BMC Microbiology最新文献

{"title":"Genomic analysis reveals multi-lineage carbapenem-resistant Pseudomonas aeruginosa mimicking a hospital outbreak.","authors":"Süleyman Yalçın, Sezin Ünlü Çelebi, Salih Rıza Ozan Yıldız, Özlem Kurt Azap, Helin Şahintürk, Aylin Üsküdar Güçlü","doi":"10.1186/s12866-026-05421-w","DOIUrl":"10.1186/s12866-026-05421-w","url":null,"abstract":"<p><strong>Background: </strong>Pseudomonas aeruginosa is a major cause of nosocomial infections, often exhibiting multidrug resistance (MDR) and high genetic adaptability. This study investigated temporal cluster of MDR P. aeruginosa isolates obtained from five different hospitalized patients within a single healthcare facility. The isolates shared similar antimicrobial resistance patterns, suggesting a common source or transmission event. However, pulsed-field gel electrophoresis (PFGE) genotyping identified four distinct clones, indicating clonal heterogeneity rather than a single-strain outbreak. To further elucidate the genetic basis of resistance, virulence, and genomic diversity, whole-genome sequencing (WGS) was performed.</p><p><strong>Results: </strong>All the isolates were resistant to cefepime, ceftazidime, meropenem, ciprofloxaxin, levofloxaxin, piperacillin-tazobactam; three of them were susceptible to amikacin, and all were susceptible to colistin. Resistome analysis revealed a diverse array of antimicrobial resistance genes, including chromosomal class C (bla_{PDC-16/37/374}) and D (bla_OXA-50 family:395/847/848/906) and bla_VIM-2 type β-lactamases, and a wide variety of efflux pumps (such as MexAB-OprM, MexCD-OprJ MexGHI-OpmD, MexJK-OprM, MexMN-OprM, MexPQ-OpmE, MuxABC-OpmB). Virulome analysis identified key pathogenicity determinants related to biofilm formation, adherence, motility, immune evasion, toxin and other virulence traits. Multiple mobile genetic elements were determined, suggesting horizontal gene transfer (HGT) as a significant factor in the dissemination of resistance traits.</p><p><strong>Conclusion: </strong>These findings demonstrate that nosocomial outbreak-like event of MDR P. aeruginosa can involve multiple unrelated clones co-circulating within the same hospital environment, challenging traditional epidemiological assumptions. Despite a high degree of core genome synteny and similar resistance profiles, the identification of four distinct clones among simultaneous patient cases indicates that the outbreak was not caused by a single strain. These results further emphasize the potential for multiple co-circulating clones in MDR P. aeruginosa outbreaks and challenge assumptions of single-source transmission. Whole-genome sequencing plays a critical role in understanding transmission dynamics and guiding infection control strategies.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":" ","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13656550/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148469041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Vaginal PRA1 identifies clinically relevant Candida albicans vaginitis and excludes asymptomatic colonization: an exploratory study.","authors":"Elena Roselletti, Barbara Kozma, David Ratonyi, Alexandra Kunkli, Bence Kozma, Peter Takacs, Duncan Wilson","doi":"10.1186/s12866-026-05405-w","DOIUrl":"10.1186/s12866-026-05405-w","url":null,"abstract":"&lt;p&gt;&lt;strong&gt;Background: &lt;/strong&gt;Accurate interpretation of Candida detection in women with vulvovaginal symptoms remains difficult, because organism recovery may reflect either clinically relevant infection or nonpathogenic colonization. We have recently demonstrated that the secreted fungal zinc-binding protein, Pra1 is responsible for driving the inflammatory immunopathology of VVC. We therefore reasoned that PRA1 expression by Candida albicans in the vagina may act as a diagnostic tool to discriminate between commensal colonisation and active disease.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Methods: &lt;/strong&gt;We conducted a 12-week prospective, single-center exploratory biomarker analysis nested within a registered parent clinical trial. Nine women with vulvovaginal symptoms provided cervicovaginal lavage samples and clinical data at baseline and at weeks 4, 8, and 12. This report does not present the primary efficacy analysis of the randomized trial. At each visit, Candida culture status and clinical severity score (CSS) were recorded. Symptomatic Candida vaginitis was defined as Candida culture positivity with CSS ≥ 3 at the same visit. Species identification of fungal isolates was performed by MALDI-TOF mass spectrometry, and vaginal PRA1 was quantified by SYBR Green real-time qPCR. Vaginal PRA1 concentrations were assessed as a time-varying same-visit biomarker using repeated-measures approaches, non-parametric comparisons, correlation analyses, and receiver operating characteristic (ROC) curves.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results: &lt;/strong&gt;PRA1 concentrations were substantially higher in Candida culture-positive than in culture-negative samples (median 4,011 vs. 21.5 pg/µL, p = 3.99 × 10⁻⁵). PRA1 was also higher in samples meeting criteria for symptomatic Candida vaginitis than in asymptomatic culture-negative samples (median 11,762 vs. 21.5 pg/µL, p = 8.15 × 10⁻⁵). Among culture-positive observations, PRA1 was associated with symptom severity (Spearman rho = 0.67; Pearson r = 0.56 after log10 transformation). Same-visit discrimination was high in this cohort for both Candida culture positivity and symptomatic Candida vaginitis (AUC approximately 0.95 for each outcome). In this small exploratory cohort, lower PRA1 thresholds achieved 100% sensitivity and negative predictive value for clinically significant Candida vaginitis. These estimates require validation in larger studies.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusions: &lt;/strong&gt;These preliminary findings suggest that vaginal PRA1 may help distinguish symptomatic Candida-associated disease from clinically insignificant Candida detection and may be particularly useful as a rule-out biomarker. Given the small sample size and exploratory design, these results should be regarded as hypothesis-generating and require validation in larger, independent cohorts. The study protocol was approved by the Hungarian National Institutional Review Medical Research Council (approval No. 3282-7/2023/EUIG). The parent trial is registered at ClinicalTrials.gov (NC","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":" ","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13656439/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148469081","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Isolation, characterization, and genomic analysis of a novel lytic bacteriophage with potent antibiofilm activity against multidrug-resistant Acinetobacter baumannii.","authors":"Ethar M Amin, Ramy K Aziz, Fathia E Murad, Marwa T Elrakaiby, Reham Samir","doi":"10.1186/s12866-026-05262-7","DOIUrl":"10.1186/s12866-026-05262-7","url":null,"abstract":"<p><p>The rapid rise of multidrug-resistant Acinetobacter baumannii (MDR A. baumannii) poses a serious threat in healthcare settings, as these bacteria can cause infections that are untreatable with conventional antibiotics. This crisis has driven the search for alternative therapies, one of which is bacteriophages. In this study, we isolated a novel bacteriophage, vB_AbaM_EA1 (E7 for short), from wastewater and evaluated its potential activity against clinical MDR A. baumannii strains. Phage E7 successfully infects (27.5%) of the 40 clinical MDR A. baumannii isolates we tested. Laboratory characterization suggested that E7 is a highly efficient lytic phage, rapidly attaching to bacterial cells and producing 1000 new viral particles.A key finding was its potent activity against bacterial biofilms, a major source of persistent infections. Not only did Phage E7 effectively prevent the formation of new biofilms, but more importantly disrupted mature ones, which typically confer higher resistance to antibiotics.Genome sequencing confirmed that Phage E7 is a new member of the Obolenskvirus genus and that its genome lacks genes encoding bacterial toxins, antibiotic resistance, or lysogenic factors, indicating a mandatory safety profile for therapeutic use. Furthermore, E7 remained stable across a broad temperature range (-20 to 45 °C) and pH values (5-9) that it might encounter during storage and administration. In conclusion, Phage E7 is a stable, safe, and highly effective candidate for phage therapy against infections by MDR A. baumannii. Its ability to target both planktonic bacteria and biofilms makes it a promising candidate for future development into clinical applications.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":"26 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13377704/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148469064","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Human salivary microbiome as a potential non-invasive biomarker for early-onset colorectal cancer screening: a prospective study.","authors":"Junhai Zhen, Mingyue Dong, Yangbo Li, Beibei Cao, Fei Liao, Dandan Lin, Jixiang Zhang, Chuan Liu, Xianwei Zheng, Weiguo Dong","doi":"10.1186/s12866-026-05397-7","DOIUrl":"10.1186/s12866-026-05397-7","url":null,"abstract":"<p><strong>Background: </strong>The incidence of early-onset colorectal cancer (EOCRC) has been increasing in recent years, the carcinogenesis of which has been linked to oral microbiota alterations. However, it is unknown if the salivary microbiome could help detect EOCRC. Therefore, we aimed to determine whether salivary microbiome profiles can distinguish patients with EOCRC from healthy individuals and to evaluate their diagnostic performance as a non-invasive screening tool.</p><p><strong>Methods: </strong>We collected saliva samples from 65 EOCRC patients and 63 control individuals, the microbiota of which was assessed using high-throughput 16S ribosomal RNA gene V3-V4 region sequencing. We then profiled the saliva microbiota and developed EOCRC screening models using machine learning (ML) algorithms.</p><p><strong>Results: </strong>The alpha diversity was comparable between salivary microbiomes of the EOCRC patients and control individuals, while the beta diversity exhibited statistical difference between two groups. A differential analysis of the genus-level saliva microbial communities revealed that, in the EOCRC patients, Prevotella, Actinomyces, and Corynebacterium were more abundant, whereas Fusobacterium, Haemophilus, norank_o__Absconditabacteriales_SR1, norank_c__Gracilibacteria, Peptococcus, Eikenella, and Eubacterium_yurii_group were less abundant. Furthermore, in developing the EOCRC screening model based on the salivary microbiome, the neural network model showed the best performance, achieving an AUC of 0.780 and a recall of 0.929, showing potential for distinguishing EOCRC patients from control individuals in this cohort.</p><p><strong>Conclusions: </strong>This study first highlights the potential dysbiosis of salivary microbiota in EOCRC patients and suggests that salivary microbiome-based biomarkers may serve as potential non-invasive tools for EOCRC screening. Additional research with larger sample sizes would help to further validate these findings.</p><p><strong>Trial registration: </strong>This study was registered with the Chinese Clinical Trial Registry (registration number: ChiCTR2400087634) on July 31, 2024, retrospectively registered.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":" ","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13660329/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148469049","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermophilic bio-factory Bacillus sonorensis SS1 for superparamagnetic iron sulfide nanoparticles (FeSNPs) synthesis: in vitro and molecular modeling studies of anticancer activity.","authors":"Samia S Abouelkheir, Shaimaa Makled, Botros Y Beshay, Ahmed Abdel-Mawgood, Sarah O Makled","doi":"10.1186/s12866-026-05140-2","DOIUrl":"10.1186/s12866-026-05140-2","url":null,"abstract":"<p><p>An eco-friendly method lets the thermophilic Bacillus sonorensis SS1 synthesize superparamagnetic nano-sized iron sulfide particles (FeSNPs) as bio-factories. These clean and non-toxic FeSNPs have led to increased interest in using inorganic nanoparticles (NPs) in health materials and industrial products. The biosynthesized FeSNPs exhibited an average particle size of approximately 4.5 nm and a negative surface charge (- 16.8 ± 0.6 mV), indicating good colloidal stability. In vitro cytotoxicity evaluation using the MTT assay demonstrated concentration-dependent growth inhibition against five cancer cell lines (A549, HeLa, MCF-7, HepG2, and HCT-116), with IC₅₀ values ranging from 18 to > 100 µg/mL. The highest cytotoxic activity was observed against A549 (IC₅₀ = 18 µg/mL) and HeLa (IC₅₀ = 27 µg/mL) cells, and MCF-7 (IC₅₀ = 75 µg/mL) showed moderate sensitivity, while comparatively lower sensitivity was detected in HepG2 and HCT-116 cells (IC₅₀ value > 100 µg/mL). In contrast, normal peripheral blood mononuclear cells (PBMCs) exhibited minimal cytotoxicity, with an IC₅₀ value > 100 µg/mL, indicating selective anticancer activity of the FeSNPs. The molecular docking studies demonstrated that the FeSNPs exhibit a strong binding affinity to the active sites of Caspase-3, VEGFR, and Aurora-A. These interactions suggest that FeSNPs can effectively inhibit critical pathways involved in tumor growth, angiogenesis, and radiotherapy resistance. The biochemical validation confirmed these interactions, showing a 14.6-fold induction of active Caspase-3 (516.8 ± 20.1 pg/mL) in A549 cells. Additionally, FeSNPs exhibited potent inhibitory activity against VEGFR2 (IC₅₀ = 0.447 ± 0.019 µg/mL) and Aurora-A (IC₅₀ = 0.268 ± 0.012 µg/mL). These findings demonstrate the potential of FeSNPs as multifunctional agents capable of simultaneously triggering apoptosis and disrupting angiogenic and proliferative pathways. The findings focus on the potential of FeSNPs as versatile therapeutic agents in cancer therapy.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":" ","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13393815/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148454804","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Carriage and susceptibility of Enterobacteria isolated from the local chickens at markets and peri-urban areas of Bobo-Dioulasso, Burkina Faso.","authors":"Drissa Zon, Victorien Yaméogo, Roland Nâg-Tiero Meda, Soufiane Sanou, Benjamin Kouliga Koama, Yerbanga R Serge, Sami Eric Kam, Eliasse Zongo, Kobo Gnada, Georges Anicet Ouédraogo, Mohamed Fawzy Ramadan","doi":"10.1186/s12866-026-05394-w","DOIUrl":"10.1186/s12866-026-05394-w","url":null,"abstract":"<p><strong>Background: </strong>Salmonella and Escherichia coli are among the main causes of foodborne illness and negatively impact poultry industry. The aim of this study is to determine the carriage rate and sensitivity of Enterobacteria isolated from the cloacae of chickens. Samples were taken only from healthy local chickens of markets (55 samples) and outlying areas (45 samples) using the swabbing technique. The swabs were pre-enriched and inoculated onto Hektoen agar at 37 °C for 24 h. Bacteria and resistance genes were identified through molecular biology. Antimicrobial susceptibility was tested by Kirby Bauer method.</p><p><strong>Results: </strong>The overall prevalence was 65% for Escherichia coli and 27% for Salmonella sp. after biochemical tests and these carrying rates of these strains were 10% for Salmonella and 53% for Escherichia coli after molecular confirmation tests. E. coli isolates (n = 53), 91.43% (32/35) originated from farms, while 75% (21/28) were collected from markets. The detection of the 16S rRNA gene was higher in market samples (25%) compared to farm samples (8.57%). Antibiotic susceptibility testing showed extremely high resistance rates to amoxicillin (> 93%) and tetracycline (> 80%) in both bacterial species. In contrast, high susceptibility rates were recorded to ceftriaxone (> 90%) and norfloxacin (> 89%). Moderate resistance levels were observed to cotrimoxazole and amoxicillin-clavulanic acid Augmentin (> 41%). Comparative statistical analysis between bacterial species showed no statistically significant difference for most antibiotics (p > 0.05). Among Escherichia coli isolates, 58.49% (31/53) exhibited a penicillinase phenotype, compared with 60% (6/10) of Salmonella spp. and ESBL phenotypes were detected in 35.80% (19/53) of E. coli isolates and 40% (4/10) of Salmonella spp. isolates. No statistically significant difference was observed between the species. The bla_TEM gene was detected in 41.5% (22/53) of E. coli isolates and in 60% (6/10) of Salmonella spp. isolates. Similarly, the bla_CTX-M-9 gene was identified in 35.58% (19/53) of E. coli isolates and 30% (3/10) of Salmonella spp. isolates although this difference was not statistically significant (p > 0.05).</p><p><strong>Conclusion: </strong>This study highlighted the presence of strains Enterobacteria resistant to many antimicrobials of therapeutic importance in healthy chickens. For the well-being of consumers, it is necessary to strengthen surveillance and prevention systems.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":" ","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13679011/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148469074","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"One-pot LAMP-CRISPR/Cas12b coupled with nanoparticle-based biosensor for point-of-care test of Neisseria gonorrhoeae.","authors":"Ling Xie, Yan Tan, Yanyan Qin, Cencen Jia, Ya Li, Yanan Liu, Xu Chen","doi":"10.1186/s12866-026-05404-x","DOIUrl":"10.1186/s12866-026-05404-x","url":null,"abstract":"<p><strong>Background: </strong>Gonorrhea, caused by the human obligate pathogen Neisseria gonorrhoeae, is the second most common bacterial sexually transmitted infection worldwide. In the absence of an effective gonococcal vaccine, convenient and accurate diagnosis of N. gonorrhoeae infection is essential for optimal patient management and for interrupting ongoing transmission.</p><p><strong>Methods: </strong>A custom-designed gold nanoparticle-based lateral flow biosensor (AuNP-LFB) was employed. The unique LAMP primers and a specific single-guide RNA (sgRNA) were designed to target the orf1 gene of N. gonorrhoeae. The key diagnostic conditions, including detection temperature and time, were optimized. The sensitivity and specificity of the assay were validated, and its clinical feasibility was validated using seventy-eight genital secretion samples from patients suspected of N. gonorrhoeae infection.</p><p><strong>Results: </strong>The custom-designed AuNP-LFB was successfully fabricated. The Ng-CRISPR-One-Pot assay achieved a limit of detection (LoD) as low as 7 copies per test and exhibits no cross-reactivity with other tested microbial species. The entire detection workflow, including nucleic acid extraction (10 min), LAMP-CRISPR/Cas12b detection (56 °C, 50 min), and AuNP-LFB visual readout (< 2 min), can be completed within 65 min without requiring specialized instrumentation. Compared with a reference N. gonorrhoeae-qPCR method, our assay achieved 100% sensitivity (95% CI: 93.94-100.00%) and 100% specificity (95% CI: 82.35-100.00%).</p><p><strong>Conclusions: </strong>Collectively, these preliminary results indicate that the Ng-CRISPR-One-Pot assay holds promise as a practical point-of-care (POC) diagnostic tool, enabling accurate and convenient detection of N. gonorrhoeae, particularly in resource-limited settings.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":" ","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13678930/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148469089","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Synergistic biofilm formation by the coexistence of nontypeable Haemophilus influenzae and Moraxella catarrhalis reduces amoxicillin efficacy.","authors":"Nafisa Khamis Umar, Ryo Ueda, Tatsuya Shiga, Taku Fujishiro, Yoshimi Onishi, Tomoko Kamiyama, Hideki Sakatani, Kazuya Mizobata, Shunji Tamagawa, Muneki Hotomi, Masamitsu Kono","doi":"10.1186/s12866-026-05420-x","DOIUrl":"10.1186/s12866-026-05420-x","url":null,"abstract":"<p><strong>Background: </strong>Nontypeable Haemophilus influenzae (NTHi) and Moraxella catarrhalis are recognized as the key pathogens that cause respiratory tract infections, and both are capable of forming biofilms. Although interspecies biofilm formation has been described, the impact of co-culture conditions on antimicrobial responsiveness remains incompletely defined. In this study, we examined biofilm formation by co-culturing NTHi and M. catarrhalis and evaluated their antimicrobial responsiveness to amoxicillin and alternative clinically relevant antibiotics, including sequential exposure following initial amoxicillin treatment, in an in vitro model.</p><p><strong>Results: </strong>Biofilm formation was quantitatively evaluated using the crystal violet staining method with a 96-well pin replicator. Twenty clinical isolates of M. catarrhalis were first cultured for 24 h to assess their biofilm-forming capacities, which varied considerably among strains, with some producing robust biofilms. To further examine interspecies interactions, M. catarrhalis and NTHi were co-cultured at different CFU ratios, revealing that increasing the proportion of M. catarrhalis in the inoculum enhanced overall biofilm production compared with either species alone. Additionally, exposure to selected antibiotics showed that respiratory quinolones were associated with greater reductions in biofilm biomass and viable bacteria within co-culture-derived biofilms compared with amoxicillin, both during direct treatment and following prior amoxicillin exposure, under the experimental conditions tested.</p><p><strong>Conclusion: </strong>Co-culture of NTHi and M. catarrhalis was shown to significantly enhance biofilm formation compared with either culture species alone. In particular, a higher proportion of M. catarrhalis was associated with increased biofilm production. These findings suggest that polymicrobial coexistence may contribute to reduced antimicrobial responsiveness through enhanced biofilm formation.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":" ","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13656627/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148469085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Divergent responses of rhizosphere microbial diversity and co-occurrence patterns to elevation and season in Quercus franchetii from the Yuanmou dry‑hot valley, Southwest China.","authors":"Xuedan Xie, Guanping Li, Jiao Wu, Cailan Liu, Haitao Yue, Dacai Zhang","doi":"10.1186/s12866-026-05364-2","DOIUrl":"10.1186/s12866-026-05364-2","url":null,"abstract":"<p><strong>Background: </strong>Dry-hot valleys suffer from severe ecological stress, with the rhizosphere being an essential microhabitat for plant adaptation. Elevation and seasonal changes are key drivers shaping rhizosphere microbial diversity and community composition. However, their impacts on rhizosphere bacteria and fungi associated with Quercus franchetii in dry-hot valleys remain poorly understood.</p><p><strong>Result: </strong>Bacterial α-diversity exhibited a V-shaped pattern along the elevational gradient, whereas fungal α-diversity generally declined with increasing elevation. Seasonal effects were pronounced, with both bacterial and fungal diversity higher in the rainy season. Soil pH had strong positive correlations with bacterial α-diversity, and both soil pH and water content were associated with variations in bacterial and fungal community composition. Bacterial co-occurrence networks were more complex than fungal networks. Rainy-season networks had higher natural connectivity, and higher random and targeted robustness AUC. Actinobacteriota, Acidobacteriota, and Ascomycota acted as keystone taxa stabilizing network interactions. Functional predictions indicated that bacterial communities were predominantly chemoheterotrophic, whereas fungal communities were dominated by symbiotrophic guilds.</p><p><strong>Conclusions: </strong>Elevational gradients exert a stronger influence than seasonal variation on rhizosphere microbial diversity and composition. Soil pH and water content are key environmental filters shaping microbial assemblages. Microbial networks maintain ecosystem functions through seasonally modulated connectivity and cooperation. Keystone taxa may mediate network stability and functional resilience under spatiotemporal environmental variation. These results provide a basis for predicting microbial responses to environmental change in dry-hot valleys.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":" ","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13679283/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148469091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Malaria exposure history shapes PD-1 expression across human B-cell subsets during acute Plasmodium falciparum infection.","authors":"Susanne E Mortazavi, Allan Lugaajju, Muyideen Kolapo Tijani, Bingyan Wu, Lena Danielsson, Hans Norrgren, Kristina E M Persson","doi":"10.1186/s12866-026-05388-8","DOIUrl":"10.1186/s12866-026-05388-8","url":null,"abstract":"<p><strong>Background: </strong>Repeated malaria exposure shapes humoral immunity in endemic regions. Programmed cell death protein 1 (PD-1) is an inhibitory immune receptor involved in immune regulation during infection, but its expression across human B-cell subsets during acute malaria, and its relationship to exposure history and antigen specificity, remain poorly defined.</p><p><strong>Methods: </strong>PD-1 expression and circulating B-cell subsets were analyzed by flow cytometry in 64 individuals from Uganda and Sweden with different malaria exposure backgrounds, including individuals with acute malaria and healthy controls. PD-1 expression was assessed across major B-cell subsets and compared between P. falciparum-binding and non-binding B cells. Associations with parasitemia and inflammatory markers were also examined.</p><p><strong>Results: </strong>PD-1 expression was higher across both naïve and memory B-cell subsets during acute malaria in Ugandan individuals with ongoing malaria exposure compared with individuals with imported malaria diagnosed in Sweden. Within memory B-cell populations, PD-1 frequencies were highest on non-class-switched (IgD⁺ and IgM⁺) subsets and on P. falciparum-binding B cells. No differences in PD-1 expression were observed between paired acute and convalescent samples. Associations between PD-1 expression, parasitemia, and inflammatory markers were limited and subset-specific.</p><p><strong>Conclusions: </strong>PD-1 expression on B cells during malaria differed according to exposure history and B-cell differentiation state. Broad PD-1 induction during acute malaria was observed only in individuals living in a malaria-endemic setting, and PD-1 expression was enriched among P. falciparum-binding B cells. Together, these findings support a potential role for checkpoint pathways in humoral immune regulation during repeated malaria infections.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":"26 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13371349/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148454712","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}