Microorganisms

13 pages, 712 KB

Open AccessArticle

Short-Term Effects of Alfalfa Silage Versus Hay, with or Without Hydrolysable Tannins, on Production Performance, Rumen Fermentation, and Nutrient Digestibility in Mid-Lactation Dairy Cows

by Xuning Miao, Chun Bai, Guofang Chen, Jiajin Sun, He Du, Chen Shen, Wenjie Huo, Qiang Liu, Cong Wang, Lei Chen and Gang Guo

Microorganisms 2025, 13(10), 2327; https://doi.org/10.3390/microorganisms13102327 - 9 Oct 2025

Abstract

This study examined the effects of alfalfa silage versus alfalfa hay in a total mixed ration (TMR) on milk yield, rumen fermentation, and nutrient digestibility in dairy cows. Hydrolyzed tannins (HT) were supplemented individually to assess changes. Thirty-two multiparous Holstein cows (DIM: 94 [...] Read more.

This study examined the effects of alfalfa silage versus alfalfa hay in a total mixed ration (TMR) on milk yield, rumen fermentation, and nutrient digestibility in dairy cows. Hydrolyzed tannins (HT) were supplemented individually to assess changes. Thirty-two multiparous Holstein cows (DIM: 94 ± 8 d; milk yield: 41 ± 2 kg) were assigned to four treatments in a 2 × 2 factorial design: basal diet (alfalfa hay, H, or alfalfa silage, S) and additive (control, C, or 100 g/d HT, T). Production performance, rumen fermentation, nutrient digestibility, and blood metabolites were evaluated. Compared with group H, group S had a 0.16% higher milk protein percentage and significantly higher fat-corrected milk yield, milk fat percentage, fat-to-protein ratio, total solids, and milk urea nitrogen. After feeding, the ST group had increased ruminal pH. HT supplementation significantly decreased ruminal NH₃-N levels (p < 0.05) and increased microbial crude protein (MCP) content (p < 0.05). Group H showed no significant changes, and the effects of HT were less evident in hay-fed cows than in silage-fed cows. In summary, alfalfa silage feeding increased ruminal microbial populations, while HT supplementation mitigated the post-feeding decline in ruminal pH. Considering the relatively small sample size (n = 32), the results should be viewed as indicative rather than conclusive, and future studies with larger cohorts will be valuable to confirm and extend these findings. Full article

(This article belongs to the Section Veterinary Microbiology)

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19 pages, 2281 KB

Open AccessArticle

Resisting the Toxic Tide: Multi-Metal Resistance of Bacteria Originating from Contaminated Šibenik Bay Sediments

by Ana Ramljak, Marta Žižek, Anastazija Huđ, Goran Palijan, Mavro Lučić and Ines Petrić

Microorganisms 2025, 13(10), 2326; https://doi.org/10.3390/microorganisms13102326 - 8 Oct 2025

Abstract

In this study, 74 bacterial isolates were obtained from sediments of Šibenik Bay, which has historically been impacted by heavy metal pollution. Isolates were tested for tolerance to cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), mercury (Hg), nickel (Ni), lead (Pb), tin [...] Read more.

In this study, 74 bacterial isolates were obtained from sediments of Šibenik Bay, which has historically been impacted by heavy metal pollution. Isolates were tested for tolerance to cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), mercury (Hg), nickel (Ni), lead (Pb), tin (Sn), and zinc (Zn), both individually and in mixtures, and for their biofilm-forming ability. Toxicity followed the trend Hg > Sn > Zn/Cd/Cr > Co/Ni > Pb, with Cu showing resistance across different concentrations. Resistance traits were observed against all tested metals, with some isolates displaying multi-metal resistance to as many as seven metals, reflecting long-term selective pressure in the Bay. The Bacillus species dominated the community (48 isolates across five clusters), confirming this genus as the principal group in metal-polluted sediments. Several less-explored genera, including Ruegeria/Cribrihabitans, Bhargavaea, Pseudoalteromonas, and Lysinibacillus/Sporosarcina, also exhibited notable resistance traits, underscoring their potential as novel candidates for bioremediation. Eleven isolates from Bacillus/Mesobacillus/Cytobacillus, Bacillus/Peribacillus/Rossellomorea, Bacillus/Pseudoalkalibacillus/Alkalibacillus, Lysinibacillus/Sporosarcina, and Ruegeria/Cribrihabitans clusters showed resistance and robust growth under metal mixtures. Among all isolates, 11, 32, 81, and 82 (Bacillus/Mesobacillus/Cytobacillus and Bacillus/Peribacillus/Rossellomorea) combined broad multi-metal tolerance with strong biofilm formation, positioning them as candidates for site-specific, nature-based bioremediation of heavy-metal-impacted coastal ecosystems such as Šibenik Bay. Full article

(This article belongs to the Special Issue Microbial Solutions for Sustainable Resource Recovery and Environmental Remediation)

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23 pages, 4220 KB

Open AccessArticle

Red Foxes (Vulpes vulpes) and European Badgers (Meles meles) as Overlooked Wildlife Hosts of Canine Parvovirus in Slovakia: First Evidence by Molecular Characterization and Virus Isolation

by Patrícia Petroušková, Andrea Pelegrinová, Jozef Lazár, Jakub Lipinský, Monika Drážovská, Marián Prokeš, Ľuboš Korytár, Boris Vojtek, Maroš Kostičák, Ladislav Molnár, Jana Mojžišová Vaščinec and Anna Ondrejková

Microorganisms 2025, 13(10), 2325; https://doi.org/10.3390/microorganisms13102325 - 8 Oct 2025

Abstract

Wild carnivores are increasingly recognized as hosts or reservoirs of canine parvovirus (CPV), a major pathogen of dogs. To investigate CPV circulation in Central Europe, we examined 221 red foxes (Vulpes vulpes) and 53 European badgers (Meles meles) from [...] Read more.

Wild carnivores are increasingly recognized as hosts or reservoirs of canine parvovirus (CPV), a major pathogen of dogs. To investigate CPV circulation in Central Europe, we examined 221 red foxes (Vulpes vulpes) and 53 European badgers (Meles meles) from seven Slovakian regions. Small intestines (n = 86), rectal swabs (n = 123), and feces (n = 65) were tested by real-time PCR, and positives were sequenced for the VP2 gene. Virus isolation was performed on MDCK cells. CPV was detected in 10.9% (30/274) of samples, with a prevalence of 10.9% (24/221) in foxes and 11.3% (6/53) in badgers. Phylogenetic analysis revealed co-circulation of CPV-2a, CPV-2b, and CPV-2c, with CPV-2b being prevalent (20/30, 66.7%) and CPV-2c detected in a single sample (1/30, 3.3%). CPV-2a/2b isolates clustered with European strains, while CPV-2c grouped within the “Asian” lineage. Several sequences carried “Asian-like” signatures (5G, 267Y, 324I, 370R), suggesting transboundary introduction and spillover into wildlife. Two infrequent substitutions were identified: S552I in CPV-2b and I447M in CPV-2a. Viable virus was isolated from all positives, with characteristic CPV-cytopathic effects. This study provides the first molecular and virological evidence of CPV in Central European wildlife. Our findings expand our understanding of CPV diversity in Europe, and underscore wildlife as an integral component of European ecology. Full article

(This article belongs to the Special Issue Detection and Identification of Emerging and Re-Emerging Pathogens)

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19 pages, 1978 KB

Open AccessArticle

The Effect of Cefazolin on the Gut Microbiome of Female Rats After Spinal Cord Injury

by Luis H. Pagán-Rivera, Filipa Godoy-Vitorino, Natalie M. Meléndez-Vázquez, Samuel E. Ocasio-Rivera, María E. Santiago-Gascot, Jose M. Santiago, Iris Salgado, Viviana González, Osmarie Martínez-Guzmán, Mauricio Cáceres-Chacón, Aranza Torrado-Tapias and Jorge D. Miranda

Microorganisms 2025, 13(10), 2324; https://doi.org/10.3390/microorganisms13102324 - 7 Oct 2025

Abstract

Spinal cord injury (SCI) is a devastating neurological state that could lead to motor, sensory, and autonomic dysfunction. In addition to its direct impact on the central nervous system, SCI exerts systemic effects, including disruption of gut homeostasis and alterations in the gut [...] Read more.

Spinal cord injury (SCI) is a devastating neurological state that could lead to motor, sensory, and autonomic dysfunction. In addition to its direct impact on the central nervous system, SCI exerts systemic effects, including disruption of gut homeostasis and alterations in the gut microbiota, which can contribute to sustained inflammation and hinder functional recovery. While antibiotic administration during the acute phase of SCI is clinically indicated, it may exacerbate microbial dysbiosis. In this study, we investigate the combined effects of SCI and cefazolin treatment on the gut microbiome of female rats. Animals were assigned to three groups: NAÏVE (no intervention), SHAM (cefazolin only), and INJURY (T10 spinal cord contusion plus cefazolin). Cefazolin was administered for seven days after the injury, fecal samples were collected at baseline (day 0), and on days 7, 14, 21, and 28 post-SCI. DNA was extracted and subjected to 16S rRNA gene amplicon sequencing, followed by bioinformatic analysis. Our findings revealed significant microbial dysbiosis in the INJURY group, including reduced alpha diversity and distinct shifts in microbial composition. These changes were most prominent during the acute phase post-SCI. Our findings highlight the compounding effects of spinal trauma and antibiotic exposure on the gut microbiome and suggest that maintaining microbial stability may represent a promising avenue to support recovery after SCI. Full article

(This article belongs to the Special Issue Novel Strategies in the Research of the Human Gut Microbiota)

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10 pages, 506 KB

Open AccessArticle

Inefficiency of Kocher and Caird’s Criteria in Septic Arthritis of the Hip Due to Kingella kingae: A Multicenter Retrospective Cohort Study

by Giacomo De Marco, Oscar Vazquez, Blaise Cochard, Piotr Foland, Ulrich Meinzer, Cindy Mallet, Brice Ilharreborde, Edouard Haumont, Zagorka Pejin-Arroyo, Pablo Yagupsky, Amadeu Gené, Eneritz Velasco Arnaiz, Catarina Gouveia, Joana Arcangelo, Nicolas Mainard, Jocelyn Gravel, Tony Walls, Nienke Hagedoorn, Ameneh Khatami, Mohamed Tashani, Silvia Valisena, Christina Steiger, Romain Dayer, Moez Chargui, Rosa Maria Alcobendas Rueda, Elisa Fernandez-Cooke, Beatriz Bravo, Laura Martin Pedraz, Sara Murias Loza, Daniel Clemente, Federico Canavese and Dimitri Ceroni Show full author list Hide full author list

Microorganisms 2025, 13(10), 2323; https://doi.org/10.3390/microorganisms13102323 - 7 Oct 2025

Abstract

In children under 4, septic arthritis of the hip (SAH) caused by Kingella kingae (SAH-KK) can be misdiagnosed, as it does not meet classic septic joint criteria (fever > 38.5°, pain, limited range of motion, and inability to bear weight). The objective of [...] Read more.

In children under 4, septic arthritis of the hip (SAH) caused by Kingella kingae (SAH-KK) can be misdiagnosed, as it does not meet classic septic joint criteria (fever > 38.5°, pain, limited range of motion, and inability to bear weight). The objective of this study was to report clinical and paraclinical characteristics in a large cohort of children with confirmed SAH-KK and to evaluate the reliability of the Kocher (KC) and Caird criteria (CC) in predicting SAH-KK. Medical records of 140 children with confirmed SAH-KK were collected. Data on sex, age, temperature on admission, weight-bearing status, white blood cell (WBC) count, platelet count, C-reactive protein (CRP) value, and erythrocyte sedimentation rate (ESR) were extracted. The study focused on the sensitivity of KC (body temperature, refusal to bear weight, leukocytosis, and ESR) and CC (KC criteria plus CRP level). All patients had bacteriologically confirmed SAH-KK; most had mild symptoms and near-normal inflammatory markers. CRP (76.2%) had the highest sensitivity, followed by weight-bearing status (73.8%) and WBC count (69.6%). Body temperature and ESR exceeded cutoff values in less than 50% of cases. Among 77 patients fulfilling all KC, 49 (63.5%) had less than a 40% probability of SAH. Of 50 children with complete CC, 20 (40%) had a 62.4% or lower probability of SAH. KC and CC are not sufficiently accurate to confidently exclude SAH-KK in preschool-aged children due to heterogeneous clinical presentations. Further studies are needed to redefine diagnostic criteria based on patient age and causative pathogens. Full article

(This article belongs to the Section Medical Microbiology)

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24 pages, 4105 KB

Open AccessArticle

Mychonastes homosphaera MHSC24 Isolated from Brackish Waters of Korea: Taxonomic, Physiological, and Biochemical Characterization

by Chang Rak Jo, Sangbum Lee, Ga Young Kim, Jeong-Mi Do, Ji Won Hong, Hae-Seo Noh, Hyung June Kim and Nam Seon Kang

Microorganisms 2025, 13(10), 2322; https://doi.org/10.3390/microorganisms13102322 - 7 Oct 2025

Abstract

Mychonastes homosphaera MHSC24 is a green microalga newly isolated from a brackish coastal site in Korea. This study represents the first indigenous record of this species in the country. It provides a comprehensive characterization of its morphological, molecular, physiological, and biochemical characteristics. This [...] Read more.

Mychonastes homosphaera MHSC24 is a green microalga newly isolated from a brackish coastal site in Korea. This study represents the first indigenous record of this species in the country. It provides a comprehensive characterization of its morphological, molecular, physiological, and biochemical characteristics. This microalga was identified through morphological observations and multilocus phylogenetic analyses. Strain MHSC24 exhibited robust growth under mesophilic temperatures (15–27 °C), moderate light intensities (88–300 μmol photons m⁻² s⁻¹), and low salinity levels (0–10 PSU). Optimal growth was observed at 27 °C, 193 μmol photons m⁻² s⁻¹, and 0 PSU. Under standard cultivation, the strain exhibited high protein levels (~54% of dry weight, DW) and accumulated substantial amounts of canthaxanthin (5.59 mg g⁻¹ DW), the predominant carotenoid in its pigment profile. Thus, MHSC24 is a promising candidate for sustainable protein- and carotenoid-based applications. Palmitic acid (11.95 mg g⁻¹ DW) and galactose (2.07 mg g⁻¹ DW) were the predominant fatty acid and monosaccharide, respectively. The physiological resilience, high protein yield, and substantial canthaxanthin accumulation of MHSC24 support its potential utilization in the functional food, feed, and nutraceutical sectors. Therefore, this study provides a basis for optimized cultivation strategies and industrial exploitation of indigenous Korean microalgae. Full article

(This article belongs to the Section Microbial Biotechnology)

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18 pages, 1427 KB

Open AccessArticle

Plant Growth-Promoting Bacteria from Tropical Soils: In Vitro Assessment of Functional Traits

by Juliana F. Nunes, Maura S. R. A. da Silva, Natally F. R. de Oliveira, Carolina R. de Souza, Fernanda S. Arcenio, Bruno A. T. de Lima, Irene S. Coelho and Everaldo Zonta

Microorganisms 2025, 13(10), 2321; https://doi.org/10.3390/microorganisms13102321 - 7 Oct 2025

Abstract

Plant growth-promoting bacteria (PGPBs) offer a sustainable alternative for enhancing crop productivity in low-fertility tropical soils. In this study, 30 bacterial isolates were screened in vitro for multiple PGP traits, including phosphate solubilization (from aluminum phosphate—AlPO₄ and thermophosphate), potassium release from phonolite [...] Read more.

Plant growth-promoting bacteria (PGPBs) offer a sustainable alternative for enhancing crop productivity in low-fertility tropical soils. In this study, 30 bacterial isolates were screened in vitro for multiple PGP traits, including phosphate solubilization (from aluminum phosphate—AlPO₄ and thermophosphate), potassium release from phonolite rock, siderophore production, indole-3-acetic acid (IAA) synthesis, ACC deaminase activity, and antagonism against Fusarium spp. Statistical analysis revealed significant differences (p < 0.05) among the isolates. The most efficient isolates demonstrated a solubilization capacity ranging from 24.0 to 45.2 mg L⁻¹ for thermophosphate and 21.7 to 23.5 mg L⁻¹ for potassium from phonolite. Among them, Pseudomonas azotoformans K22 showed the highest AlPO₄ solubilization (16.6 mg L⁻¹). IAA production among the isolates varied widely, from 1.34 to 9.65 µg mL⁻¹. Furthermore, 17 isolates produced carboxylate-type siderophores, and only Pseudomonas aeruginosa SS183 exhibited ACC deaminase activity, coupled with strong antifungal activity (91% inhibition). A composite performance index identified P. azotoformans K22, E. hormaechei SS150, S. sciuri SS120, and B. cereus SS18 and SS17 as the most promising isolates. This study provides a valuable foundation for characterizing plant growth-promoting traits and identifies key candidates for future validation and the development of microbial consortia. Full article

(This article belongs to the Special Issue Plant Growth-Promoting Bacteria)

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14 pages, 786 KB

Open AccessArticle

Typing of Yersinia pestis in Challenging Forensic Samples Through Targeted Next-Generation Sequencing of Multilocus Variable Number Tandem Repeat Regions

by Hyeongseok Yun, Seung-Ho Lee, Se Hun Gu, Seung Hyun Lim and Dong Hyun Song

Microorganisms 2025, 13(10), 2320; https://doi.org/10.3390/microorganisms13102320 - 7 Oct 2025

Abstract

Microbial forensics involves analyzing biological evidence to evaluate weaponized microorganisms or their toxins. This study aimed to detect and type Yersinia pestis from four simulated forensic samples—human plasma diluted in phosphate-buffered saline (#24-2), tomato juice (#24-5), grape juice (#24-8), and a surgical mask [...] Read more.

Microbial forensics involves analyzing biological evidence to evaluate weaponized microorganisms or their toxins. This study aimed to detect and type Yersinia pestis from four simulated forensic samples—human plasma diluted in phosphate-buffered saline (#24-2), tomato juice (#24-5), grape juice (#24-8), and a surgical mask (#24-10). Notably, samples #24-10 may have contained live bacteria other than Y. pestis. A real-time polymerase chain reaction confirmed the presence of Y. pestis in all samples; however, whole-genome sequencing (WGS) coverage of the Y. pestis chromosome ranged from 0.46% to 97.1%, largely due to host DNA interference and low abundance. To address these limitations and enable strain-level identification, we designed a hybridization-based target enrichment approach focused on multilocus variable number tandem repeat analysis (MLVA). Next-generation sequencing (NGS) using whole-genome amplification revealed that the accuracy of the 25 MLVA profiles of Y. pestis for samples #24-2, #24-5, #24-8, and #24-10 was 4%, 100%, 52%, and 0%, respectively. However, all samples showed 100% accuracy with target-enriched NGS, confirming they all belong to the same strain. These findings demonstrate that a targeted enrichment strategy for MLVA loci can overcome common obstacles in microbial forensics, particularly when working with trace or degraded samples where conventional WGS proves challenging. Full article

(This article belongs to the Special Issue Advancements in Pathogenic Bacteria: Detection, Genomic Analysis, and Antibiotic Resistance)

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16 pages, 1146 KB

Open AccessArticle

Rotavirus Quantification and Genotyping in Wastewater: A Molecular Surveillance Study in Italy (2024–2025)

by Giusy Bonanno Ferraro, Carolina Veneri, Agata Franco, David Brandtner, Daniele Congiu, Pamela Mancini, Marcello Iaconelli, Elisabetta Suffredini and Giuseppina La Rosa

Microorganisms 2025, 13(10), 2319; https://doi.org/10.3390/microorganisms13102319 - 7 Oct 2025

Abstract

Rotavirus remains a leading cause of acute gastroenteritis worldwide, particularly in young children, despite widespread vaccination efforts. This study aims to evaluate rotavirus circulation at the population level through wastewater-based epidemiology (WBE), offering a non-invasive, complementary approach to clinical surveillance. Between 2024 and [...] Read more.

Rotavirus remains a leading cause of acute gastroenteritis worldwide, particularly in young children, despite widespread vaccination efforts. This study aims to evaluate rotavirus circulation at the population level through wastewater-based epidemiology (WBE), offering a non-invasive, complementary approach to clinical surveillance. Between 2024 and 2025, a total of 172 composite 24 h samples were collected from eight urban wastewater treatment plants across Northern, Central, and Southern Italy. Viral RNA was concentrated by PEG precipitation and quantified using digital RT-PCR, while genotypes were determined via nested PCR targeting VP7 and VP4 genes. Rotavirus RNA was detected in 143 out of 172 samples (83.1%), with viral loads ranging between 4.2 × 10² to 7.3 × 10⁵ genome copies per liter (g.c./L). Genotyping revealed G3 as the predominant VP7 type, followed by G1, G2, G6, and G9. All VP4-positive samples were classified as P8. This investigation expands current knowledge of rotavirus epidemiology in Italy using molecular surveillance of urban wastewater. By combining digital RT-PCR and genotyping, it offers a robust framework for integrating WBE into rotavirus monitoring programs, especially in settings where clinical surveillance is limited. Full article

(This article belongs to the Special Issue Surveillance of Health-Relevant Pathogens Employing Wastewater)

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22 pages, 6307 KB

Open AccessArticle

Evaluation of Challenge Models for Flavobacterium covae Infection of Grass Carp (Ctenopharyngodon idellus)

by Rui Han, Huicheng Wu, Zhongning He, Zequan Mo, Xueming Dan and Yanwei Li

Microorganisms 2025, 13(10), 2318; https://doi.org/10.3390/microorganisms13102318 - 7 Oct 2025

Abstract

Columnaris disease is a highly contagious infection that affects nearly all freshwater fish species worldwide. Grass carp, one of the most economically significant freshwater fish species in China, is particularly susceptible to the disease, leading to large-scale mortality. Flavobacterium columnare and F. covae [...] Read more.

Columnaris disease is a highly contagious infection that affects nearly all freshwater fish species worldwide. Grass carp, one of the most economically significant freshwater fish species in China, is particularly susceptible to the disease, leading to large-scale mortality. Flavobacterium columnare and F. covae are the primary pathogens causing columnaris disease in Chinese grass carp aquaculture. Herein, we compare mortality rates, replication rates of typical columnaris symptoms, histopathological changes, and bacterial content in the tissues of grass carp following infection using four challenge models. The mortality rate in grass carp challenged via intraperitoneal injection was 86.7%. All fish infected via intramuscular and intradermal injections died, while immersion resulted in lower mortality. Gill corrosion rates were 67%, 53%, and 87%, respectively, in the intramuscular injection, intradermal injection, and immersion groups. Correspondingly, skin ulceration rates were 75%, 91%, and 63%. However, surface symptoms in the intraperitoneal injection group were milder. Histopathological analysis revealed similar lesions in grass carp subjected to immersion, intramuscular, and intradermal infection, which differed from carp infected via intraperitoneal injection. The trends in bacterial loads in the gills and skin were similar, although the absolute bacterial content varied between tissues. Bacterial loads in the immersion and intraperitoneal injection groups were lower than those in the other groups. Based on these findings, we determined that the optimal model for simulating columnaris disease in grass carp is the intradermal injection of F. covae in 10–12 cm fish. The infection model generated via intradermal injection resembles natural F. covae infection and can serve as a good tool for evaluating the protective effect of anti-F. covae infection vaccines in grass carp. Full article

(This article belongs to the Section Veterinary Microbiology)

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17 pages, 4925 KB

Open AccessArticle

Bacterial Infections and Their Cell Wall Ligands Differentially Modulate Doxorubicin Sensitivity in Triple-Negative Breast Cancer Cells

by Sima Kianpour Rad, Runhao Li, Kenny K. L. Yeo, Fangmeinuo Wu, Yoko Tomita, Timothy J. Price, Wendy V. Ingman, Amanda R. Townsend and Eric Smith

Microorganisms 2025, 13(10), 2317; https://doi.org/10.3390/microorganisms13102317 - 7 Oct 2025

Abstract

Background: Triple-negative breast cancer (TNBC) is an aggressive subtype with limited treatment options and poor clinical outcomes. Emerging evidence suggests that the tumor-associated microbiome may influence disease progression and therapy response. Methods: We investigated how the Gram-negative bacterium Pseudomonas aeruginosa and Gram-positive bacterium [...] Read more.

Background: Triple-negative breast cancer (TNBC) is an aggressive subtype with limited treatment options and poor clinical outcomes. Emerging evidence suggests that the tumor-associated microbiome may influence disease progression and therapy response. Methods: We investigated how the Gram-negative bacterium Pseudomonas aeruginosa and Gram-positive bacterium Staphylococcus aureus, together with their cell wall components lipopolysaccharide (LPS) and lipoteichoic acid (LTA), modulate doxorubicin (DOX) efficacy in TNBC cells. Using gentamicin protection combined with flow cytometry of eFluor 450-labeled bacteria and CFU quantification, we assessed bacterial uptake, persistence, and effects on drug response in MDA-MB-468, MDA-MB-231, and MDA-MB-453 cells. Results: Both bacteria entered TNBC cells and survived for several days in a cell line-dependent manner. Notably, bacterial infection and purified cell wall ligands (LPS and LTA) significantly increased DOX accumulation and enhanced cytotoxicity in MDA-MB-468 and MDA-MB-231, but not in MDA-MB-453. The similar effects of LPS and LTA implicate Toll-like receptor signaling (TLR2 and TLR4) in modulating drug uptake. Conclusions: These findings demonstrate that bacterial infection and associated ligands can enhance doxorubicin uptake and cytotoxicity in TNBC cells, implicating TLR signaling as a potential contributor. Our results highlight the importance of host–microbe interactions in shaping chemotherapy response and warrant further investigation into their therapeutic relevance. Full article

(This article belongs to the Collection Microbiomes and Cancer: A New Era in Diagnosis and Therapy)

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22 pages, 2521 KB

Open AccessArticle

The Remediation of Arsenic-Contaminated Soil by Pteris vittata L. Facilitates the Recovery of Soil Bacterial Diversity and Network Complexity

by Feng Li, Jinhua Liu, Tao Tian, Bin Deng and Haifeng Xiao

Microorganisms 2025, 13(10), 2316; https://doi.org/10.3390/microorganisms13102316 - 7 Oct 2025

Abstract

The remediation of contaminated soils is essential for restoring land productivity and soil health. Pteris vittata L., an arsenic hyperaccumulator, has been widely used for phytoremediation, yet its ecological effects on soil systems remain insufficiently understood. In this field study, we evaluated the [...] Read more.

The remediation of contaminated soils is essential for restoring land productivity and soil health. Pteris vittata L., an arsenic hyperaccumulator, has been widely used for phytoremediation, yet its ecological effects on soil systems remain insufficiently understood. In this field study, we evaluated the influence of Pteris vittata L. remediation on soil physico-chemical properties, microbial diversity, and molecular ecological networks. The results showed that long-term arsenic contamination significantly reduced soil total carbon, total nitrogen, and available phosphorus, simplified bacterial network structures, and markedly altered the keystone taxa that maintain microbial interactions. In contrast, soils under Pteris vittata L. remediation exhibited higher nutrient availability, greater bacterial diversity, and more complex microbial networks than contaminated soils, indicating partial recovery of ecosystem functions. These findings demonstrate that Pteris vittata L. remediation can mitigate arsenic-induced soil degradation and provide an important scientific basis for assessing the long-term impacts of arsenic contamination and the role of remediation measures in soil health evolution. Full article

(This article belongs to the Topic Recent Advances in Soil Health Management)

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12 pages, 724 KB

Open AccessCase Report

Fulminant Multidrug-Resistant Streptococcus pneumoniae Meningoencephalitis After Elective ENT Surgery: A Case Report

by Corina-Ioana Anton, Madalina Maria Zamfir, Alexandru Ghiță and Mihaela Raluca Mititelu

Microorganisms 2025, 13(10), 2315; https://doi.org/10.3390/microorganisms13102315 - 7 Oct 2025

Abstract

Pneumococcal meningoencephalitis is a severe infection associated with high morbidity and mortality. Although typically community-acquired, postoperative cases following elective ENT surgery are exceedingly rare. Antimicrobial resistance (AMR) among Streptococcus pneumoniae further complicates management, and missed opportunities for vaccination represent preventable risks. We report [...] Read more.

Pneumococcal meningoencephalitis is a severe infection associated with high morbidity and mortality. Although typically community-acquired, postoperative cases following elective ENT surgery are exceedingly rare. Antimicrobial resistance (AMR) among Streptococcus pneumoniae further complicates management, and missed opportunities for vaccination represent preventable risks. We report a case of a 41-year-old man with multiple comorbidities who developed fulminant S. pneumoniae meningitis 48 h after septoturbinoplasty. The clinical course was atypical, with altered consciousness but no classical meningeal signs, necessitating urgent intubation and intensive care admission. Cerebrospinal fluid cultures identified an MDR pneumococcal strain resistant to penicillin and macrolides but susceptible to vancomycin and meropenem. Empirical therapy with vancomycin and meropenem, combined with adjunctive corticosteroids and multidisciplinary ICU care, led to complete neurological recovery. This case highlights a rare but life-threatening postoperative complication and underscores two critical lessons. First, the growing challenge of multidrug-resistant pneumococcus requires timely recognition, aggressive empiric therapy, and access to effective agents. Second, the absence of pneumococcal vaccination in this high-risk surgical patient illustrates a preventable gap in care. Integrating vaccination screening into preoperative evaluations may reduce the risk of catastrophic postoperative CNS infections. Full article

(This article belongs to the Section Medical Microbiology)

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15 pages, 1886 KB

Open AccessArticle

Identification and Genetic Characterization of a Strain of African Horse Sickness Virus Serotype 1 and Its Safety Evaluation in a Mouse Model

by Min Zhang, Xue-Feng Wang, Si-Fan Guo, Lei Wang, Bo-Fan Fu, Jing-Wen Wang, Ya-Fen Song, Xiao-Yue Yang, Si-Yuan Hao, Qian-Yi Zhang, Bing Zhang and Cheng-Huai Yang

Microorganisms 2025, 13(10), 2314; https://doi.org/10.3390/microorganisms13102314 - 6 Oct 2025

Abstract

African horse sickness (AHS) is an arthropod-borne, severe equid disease caused by African horse sickness virus (AHSV). AHSV has high mortality and is endemic to sub-Saharan Africa. It has been classified into nine distinct serotypes (AHSV-1 to AHSV-9) based on VP2 immunogenicity. The [...] Read more.

African horse sickness (AHS) is an arthropod-borne, severe equid disease caused by African horse sickness virus (AHSV). AHSV has high mortality and is endemic to sub-Saharan Africa. It has been classified into nine distinct serotypes (AHSV-1 to AHSV-9) based on VP2 immunogenicity. The AHS outbreak in Thailand in 2020, caused by AHSV-1, marked the first occurrence of this disease in Southeast Asia. It posed a substantial threat to the security of the equine industry in the nations across the region. To ensure the emergency reserve for AHS prevention and control, the AHSV strain imported to China from abroad over 60 years ago was characterized in this study. The strain was passaged in mice and then blind-passaged in Vero cells. The plaque purification method was then used to purify the strain and obtain its cell-adapted version, named AHSV/C. Neutralization tests confirmed that the virus belongs to AHSV-1. Whole-genome sequencing revealed that AHSV/C was highly homologous to AHSV-1 isolate 1180, with over 95% homology of major antigenic protein VP2, as compared to other AHSV-1 strains, including the prevalent strain in Thailand. In the mouse models, AHSV/C exhibited no clinical signs or histopathological lesions, suggesting low virulence and safety. This research for the first time characterized the in vitro growth characteristics and viral subtypes of the AHSV in China, determined its complete whole-genome sequence, and evaluated its safety using a mouse model. It provides crucial experimental materials and scientific foundations for the development of diagnostic methods and vaccines against AHSV-1. Full article

(This article belongs to the Section Veterinary Microbiology)

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12 pages, 369 KB

Open AccessArticle

Seroepidemiology of Severe Acute Respiratory Syndrome Coronavirus 2 Infection in Blood Donors from Western Romania, August–September 2023

by Tudor Rares Olariu, Rodica Lighezan, Sorin Ursoniu, Alina Cristiana Craciun, Alexander Tudor Olariu, Sergiu Adrian Sprintar, Daniela Adriana Oatis, Maria Alina Lupu and Alin Gabriel Mihu

Microorganisms 2025, 13(10), 2313; https://doi.org/10.3390/microorganisms13102313 - 6 Oct 2025

Abstract

Serological testing for SARS-CoV-2-specific antibodies, particularly those targeting the nucleocapsid protein, plays a key role in assessing past infection and estimating population-level seroprevalence. The seroprevalence of nucleocapsid antibodies against SARS-CoV-2 was evaluated in 1048 blood donors using the Elecsys Anti-SARS-CoV-2 electrochemiluminescence immunoassay. Participants [...] Read more.

Serological testing for SARS-CoV-2-specific antibodies, particularly those targeting the nucleocapsid protein, plays a key role in assessing past infection and estimating population-level seroprevalence. The seroprevalence of nucleocapsid antibodies against SARS-CoV-2 was evaluated in 1048 blood donors using the Elecsys Anti-SARS-CoV-2 electrochemiluminescence immunoassay. Participants completed a questionnaire to assess risk factors, symptoms during SARS-CoV-2 infection and vaccination status. The overall SARS-CoV-2 seroprevalence was 89.69%. Seroprevalence was not significantly associated with gender or age. In multivariate logistic regression, most investigated risk factors showed no significant association with seroprevalence. However, residence area and vaccination status were independently associated with SARS-CoV-2 seropositivity. Donors from rural areas had significantly higher odds of seropositivity (aOR = 1.68; 95% CI: 1.01–2.79; p = 0.045) compared to those from urban areas. Unvaccinated individuals were more likely to test positive for SARS-CoV-2 compared to vaccinated participants (aOR: 2.59; 95% CI: 1.35–4.99; p = 0.004). After three years of the COVID-19 pandemic, the prevalence of SARS-CoV-2 among blood donors was remarkably high, indicating that the vast majority of this population group had been exposed to the virus. This study highlights the risk factors for SARS-CoV-2 infection and the differences in antibody prevalence between vaccinated and unvaccinated individuals. Our findings underscore the pivotal role of vaccination in controlling the pandemic and provide valuable insights for policymakers in designing targeted strategies to curb future SARS-CoV-2 transmission. Full article

(This article belongs to the Special Issue Epidemics in Humans)

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13 pages, 288 KB

Open AccessReview

Research Progress in the Development of Vaccines Against Riemerella anatipestifer

by Junxvan Lan, Shaopeng Wu, Lu Zhao, Fakai Li, Dongyi Xing, Fan Li, Hui Tian, Xiaoxue Yang, Shuhong Sun and Miaoli Wang

Microorganisms 2025, 13(10), 2312; https://doi.org/10.3390/microorganisms13102312 - 6 Oct 2025

Abstract

Riemerella anatipestifer (R. anatipestifer, RA) is a globally distributed pathogen responsible for duck serositis, an acute multisystemic disease whose infection leads to substantial economic impacts in duck production. There is currently no specific therapeutic drug available for effective treatment. Importantly, the [...] Read more.

Riemerella anatipestifer (R. anatipestifer, RA) is a globally distributed pathogen responsible for duck serositis, an acute multisystemic disease whose infection leads to substantial economic impacts in duck production. There is currently no specific therapeutic drug available for effective treatment. Importantly, the severity of the disease is closely associated with multiple environmental factors, including feeding conditions, management practices, weather fluctuations, and air quality parameters. Furthermore, the prevalence of various serotypes is a matter of concern, and the emergence of multi-drug-resistant mutants through continuous use of various antibiotics is a major challenge. Recently, it has been reported that RA infects domestic ducks, turkeys, geese, wild birds and chicken, which leads to its remarkable influence on the healthy development of waterfowl breeding industry and even poultry breeding industry. Given these challenges, vaccination is essential for disease control. Various vaccine types are currently available, including but not limited to live vaccines, inactivated vaccines, subunit vaccines and vector vaccines. This paper provides a comprehensive review of the development of vaccines for RA. Full article

(This article belongs to the Special Issue Advances in Veterinary Microbiology)

19 pages, 2404 KB

Open AccessSystematic Review

Multifaceted Antibiotic Resistance in Diabetic Foot Infections: A Systematic Review

by Weiqi Li, Oren Sadeh, Jina Chakraborty, Emily Yang, Paramita Basu and Priyank Kumar

Microorganisms 2025, 13(10), 2311; https://doi.org/10.3390/microorganisms13102311 - 6 Oct 2025

Abstract

Diabetic foot infections (DFIs) are a significant complication in patients with diabetes, often leading to severe clinical complications including amputation and increased mortality rates. The effective management of these infections is complicated by the rise in antibiotic resistance among the microbial populations involved. [...] Read more.

Diabetic foot infections (DFIs) are a significant complication in patients with diabetes, often leading to severe clinical complications including amputation and increased mortality rates. The effective management of these infections is complicated by the rise in antibiotic resistance among the microbial populations involved. In this paper, we undertake a systematic review and meta-analysis to explore the bacterial profiles, as well as their antibiotic resistance patterns in DFIs, encompassing studies published between 2014 and 2024. A total of 28 studies were selected from several databases, including PubMed, Google Scholar, EBSCOhost, and ScienceDirect, published from 2014 to 2024, specifically focusing on diabetic foot infections and antibiotic resistance. Diabetic foot infections arise from a combination of factors, including peripheral neuropathy, poor circulation, and immune system impairment, making diabetic patients prone to unnoticed injuries, impaired wound healing, and a higher risk of infections. The severity of DFIs often depends on the size and depth of the ulcers, with larger, deeper ulcers posing additional risks of infection and complications, such as osteomyelitis and sepsis. Our study synthesizes information on the total isolates of microbes, their resistance to one or more groups of antibiotics, and resistance panel results across multiple antibiotics, including amoxicillin/clavulanate, trimethoprim/sulfamethoxazole, ciprofloxacin, and others. We meticulously catalog the resistance of key bacterial strains—Escherichia coli, Enterobacter spp., Proteus spp., Pseudomonas spp., Staphylococcus aureus, and others—highlighting patterns of resistance to single and multiple antibiotic groups. This systematic review also analyzes the correlations of various comorbidities reported by the diabetic foot infection patient populations in the included studies with multiple antibiotic resistance patterns. Subsequently, this analytical review study addresses the rising prevalence of antibiotic-resistant pathogens and underscores the need for antibiotic stewardship programs to promote judicious use of antibiotics, reduce the spread of resistant strains, and enhance therapeutic outcomes. In addition, the review discusses the implications of resistance to empirical antibiotic treatments, underscoring the necessity for tailored antibiotic therapy based on culture and sensitivity results to optimize treatment outcomes. Full article

(This article belongs to the Section Antimicrobial Agents and Resistance)

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22 pages, 6595 KB

Open AccessArticle

Integrated Pathogen–Host Analysis of Citrobacter braakii SCGY-1L: Genomic Determinants and Host Transcriptional Dynamics During Infection

by Zhixiu Wang, Tingting Zhou, Shaoxuan Gu, Jiaqi Yao, Suli Liu and Jiaming Mao

Microorganisms 2025, 13(10), 2310; https://doi.org/10.3390/microorganisms13102310 - 6 Oct 2025

Abstract

Citrobacter braakii is an emerging opportunistic pathogen of escalating clinical significance in animal hosts, though its pathogenic mechanisms remain poorly characterized. This study isolated a C. braakii strain (SCGY-1L) from diseased Siniperca chuatsi and confirmed its identity through integrated morphological, physiological, and molecular [...] Read more.

Citrobacter braakii is an emerging opportunistic pathogen of escalating clinical significance in animal hosts, though its pathogenic mechanisms remain poorly characterized. This study isolated a C. braakii strain (SCGY-1L) from diseased Siniperca chuatsi and confirmed its identity through integrated morphological, physiological, and molecular analyses. Comprehensive genomic sequencing revealed a 5.75 Mb genome comprising one circular chromosome and two plasmids. A Circos plot was constructed to visualize the genomic architecture of strain SCGY-1L, revealing 5482 protein-coding genes, 25 tRNA genes, and 86 rRNA genes. Additionally, 738 virulence-associated genes and 366 antibiotic resistance determinants were annotated, elucidating multidrug-resistant phenotypes including insensitivity to erythromycin and penicillin. Pathogenicity assessment established an LD₅₀ of 1.28 × 10⁶ CFU/mL in infected hosts, with histopathological analysis showing significant hemorrhage and necrosis in target organs (liver, spleen, kidney). Host transcriptome profiling generated 41.21 Gb of high-quality clean data, identifying 2201 differentially expressed genes post-infection (1568 up-regulated; 633 down-regulated). These were significantly enriched in phagocytosis, cytokine-mediated signaling, and inflammatory regulation pathways. These molecular insights establish C. braakii’s mechanistic framework for pathogenesis and host adaptation, providing critical targets for diagnostics and therapeutics against emerging Citrobacter infections. Full article

(This article belongs to the Section Molecular Microbiology and Immunology)

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15 pages, 2194 KB

Open AccessArticle

Methylocystis hydrogenophila sp. nov.—A Type IIa Methanotrophic Bacterium Able to Utilize Hydrogen as an Alternative Energy Source

by Kangli Guo, Thomas Heimerl, Anna Hakobyan, Dongfei Han and Werner Liesack

Microorganisms 2025, 13(10), 2309; https://doi.org/10.3390/microorganisms13102309 - 5 Oct 2025

Abstract

A novel species of the genus Methylocystis is proposed based on polyphasic evidence from strain SC2^T, isolated from the heavily polluted Saale River near Wichmar, Germany. Digital DNA–DNA hybridization and phylogenomic analyses demonstrate that strain SC2^T represents a distinct species [...] Read more.

A novel species of the genus Methylocystis is proposed based on polyphasic evidence from strain SC2^T, isolated from the heavily polluted Saale River near Wichmar, Germany. Digital DNA–DNA hybridization and phylogenomic analyses demonstrate that strain SC2^T represents a distinct species within the genus, clearly separated from its closest relatives, namely Methylocystis suflitae NLS-7^T, Methylocystis rosea SV97^T, Methylocystis silviterrae FS^T, and Methylocystis hirsuta CSC1^T. As is typical of the family Methylocystaceae, cells possess intracytoplasmic membranes arranged parallel to the cytoplasmic membrane, and the dominant fatty acids are C18:1ω8c and C18:1ω7c. The strain grows aerobically on methane as the primary carbon and energy source and expresses both low- and high-affinity particulate methane monooxygenase (pMMO), but lacks the soluble form. The species epithet reflects the strain’s ability to utilize hydrogen as an alternative energy source. A further feature is its use of asparagine as an osmoprotectant, enhancing salt tolerance. Genomic analysis reveals complete pathways for nitrogen fixation, denitrification, and hydrogen oxidation. These genetic and physiological characteristics support the designation of a novel species, for which the name Methylocystis hydrogenophila sp. nov. is proposed. The type strain is SC2^T (=DSM 114506 = NCIMB 15437). Full article

(This article belongs to the Section Microbial Biotechnology)

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