BMC Microbiology最新文献

{"title":"Synthesis of zinc oxide nanoparticles and their effect on biofilm of methicillin-resistant Staphylococcus aureus isolates.","authors":"Aytan Marandi Moghaddam, Shiva Ahmadishoar, Sedigheh Fekri Aval","doi":"10.1186/s12866-026-05382-0","DOIUrl":"https://doi.org/10.1186/s12866-026-05382-0","url":null,"abstract":"<p><strong>Background: </strong>Methicillin-resistant Staphylococcus aureus (MRSA) poses a growing threat in Iranian healthcare settings, and biofilm formation exacerbates treatment challenges. This study assessed the antibacterial and anti-biofilm potential of zinc oxide nanoparticles ZnONPs against 58 clinical MRSA isolates collected from hospitals in Iran.</p><p><strong>Methods: </strong>Isolates were identified via microbial and biochemical tests and confirmed by PCR targeting nuc (279 bp) and mecA (310 bp) genes. Antimicrobial susceptibility was evaluated using CLSI disk diffusion guidelines. The ZnONPs were synthesized by chemical precipitation. Minimum inhibitory concentrations (MICs) of ZnONPs were determined by broth microdilution, and biofilm formation/inhibition was quantified using crystal violet staining.</p><p><strong>Results: </strong>Of 131 S. aureus isolates, 58 (44.3%) were MRSA, exhibiting high resistance to Penicillin (100%), Erythromycin (91.4%), and Ciprofloxacin (74.1%), but full susceptibility to Trimethoprim-Sulfamethoxazole. ZnONPs displayed potent activity, with MICs ranging from 8 to 1024 µg/mL (MIC₅₀ = 64 µg/mL; MIC₉₀ = 512 µg/mL); 27.6% of isolates were inhibited at ≤ 16 µg/mL. Among MRSA, 15.5% were strong biofilm producers, and sub-MIC (½ MIC) concentrations of ZnONPs reduced biofilm by 82.3 ± 7.6% (P  < 0.001). Dynamic light scattering confirmed nanoparticle stability (size: 29.4 ± 4.2 nm; PDI: 0.19).</p><p><strong>Conclusions: </strong>These findings highlight ZnONPs as a promising, low-cost alternative for managing MRSA infections, particularly in biofilm-associated cases, warranting further clinical exploration in resource-limited settings.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":" ","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148396076","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":"Overcoming the bottleneck in Treponema pallidum quantification: a novel flow cytometric assay for rapid, precise, and cost-effective detection.","authors":"Yan-Li Zeng, Wen-Long Xu, Yun Xiao, Xi-E Xu, Mi-Jie Gao, Si-Ya Wang, Li-Rong Lin, Tian-Ci Yang","doi":"10.1186/s12866-026-05366-0","DOIUrl":"https://doi.org/10.1186/s12866-026-05366-0","url":null,"abstract":"<p><p>Precise quantification of the causative agent of syphilis, Treponema pallidum (T. pallidum) is critical for advancing research in pathogenesis, treatment response, and vaccine development. However, current methods have certain limitations. Dark-field microscopy (DFM) suffers from low sensitivity, poor reproducibility, and strong operator dependence, while quantitative PCR (qPCR) offers high precision but is time-consuming, technically demanding, and reliant on high-quality, consistent commercial reagents. This methodological bottleneck highlights the urgent need for a technique that integrates the speed and simplicity of direct detection with the precision, objectivity, and throughput of an automated assay. Herein, to bridge this gap, we propose a strategy for rapid, high-throughput quantification of T. pallidum using a novel, fluorescence-based flow cytometric assay implemented on an automated urine analyzer (the Sysmex UF-5000 analyzer). The assay demonstrated a limit of detection of 7.02 × 10^³T. pallidum/mL and excellent precision (all coefficients of variation < 20%). It showed strong quantitative agreement with qPCR across a wide dynamic range (4.98 × 10³-2.10 × 10⁷T. pallidum/mL), with an excellent correlation (r = 0.9967), without significant proportional or constant bias (Passing-Bablok slope = 1.003). Bland-Altman analysis confirmed a close agreement (mean difference: -1.14 × 10⁵T.pallidum/mL). In contrast, DFM exhibited substantially higher variability (CVs 15.19-83.52%) and failed to detect low-concentration samples. Operationally, the flow cytometric assay provides results within 30 s per sample at a low consumable cost (approximately $0.35 per test), outperforming DFM in objectivity and throughput and qPCR in both speed and cost-effectiveness. In summary, this novel flow cytometric assay effectively overcomes the historical challenges associated with T.pallidum quantification. This automated, precise, and rapid assay integrates the simplicity of direct detection with the accuracy of molecular quantification, offering a standardized and practical tool to enhance research in syphilis microbiology, pharmacology, and immunology, paving the way for more reproducible and translatable scientific discoveries.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":" ","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148387432","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":"Synergistic anti-Helicobacter pylori efficacy of a molecularly identified Limosilactobacillus fermentum isolate in combination with multiple antibiotics.","authors":"Menna M M Mohammed Ali, Hala Mohamed Abu Shady, Sayed M M, Hayam A E Sayed","doi":"10.1186/s12866-026-05350-8","DOIUrl":"10.1186/s12866-026-05350-8","url":null,"abstract":"&lt;p&gt;&lt;strong&gt;Background: &lt;/strong&gt;Helicobacter pylori (H. pylori) is a Gram-negative gastric pathogen resistant to the acidic stomach environment through urease-mediated neutralization, enabling colonization of the gastric mucosa. It is a major cause of gastritis, peptic ulcer disease, and gastric cancer, and was classified as a Class I carcinogen by the International Agency for Research on Cancer (IARC) in 1994. Rising antibiotic resistance has limited the efficacy of conventional therapies, highlighting the need for alternative or adjunct antimicrobial strategies.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Methods: &lt;/strong&gt;Forty lactic acid bacteria (LAB) isolates were screened for anti-H. pylori activity against twenty clinical H. pylori isolates previously recovered from gastric biopsies of Egyptian patients using neutralized cell-free supernatants (CFSs). The CFSs were evaluated alone and in combination with standard therapeutic antibiotics. The most potent CFS was subsequently evaluated for cytotoxic activity against colorectal adenocarcinoma (Caco-2) cells as a preliminary assessment of its potential anticancer-related properties. The CFS was then subjected to fast protein liquid chromatography (FPLC), and the active fraction was further analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) to estimate its molecular weight. Following verification of its probiotic characteristics, the producer strain was identified by 16 S rRNA gene sequencing.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results: &lt;/strong&gt;Nine out of forty LAB isolates demonstrated anti-H. pylori activity, with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values ranging from 93.7 to 750 µg/mL. Combination assays demonstrated isolate-dependent interactions, with synergistic effects observed with clarithromycin (CLR), amoxicillin (AX), metronidazole (MET), tetracycline (TE), rifampicin (RA), and levofloxacin (LEV) against certain H. pylori isolate groups. L. fermentum strain M98, identified as the most potent isolate, exhibited the highest inhibitory activity both alone and in combination with antibiotics. The protein-enriched precipitate containing a putative bacteriocin exhibited cytotoxic activity against Caco-2 cells, with an IC₅₀ value of 19.73 ± 0.16 µg/mL. FPLC of its CFS yielded 22 protein fractions, three of which exhibited anti-H. pylori activity, suggesting the presence of bacteriocin-like compounds. Subsequent SDS-PAGE analysis of the active fraction revealed a prominent protein band of approximately 34 kDa.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusion: &lt;/strong&gt;The CFS of L. fermentum strain M98 exhibits significant in vitro anti-H. pylori activity and enhances the efficacy of tested antibiotics, supporting its potential as an adjunct therapeutic agent against antibiotic-resistant H. pylori. In addition, LAB-precipitated proteins containing a putative bacteriocin demonstrated cytotoxic activity against Caco-2 cells, suggesting the presence of bioactive compounds with potential","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":"26 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13332602/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148387427","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":"Genome-to-function integrated exploration of polyethylene biodegradation by Rhodococcus opacus R7.","authors":"Jessica Zampolli, Mattia Salvadori, Valentina Vincenti, Marina Lasagni, Patrizia Di Gennaro","doi":"10.1186/s12866-026-05315-x","DOIUrl":"https://doi.org/10.1186/s12866-026-05315-x","url":null,"abstract":"<p><strong>Background: </strong>Polyethylene (PE) is the most widely produced polyolefin and represents a major contributor to plastic waste, largely due to its chemical stability and resistance to biological degradation. PE biodegradation is typically characterized as a series of oxidative metabolic processes rather than mineralization. An urgent priority is the development of integrated experimental setups that bring together physiological, biochemical, and molecular analyses under controlled cultivation conditions to unlock the metabolic traits of PE biodegradation. This study aims to elucidate the molecular mechanisms of commercial low-molecular-weight PE (LDPE) attack by Rhodococcus opacus R7 through an integrated genome-to-function approach, including growth and extracellular laccase assays, intracellular lipid quantification, gas chromatography coupled with mass spectrometry (GC-MS) analysis of compounds associated with untreated LDPE, and transcriptional profiling of oxidative enzymes.</p><p><strong>Results: </strong>LDPE utilization was evaluated under multiple cultivation strategies (1% single-dose vs. 0.4% fed-batch), inoculum conditions, and polymer types (untreated or UV-pretreated) over 28 days. Fed-batch LDPE (0.4%) supported slightly higher viable cell numbers than fixed-dose LDPE (1%), while prolonged PE pre-adaptation did not enhance growth. Extracellular laccase activity was detected under all conditions, but was more influenced by the physiological status of the inoculum than by PE concentration or pretreatment. Lipid accumulation was early detected in case of 1% PE, while the fed-batch conditions reflected the growth phase and physiological responses. GC-MS analyses revealed that LDPE oxidation products vary compared to abiotic and control samples. Specifically, fixed-dose LDPE favored a progressive change in the pattern-profile of carboxylic acids and medium- to long-chain alkanes, while fed-batch LDPE produced a heterogeneous mixture, including alcohols and ketones, consistent with a continuous and asynchronous transformation of the polymer. The fed-batch condition induced a broader and earlier transcriptional activation of oxidative genes, including seven laccase-like multicopper oxidases (LMCOs), alkane monooxygenase (alkB), benzoate dioxygenase (benA), and cytochrome P450 hydroxylase. Long-chain n-alkanes, particularly tetracosane (C24), strongly induced oxidative enzymes, suggesting their role as metabolic signals during PE degradation.</p><p><strong>Conclusions: </strong>Overall, LDPE attack by R. opacus R7 emerges as a dynamic process shaped by substrate accessibility and cultivation strategy, highlighting its potential as a platform for controlled plastic biodegradation.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":" ","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148387456","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":"Unraveling a new Klebsiella phage KP47 against Klebsiella spp.","authors":"Giovane Böerner Hypolito, Caio Felipe Cavicchia Zamunér, Layla Farage Martins, Mark Enright, Henrique Ferreira","doi":"10.1186/s12866-026-05359-z","DOIUrl":"https://doi.org/10.1186/s12866-026-05359-z","url":null,"abstract":"<p><strong>Background: </strong>The increase in cases of infectious diseases related to multidrug-resistant bacteria and the spread of multidrug-resistant genes have driven the search for therapeutic alternatives that can circumvent this global phenomenon. One of these alternatives is the use of bacteriophages, which are viruses capable of infecting and killing specific bacteria. Klebsiella pneumoniae species complex (KpSC) is an important opportunistic group associated with multidrug resistance. This group includes Klebsiella quasipneumoniae subsp. similipneumoniae, a species recognized as a clinically relevant pathogen, and that was used as a host (designated Klebsiella KH1) to isolate the phage characterized in the present study. The characterization of new phages is essential to expand the therapeutic arsenal and to improve our understanding on phage diversity. In this study, we evaluated a Klebsiella bacteriophage named KP47 that was isolated from sewage in the United Kingdom. We performed phage biological and genomic characterization in order to assess its therapeutic attributes. KP47 represents a newly isolated Klebsiella phage, being able to infect both K. pneumoniae and K. quasipneumoniae subsp. similipneumoniae, which also shows evidence of depolymerase activity and an efficient bacteriolytic performance.</p><p><strong>Results: </strong>The phage KP47 showed a typical morphology of the Caudoviricetes class, with a capsid of 48 nm and a tail of 161 nm. Its genome has 47,396 bp, 63 CDSs, and a GC content of 57.52%, which apparently encodes a depolymerase. ViPTree analysis placed KP47 near Drexlerviridae-related phages, while comparative analyses using representative RefSeq genomes revealed low intergenomic similarity. This phage demonstrated strictly lytic behavior and fast adsorption (90% in 6 min). MOI experiments indicated complete inhibition of bacterial growth in MOIs ≥ 1. The phage infected two out of nine tested strains belonging to the strains of KpSC.</p><p><strong>Conclusions: </strong>In this study, we described the Klebsiella phage KP47, likely representing a new viral genus, that exhibits a strictly lytic lifestyle, rapid adsorption (90% within 6 min), and an effective bacterial growth inhibition at MOIs ≥ 1. KP47 was able to infect clinically relevant members of the Klebsiella pneumoniae species complex. Further investigations of its potential to act on biofilms and against Klebsiella species in in vivo models are of interest to evaluate its potential for clinical application.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":" ","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148387412","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":"Multidrug-resistant Bacillus cereus in retail poultry meat: molecular insights into toxigenicity and antimicrobial resistance.","authors":"Reham M El-Tarabili, Ahmed Alfifi, Mohammed Y Behairy, Sherief M Abdel-Raheem","doi":"10.1186/s12866-026-05337-5","DOIUrl":"10.1186/s12866-026-05337-5","url":null,"abstract":"<p><strong>Background: </strong>Bacillus cereus (B. cereus) is a spore-forming foodborne pathogen linked to poultry contamination. This study evaluated its prevalence, groEL phylogeny, toxigenic potential, and antimicrobial resistance in Egyptian retail poultry meat.</p><p><strong>Methods: </strong>A total of 110 retail poultry meat samples were collected from commercial supermarkets in Port Said, Egypt, between April and May 2025. Afterwards, samples underwent bacteriological examination. The isolated samples were subjected to groEL gene sequence analysis, antibiotic sensitivity testing, and PCR detection for toxigenic and resistance genes.</p><p><strong>Results: </strong>The total prevalence of B. cereus in the food samples examined was 14.5%. The groEL-based phylogeny revealed high genetic similarity between our isolates and human clinical strains, suggesting a potential for zoonotic transmission and highlighting the public health risk. Furthermore, the isolated B. cereus strains exhibited β-hemolytic and lecithinase activities, and PCR analysis demonstrated that the examined B. cereus strains usually harbored hbl complex (hblD: 81.3%, hblA:81.3%, and hblC: 75%), nhe complex genes (nheB: 62.5%, and nheA: 50%), pc-plc (100%), ent-FM (100%), cytK (50%), and ces (31.25%) virulence genes. In addition, all isolates encoded bla1, bla2, and tetA (100% each), and 75% carried ermA. Overall, 62.5% of isolates were multidrug resistant to seven agents from six antimicrobial classes and harbored bla1, bla2, ermA, and tetA.</p><p><strong>Conclusion: </strong>This study highlights the prevalence of multidrug-resistant B. cereus in poultry meat, underscoring the importance of molecular monitoring of MDR B. cereus strains. These findings indicate that toxigenic B. cereus persists in poultry meat and exhibits evolving resistance profiles, underscoring the need for multiple control strategies to reduce food contamination in poultry production and retail settings and highlighting the significant public health concern posed by this pathogen.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":"26 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13330227/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148374649","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 and characterization of phage vB_KpnS_SXK7 against multidrug-resistant Klebsiella pneumoniae and the mechanism of O-antigen-associated phage resistance.","authors":"Jiao Feng, Li Sun, Yanran Li, Yuming Zhang, Jinyu Liang, Runru Wang, Liangyu Wang, Yan Meng, Zhiqiang Yang, Xiaogang Cui, Changxin Wu, Zhouguang Jiao, Chenrui Hou","doi":"10.1186/s12866-026-05370-4","DOIUrl":"https://doi.org/10.1186/s12866-026-05370-4","url":null,"abstract":"<p><p>The increasing prevalence of multidrug-resistant (MDR) Klebsiella pneumoniae necessitates alternative therapeutic strategies. Here, we isolated and characterized a lytic phage, vB_KpnS_SXK7, from hospital sewage and investigated the host's resistance mechanism. Morphological analysis identified it as a siphovirus-type phage. It exhibited a 30-min latent period, a burst size of 270 PFU/infected cell, and stability across pH 5-12 and temperatures up to 60 °C. Host range testing against 25 K. pneumoniae strains showed that vB_KpnS_SXK7 lysed 9 strains (36%). Whole-genome sequencing revealed a 49.1-kb circular dsDNA genome lacking tRNA, virulence, or antibiotic-resistance genes, confirming its safety profile. In vitro, vB_KpnS_SXK7 reduced bacterial viability within 2 h. In a Galleria mellonella infection model, a single dose (MOI 100) rescued 80% of larvae from lethal challenge without toxicity. Genomic analysis of resistant mutant SXK7-R11 identified a single-nucleotide deletion in wzm, which encodes an ABC transporter permease essential for O-antigen assembly. This mutation impaired phage adsorption, which was restored by genetic complementation. These findings establish vB_KpnS_SXK7 as a promising preclinical candidate but highlight its vulnerability to resistance mechanisms involving O‑antigen‑associated pathways, supporting the development of phage cocktails targeting multiple receptors against MDR infections.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":" ","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148381770","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":"High burden of bla_KPC-2-positive carbapenem-resistant Klebsiella pneumoniae among inpatients in a Tertiary Care Hospital in Kathmandu.","authors":"Shashi Gurung, Milan Kumar Upreti, Agrani Paudel, Khadga Bikram Angbuhang, Sanjit Shrestha, Upendra Thapa Shrestha, Megha Raj Banjara","doi":"10.1186/s12866-026-05290-3","DOIUrl":"https://doi.org/10.1186/s12866-026-05290-3","url":null,"abstract":"<p><strong>Objective: </strong>Klebsiella pneumoniae, a major nosocomial pathogen, is increasingly associated with multidrug resistance and carbapenem production, posing a significant therapeutic challenge on a global scale. The study aimed to determine the distribution, antimicrobial susceptibility pattern, and molecular identification of bla_KPC-2 and bla_VIM genes among carbapenem-resistant K. pneumoniae isolated from clinical specimens.</p><p><strong>Methods: </strong>Between January and June 2024, a hospital-based cross-sectional study was carried out at Kirtipur Hospital in Nepal. Standard microbiological protocols were adopted for the processing of 5002 clinical samples. Antimicrobial susceptibility testing was performed using the Kirby-Bauer disk diffusion method following CLSI guidelines. The modified carbapenem inactivation method (mCIM) and the EDTA-modified carbapenem inactivation method (eCIM) were used to confirm carbapenemase production phenotypically, and the polymerase chain reaction (PCR) was used to detect the bla_KPC-2 and bla_VIM genes at the molecular level.</p><p><strong>Results: </strong>Of the total samples, 18.3% (917) showed bacterial growth, with K. pneumoniae accounting for 7.6% (n = 70) of isolates, predominantly from wound/pus (35.7%), urine (32.8%), and blood (17.1%) specimens. High resistance was observed against imipenem (68.6%), ceftazidime (64.3%), and ceftriaxone (62.9%), whereas tigecycline and doxycycline remained the most effective ones. Twelve (30.8%) of the 39 carbapenem-resistant isolates were determined to be carbapenemases producers, all harboring bla_KPC-2 (100%) and three (25%) additionally carrying bla_VIM.</p><p><strong>Conclusion: </strong>The dominance of KPC-mediated resistance among the hospitalized patients, underscores the need for rigorous infection control, ongoing molecular surveillance, and prudent antimicrobial stewardship to stop the spread of high-risk K. pneumoniae strains in healthcare environments.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":" ","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148381650","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":"Analysis of risk factors for carbapenem-resistant Klebsiella pneumoniae bloodstream infections in children: a case-control study.","authors":"Jing Jia, Hailing Shi, Panpan Fang, Juanjuan Zhou, Lu Xu, Kaijie Gao, Haizhen Xie, Bing Yang, Mingfa Guo","doi":"10.1186/s12866-026-05342-8","DOIUrl":"https://doi.org/10.1186/s12866-026-05342-8","url":null,"abstract":"<p><strong>Objective: </strong>To analyze the risk factors for carbapenem-resistant Klebsiella pneumoniae bloodstream infection (CRKP-BSI) in children.</p><p><strong>Methods: </strong>A total of 235 pediatric patients with Klebsiella pneumoniae bloodstream infection (KPN-BSI) admitted to our hospital from January 2015 to December 2025 were collected. According to the CLSI criteria, infections in which carbapenem- resistant Klebsiella pneumoniae was isolated from blood culture were defined as CRKP-BSI (n=110), and those in which carbapenem-susceptible Klebsiella pneumoniae was isolated were defined as CSKP-BSI (n=125). We compared clinical profiles of the two groups with the Mann-Whitney U test and chi-square test, and binary logistic regression was used to identify independent risk factors for CRKP-BSI.</p><p><strong>Results: </strong>Children with CRKP-BSI were mainly distributed in the Premature Infant Department (49 cases, 44.60 %) and intensive care unit (36 cases, 32.70 %). Analysis of clinical characteristics showed that patient age, underlying diseases, antibiotic use duration ≥ 14 days, mechanical ventilation, surgical procedures during hospitalization, and hospital stay > 5 days were significantly associated with CRKP-BSI (all P < 0.05). Binary logistic regression multivariate analysis demonstrated that the mechanical ventilation (β = 2.896, OR = 18.106), surgical procedures during hospitalization (β = 1.116, OR = 3.052), and hospital stay > 5 days (β = 0.957, OR = 2.603) were independently associated with CRKP-BSI.</p><p><strong>Conclusion: </strong>It is concluded that mechanical ventilation, surgical interventions and prolonged hospitalization independently contribute to the development of CRKP-BSI in children. Enhanced monitoring and precise infection control strategies are required for vulnerable children to prevent CRKP-BSI.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":" ","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148381603","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":"Proline protects Wickerhamomyces anomalus against ethanol‑induced damage during logarithmic growth: integrated physiological, transcriptomic, and metabolomic analyses.","authors":"Xiaozhu Liu, Yujie Wang, Guilan Jiang, Shuang Yan Liu, Yinfeng Li","doi":"10.1186/s12866-026-05373-1","DOIUrl":"https://doi.org/10.1186/s12866-026-05373-1","url":null,"abstract":"<p><strong>Background: </strong>Proline plays a critical regulatory role in microbial stress responses; however, its specific mechanism of action under ethanol stress in Wickerhamomyces anomalus during logarithmic growth remains poorly understood.</p><p><strong>Results: </strong>This study investigated the protective effects of proline against ethanol-induced injury and elucidated the mechanism by which it enhances resistance to 9% (v/v) ethanol stress. The results indicated that proline supplementation significantly increased the viability of ethanol-stressed yeast and stimulated cellular proline transport and catabolism. Furthermore, proline mitigated the impairment in morphology and ultrastructure of yeast cells by maintaining cell wall, cell membrane, and mitochondrial integrity, ameliorating oxidative stress, and restoring cellular homeostasis under ethanol stress. Further analysis revealed that the protective effect of proline on cell membrane homeostasis was related to decreased membrane permeability, increased membrane fluidity, and elevated intracellular K⁺ levels. The alleviation of oxidative stress by proline supplementation was associated with enhanced antioxidant enzyme activities and increased glutathione levels. Transcriptomic and metabolomic analyses indicated that proline regulated ribosome synthesis, the cell wall integrity pathway, ABC transporters, and arginine and proline metabolism.</p><p><strong>Conclusions: </strong>These findings indicate that proline effectively protects yeast from ethanol stress, supporting the development of ethanol-tolerant W. anomalus strains for industrial fermentation.</p>","PeriodicalId":9233,"journal":{"name":"BMC Microbiology","volume":" ","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148381767","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}