Microorganisms最新文献

{"title":"Subgingival Microbiome Profiles in Bulgarian Children Aged 10-14 with Gingival Inflammation and Healthy Periodontium: A Targeted PCR Study.","authors":"Hristina Tankova, Nadezhda Mitova","doi":"10.3390/microorganisms13071656","DOIUrl":"https://doi.org/10.3390/microorganisms13071656","url":null,"abstract":"<p><p>The subgingival microbiome is a critical component of the oral microbiota and plays a central role in pediatric periodontology. This study investigated differences in periodontopathogen profiles in children with gingival inflammation compared to healthy controls using real-time PCR, with a focus on the microbial complexes defined by Socransky. A total of 73 children (ages 10-14) underwent comprehensive periodontal assessment, including assessments of general health status, the O'Leary hygiene index (HI), gingival condition, and the papillary bleeding index (PBI). Subgingival plaque samples were analyzed using real-time PCR to identify key bacterial species associated with gingival health and disease. Highly pathogenic periodontopathogens such as <i>Aggregatibacter actinomycetemcomitans</i>, <i>Porphyromonas gingivalis</i>, <i>Treponema denticola</i>, and <i>Eubacterium nodatum</i> were absent in healthy subjects. In contrast, <i>Tannerella forsythia</i> was significantly more frequently detected in children with gingival inflammation (<i>p</i> < 0.05). The most abundant species in the inflammation group were <i>Prevotella intermedia</i> and <i>Capnocytophaga gingivalis.</i> Children with gingival inflammation exhibit a distinct subgingival microbiome profile characterized by an increased presence of specific periodontopathogens, including a higher prevalence of red complex species as defined by Socransky. However, the cross-sectional nature of this study limits the ability to establish causal relationships.</p>","PeriodicalId":18667,"journal":{"name":"Microorganisms","volume":"13 7","pages":""},"PeriodicalIF":4.2,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144743001","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fermentation of Microalgae as a Platform for Naturally Encapsulated Oil Powders: Characterization of a High-Oleic Algal Powder Ingredient.","authors":"Walter Rakitsky, Leon Parker, Kevin Ward, Thomas Pilarski, James Price, Mona Correa, Roberta Miller, Veronica Benites, Dino Athanasiadis, Bryce Doherty, Lucy Edy, Jon Wittenberg, Gener Eliares, Daniel Gates, Manuel Oliveira, Frédéric Destaillats, Scott Franklin","doi":"10.3390/microorganisms13071659","DOIUrl":"https://doi.org/10.3390/microorganisms13071659","url":null,"abstract":"<p><p>Powdered oil ingredients are widely used across food, nutrition, and personal care industries, but they are typically produced through encapsulation technologies that involve multiple additives and stabilizers. These systems can compromise oxidative stability, clean-label compliance, and functional performance. Here, we present the development and characterization of a novel high-oleic algal powder (HOAP) produced from a heterotrophically fermented microalgae. The production strain was developed through classical mutagenesis to enhance oleic acid and lipid accumulation. Three independent fermentation batches at a 20 L scale demonstrated strong reproducibility in key metrics, including dried-cell weight (210.0 g per L on average, CV% = 0.7), oil content (62.0% of DCW on average, CV% = 2.0), and oleic acid (88.8% of total fatty acids on average, CV% = 0.1). HOAP exhibited a favorable nutritional profile (e.g., high monounsaturated fat and fiber, low sugar and moisture) and good oxidative stability under ambient and accelerated storage conditions. Microbiological analyses confirmed compliance with food-grade standards, and in silico allergenicity screening revealed no clinically relevant homologs. Unlike traditional oil powders, HOAP does not require encapsulation and retains oil within a natural protein-fiber matrix, offering both functional and clean-labeling advantages. Its compositional attributes and stability profile support potential use in food, nutrition, and the delivery of bioactive nutrients. These findings establish HOAP as a next generation of oil powder ingredients with broad application potential.</p>","PeriodicalId":18667,"journal":{"name":"Microorganisms","volume":"13 7","pages":""},"PeriodicalIF":4.2,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144742950","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Risk of Secondary Bacterial Infections Revealed by Changes in <i>Trachinotus ovatus</i> Skin and Gill Microbiota During a <i>Cryptocaryon irritans</i> Infection Cycle.","authors":"Naiqi Liang, Li Zhu, Shifeng Wang, Weihao Zhang, Xinlei Lin, Yongcan Zhou, Haizhu Ke, Shanheng Yuan, Meijing Li, Yan Cai","doi":"10.3390/microorganisms13071660","DOIUrl":"https://doi.org/10.3390/microorganisms13071660","url":null,"abstract":"<p><p>This study aims to investigate the response of surface bacterial communities in <i>Trachinotus ovatus</i> to <i>Cryptocaryon irritans</i> infection at different stages of a single infection cycle (0~168 h). These samples were analyzed using high-throughput 16S rRNA sequencing. Alpha diversity analysis showed a reduction in the richness and diversity of skin microbiota during infection, with partial recovery post-detachment. Beta diversity analysis revealed distinct structural shifts in skin microbiota at early (24 h) and post-detachment (168 h) stages compared to other phases, while gill microbiota remained stable except during detachment. At the phylum level, Proteobacteria, Actinobacteriota, Bacteroidetes, and Firmicutes were dominant on the skin at different stages, whereas the gill microbiota was predominantly Proteobacteria (>90%). At the genus level, opportunistic pathogens, such as <i>Vibrio</i> and <i>Nautella</i>, increased in relative abundance on the skin with the infection progression, while gill microbiota composition barely changed. The hepatic bacterial load continued to increase with infection duration. These findings indicate that <i>C. irritans</i> alters microbiota composition on skin, facilitating pathogen invasion, thereby elevating the risk of secondary bacterial infections in <i>T. ovatus</i>.</p>","PeriodicalId":18667,"journal":{"name":"Microorganisms","volume":"13 7","pages":""},"PeriodicalIF":4.2,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144743054","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"IL-24 Is a Promising Molecular Adjuvant for Enhancing Protective Immunity Induced by DNA Vaccination Against <i>Toxoplasma gondii</i>.","authors":"Bohuai Xu, Xiuqiang Zhang, Yaowen Wang, Jia Chen","doi":"10.3390/microorganisms13071661","DOIUrl":"https://doi.org/10.3390/microorganisms13071661","url":null,"abstract":"<p><p><i>Toxoplasma gondii</i>, a parasitic protozoan, causes zoonotic infections with severe health impacts in humans and warm-blooded animals, underscoring the urgent need for effective vaccines to control these infections. In this study, a DNA vaccine encoding TgROP5, TgROP18, TgGRA7, TgGRA15, and TgMIC6 was formulated using the eukaryotic expression vector pVAX I. IL-24 was delivered as a molecular adjuvant using plasmid pVAX-IL-24. BALB/c, C57BL/6, and Kunming mouse strains received the DNA immunization, after which antibody levels, cytokine production, and lymphocyte surface markers were analyzed to assess immune responses. Additionally, survival rates and brain cyst counts were measured 1 to 2 months post-vaccination in experimental models of toxoplasmosis. As a result, compared to controls, the DNA vaccine cocktail significantly increased serum IgG levels, Th1 cytokine production, and proportions of CD4+/CD8+ T cells, leading to extended survival and reduced brain cyst counts post-challenge with <i>T. gondii</i> ME49. Furthermore, the five-gene DNA vaccine cocktail conferred greater protection compared to single-gene immunizations. Co-administration of IL-24 significantly enhanced the immune efficacy of the multi-gene DNA vaccination. Our findings suggest that IL-24 is an effective molecular adjuvant, enhancing the protective immunity of DNA vaccines against <i>T. gondii</i>, supporting its potential role in vaccine strategies targeting other apicomplexan parasites.</p>","PeriodicalId":18667,"journal":{"name":"Microorganisms","volume":"13 7","pages":""},"PeriodicalIF":4.2,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144742927","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Healthy Ageing and Gut Microbiota: A Study on Longevity in Adults.","authors":"Lihua Deng, Jun Xu, Qian Xue, Yanan Wei, Jingtong Wang","doi":"10.3390/microorganisms13071657","DOIUrl":"https://doi.org/10.3390/microorganisms13071657","url":null,"abstract":"<p><p>Many studies have focused on ageing and gut microbiota, but the correlation between gut microbiota and physical function in older adults, especially those with longevity, remains obscure and deserves further exploration. In this study we investigated changes in the gut microbiota and the association between gut microbiota and physical function in adults with longevity. This is a prospective observational study. Fifty-one older adults aged ≥ 60 years (including 27 participants aged 90 years and above) were enrolled. Information on clinical data, physical function including intrinsic capacity by Integrated Care for Older People (ICOPE) tool, and dietary habits of participants was collected and analysed. Gut microbiota structure and functional pathways were analysed by Metagenomics. Intrinsic capacity (measured as ICOPE scores) of adults' longevity (aged 90-98, longe group) was significantly lower than older adults aged 60-89 years (CON group) (5.44 ± 2.15 vs. 6.71 ± 1.46, <i>p</i> = 0.017). Gut microbiota of the longe group is enriched in <i>Akkermansia</i> and <i>Bifidobacterium</i>, which may be beneficial to health. Gut microbiota was closely related to daily milk (including plain milk, flavoured milk with a content of cow's milk or reconstituted milk of ≥80%, or reconstituted milk or fermented milk with a content of cow's milk or milk powder of ≥80%) consumption, anxiety, and physical function including grip strength by the Short Physical Performance Battery (SPPB). <i>Bacteroides plebeius</i> and <i>Bacteroides eggerthii</i> were increased in long-living adults with better physical function. <i>Escherichia coli</i> was more abundant in frail young-old adults. Grip strength is positively correlated with the abundance of <i>Roseburia hominis</i>, <i>Eubacterium rectale</i>, <i>Eubacterium eligens</i>, and <i>Roseburia intestinalis</i> (<i>p</i> < 0.05). Pathways related to amino acid synthesis that include L-isoleucine, L-valine, and L-threonine were over-presented in long-living adults of better physical function. Adults with longevity showed comparable gut microbiota abundance to younger elderly individuals. The gut microbiota of long-living adults showed higher abundance of potentially beneficial bacteria, and the altered bacteria are closely associated with physical function. Changes in the gut microbiota may precede clinical indicators during the process of ageing. Gut microbiota may be a potential biomarker for longevity and healthy ageing. Nutrition and emotional state can be important influencing factors.</p>","PeriodicalId":18667,"journal":{"name":"Microorganisms","volume":"13 7","pages":""},"PeriodicalIF":4.2,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144742906","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of Antibiotic Residues on Fecal Microbiota Composition and Antimicrobial Resistance Gene Profiles in Cattle from Northwestern China.","authors":"Wei He, Xiaoming Wang, Yuying Cao, Cong Liu, Zihui Qin, Yang Zuo, Yiming Li, Fang Tang, Jianjun Dai, Shaolin Wang, Feng Xue","doi":"10.3390/microorganisms13071658","DOIUrl":"https://doi.org/10.3390/microorganisms13071658","url":null,"abstract":"<p><p>Grazing is a free-range farming model commonly practiced in low-external-input agricultural systems. The widespread use of veterinary antibiotics in livestock farming has led to significant environmental accumulation of antibiotic residues and antibiotic resistance genes (ARGs), posing global health risks. This study investigated the antibiotic residues, bacterial community, ARG profiles, and mobile genetic elements (MGEs) in cattle feces from three provinces in western China (Ningxia, Xinjiang, and Inner Mongolia) under grazing modes. The HPLC-MS detection showed that the concentration of tetracycline antibiotics was the highest in all three provinces. Correlation analysis revealed a significant negative correlation between antibiotic residues and the diversity and population abundance of intestinal microbiota. However, the abundance of ARGs was directly proportional to antibiotic residues. Then, the Sankey analysis revealed that the ARGs in the cattle fecal samples were concentrated in 15 human pathogenic bacteria (HPB) species, with 9 of these species harboring multiple drug resistance genes. Metagenomic sequencing revealed that carbapenemase-resistant genes (<i>bla</i>_KPC and <i>bla</i>_VIM) were also present in considerable abundance, accounting for about 10% of the total ARGs detected in three provinces. Notably, <i>Klebsiella pneumoniae</i> strains carrying <i>bla</i>_CTX-M-55 were detected, which had a possibility of IncFII plasmids harboring transposons and IS19, indicating the risk of horizontal transfer of ARGs. This study significantly advances the understanding of the impact of antibiotic residues on the fecal microbiota composition and ARG profiles in grazing cattle from northwestern China. Furthermore, it provides critical insights for the development of rational antibiotic usage strategies and comprehensive public health risk assessments.</p>","PeriodicalId":18667,"journal":{"name":"Microorganisms","volume":"13 7","pages":""},"PeriodicalIF":4.2,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144742933","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Population Structure, Genomic Features, and Antibiotic Resistance of Avian Pathogenic <i>Escherichia coli</i> in Shandong Province and Adjacent Regions, China (2008-2023).","authors":"Shikai Song, Yao Wang, Zhihai Liu, Rongling Zhang, Kaiyuan Li, Bin Yin, Zunxiang Yan, Shifa Yang, Shuqian Lin, Yunpeng Yi","doi":"10.3390/microorganisms13071655","DOIUrl":"https://doi.org/10.3390/microorganisms13071655","url":null,"abstract":"<p><p>Avian pathogenic <i>Escherichia coli</i> (APEC) poses a global threat to poultry health and public safety due to its high lethality, limited treatment options, and potential for zoonotic transmission via the food chain. However, long-term genomic surveillance remains limited, especially in countries like China where poultry farming is highly intensive. This study aimed to characterize the population structure, virulence traits, and antimicrobial resistance of 81 APEC isolates from diseased chickens collected over 16 years from Shandong and neighboring provinces in eastern China. The isolates were grouped into seven Clermont phylogroups, with A and B1 being dominant. MLST revealed 27 STs, and serotyping identified 29 O and 16 H antigens, showing high genetic diversity. The minor phylogroups (B2, C, D, E, G) encoded more virulence genes and had higher virulence-plasmid ColV carriage, with enrichment for iron-uptake, protectins, and extraintestinal toxins. In contrast, the dominant phylogroups A and B1 primarily carried adhesin and enterotoxin genes. Antimicrobial resistance was widespread: 76.5% of isolates were multidrug-resistant. The minor phylogroups exhibited higher tetracycline resistance (mediated by <i>tet</i>(A)), whereas the major phylogroups showed increased resistance to third- and fourth-generation cephalosporins (due to <i>bla</i>_CTX-M-type ESBL genes). These findings offer crucial data for APEC prevention and control, safeguarding the poultry industry and public health.</p>","PeriodicalId":18667,"journal":{"name":"Microorganisms","volume":"13 7","pages":""},"PeriodicalIF":4.2,"publicationDate":"2025-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144743042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Taxon-Dependent Community Assembly of Bacteria and Protists in River Ecosystems: A Case Study from the Yujiang River.","authors":"Yusen Li, Wenjian Chen, Yaoquan Han, Jianjun Lei, Bo Huang, Youjie Qin, Feng Lin, Caijin Li, Dapeng Wang, Lei Zhou","doi":"10.3390/microorganisms13071650","DOIUrl":"https://doi.org/10.3390/microorganisms13071650","url":null,"abstract":"<p><p>Understanding the processes that drive microbial community assembly is a fundamental question in ecology, with important implications for predicting community responses to environmental disturbances. River ecosystems are under growing pressure from human disturbances, jeopardizing their ecological functions. Here, we investigated bacterial and protistan communities along the Yujiang River using environmental DNA metabarcoding. Bacterial communities exhibited significantly greater alpha diversity and broader habitat niches compared to protists. Additionally, a negative correlation was found between alpha diversity and niche breadth for both groups. Protistan communities exhibited significantly higher beta diversity (Bray-Curtis distance) than bacterial communities, with species turnover being the principal factor driving the variations in both communities. Null model results indicated that heterogeneous selection primarily structured bacterial communities, while stochastic processes (drift) mainly governed protist communities. Redundancy analysis and Mantel tests showed significant associations between environmental factors (e.g., temperature and pH) and bacterial community composition. Moreover, the longitude of sampling sites was linked to spatial variations in both bacterial and protistan communities. Further analyses, including distance-decay patterns, variation partitioning, and multiple regression on distance matrices, demonstrated that bacterial communities were driven by both environmental and spatial factors, while protist communities exhibited a stronger response to spatial factors. These results enhance our understanding of microbial community assembly in river ecosystems and provide valuable insights for the conservation and sustainable management of freshwater systems.</p>","PeriodicalId":18667,"journal":{"name":"Microorganisms","volume":"13 7","pages":""},"PeriodicalIF":4.2,"publicationDate":"2025-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144743006","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Responses of Different Temperature-Acclimated Diatom Species, Smaller <i>Thalassiosira pseudonana</i> and Larger <i>Thalassiosira rotula</i>, to Increased Ambient Temperature.","authors":"Wei Zhao, Jihua Liu, Hui Song, Bokun Chen, Hongli Ji, Xue Yang, Gang Li","doi":"10.3390/microorganisms13071652","DOIUrl":"https://doi.org/10.3390/microorganisms13071652","url":null,"abstract":"<p><p>The acute rise in temperature due to marine heatwaves has a strong impact on marine phytoplankton. To determine whether these effects depend on ambient temperature and cell size, we acclimated two diatom species, smaller <i>Thalassiosira pseudonana</i> (Hasle and Heimdal, 1970) and larger <i>Thalassiosira rotula</i> (Meunier, 1910), at low (LAT), medium (MAT) and high ambient temperatures (HAT) and examined their physiochemical and transcriptional responses to temperature rise (AT + 6 °C). The specific growth rate (µ) of smaller cells was increased by 32% due to temperature rise at LAT, but decreased by 13% at HAT, with the stimulatory and inhibitory extent being ~50% less than that of larger cells. At LAT, chlorophyll <i>a</i> (Chl <i>a</i>), carotenoid (Car) and carbon (POC) contents were increased in smaller cells due to temperature rise, but were decreased in larger cells; at HAT, Chl <i>a</i> and Car were increased in both smaller and larger cells and POC was increased in only smaller cells. At LAT, temperature rise led to a disproportionate increase in photosynthesis and dark respiration, resulting in an increase in carbon utilization efficiency (CUE) in smaller cells and a decrease in CUE in larger cells; at HAT, there was a decrease in CUE in both the smaller and larger cells, but to a lesser extent in the former than in the latter. Our results also show that smaller cells cope with the acute temperature rise mainly by strengthening their enzyme activity (e.g., the antioxidant system) and conservatively regulating their metabolism, while larger cells mainly regulate their photosynthetic and central carbon metabolism. Moreover, larger cells can outperform their smaller counterparts when the temperature rise occurs at lower ambient temperature.</p>","PeriodicalId":18667,"journal":{"name":"Microorganisms","volume":"13 7","pages":""},"PeriodicalIF":4.2,"publicationDate":"2025-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144743051","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hybrid Whole Genomes of <i>Brucella melitensis</i> from Tunisian Animal Isolates: Virulence Factors, Antimicrobial Susceptibility, and Phylogeny.","authors":"Ibtihel Ben Abdallah, Germán Kopprio, Awatef Béjaoui, Susanne Köhler, Kaouther Guesmi, Sana Kalthoum, Jacob Gatz, Amel Arfaoui, Monia Lachtar, Haikel Hajlaoui, Mohamed Naceur Baccar, Holger Scholz, Abderrazak Maaroufi","doi":"10.3390/microorganisms13071651","DOIUrl":"https://doi.org/10.3390/microorganisms13071651","url":null,"abstract":"<p><p>Brucellosis remains endemic in Tunisia, causing abortions in small ruminants, and represents a public health threat through occupational exposure and the consumption of contaminated animal products. The aims of this study are to assess the antibiotic susceptibility of two <i>Brucella melitensis</i> isolates (TATA and SBZ) from aborted sheep, to analyze their genomes using hybrid whole-genome sequencing, and to investigate their antimicrobial resistance (AMR), potential virulence factors (VFs), and phylogenetic relationships. Both isolates were phenotypically confirmed to be susceptible to doxycycline, gentamicin, rifampicin, streptomycin, and trimethoprim-sulfamethoxazole, and no corresponding classical AMR genes were identified. However, several potential AMR-related genes (<i>mprF</i>, <i>bepCDEFG</i>, <i>qacG</i>, and <i>adeF</i>) and a mutation in the <i>parC</i> gene were detected. The analysis of the genotypes revealed 74 potential virulence genes, primarily involved in lipopolysaccharide synthesis and type IV secretion systems. Genomic comparison showed over 99% nucleotide identity between the Tunisian strains, <i>B. melitensis</i> bv. 1 16M and <i>B. melitensis</i> bv. 3 Ether. Five gene clusters, including three hypothetical proteins with 100% identity, were detected exclusively in the TATA and SBZ strains. Additionally, two unique gene clusters were identified in SBZ: a rhodocoxin reductase and another hypothetical protein. Both isolates were assigned to sequence types ST11 and ST89. Core-genome-based phylogenetic analysis clustered both strains with biovar 3 and ordered the Tunisian strains into two distinct groups: TATA within Tunisian Cluster 1 is closely related to strains from Egypt and Italy, while SBZ near MST Cluster 4 is more related to isolates from Austria and two outliers from Italy and Tunisia. This study provides the first genomic characterization of <i>B. melitensis</i> from aborted sheep in Tunisia and offers valuable insights into AMR, virulence, and phylogenetic distribution.</p>","PeriodicalId":18667,"journal":{"name":"Microorganisms","volume":"13 7","pages":""},"PeriodicalIF":4.2,"publicationDate":"2025-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144742922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}