei-Chiung Jo Huang, Goran Periz, Mi Sun Moon and Rachel Binet

Microbiol. Res. 2026, 17(1), 26; https://doi.org/10.3390/microbiolres17010026 - 19 Jan 2026

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Abstract

Cosmetic wipes are made for multiple functions, baby care, hand washing, feminine and personal cleansing, removing makeup, and applying products such as deodorants and sunless tanners among other uses. Despite the presence of preservatives, cosmetic wipes can become contaminated during processing steps and [...] Read more.

Cosmetic wipes are made for multiple functions, baby care, hand washing, feminine and personal cleansing, removing makeup, and applying products such as deodorants and sunless tanners among other uses. Despite the presence of preservatives, cosmetic wipes can become contaminated during processing steps and usage, which may lead to skin infections and other health issues for consumers. No validated method exists for the microbiological testing of cosmetic wipes. The goal of this study was to develop and validate a specific sample preparation method for the quantitative detection of microorganisms in cosmetic wipes for inclusion in the FDA Biological Analytical Manual (BAM). Ten wipe types differing in their composition and preservative combinations were inoculated with Bacillus cereus spore suspensions at three concentration levels and aged for 14 days. Three extraction methods were compared: mBAM1g (reference method using 1 g samples), mBAMww (whole wipe method based on BAM Chapter 23), and ISOww (whole wipe method based on ISO method without Tween 80). For commercial wipes, mBAMww and ISOww, using whole wipes, performed similarly (p ≥ 0.05) or significantly better (p < 0.05) than mBAM1g. For laboratory-made wipes, 1 g samples showed higher recovery rates than whole wipes, likely due to cell loss during aging. Inoculation method and preservatives affect microbial distribution, survival, and recovery rates. T80 may have a positive effect on the recovery of B. cereus from wipes. This study recommends mBAMww for the microbiological analysis of cosmetic wipes. Full article

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18 pages, 4905 KB

Open AccessCase Report

Preliminary Assessment of Cow-Derived Fermented Product (CDFP) Effects on the Human Gut Microbiome: A Single-Subject Case Study

by Niyati Desai, Nilam Vaghamshi, Komal Antaliya, Ashaka Vansia, Arpan Tapaniya, Anjana Ghelani, Rajesh Chaudhari, Rajesh Patel, Pravin Dudhagara and Douglas J. H. Shyu

Microbiol. Res. 2026, 17(1), 25; https://doi.org/10.3390/microbiolres17010025 - 18 Jan 2026

Cited by 1 | Viewed by 1202

Abstract

Cow’s milk, urine, dung, ghee, and curd possess significant medicinal value in Ayurveda and have been integral to traditional Indian clinical practices for centuries. The cow-derived fermented product (CDFP), a formulation rooted in Ayurvedic tradition, combines these five components as a panchgavya and [...] Read more.

Cow’s milk, urine, dung, ghee, and curd possess significant medicinal value in Ayurveda and have been integral to traditional Indian clinical practices for centuries. The cow-derived fermented product (CDFP), a formulation rooted in Ayurvedic tradition, combines these five components as a panchgavya and is believed to offer multifaceted health benefits. In this preliminary single-subject case study, we evaluated the microbial composition of CDFP itself and assessed its effects on the human gut microbiome before and after 7 and 15 days of administration. A single healthy male subject consumed CDFP daily for seven consecutive days. Using 16S rRNA metagenomic sequencing, we observed a prominent increase in gut microbial diversity and a rise in beneficial bacterial genera such as Bifidobacterium, Faecalibacterium, and Akkermansia during and after treatment. Functional profiling revealed significant enhancements in pathways associated with amino acid metabolism, vitamin biosynthesis (e.g., folate, riboflavin), and energy metabolism, along with transient boosts in secondary metabolite synthesis. Metabolomic analysis identified 171 bioactive compounds within CDFP, with 33 exhibiting interactions with human proteins involved in immune modulation, oxidative stress response, and gut barrier integrity. Although conducted on a single participant, this study is the first to elucidate the distinct changes observed in gut microbial composition and function following the seven-day CDFP regimen and provides initial insights that warrant further investigation in larger, controlled studies. These findings highlight the potential of CDFP as a microbiota-targeted intervention with health-supportive properties. Full article

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19 pages, 2955 KB

Open AccessArticle

Interspecific Plant Interactions Drive Rhizosphere Microbiome Assembly to Alter Nutrient Cycling in Ilex asprella and Grona styracifolia

by Ding Lu, Jixia Guo, Xin Yan, Quan Yang and Xilong Zheng

Microbiol. Res. 2026, 17(1), 24; https://doi.org/10.3390/microbiolres17010024 - 18 Jan 2026

Viewed by 534

Abstract

To address the challenges of low land use efficiency, soil degradation, and high management costs in Ilex asprella cultivation, this study established an I. asprella–Grona styracifolia intercropping system and systematically evaluated its effects on soil nutrient cycling, microbial communities, and crop [...] Read more.

To address the challenges of low land use efficiency, soil degradation, and high management costs in Ilex asprella cultivation, this study established an I. asprella–Grona styracifolia intercropping system and systematically evaluated its effects on soil nutrient cycling, microbial communities, and crop growth. Field experiments were conducted in Yunfu City, Guangdong Province, with monoculture (LCK for I. asprella, DCK for G. styracifolia) and three intercropping densities (HDT, LDT, MDT). Combining 16S rRNA sequencing and metagenomics, we analyzed the functional profile of the rhizosphere microbiome. The results showed that intercropping significantly increased the biomass of G. styracifolia, with the medium-density (MDT) treatment increasing plant length and fresh weight by 41.2% and 2.4 times, respectively, compared to monoculture. However, high-density intercropping suppressed the accumulation of medicinal compounds. In terms of soil properties, intercropping significantly enhanced soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), and available nitrogen (AN) in the rhizosphere of both plants. Specifically, AN in the I. asprella rhizosphere increased by 18.9%. Soil urease and acid phosphatase activities were also elevated, while pH decreased. Microbial analysis revealed that intercropping reshaped the rhizosphere microbial community structure, significantly increased the Shannon diversity index of bacteria in the G. styracifolia rhizosphere, and enhanced the complexity of the microbial co-occurrence network. Metagenomic analysis further confirmed that intercropping enriched functional genes related to carbon fixation, nitrogen cycling (nitrogen fixation, assimilatory nitrate reduction), and organic phosphorus mineralization (the phoD gene), thereby driving the transformation and availability of soil nutrients. These findings demonstrate that the I. asprella–G. styracifolia intercropping system, particularly at medium density, effectively improves soil fertility and land use efficiency by regulating rhizosphere microbial functions, providing a theoretical basis for the sustainable ecological cultivation of I. asprella. Full article

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17 pages, 1596 KB

Open AccessArticle

Whole-Genome Sequencing and Genomic Features of Vagococcus sp. JNUCC 83 Isolated from Camellia japonica Flowers

by Kyung-A Hyun, Ji-Hyun Kim, Min Nyeong Ko and Chang-Gu Hyun

Microbiol. Res. 2026, 17(1), 23; https://doi.org/10.3390/microbiolres17010023 - 18 Jan 2026

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Abstract

Vagococcus species have been isolated from diverse environments, including aquatic, terrestrial, food-associated, and clinical sources; however, plant- and flower-associated representatives remain poorly characterized at the genomic level. In this study, we report the complete genomic sequence and analysis of Vagococcus sp. JNUCC 83, [...] Read more.

Vagococcus species have been isolated from diverse environments, including aquatic, terrestrial, food-associated, and clinical sources; however, plant- and flower-associated representatives remain poorly characterized at the genomic level. In this study, we report the complete genomic sequence and analysis of Vagococcus sp. JNUCC 83, isolated from flowers of Camellia japonica collected on Jeju Island, Republic of Korea. The genome comprises a single circular chromosome of 2,472,896 bp with a GC content of 33.5 mol% and was assembled at high depth (555.43×), resulting in a high-quality complete genome. Genome-based phylogenomic analysis using the Type (Strain) Genome Server (TYGS) showed that strain JNUCC 83 forms a distinct lineage within the genus Vagococcus. Digital DNA–DNA hybridization (dDDH) values were far below the 70% species threshold, and 16S rRNA gene-based phylogeny consistently supported its independent placement, suggesting that JNUCC 83 represents a previously undescribed genomic species. Functional annotation based on EggNOG/COG analysis indicated the enrichment of genes involved in core metabolism and genome maintenance, while antiSMASH analysis identified a terpene-precursor-type biosynthetic locus encoding a polyprenyl synthase. Overall, this study expands the genomic understanding of flower-associated Vagococcus lineages and provides a foundation for future investigations into their ecological roles and potential applications as plant-derived microbial resources. Full article

(This article belongs to the Special Issue Advances in Plant–Pathogen Interactions)

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13 pages, 2699 KB

Open AccessReview

Regulatory Mechanisms of Zinc on Bacterial Antibiotic Resistance and Virulence in a One Health Context

by Yang Wang, Yue Li, Jingyi Wu, Mengge Shen, Aoqi Zhan, Yuxin Wang and Baobao Liu

Microbiol. Res. 2026, 17(1), 22; https://doi.org/10.3390/microbiolres17010022 - 15 Jan 2026

Cited by 1 | Viewed by 1517

Abstract

Zinc (Zn), a ubiquitous environmental transition metal primarily existing as Zinc ions (Zn²⁺), plays a critical role in various biological processes. Its extensive application in agriculture, industry, and healthcare has led to significant environmental contamination. However, the mechanistic contribution of Zn [...] Read more.

Zinc (Zn), a ubiquitous environmental transition metal primarily existing as Zinc ions (Zn²⁺), plays a critical role in various biological processes. Its extensive application in agriculture, industry, and healthcare has led to significant environmental contamination. However, the mechanistic contribution of Zn²⁺ to bacterial antibiotic resistance and virulence remains insufficiently understood. This review explores the sources, cycling, and environmental accumulation of Zn²⁺ in a One Health context, emphasizing their impact on bacterial antibiotic resistance and virulence. Zn²⁺ promote bacterial antibiotic resistance by regulating efflux pumps, biofilm formation, expression and transfer of antibiotic resistance genes, as well as synergistic effects with other heavy metals and antibiotics. Meanwhile, Zn²⁺ promote bacterial virulence by regulating quorum sensing, secretion and metal homeostasis systems, as well as oxidative stress response and virulence factor expression. Additionally, it highlights the potential of targeting Zn homeostasis as a strategy to combat environmental antibiotic resistance. Collectively, these findings provide key insights into the mechanisms by which Zn²⁺ regulate bacterial antibiotic resistance and pathogenicity, offering valuable guidance for developing strategies to mitigate the global threat of antibiotic resistance. Full article

(This article belongs to the Special Issue Zoonotic Bacteria: Infection, Pathogenesis and Drugs—Second Edition)

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15 pages, 1622 KB

Open AccessArticle

Seasonal Surveillance of Urban Water Quality in Southern Brazil Reveals Persistent Carbapenem Resistance Genes Despite Compliance with Bacteriological Standards

by Laura Haleva, Tiane Martin de Moura, Luciana Costa Teixeira, Horst Mitteregger Júnior, Evgeni Evgeniev Gabev, Adriana Ambrosini da Silveira and Fabrício Souza Campos

Microbiol. Res. 2026, 17(1), 21; https://doi.org/10.3390/microbiolres17010021 - 15 Jan 2026

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Abstract

Quality control of drinking water is essential for safeguarding public health, particularly in densely populated urban environments. Environmental microbiological monitoring can complement conventional surveillance by providing deeper insights into the dissemination of pathogens and antimicrobial resistance genes within aquatic systems. In this study, [...] Read more.

Quality control of drinking water is essential for safeguarding public health, particularly in densely populated urban environments. Environmental microbiological monitoring can complement conventional surveillance by providing deeper insights into the dissemination of pathogens and antimicrobial resistance genes within aquatic systems. In this study, we assessed the quality of wastewater and treated water from two urban water supply systems, representing the southern and northern regions of Porto Alegre, Rio Grande do Sul, Brazil, across four climatic seasons between 2024 and 2025. Fifteen water samples were analyzed, including raw water from Guaíba Lake and treated water collected from public distribution points. The Water Quality Index was calculated, microbiological indicators were quantified, and carbapenem resistance genes were detected using molecular assays. Most treated water samples complied with established bacteriological standards; however, the bla_OXA-48-like gene was recurrently detected in both wastewater and treated water. No resistance genes were identified during the summer, whereas the bla_VIM gene was detected exclusively in spring samples. The presence of carbapenem resistance genes in the absence of cultivable coliforms suggests the persistence of extracellular DNA or viable but non-culturable bacteria, highlighting limitations inherent to conventional microbiological monitoring. Integrating classical microbiological methods with molecular assays enables a more comprehensive assessment of water quality and strengthens evidence-based decision-making within a One Health framework. Full article

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22 pages, 2060 KB

Open AccessArticle

A One Health Perspective: Occurrence Study of Carbapenem-Resistant Bacteria and Other Emerging Pathogens from Recycled Wastewater Used in Agriculture

by Maria Martínez-Ruiz, Miriam Hernández-Porto, Cintia Hernández-Sánchez, Ángeles Arias, José Carlos de Gracia, Adolfo Perdomo-González, Raquel Pérez-Reverón and Francisco Javier Díaz Peña

Microbiol. Res. 2026, 17(1), 20; https://doi.org/10.3390/microbiolres17010020 - 14 Jan 2026

Cited by 2 | Viewed by 1275

Abstract

Recycled wastewater is vital for the circular economy, especially on water-scarce islands. This study explored the presence of Carbapenem-Resistant Enterobacterales and other emerging pathogens in irrigation water on four Canarian Islands, applying a One Health perspective. Using membrane filtration and MALDI-TOF mass spectrometry, [...] Read more.

Recycled wastewater is vital for the circular economy, especially on water-scarce islands. This study explored the presence of Carbapenem-Resistant Enterobacterales and other emerging pathogens in irrigation water on four Canarian Islands, applying a One Health perspective. Using membrane filtration and MALDI-TOF mass spectrometry, 69 bacterial isolates were identified. The findings revealed that 78% were Gram-negative bacilli like Pseudomonas aeruginosa, Acinetobacter spp., Enterobacteriaceae, etc., while 22% were Gram-positive bacteria, including Enterococcus spp. The main mechanisms of carbapenem resistance in Pseudomonas spp. and Acinetobacter spp. were oxacillinases, followed by metallo-β-lactamases (MBL). In Enterobacteriaceae, characterization of carbapenemase types was less frequent, with oxacillinase 48 (OXA-48) being the most prevalent. The detection of multidrug-resistant organisms in recycled wastewater highlights an urgent need for routine microbiological monitoring in water management to protect both public health and agricultural sustainability. Full article

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14 pages, 4099 KB

Open AccessArticle

Genetic Characterization of Avian Influenza Virus A (H1N1) Isolated from a Fieldfare Turdus pilaris in Ukraine

by Alla Mironenko, Nataliia Muzyka, Nataliia Teteriuk, Larysa Radchenko, Anastasia Popova, Jonas Waldenström and Denys Muzyka

Microbiol. Res. 2026, 17(1), 19; https://doi.org/10.3390/microbiolres17010019 - 14 Jan 2026

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Abstract

Avian influenza viruses are predominantly associated with waterfowl and shorebirds, and are rarely detected in other avian hosts in nature. In 2021, an H1N1 virus was isolated from a Fieldfare Turdus pilaris in Zaporizhzhia Oblast, Ukraine. A phylogenetic analysis revealed that all eight [...] Read more.

Avian influenza viruses are predominantly associated with waterfowl and shorebirds, and are rarely detected in other avian hosts in nature. In 2021, an H1N1 virus was isolated from a Fieldfare Turdus pilaris in Zaporizhzhia Oblast, Ukraine. A phylogenetic analysis revealed that all eight gene segments belonged to the Eurasian low-pathogenic avian influenza lineages. The highest nucleotide identity of the HA gene was observed with viruses detected in Georgia, Sweden, and Ukraine (99.11%), while the NA gene showed the greatest identity to viruses from Western Europe (99.14–99.57%). Genetic analysis of the HA cleavage site showed a sequence (PSIQSR↓GLF) that contained a single basic amino acid. No deletions were detected in the stalk region of NA gene, and no specific mutations in PB2 protein were found. However, several amino acid substitutions were identified in the HA gene (D204E, S207T, and D239G) that may affect the binding affinity to specific antibodies. The occurrence of this virus in a wild, seemingly healthy thrush indicate that additional surveillance in poorly studied ecological groups such as Passeriformes is warranted. Full article

(This article belongs to the Special Issue Emerging and Re-Emerging Viruses in Animal Health: Pathogenesis, Diagnosis, and One Health Strategies)

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32 pages, 442 KB

Open AccessReview

Bacterial Bovine Respiratory Disease: A Comprehensive Review of Etiology, Pathogenesis and Management Strategies

by Chiara Storoni, Silvia Preziuso, Anna-Rita Attili, Yubao Li and Vincenzo Cuteri

Microbiol. Res. 2026, 17(1), 18; https://doi.org/10.3390/microbiolres17010018 - 11 Jan 2026

Cited by 3 | Viewed by 2667

Abstract

Bovine Respiratory Disease (BRD) represents one of the largest causes of economic loss and animal morbidity in the global cattle industry, second only to neonatal diarrhea. Its etiology is complex, originating from a multifactorial combination of host susceptibility, environmental stressors, viral infections, and [...] Read more.

Bovine Respiratory Disease (BRD) represents one of the largest causes of economic loss and animal morbidity in the global cattle industry, second only to neonatal diarrhea. Its etiology is complex, originating from a multifactorial combination of host susceptibility, environmental stressors, viral infections, and secondary bacterial pathogens. Although viruses are often the initial cause of disease, suppressing the host’s respiratory defense mechanisms, most of the severe pneumonic damage and clinical signs can be attributed to bacterial infections. This review provides an overview of the primary bacterial agents identified within the BRD complex, including Mannheimia haemolytica, Pasteurella multocida, Histophilus somni, and Mycoplasma bovis. We discuss their role as commensals that then become opportunistic pathogens, and further how they interact in a synergistic relationship with a primary viral insult, leading to the resulting pathogenesis and the development of pneumonia. This manuscript discusses in further detail some of the challenges in BRD management, such as the limitations of current diagnostic methodologies, overreliance on antimicrobial therapy, and the growing concern of antimicrobial resistance. Lastly, the need for integrated approaches in management, better husbandry and biosecurity, coupled with the development of novel therapeutic alternatives, is underlined as a means of assuring a sustainable control of this serious syndrome. Full article

(This article belongs to the Special Issue Diagnostics and Molecular Epidemiology of Infectious Diseases in Veterinary Medicine)

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14 pages, 1746 KB

Open AccessArticle

Resistance Patterns in Gram-Negative Bacilli Isolated in a Secondary Care Hospital: A Therapeutic Challenge in Western Mexico

by César Ricardo Cortez-Álvarez, Benjamín de Jesús Gutiérrez-García, Pablo Ulises Romero-Mendoza, María del Rosario Cabral-Medina, Monserratt Abud-Gonzalez, Susana Olivia Guerra-Martínez, Livier Amalia Gutiérrez-Morales, María Luisa Muñoz-Almaguer, Santiago José Guevara-Martínez, Daniel Osmar Suárez-Rico, Marco Pérez-Cisneros and Martin Zermeño-Ruiz

Microbiol. Res. 2026, 17(1), 17; https://doi.org/10.3390/microbiolres17010017 - 10 Jan 2026

Cited by 1 | Viewed by 935

Abstract

Antimicrobial resistance (AMR) continues to represent a significant global public health concern. Gram-negative bacilli (GNB) are the primary causative agents of severe nosocomial infections and possess a notable capacity to develop resistance mechanisms that restrict therapeutic options. The objective of this study was [...] Read more.

Antimicrobial resistance (AMR) continues to represent a significant global public health concern. Gram-negative bacilli (GNB) are the primary causative agents of severe nosocomial infections and possess a notable capacity to develop resistance mechanisms that restrict therapeutic options. The objective of this study was to characterize the antimicrobial susceptibility profiles of GNB isolated at a secondary-level hospital in Guadalajara, Mexico, with the aim of identifying predominant resistance patterns and the most effective therapeutic alternatives. A descriptive, retrospective, cross-sectional study was conducted using clinical isolates of Acinetobacter spp., Pseudomonas spp., Escherichia coli, Klebsiella spp., Morganella morganii, Proteus spp., and Enterobacter spp. collected during 2024. The identification and susceptibility testing were carried out using the VITEK^® 2 automated system, and the results were interpreted in accordance with CLSI guidelines. High resistance rates were observed in Acinetobacter spp. and Pseudomonas spp., particularly to carbapenems (>50% and >40%, respectively). Escherichia coli and Klebsiella spp. demonstrated resistance to third-generation cephalosporins and trimethoprim/sulfamethoxazole, exhibiting high susceptibility to amikacin and carbapenems (>90%). New-generation β-lactam/β-lactamase inhibitor combinations, such as ceftazidime/avibactam and ceftolozane/tazobactam, have demonstrated high efficacy against resistant strains. Overall, GNB isolates in this secondary-level hospital demonstrated elevated resistance levels, particularly to β-lactams and carbapenems, which pose a significant therapeutic challenge. Nevertheless, amikacin, carbapenems, and new-generation β-lactams persist as valuable therapeutic options. In order to contain the spread of multidrug-resistant organisms, it is imperative to strengthen local surveillance, optimize antibiotic stewardship, and reinforce infection control measures. Full article

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17 pages, 1405 KB

Open AccessArticle

Heat-Assisted Extraction and Bioactivity Evaluation of a Dinactin-Associated Compound from Streptomyces UP Strains

by Grissana Pook-In, Somsak Tammawong, Chorpaka Phuangsri, Khwanla Seansupa, Sontaya Sookying, Tomoko Takahashi and Anchalee Rawangkan

Microbiol. Res. 2026, 17(1), 16; https://doi.org/10.3390/microbiolres17010016 - 9 Jan 2026

Viewed by 1083

Abstract

Streptomyces is a versatile genus widely used in drug production and biotechnological applications. This study aimed to identify and characterize bioactive compounds produced by Streptomyces UP-AC4 and UP-3.2 strains and evaluate their antibacterial and anticancer activities. The strains were identified as Streptomyces californicus [...] Read more.

Streptomyces is a versatile genus widely used in drug production and biotechnological applications. This study aimed to identify and characterize bioactive compounds produced by Streptomyces UP-AC4 and UP-3.2 strains and evaluate their antibacterial and anticancer activities. The strains were identified as Streptomyces californicus and Streptomyces purpurascens via chemotaxonomy, 16S rRNA sequencing, amplified ribosomal DNA restriction analysis, and phylogenetic analysis. Bioactive compounds were extracted using heat treatments at 63 °C for 30 min or 73–110 °C for 10 min. Antibacterial activity against Staphylococcus aureus, Bacillus cereus, and Escherichia coli was assessed by agar disc assay, with MICs of 0.024–0.195 mg/mL and MBCs of 0.098–0.391 mg/mL for the most effective extracts. Anticancer activity against A549, H1299, and Lu99 lung cancer cells was evaluated using the MTT assay, showing IC₅₀ values of 0.23 ± 0.06 to 4.85 ± 0.64 mg/mL, while exhibiting no toxicity to normal fibroblast cells. HPLC analysis indicated that heat-assisted extraction of UP-AC4 at 73 °C for 10 min enriched a dinactin-associated compound as a predominant metabolite with antibiotic and anticancer activities. In conclusion, Streptomyces UP-AC4 and UP-3.2 produce promising low-cost bioactive compounds with strong potential for pharmaceutical and healthcare applications. Full article

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23 pages, 3886 KB

Open AccessReview

Microbial Steroids: Novel Frameworks and Bioactivity Profiles

by Valery M. Dembitsky and Alexander O. Terent’ev

Microbiol. Res. 2026, 17(1), 15; https://doi.org/10.3390/microbiolres17010015 - 9 Jan 2026

Cited by 2 | Viewed by 1236

Abstract

Microorganisms have emerged as prolific and versatile producers of steroidal natural products, displaying a remarkable capacity for structural diversification that extends far beyond classical sterol frameworks. This review critically examines steroidal metabolites isolated from microbial sources, with a particular emphasis on marine-derived and [...] Read more.

Microorganisms have emerged as prolific and versatile producers of steroidal natural products, displaying a remarkable capacity for structural diversification that extends far beyond classical sterol frameworks. This review critically examines steroidal metabolites isolated from microbial sources, with a particular emphasis on marine-derived and endophytic fungi belonging to the genera Aspergillus and Penicillium, alongside selected bacterial and lesser-studied fungal taxa. Comparative analysis reveals that these organisms repeatedly generate distinctive steroid scaffolds, including highly oxygenated ergostanes, secosteroids, rearranged polycyclic systems, and hybrid architectures arising from oxidative cleavage, cyclization, and Diels–Alder-type transformations. While many reported compounds exhibit cytotoxic, anti-inflammatory, antimicrobial, or enzyme-inhibitory activities, the biological relevance of these metabolites varies considerably, highlighting the need to distinguish broadly recurring bioactivities from isolated or strain-specific observations. By integrating structural classification with biosynthetic considerations and bioactivity trends, this review identifies key steroidal frameworks that recur across taxa and appear particularly promising for further pharmacological investigation. In addition, current gaps in mechanistic understanding and compound prioritization are discussed. Finally, emerging strategies such as genome mining, biosynthetic gene cluster analysis, co-culture approaches, and synthetic biology are highlighted as powerful tools to unlock the largely untapped potential of microbial genomes for the discovery of novel steroidal scaffolds. Together, this synthesis underscores the importance of microorganisms as a dynamic and expandable source of structurally unique and biologically relevant steroids, and provides a framework to guide future discovery-driven and mechanism-oriented research in the field. Full article

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17 pages, 11709 KB

Open AccessArticle

Exploring Arid Soils as a Source of Bacillus thuringiensis Biocontrol Agents Active Against Dipteran and Lepidopteran Larvae

by Kareem Badr, Fatima Al-Maadeed, Alaa Azouz, Zahoor Ul Hassan, Quirico Migheli and Samir Jaoua

Microbiol. Res. 2026, 17(1), 14; https://doi.org/10.3390/microbiolres17010014 - 8 Jan 2026

Viewed by 1074

Abstract

Microbial communities found in arid environments often exhibit unique genetic and metabolic adaptations that enable them to synthesize potent bioactive compounds. Bacillus thuringiensis (Bt) is widely recognized for its biocontrol potential against various insects. This study aims to investigate the insecticidal [...] Read more.

Microbial communities found in arid environments often exhibit unique genetic and metabolic adaptations that enable them to synthesize potent bioactive compounds. Bacillus thuringiensis (Bt) is widely recognized for its biocontrol potential against various insects. This study aims to investigate the insecticidal potential of Bt strains isolated from Qatar’s soil against dipteran and lepidopteran larvae. The microscopic analysis identified distinct crystal types, including bipyramidal, cuboidal, spherical smooth, and spherical rough forms, with distinct cry, cyt, and vip genes. Strains producing bipyramidal crystals carry cry1A, cry2A, and vip3A genes, while only two strains producing spherical crystals carry cry4B and cyt1A genes. Bipyramidal crystal-producing strains (QBT552 and QBT877) showed potent insecticidal activity, achieving 100% mortality against Corcyra cephalonica larvae, with LC₅₀ values of 25 µg/g. Spherical smooth crystal-producing strain (QBT862) exhibited high toxicity against Culex pipiens insect larvae (LC₅₀ = 2 µg/L). The quantification of bipyramidal crystal protein production of strains QBT877 and QBT552 exhibited the highest δ-endotoxin yield (1334.4 ± 6.7 and 1188.7 ± 5.0 µg/mL, respectively), while smooth spherical crystal strains QBT758 and QBT862 were 577.5 ± 8.4 and 567.6 ± 8.4 µg/mL, respectively. These findings highlighted the potential of Bt QBT strains for biocontrol applications, with strains showing promise for producing effective δ-endotoxins. Full article

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10 pages, 347 KB

Open AccessArticle

Heat Tolerance of Wildtype Salmonella Tennessee and Its Knock-Off Mutants in Peanut Butter and Peanut Spread

by Seulgi Lee, Fanbin Kong and Jinru Chen

Microbiol. Res. 2026, 17(1), 13; https://doi.org/10.3390/microbiolres17010013 - 8 Jan 2026

Viewed by 713

Abstract

Salmonella enterica from low-moisture food has been found to have a higher thermal tolerance than from high-moisture food. However, the molecular mechanism underlying the association of thermal tolerance of this pathogen with low-moisture foods, such as peanut butter and peanut spread, has not [...] Read more.

Salmonella enterica from low-moisture food has been found to have a higher thermal tolerance than from high-moisture food. However, the molecular mechanism underlying the association of thermal tolerance of this pathogen with low-moisture foods, such as peanut butter and peanut spread, has not been fully elucidated. We previously found that mutants of S. Tennessee with a defective gene encoding a cell membrane lipoprotein (Lpa) or cell division protein (ZapC) formed significantly (p ≤ 0.05) less biofilm than the wildtype strain. To assess the possible role of these genes in the thermal tolerance of S. Tennessee, this study compared the surviving populations of the wildtype S. Tennessee and its mutants defective in Lpa or ZapC in different types of peanut products (regular, reduced-fat, and natural) at 74 °C for 0, 2.5, 5, 10, 15, 20, 30, 40, or 50 min. Results showed that mutants with a defective lpa or zapC significantly affected the survival of Salmonella in peanut products during heat treatments. Significantly, a higher reduction in Salmonella population was observed in regular peanut butter, followed by natural and reduced-fat peanut spreads. The study provides new insight into one of the molecular mechanisms underlying the thermal tolerance of Salmonella enterica. Full article

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18 pages, 2484 KB

Open AccessArticle

Genetic Diversity of Streptococcus pneumoniae Isolated from Thirteen Arab Countries and over 22 Years: A Retrospective Bioinformatics Analysis

by Muhammad Halwani, Manal Al Daajani and Safa Boujemaa

Microbiol. Res. 2026, 17(1), 12; https://doi.org/10.3390/microbiolres17010012 - 7 Jan 2026

Viewed by 1285

Abstract

Streptococcus pneumoniae (S. pneumoniae) is responsible for a wide range of infections. The aim of this study was to investigate the clonal diversity of S. pneumoniae in thirteen Arab countries. Multi-Locus Sequence Typing (MLST) data were extracted from PubMLST database. Genetic [...] Read more.

Streptococcus pneumoniae (S. pneumoniae) is responsible for a wide range of infections. The aim of this study was to investigate the clonal diversity of S. pneumoniae in thirteen Arab countries. Multi-Locus Sequence Typing (MLST) data were extracted from PubMLST database. Genetic analysis was performed using DnaSP software version 6.0. A Minimum Spanning Tree (MST) analysis was conducted to evaluate the population structure of S. pneumoniae strains. Genetic data from 1008 Arab S. pneumoniae strains, collected over 22 years (1996–2018), were analyzed. MLST analysis identified a highly diverse population comprising 600 sequence types grouped into 87 clonal complexes and 295 singletons. Both internationally disseminated clones (e.g., ST156) and country-specific lineages (e.g., ST2307, Saudi Arabia) were observed, indicating substantial geographic structuring. Significant associations were detected between sequence types and geographical origin, decade of isolation, patient age, disease type, and serotype (p < 0.05). Although recombination events were presented, the population retained a predominantly clonal structure over time (I^S_A = 0.0715, p < 0.001). Overall, these findings demonstrated extensive genetic heterogeneity and spatiotemporal structuring of S. pneumoniae in the Arab region, providing valuable insights for regional surveillance and vaccine-related strategies. Full article

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18 pages, 2860 KB

Open AccessArticle

Urinalysis and Antimicrobial Susceptibility of Bacteria Isolated from Urine of Dogs and Cats in Poland in 2023: Associations Between Urine Parameters and Bacteriuria

by Dawid Jańczak, Piotr Górecki, Natalia Skrzypek, Dominika Sobkiewicz, Magda Paczocha, Aleksander Chrzanowski, Aleksandra Kornelia Maj, Rafał Stryjek, Aleksandra Anna Zasada and Anna Golke

Microbiol. Res. 2026, 17(1), 11; https://doi.org/10.3390/microbiolres17010011 - 7 Jan 2026

Viewed by 1466

Abstract

Bacterial urinary tract infections (UTIs) are common in dogs and cats. This study examined the correlations between routine urinalysis and culture-confirmed infections and described the etiologic agents and antimicrobial susceptibility to support stewardship. In 2023, 1787 urine samples (854 dogs, 933 cats) underwent [...] Read more.

Bacterial urinary tract infections (UTIs) are common in dogs and cats. This study examined the correlations between routine urinalysis and culture-confirmed infections and described the etiologic agents and antimicrobial susceptibility to support stewardship. In 2023, 1787 urine samples (854 dogs, 933 cats) underwent urinalysis, aerobic culture with species identification, and disk-diffusion testing per Clinical and Laboratory Standards Institute standards; non-parametric statistics with effect sizes were applied. Pyuria was the strongest correlate of infection in both species. Low urine specific gravity was associated with infection and crystal detection, and urine pH correlated weakly with growth in dogs. Nitrite positivity was strongly associated with infection in dogs but showed no diagnostic value in cats. Hematuria showed a weak inverse association in dogs and no association in cats. Females and older animals were more frequently infected, and infections were slightly more common in summer. Most episodes were monomicrobial (85%), predominantly caused by Escherichia coli (48.4% of dogs; 51.5% of cats). E. coli remained broadly susceptible to nitrofurantoin and aminoglycosides. Fluoroquinolone activity was variable. Pseudomonas spp. showed the highest susceptibility to ceftazidime, cefepime, and aminoglycosides. These findings support culture when pyuria, dilute urine, or nitrite positivity is detected and favour short, targeted empiric therapy pending results, guided by a stepwise clinical decision pathway. Full article

(This article belongs to the Special Issue Diagnostics and Molecular Epidemiology of Infectious Diseases in Veterinary Medicine)

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28 pages, 2907 KB

Open AccessReview

Mapping Research on Microbial Remediation of Metals in Soil (2020–2025)

by Aziza Usmonkulova, Massimo Pugliese, Mukhiddin Juliev, Ilkhom Khalilov, Nafosat Kurbonova, Nigora Tillyaxodjayeva, Rixsiniso Karimova, Wei Liu, Feruza Khalilova and Oysha Jabborova

Microbiol. Res. 2026, 17(1), 10; https://doi.org/10.3390/microbiolres17010010 - 7 Jan 2026

Cited by 2 | Viewed by 1851

Abstract

This study involved a systematic literature review using bibliometric analysis to examine the evolution and current trends of Biological Remediation studies. The bibliometric analysis was used for the descriptive, intellectual, social, and conceptual network analyses, while systematic reviews were used to identify the [...] Read more.

This study involved a systematic literature review using bibliometric analysis to examine the evolution and current trends of Biological Remediation studies. The bibliometric analysis was used for the descriptive, intellectual, social, and conceptual network analyses, while systematic reviews were used to identify the application of the Biological Remediation. A total of 4835 papers were selected and extracted from Scopus between 2020 and 2025. The publication trends, most influential countries and articles, leading journals, collaboration networks, coupling networks, and application of the Biological Remediation in various disciplines were described. This study summarized the research agenda of the Biological Remediation field, which would be helpful for researchers and funding agencies. This article highlights four new research directions in Current Bioremediation Trends: (1) understanding the interactions between petroleum hydrocarbons and heavy metals in composite pollution systems; (2) exploring microbial community succession during bioremediation; (3) utilizing biosurfactants to enhance contaminant solubilization and biodegradation; and (4) developing integrative, multi-mechanistic remediation approaches. Full article

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12 pages, 2388 KB

Open AccessArticle

Gamsia batmanii sp. nov. Isolated from a Common Bent-Wing Bat and the Review of the Genus Gamsia

by Žejko Savković, Jelena Burazerović, Marija Jovanović, Sara Arsenijević and Miloš Stupar

Microbiol. Res. 2026, 17(1), 9; https://doi.org/10.3390/microbiolres17010009 - 3 Jan 2026

Cited by 1 | Viewed by 1319

Abstract

Cave ecosystems represent environmentally constrained habitats that host diverse and highly specialized fungal communities. Many cave-dwelling fungi act as decomposers, transient colonizers, or cave fauna symbionts. During a mycological survey of Sesalačka cave (Serbia), a previously undescribed species was isolated from the skin [...] Read more.

Cave ecosystems represent environmentally constrained habitats that host diverse and highly specialized fungal communities. Many cave-dwelling fungi act as decomposers, transient colonizers, or cave fauna symbionts. During a mycological survey of Sesalačka cave (Serbia), a previously undescribed species was isolated from the skin of a Miniopterus schreibersii. The aim of this study was to characterize this isolate using an integrative taxonomic approach combining morphology, physiology, and multilocus phylogenetics. The fungus was cultured on different media under and its morphophysiological traits were recorded. DNA sequences of ITS, LSU, SSU, and TEF1α were compared with existing Gamsia species and phylogenetic analysis placed the isolate within the Gamsia clade, forming a well-supported lineage the most closely related to G. aggregata, but differing from it by 8–12 base pairs across loci. Distinctive morphological features of this species include obovoid to pyriform polyblastic conidia, hyaline to pale-brown annelloconidia, and reduced conidiophores, clearly separating the species from described congeners. It is psychrotolerant and does not grow at 37 °C, suggesting it is a cave-associated saprobe rather than a mammalian pathogen. This study expands the known diversity of Gamsia species and contributes to the growing evidence that subterranean habitats harbor numerous undescribed fungal kingdom members. Full article

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16 pages, 1355 KB

Open AccessArticle

Bacterial Resistance in the ICU: A Comparative Analysis of Pre-Pandemic and Pandemic Periods and the Impact on Clinical Outcomes

by Geane Andriollo Paradynski, Ronaldo dos Santos Machado, Lucas Machado Sulzbacher, Maicon Machado Sulzbacher, Vítor Antunes de Oliveira, Pauline Brendler Goettems Fiorin, Mirna Stela Ludwig, Thiago Gomes Heck and Matias Nunes Frizzo

Microbiol. Res. 2026, 17(1), 8; https://doi.org/10.3390/microbiolres17010008 - 30 Dec 2025

Viewed by 1168

Abstract

Inappropriate use of antibiotics can stimulate antimicrobial resistance, since bacteria are capable of circumventing pharmacological action through various resistance mechanisms. Recently, during the COVID-19 pandemic, there has been an increase in the use of antimicrobials. This is an analytical, quantitative, and retrospective study [...] Read more.

Inappropriate use of antibiotics can stimulate antimicrobial resistance, since bacteria are capable of circumventing pharmacological action through various resistance mechanisms. Recently, during the COVID-19 pandemic, there has been an increase in the use of antimicrobials. This is an analytical, quantitative, and retrospective study on bacterial resistance and mortality in Intensive Care Unit (ICU) patients from 2017 to 2022. This study analyzed sociodemographic aspects, clinical, and laboratory parameters in patients admitted to the ICU. A total of 221 medical records of patients with multidrug-resistant bacteria in the ICU were included, with an outcome of 95 discharges (42.98%) and 126 deaths (53.01%). An increase in the prevalence of bacterial resistance in the ICU was identified during the Pandemic period, when compared to the Pre-Pandemic period. It was identified that the increase in bacterial resistance of some pathogens was associated with death. It was also observed that age was a factor for an increased risk of mortality in the ICU, no matter the sex of the patient. Importance of careful analysis in the use of antimicrobials, as well as in the care of ICU patients and in the surveillance of bacterial infections by health professionals. Full article

(This article belongs to the Topic Multidrug Resistance Across Pathogens: Fungi, Bacteria, Parasites, and Viruses)

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14 pages, 1547 KB

Open AccessArticle

Salivary Oral Microbiota in Patients with Prediabetes Undergoing Intragastric Balloon Surgery

by Rabab A. D. Meshan, Norah Ahmed AlOsaimi, Abdulmohsen Redha and Maribasappa Karched

Microbiol. Res. 2026, 17(1), 7; https://doi.org/10.3390/microbiolres17010007 - 30 Dec 2025

Viewed by 648

Abstract

Kuwait faces a significant public health challenge from obesity and Type 2 Diabetes Mellitus (T2DM), conditions known to disrupt the natural balance of oral bacteria. This imbalance, or dysbiosis, can promote gum disease and may worsen metabolic health. While the intragastric balloon (IGB) [...] Read more.

Kuwait faces a significant public health challenge from obesity and Type 2 Diabetes Mellitus (T2DM), conditions known to disrupt the natural balance of oral bacteria. This imbalance, or dysbiosis, can promote gum disease and may worsen metabolic health. While the intragastric balloon (IGB) is a common, less invasive weight-loss procedure, its specific effect on the community of bacteria in saliva remains unclear, especially for high-risk groups. The objective of this study was to investigate changes in the salivary microbiota of obese prediabetic patients following IGB placement. We recruited 20 obese patients (11 female, 9 male; average age 31.5) from a clinic in Kuwait. Saliva samples were collected just before IGB (Allurion™) insertion and again 6 weeks after that. Using 16S rRNA gene sequencing, we identified the bacterial species present and used bioinformatic tools to analyze diversity and abundance. Our analysis revealed that the overall diversity and structure of the salivary microbial community remained stable after the procedure. However, we detected notable changes in specific types of bacteria. The relative abundance of several genera, including Veillonella, Porphyromonas, and Fusobacterium, shifted significantly. At the species level, Porphyromonas pasteri and Haemophilus parainfluenzae became less abundant, while certain Veillonella and Streptococcus species increased in number after the IGB was placed. In conclusion, for obese prediabetic patients in Kuwait, the salivary microbiome demonstrates remarkable stability in the weeks following IGB surgery. The procedure did not drastically alter the overall ecosystem, but it did trigger specific, subtle changes in certain bacterial populations. This suggests the oral microbiota is resilient, adapting to the new physiological conditions without a major upheaval. Full article

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14 pages, 2169 KB

Open AccessArticle

Identification and Characterization of a Proteinaceous Antibacterial Factor from Pseudomonas extremorientalis PEY1 Active Against Edwardsiella tarda

by Hyun-Sol Jo, Youl-Lae Jo and Sun-Mee Hong

Microbiol. Res. 2026, 17(1), 6; https://doi.org/10.3390/microbiolres17010006 - 30 Dec 2025

Viewed by 747

Abstract

Pseudomonas extremorientalis PEY1, isolated from the intestinal contents of marine fish, was evaluated for the production and properties of antibacterial proteins active against Edwardsiella tarda, a major pathogen in aquaculture. Antibacterial production was maximized in a minimal medium supplemented with 1% yeast [...] Read more.

Pseudomonas extremorientalis PEY1, isolated from the intestinal contents of marine fish, was evaluated for the production and properties of antibacterial proteins active against Edwardsiella tarda, a major pathogen in aquaculture. Antibacterial production was maximized in a minimal medium supplemented with 1% yeast extract and 1% galactose under stationary cultivation at 25 °C and pH 7.0. Growth and bioactivity assays were conducted under varying carbon and nitrogen sources, temperatures, and pH levels. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis revealed a distinct ~37 kDa protein band corresponding to antibacterial activity, exhibiting an inhibition zone of 2.4 ± 0.1 cm against E. tarda. The activity was completely abolished by papain digestion but remained detectable after exposure to 55 °C and pH 8, indicating that the active compound is a moderately heat-stable, proteinaceous antibacterial molecule. LC–MS/MS analysis identified the protein as a putative disulfide reductase with ~40% sequence coverage. The antibacterial factor exhibited strong physicochemical stability, retaining activity in the presence of surfactants and metal ions. Collectively, these findings demonstrate that P. extremorientalis PEY1 produces a thermostable, papain-sensitive antibacterial protein with selective activity against E. tarda, highlighting its potential as a promising natural biocontrol or postbiotic candidate for sustainable aquaculture. Full article

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9 pages, 572 KB

Open AccessCommunication

Growth of Ectomycorrhizal Fungi on Inorganic and Organic Nitrogen Sources

by Burenjargal Otgonsuren, Hangyu Lan and Douglas L. Godbold

Microbiol. Res. 2026, 17(1), 5; https://doi.org/10.3390/microbiolres17010005 - 25 Dec 2025

Viewed by 1067

Abstract

In forest soils, nitrogen (N) is present in inorganic and organic forms. The organic forms include monomeric amino acids, but also polymers such as chitin. Ectomycorrhizal fungi are known to take up both inorganic and organic N forms, and to depolymerize large organic [...] Read more.

In forest soils, nitrogen (N) is present in inorganic and organic forms. The organic forms include monomeric amino acids, but also polymers such as chitin. Ectomycorrhizal fungi are known to take up both inorganic and organic N forms, and to depolymerize large organic compounds; however, it is unknown if the compounds are used for growth. The aim of this investigation was to determine the growth of a range of ectomycorrhizal fungi on inorganic and organic N sources. Seven ectomycorrhizal fungi and one endophyte originating from mountain regions either in Austria, Mongolia, or Slovenia were grown in in-vitro cultures containing ammonium, nitrate, or chitin. Four ectomycorrhizal fungi were used to investigate growth on amino acids. All fungi, except Paxillus involutus, utilized nitrate as a N source. All fungi also grew on both chitin and N-acetylglucosamine, the amino sugar precursor of chitin. Paxillus involutus and Melanogaster broomeanus showed enhanced growth on chitin-containing media. Amanita muscaria, Rhizopogon roseolus, and Suillus granulatus, but not Paxillus involutus, were able to utilize the amino acids glycine and glutamate, as well as the tripeptide triglycine. The ability to utilize the different N sources was independent of the origin of the fungi. Full article

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27 pages, 1607 KB

Open AccessReview

Regulatory Mechanisms of Fumonisin Biosynthesis and Applications in Food Safety and Biotechnology

by Lei Fan, Yuqing Lei, Zhihui Qi, Haiyang Zhang, Lin Tian and Fang Tang

Microbiol. Res. 2026, 17(1), 4; https://doi.org/10.3390/microbiolres17010004 - 24 Dec 2025

Viewed by 1394

Abstract

Fumonisins, a major class of mycotoxins, pose significant health risks to humans and animals due to their widespread contamination and potent toxicity. Recent advances in molecular biology, biochemistry, and enzymology have greatly enhanced the understanding of fumonisin biosynthesis and its genetic regulation. The [...] Read more.

Fumonisins, a major class of mycotoxins, pose significant health risks to humans and animals due to their widespread contamination and potent toxicity. Recent advances in molecular biology, biochemistry, and enzymology have greatly enhanced the understanding of fumonisin biosynthesis and its genetic regulation. The key biosynthetic genes are typically organized in clusters and regulated by specific transcription factors; increasing evidence also highlights the involvement of complex transcriptional and epigenetic mechanisms. Environmental factors such as nitrogen, carbon, and pH also modulate these regulatory networks. Despite substantial progress, critical gaps remain in fully elucidating the regulatory pathways that control fumonisin production. This review synthesizes current knowledge regarding fumonisin biosynthesis, gene clusters, and multi-level regulatory mechanisms, while emphasizing recent trends, existing challenges, and potential applications in food safety and biotechnology to enhance food security and promote sustainable development. Full article

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15 pages, 890 KB

Open AccessArticle

Ureaplasma Species and Human Papillomavirus Coinfection and Associated Factors Among South African Adolescent Girls and Young Women

by Sinazo Kondlo and Zizipho Z. A. Mbulawa

Microbiol. Res. 2026, 17(1), 3; https://doi.org/10.3390/microbiolres17010003 - 23 Dec 2025

Viewed by 1497

Abstract

Ureaplasma species are associated with various reproductive health issues, while human papillomavirus (HPV) is associated with cervical, vaginal and vulvar cancers. Data on the association between Ureaplasma species and HPV are limited in South Africa. This study investigated the prevalence of Ureaplasma urealyticum [...] Read more.

Ureaplasma species are associated with various reproductive health issues, while human papillomavirus (HPV) is associated with cervical, vaginal and vulvar cancers. Data on the association between Ureaplasma species and HPV are limited in South Africa. This study investigated the prevalence of Ureaplasma urealyticum (U. urealyticum), Ureaplasma parvum (U. parvum), and HPV coinfection and their associated factors, among adolescent girls and young women (AGYW) in the Eastern Cape Province, South Africa. A total of 214 participants were retrospectively recruited, and secondary data on HPV, U. urealyticum, U. parvum, demographics, and sexual behavior were used. HPV was detected using the Roche Linear Array HPV Genotyping Test, while U. urealyticum and U. parvum were detected using Allplex™ sexually transmitted infection (STI) essential Assay. Statistical analyses were performed using GraphPad Prism Version 8.0.1.244. The prevalence of U. urealyticum was 43.9% (94/214) and increased significantly with age (p = 0.036, R² = 0.8497); while U. parvum prevalence was 68.7% (147/214) and was not influenced by age. Having four to six lifetime sexual partners (PR: 1.77, 95% CI: 1.04–3.00, p = 0.043) was associated with increased risk of U. urealyticum. A proportion of 36.3% (77/212) had HPV-U. urealyticum coinfection and its risk was increased among those with 3–6 lifetime sexual partners (PR: 1.59, 95% CI: 1.10–2.53, p = 0.017), 2–4 new partners past three months (PR: 2.14, 95% CI: 1.19–2.42, p = 0.021); vaginal sexual intercourse frequency past 1-month (2–3 vaginal intercourse: PR: 1.54, 95% CI: 1.06–2.53, p = 0.037; 4–10 vaginal intercourse: PR: 1.91, 95% CI: 1.83–1.91, p = 0.005) and alcohol consumption (PR: 1.85, 95% CI: 1.20–3.28, p = 0.004). U. urealyticum positives had a significantly higher risk of HPV types targeted by Cervarix^® HPV vaccine than negatives (PR: 2.56, 95% CI: 1.23–5.37, p = 0.013), Gardasil^®4 (PR: 2.16, 95% CI: 1.25–3.75, p = 0.006) and Gardasil^®9 (PR: 1.70, 95% CI: 1.25–2.32, p = 0.001). AGYW of Eastern Cape Province, South Africa had high prevalence of U. urealyticum-HPV and U. parvum-HPV coinfections. Ureaplasma species coinfection was associated with HPV prevalence and distribution of genotypes. The U. urealyticum prevalence and its coinfection with HPV were associated with sexual behavior. Data from this study could contribute to the design of sexual health and STI interventions and could serve as a baseline for future epidemiological studies, which include ongoing surveillance of HPV genotype prevalence to evaluate the impact and effectiveness of HPV vaccination programs in the population. Full article

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13 pages, 1447 KB

Open AccessArticle

Spatio-Temporal Presumptive Identification of Enterococcus spp. and Vibrio spp. in Water from the Veracruz Reef System National Park in the Central Gulf of Mexico

by Fátima Jael Olvera-Muñoz, Martina Hilda Gracia-Valenzuela, Fabiola Lango-Reynoso, Olaya Pirene Castellanos-Onorio, Jesús Montoya-Mendoza, Christian Reyes-Velázquez, María de Lourdes Fernández-Peña, Bani Mariana Ruesgas-Ramon and María del Refugio Castañeda-Chávez

Microbiol. Res. 2026, 17(1), 2; https://doi.org/10.3390/microbiolres17010002 - 21 Dec 2025

Viewed by 1312

Abstract

The Veracruz Reef System National Park (VRSNP), located in the central Gulf of Mexico, is one of the country’s most ecologically and economically significant coral systems. Despite its high biodiversity and ecosystem functionality, it is affected by anthropogenic inputs such as fluvial discharges, [...] Read more.

The Veracruz Reef System National Park (VRSNP), located in the central Gulf of Mexico, is one of the country’s most ecologically and economically significant coral systems. Despite its high biodiversity and ecosystem functionality, it is affected by anthropogenic inputs such as fluvial discharges, urban effluents, and port and tourism activities that contribute organic and bacteriological loads. This study aimed to identify the presence of Enterococcus spp. and Vibrio spp. during three climatic seasons—dry, rainy, and north winds—at two water column depths (surface and bottom) across three reefs (Enmedio, Chopas, and Gallega) within the VRSNP during the 2022 annual cycle. Samples were analyzed according to national and international standards. Results showed that Vibrio spp. were influenced mainly by temporal factors, with higher values during north winds and the dry season (>1100 MPN/100 mL); otherwise, rainy conditions reported the lowest load (184.89 ± 15.00 MPN/100 mL). While Enterococcus spp. exhibited greater spatial influence, particularly in surface waters, Enmedio Reef recorded the highest load (478.34 ± 37.28 CFU/100 mL); in addition, Chopas Reef reported the lowest at the bottom (12.43 ± 1.26 CFU/100 mL). The findings highlight the need to strengthen microbiological monitoring protocols in marine coastal ecosystems to assess water quality, public health risks, and the ecological integrity of coral reef environments, as well as the implementation of molecular identification techniques. Full article

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19 pages, 3676 KB

Open AccessArticle

Lysinibacillus as Microbial Nanofactories: Genomic Mechanisms for Green Synthesis of Silver Nanoparticles (AgNPs)

by José Luis Aguirre-Noyola, Gustavo Cuaxinque-Flores, Jorge David Cadena-Zamudio, Marco A. Ramírez-Mosqueda, Lorena Jacqueline Gómez-Godínez and Juan Ramos-Garza

Microbiol. Res. 2026, 17(1), 1; https://doi.org/10.3390/microbiolres17010001 - 19 Dec 2025

Viewed by 1035

Abstract

The green synthesis of silver nanoparticles (AgNPs) by bacteria is a strategic route for sustainable nanobiotechnology; however, the genomic and biochemical mechanisms that make it possible remain poorly defined. In this study, bacteria native to silver-bearing mine tailings in Taxco (Mexico) were isolated, [...] Read more.

The green synthesis of silver nanoparticles (AgNPs) by bacteria is a strategic route for sustainable nanobiotechnology; however, the genomic and biochemical mechanisms that make it possible remain poorly defined. In this study, bacteria native to silver-bearing mine tailings in Taxco (Mexico) were isolated, capable of tolerating up to 5 mM of AgNO₃ and producing extracellular AgNPs. Spectroscopic (430–450 nm) and structural (XRD, fcc cubic phase) characterization confirmed the formation of AgNPs with average sizes of 17–21 nm. FTIR evidence showed the participation of extracellular proteins and polysaccharides as reducing and stabilizing agents. Genomic analyses assigned the isolates as Lysinibacillus fusiformis 31HCl and L. xylanilyticus G1-3. Genome mining revealed extensive repertoires of genes involved in uptake, transport, efflux and detoxification of metals, including P-type ATPases, RND/ABC/CDF transporters, Fe/Ni/Zn uptake systems, and metal response regulators. Notably, homologues of the silP gene, which encode Ag⁺ translocator ATPases, were identified, suggesting convergent adaptation to silver-rich environments. Likewise, multiple nitroreductases (YodC, YdjA, YfKO) were detected, candidates for mediating electron transfer from NAD(P)H to Ag⁺. These findings support the role of Lysinibacillus as microbial nanofactories equipped with specialized molecular determinants for silver tolerance and AgNP assembly, providing a functional framework for microorganism-based nanobiotechnology applications. Full article

(This article belongs to the Topic Exploring Nanoparticle-Based Antivirals for a Virus-Free Future)

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