Journal of global antimicrobial resistance最新文献

{"title":"Convergence of genetic variants in MCR-1 and O-antigen conferring polymyxin resistance and fitness cost","authors":"Jinfeng Lu ,&nbsp;Aiping Zhou ,&nbsp;Dongjiang Wang ,&nbsp;Shuang Wan ,&nbsp;Yuting Yang ,&nbsp;Na Lv ,&nbsp;Jun Li ,&nbsp;Guoping Wu","doi":"10.1016/j.jgar.2025.10.005","DOIUrl":"10.1016/j.jgar.2025.10.005","url":null,"abstract":"<div><h3>Objective</h3><div>The emergence of multidrug-resistant bacteria alongside the extensive spread of opportunistic pathogens with a diversity of serotypes threatens public health. Fitness cost and morphological variation are hypothesised to result from O-antigen diversity and lipid A modification, whereas these reconfigurations within lipopolysaccharides (LPS) confer polymyxin resistance.</div></div><div><h3>Methods</h3><div>In this study, a multidrug-resistant <em>Escherichia coli</em> named EcE.CRE.COL was isolated from a patient undergoing therapeutic laparoscope for liver cancer. Antibiotic susceptibility was measured using the VITEK 2 system (bioMérieux, Marcy-l'Étoile, France), and whole-genome sequencing revealed a chromosome and three plasmids (namely pEcE.CRE.COL015, pEcE.CRE.COL016, and pEcE.CRE.COL032). Comparative genomics was then conducted to identify genetic determinants accounting for multi-drug resistance.</div></div><div><h3>Results</h3><div>This isolate exhibited characteristic resistance to carbapenems and polymyxin. Interestingly, pEcE.CRE.COL015 and pEcE.CRE.COL032 were shown to harbour <em>bla</em>_NDM-5 and <em>mcr-1</em>, accounting for corresponding antimicrobial resistance. We consequently proposed an evolutionary pattern for the spread of <em>mcr-1</em>, demonstrating that transposon-like architecture could play a key role in the dissemination of polymyxin resistance driven by <em>mcr-1</em>. In addition, a novel serotype gene cluster related to defective O-antigen synthesis was determined, likely resulting from a genetic insertion. SDS-PAGE indicated LPS defectiveness within this isolate, suggesting a variable charge on the membrane surface of EcE.CRE.COL.</div></div><div><h3>Conclusions</h3><div>Collectively, the co-occurrence of plasmid-borne <em>mcr-1</em> and <em>bla</em>_NDM-5 was determined, with genetic variations in LPS biosynthesis genes potentially contributing to a synergistic change in bacterial surface charge and corresponding electrostatics to polymyxin.</div></div>","PeriodicalId":15936,"journal":{"name":"Journal of global antimicrobial resistance","volume":"45 ","pages":"Pages 228-231"},"PeriodicalIF":3.2,"publicationDate":"2025-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145308322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Colistin- and octenidine-induced selective pressure on Pseudomonas aeruginosa clinical isolates in vitro: Antimicrobial activity and mechanisms of cross-resistance","authors":"Samanta Freire ,&nbsp;Otávio Hallal Ferreira Raro ,&nbsp;Patrice Nordmann ,&nbsp;Laurent Poirel","doi":"10.1016/j.jgar.2025.10.008","DOIUrl":"10.1016/j.jgar.2025.10.008","url":null,"abstract":"<div><h3>Objective</h3><div>Infection prevention using antiseptics is crucial to control the transmission of multidrug-resistant Gram-negative pathogens.</div></div><div><h3>Methods</h3><div>This in vitro study aimed to evaluate: (1) the susceptibility to octenidine (OCT) of 104 <em>Pseudomonas aeruginosa</em> (including multidrug-resistant) clinical isolates; (2) whether resistant mutants can be obtained by applying selective pressure using increasing concentrations of OCT and colistin (COL); (3) the genetic basis of underlying resistance mechanisms; (4) the co-lateral effects on various antibiotics and chlorhexidine (CHX); and (5) the efficacy of OCT-based products in mutant strains according to EN13727.</div></div><div><h3>Results</h3><div>OCT showed high activity against all isolates. Long-term exposure of four <em>P. aeruginosa</em> strains to OCT resulted in five mutants predominantly exhibiting mutations in genes involved in the regulation of efflux pumps. No co-lateral effect of the OCT mutants on CHX, COL or any other antibiotics was detected. OCT as well as OCT-based products were still fully effective in all OCT mutants under “dirty conditions” within a 1 min contact time. Using COL as a selective molecule, four mutants exhibiting decreased susceptibility to COL were identified that harboured mutations in <em>pmrB</em>. Cross-resistance to gentamicin was observed in two mutants, but not to OCT, CHX or any other antibiotics.</div></div><div><h3>Conclusions</h3><div>Rare mutations triggered within <em>P. aeruginosa</em> by OCT during long-term in vitro exposure showed no impact on the efficacy of OCT and did not select for other antiseptic or antibiotic cross-resistance.</div></div>","PeriodicalId":15936,"journal":{"name":"Journal of global antimicrobial resistance","volume":"45 ","pages":"Pages 209-214"},"PeriodicalIF":3.2,"publicationDate":"2025-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145308248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Plasmid-mediated blaGES-24 in Acinetobacter nosocomialis: Genetic context and resistance profile","authors":"Raita Yano ,&nbsp;Shizuo Kayama ,&nbsp;Masato Suzuki ,&nbsp;Koji Yahara ,&nbsp;Junzo Hisatsune ,&nbsp;Liansheng Yu ,&nbsp;Chika Arai ,&nbsp;Taijiro Sueda ,&nbsp;Shinya Takahashi ,&nbsp;Yumiko Koba ,&nbsp;Hiroki Ohge ,&nbsp;Motoyuki Sugai","doi":"10.1016/j.jgar.2025.10.003","DOIUrl":"10.1016/j.jgar.2025.10.003","url":null,"abstract":"<div><h3>Objectives</h3><div>A clinical isolate of <em>Acinetobacter</em> spp. MS5394 carrying a novel GES-type β-lactamase gene, <em>bla</em>_GES_-24, was first identified in 2013. This study aimed to characterize the genetic and phenotypic features of GES-24.</div></div><div><h3>Methods</h3><div>The complete genome of <em>A. nosocomialis</em> MS5394 was sequenced using Illumina MiSeq and Oxford Nanopore technologies. Plasmid pAC-GES-24 was analysed for resistance gene content and sequence. Site-directed mutagenesis was used to examine the functional role of amino acid substitutions at positions 62, 104, and 170 in GES-24. Antimicrobial susceptibility testing was performed in <em>E. coli</em> expressing different GES variants.</div></div><div><h3>Results</h3><div>The <em>bla</em>_GES-24, is on a ∼153-kb plasmid pAC-GES-24. The complete nucleotide sequence of the pAC-GES-24 indicated that the backbone sequence was possibly a hybrid of two independent plasmids, pNDM-AP_882 and pOXA-588-AP_882, carrying <em>bla</em>_NDM and <em>bla</em>_OXA, respectively, from <em>Acinetobacter pitti</em> AP_882 isolated in Malaysia. A comparison of the amino acid sequence of GES-24 with that of highly homologous GES identified three amino acid differences at ambler positions 62, 104, and 170. Phenotypic investigation of <em>E. coli</em> producing GES-24 in comparison with <em>E. coli</em> producing GES variants at Ambler positions 62, 104, and 170 under isogenic conditions confirmed that GES-24 is a β-lactamase that possesses carbapenemase activity but is relatively weak in hydrolysing CTX, CAZ, AZT, and CFPM when compared to the other GES-type tested.</div></div><div><h3>Conclusions</h3><div>GES-24 represents a GES-type β-lactamase with carbapenemase activity but relatively weak hydrolytic activity against certain β-lactams. The genetic analysis suggests that the plasmid carrying <em>bla</em>_GES-24 may have evolved from a hybrid plasmid.</div></div>","PeriodicalId":15936,"journal":{"name":"Journal of global antimicrobial resistance","volume":"45 ","pages":"Pages 202-208"},"PeriodicalIF":3.2,"publicationDate":"2025-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145301453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"96-week real-world effectiveness of bictegravir/emtricitabine/tenofovir alafenamide in HIV-infected adults with pre-existing NRTI resistance: A retrospective cohort study","authors":"Laura Mezzogori ,&nbsp;Marco Muccio ,&nbsp;Riccardo Schiavoni ,&nbsp;Lucia Taramasso ,&nbsp;Filippo Giacomini ,&nbsp;Bianca Bruzzone ,&nbsp;Federica Stefanelli ,&nbsp;Nadia Randazzo ,&nbsp;Franco Maggiolo ,&nbsp;Maurizio Zazzi ,&nbsp;Matteo Bassetti ,&nbsp;Antonio Di Biagio","doi":"10.1016/j.jgar.2025.10.002","DOIUrl":"10.1016/j.jgar.2025.10.002","url":null,"abstract":"<div><h3>Objectives</h3><div>This study evaluated the impact of pre-existing resistance-associated mutations (RAMs) to nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) on treatment outcomes in people living with HIV (PWH) receiving bictegravir/emtricitabine/tenofovir alafenamide (B/F/TAF) in a real-world setting.</div></div><div><h3>Methods</h3><div>We conducted a single-centre, retrospective review of treatment-experienced adult PWH switched to B/F/TAF, comparing those with and without NRTI RAMs. The primary endpoint was virological success at week 96 (&lt;50 HIV RNA copies/mL). Secondary endpoints were changes in absolute CD4+ counts and CD4+/CD8+ ratio. Continuous variables were analysed using the Wilcoxon rank sum test and categorical variables with the Chi-square or Fisher’s exact test. Longitudinal changes in absolute CD4+ counts and CD4+/CD8+ ratio were assessed using linear mixed-effects models, accounting for repeated measurements over time.</div></div><div><h3>Results</h3><div>A total of 257 PWH were included, of whom 21 were viraemic at the time of switch; 41 had pre-existing NRTI RAMs, while no RAMs were documented in the remaining 216 participants. At week 96, virological suppression was achieved in 100% of individuals with RAMs and 97.2% of those without NRTI RAMs, respectively (<em>P</em> = ns). Absolute CD4+ counts increased in 44.4% of participants, with no significant impact of NRTI RAMs. The CD4+/CD8+ ratio showed an apparent increase of more than 50% in 73.2% and 62.0% of participants with and without NRTI RAMs, respectively. However, longitudinal trend analysis revealed a significant negative rate of change in both groups, which was less pronounced among participants with RAMs.</div></div><div><h3>Conclusions</h3><div>B/F/TAF is an effective treatment option for PWH with NRTI RAMs.</div></div>","PeriodicalId":15936,"journal":{"name":"Journal of global antimicrobial resistance","volume":"45 ","pages":"Pages 215-219"},"PeriodicalIF":3.2,"publicationDate":"2025-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145286036","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Emergence of ST23-K1 blaKPC-3-positive hypervirulent carbapenem-resistant Klebsiella pneumoniae from China: A molecular, biological, and epidemiological study","authors":"Ling Xin,&nbsp;Jing Wang,&nbsp;Cong Qin,&nbsp;Yi Sun,&nbsp;Hongwei Zhou,&nbsp;Rong Zhang,&nbsp;Gongxiang Chen","doi":"10.1016/j.jgar.2025.09.007","DOIUrl":"10.1016/j.jgar.2025.09.007","url":null,"abstract":"<div><h3>Objective</h3><div>A highly virulent <em>Klebsiella pneumoniae</em> ST23-K1 carrying <em>bla</em>_KPC-3, named as Kpn_24-5, was identified in the blood samples of a patient with multiple complications. We investigated the transfer and pathogenic mechanism of this strain, and elucidated the epidemiological situation of the strain.</div></div><div><h3>Methods</h3><div>A <em>bla</em>_KPC-3-positive ST23-K1 <em>K. pneumoniae</em> was isolated. Antimicrobial susceptibility test and whole genome sequencing were used to study the phenotypes and genotypes of the strain. The transmission and pathogenic mechanism were investigated by means of conjugation transfer test, neutrophil killing test, and serum inhibition test.</div></div><div><h3>Results</h3><div>The Kpn_24-5 strain was ST23 sequence type and K64:O1 capsular serotype, which contains four plasmids. Plasmid 1 carries several virulence genes, belonging to the same clade as <em>K. pneumoniae</em> plasmid isolated from the USA in 2023. Plasmid 2 is an anti-plasmid containing <em>bla</em>_KPC-3 carbapenem resistance gene, belonging to the same clade as <em>K. pneumoniae</em> plasmid isolated from China in 2024. The genetic characteristics of plasmids indicated that the genetic environment of <em>bla</em>_KPC-3 in plasmid 2 of Kpn_24-5 strain was IS26-ISKpn27-<em>bla</em>_KPC-3-Tn21. The resistance plasmid 2 of Kpn_24-5 strain was transferable. The Kpn_24-5 strain has higher tolerance to neutrophils, is not easily inhibited by serum, and has significantly higher infectivity.</div></div><div><h3>Conclusions</h3><div>The present study corroborates the emergence of hypervirulent CR-hvKP in the Zhejiang region, a phenomenon that is presumably attributable to the acquisition of an IncFIB virulence plasmid and a <em>bla</em>_KPC-3 resistance plasmid by the ST23-K1 type <em>K. pneumoniae</em>. Our findings highlight the urgent need to use antibiotics more wisely to limit the emergence of resistance.</div></div>","PeriodicalId":15936,"journal":{"name":"Journal of global antimicrobial resistance","volume":"45 ","pages":"Pages 234-239"},"PeriodicalIF":3.2,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145280415","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"30-d mortality risk factors in paediatric patients with bloodstream infection due to Enterobacterales: A retrospective observational cohort study","authors":"Ojeda-Diezbarroso Karla ,&nbsp;Jimenez-Juarez Rodolfo Norberto ,&nbsp;Avilés-Robles Martha ,&nbsp;Laris-González Almudena ,&nbsp;Bonilla-Pellegrini Sergio ,&nbsp;Pichardo-Villalón Liliana ,&nbsp;Castellanos-Cruz Carmen","doi":"10.1016/j.jgar.2025.09.014","DOIUrl":"10.1016/j.jgar.2025.09.014","url":null,"abstract":"<div><h3>Objective</h3><div>Data on paediatric bloodstream infection (BSI) in low- and middle-income countries remain scarce. Consequently, this study aims to elucidate the risk factors associated with mortality in paediatric patients with enterobacterial BSIs.</div></div><div><h3>Methods</h3><div>This was a retrospective analysis of patients with bloodstream infection due to Enterobacterales attended at Hospital Infantil de Mexico during 2013–2019. Factors influencing mortality were assessed. The baseline characteristics of the population, bloodstream infection and antimicrobial treatment were compared between survivors and non-survivors as well.</div></div><div><h3>Results</h3><div>Of 527 cases of BSIs, 63.6% (n = 335) were caused by Enterobacterales and 307 cases were included. The overall mortality rate was 11.1% (n = 34). In the multivariable regression model, septic shock/multiorgan failure (HR 9.69, 95% CI: 3.28–28.63), and empirical treatment failure (HR 3.4, 95% CI: 1.36–8.45) were associated with an increased mortality risk.</div></div><div><h3>Conclusions</h3><div>in this study, the mortality in paediatric BSIs was driven by severe clinical presentation and failure to control inflammatory response and infection. Improving outcomes requires proactive measures, including early detection of sepsis by caregivers, education of healthcare providers for timely recognition and treatment, vigilant monitoring of systemic inflammatory response with adaptable therapeutic approaches and reinforcement of antimicrobial stewardship programs.</div></div>","PeriodicalId":15936,"journal":{"name":"Journal of global antimicrobial resistance","volume":"45 ","pages":"Pages 299-304"},"PeriodicalIF":3.2,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145280354","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Detection of zoonotic Coxiella burnetii causing chronic Q fever endocarditis in a Chinese geriatric patient by mNGS","authors":"Hui Wang ,&nbsp;Jie Sheng ,&nbsp;Ying Zhang ,&nbsp;Hao Lan ,&nbsp;Xiaofeng Lu ,&nbsp;Xi Li ,&nbsp;Xiaofei Zhao","doi":"10.1016/j.jgar.2025.09.015","DOIUrl":"10.1016/j.jgar.2025.09.015","url":null,"abstract":"<div><h3>Objective</h3><div>Q (query) fever, caused by <em>Coxiella burnetii</em>, is often linked to negative bacterial cultures, with infective endocarditis with negative cultures difficult to diagnose and treat. Our case demonstrates that metagenomic next-generation sequencing (mNGS) is able to provide a rapid and accurate method for pathogenetic diagnosis in infectious diseases.</div></div><div><h3>Case presentation</h3><div>A case of infective endocarditis with negative blood cultures is reported in a male patient with a history of sheep farming and previous aortic valve replacement and atrial septal defect atrial septal defect repair. Blood tests showed positive serum immunofluorescent antibodies to <em>Rickettsia</em>, while mNGS of perivalvular abscess tissue suggested <em>C. burnetii</em>. Doxycycline 0.1 g q12h and hydroxychloroquine 0.2 g q12h were used for postoperative antibiotic treatment. The genome of <em>C. burnetii</em> C2245173Z was assembled on the Illumina platform and no known antibiotic resistance genes were detected. Phylogenetic analysis of the <em>C. burnetii</em> genome showed a genetic relationship between animal- and human-derived strains.</div></div><div><h3>Conclusions</h3><div>mNGS could provide a rapid and accurate assay for clinical diagnosis and play a decisive role in the pathogenetic diagnosis of some infectious diseases. Doxycycline plus hydroxychloroquine remains an effective treatment for chronic Q fever endocarditis. In addition, phylogenetic tree analysis indicates that <em>C. burnetii</em> infection may pose a potential risk to humans working with livestock.</div></div>","PeriodicalId":15936,"journal":{"name":"Journal of global antimicrobial resistance","volume":"45 ","pages":"Pages 192-195"},"PeriodicalIF":3.2,"publicationDate":"2025-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145251360","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Epidemiological and genetic profiles of ceftazidime/avibactam-resistant Klebsiella pneumoniae conferred by KPC variants in a tertiary hospital in China","authors":"Min Xu ,&nbsp;Xiaofen Mo ,&nbsp;Yuchao Zhang ,&nbsp;Huinan Xia ,&nbsp;Huiqiong Jia ,&nbsp;Haishen Kong ,&nbsp;Qixia Luo ,&nbsp;Yiqi Fu","doi":"10.1016/j.jgar.2025.09.013","DOIUrl":"10.1016/j.jgar.2025.09.013","url":null,"abstract":"<div><h3>Objective</h3><div>The emergence of <em>Klebsiella pneumoniae</em> carbapenemase variants (KPCVs), conferring resistance to ceftazidime/avibactam (CAZ/AVI), represents a critical clinical challenge. However, investigations into KPCV-producing <em>K. pneumoniae</em> (KPCV-Kp) are confined to sporadic clinical cases.</div></div><div><h3>Methods</h3><div>Clinical isolates of KPCV-Kp exhibiting resistance to CAZ/AVI were collected from a Chinese tertiary hospital from February 2015 to March 2024. The clinical characteristics, antimicrobial susceptibility, molecular epidemiology and genetic phylogeny were subjected to analysis.</div></div><div><h3>Results</h3><div>A total of 25 KPCV-Kp strains displaying high-level resistance to CAZ/AVI were identified, with their initial isolation in 2018 and the majority obtained in 2023 (64.0%, 16/25). All patients except one had prior CAZ/AVI exposure for 3 to 38 days. Twelve KPCVs, including four novel variants (designated as KPC-219 to KPC-222), were identified. KPC-33 predominated (40.0%, 10/25), followed by KPC-71 (12.0%, 3/25), KPC-14, and KPC-90 (8.0%, 2/25 for each). Notably, 50.0% (6/12) of the KPCVs exhibited multiple mutations in the Ω-loop as well as in other regions, which were associated with a significantly longer CAZ/AVI exposure (<em>P</em> = 0.033). Molecular analysis highlighted the circulation of ST11-KL64 clone (72.0%, 18/25), followed by ST11-KL47 and ST11-KL25 clones (12.0%, 3/25 for each). Phylogenetic analysis revealed no epidemiological linkage between cases, and the KPCV-Kp evolved from their individual parental KPC-2-producing strains.</div></div><div><h3>Conclusions</h3><div>Our study provided a preliminary glimpse into the epidemiology and genetic characteristics of KPCV-Kp in China, underscoring the critical need for continuous monitoring in patients treated with CAZ/AVI, even in short-term therapy, to better grasp the evolving threat posed by these variants.</div></div>","PeriodicalId":15936,"journal":{"name":"Journal of global antimicrobial resistance","volume":"45 ","pages":"Pages 176-181"},"PeriodicalIF":3.2,"publicationDate":"2025-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145232618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Molecular characterization and resistance mechanisms of linezolid-resistant enterococci clinical isolates and identification of a clinical Enterococcus faecium strain co-harboring optrA, poxtA, and cfr(D) in a tertiary hospital in China","authors":"Ni Suo ,&nbsp;Jing Yu ,&nbsp;Haijun Li ,&nbsp;Nan Yi ,&nbsp;Cailin Liu ,&nbsp;Wanhai Wang","doi":"10.1016/j.jgar.2025.09.008","DOIUrl":"10.1016/j.jgar.2025.09.008","url":null,"abstract":"<div><h3>Objectives</h3><div>The emergence of linezolid-resistant enterococci has become a significant global health concern. This study aimed to investigate the molecular characterization and resistance mechanisms in clinical isolates in a tertiary hospital in China.</div></div><div><h3>Methods</h3><div>The VITEK®2 Compact system, VITEK® MS, and whole-genome sequencing (WGS) were used to identify 59 linezolid-resistant enterococci isolates. Antimicrobial susceptibilities were assessed by broth microdilution. WGS and bioinformatics tools analyzed resistance mechanisms and molecular characteristics. Plasmid-borne linezolid resistance gene transfer was assessed via conjugation and transformation assays.</div></div><div><h3>Results</h3><div>We collected 59 linezolid-resistant enterococci isolates, including 54 <em>Enterococcus faecalis</em> and 5 <em>Enterococcus faecium</em> strains. One strain carried the <em>poxtA</em> gene, one isolate carried the G2576T mutation in the 23S rRNA gene, and 56 isolates harbored the <em>optrA</em> gene. Notably, one isolate co-harbored the <em>optrA, poxtA</em>, and <em>cfr</em>(D) genes. Twenty-three sequence types (STs) were identified. ST16 (48.1%, 26/54) predominated in <em>E. faecalis</em>. Multilocus sequence typing (MLST) and evolutionary analysis indicated that <em>E. faecalis</em> strains of the same ST were genetically related. Among the seven strains (two <em>E. faecium</em> and five <em>E. faecalis</em> strains) selected for further investigation, IS<em>1216E</em> was detected on plasmids carrying linezolid resistance genes in all five strains. Additionally, transposon Tn<em>554</em> was detected on the chromosome of an <em>optrA</em>-carrying strain.</div></div><div><h3>Conclusion</h3><div>This study describes the molecular characteristics and resistance mechanisms of linezolid-resistant enterococci in our hospital, including a novel <em>E. faecium</em> isolate with <em>optrA, poxtA,</em> and <em>cfr</em>(D), highlighting the need for enhanced surveillance to control the dissemination of resistant strains.</div></div>","PeriodicalId":15936,"journal":{"name":"Journal of global antimicrobial resistance","volume":"45 ","pages":"Pages 182-191"},"PeriodicalIF":3.2,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145206674","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Molecular characterization of blaVIM-2-carrying Pseudomonas asiatica L2126: identification of a ∼44 kb untypable plasmid with intra-genus dissemination potential","authors":"Jinhua Zhang ,&nbsp;Yi Liu ,&nbsp;Lei Fang ,&nbsp;Xinrui Wang ,&nbsp;Hao Xu ,&nbsp;Danfeng Lou","doi":"10.1016/j.jgar.2025.09.012","DOIUrl":"10.1016/j.jgar.2025.09.012","url":null,"abstract":"<div><h3>Objectives</h3><div>This study aims to elucidate the molecular characteristics of a <em>bla</em>_VIM-2-carrying <em>Pseudomonas asiatica</em> isolate (L2126) from China and to characterize a ∼44 kb untypable plasmid harboring <em>bla</em>_VIM-2. We investigated the genetic context of <em>bla</em>_VIM-2, assessed the associated antimicrobial resistance determinants, and explored the role of this plasmid in mediating gene dissemination.</div></div><div><h3>Methods</h3><div>The isolate L2126 was recovered from an intestinal colonization sample in a patient from Hangzhou, China. Species identification was confirmed by average nucleotide identity (ANI) analysis. Hybrid whole-genome sequencing was performed using Illumina short-read and Oxford Nanopore long-read platforms. Genome assembly was conducted using Unicycler and annotated with Prokka. Antimicrobial resistance genes were identified via ResFinder and CARD. The genetic context of <em>bla</em>_VIM-2 was delineated using IntegronFinder. Plasmid profiles were determined by S1-nuclease pulsed-field gel electrophoresis (S1-PFGE) and <em>in silico</em> replicon analysis.</div></div><div><h3>Results</h3><div>L2126 exhibited a multidrug-resistant profile with high-level resistance to carbapenems, cephalosporins, and fluoroquinolones. Genome analysis revealed 7 resistance genes, including <em>bla</em>_VIM-2 and <em>sul1</em>. Notably, <em>bla</em>_VIM-2 resides within a class 1 integron (<em>intI1-attI1-bla</em>_VIM-2<em>-qacEΔ1-sul1</em>) embedded in a Tn<em>402</em>-like platform on a ∼44 kb untypable plasmid. The adjacent <em>tni</em> module (<em>tniR-tniQ-tniB-tniA</em>) is encoded on the opposite strand, indicating that it is part of the transposition platform rather than the integron cassette array. S1-PFGE confirmed the presence of the ∼44 kb plasmid, and <em>in silico</em> analysis provided a schematic representation of its genetic organization. BLAST analysis demonstrated that this plasmid shares high sequence homology with a plasmid previously identified in <em>Pseudomonas monteilii</em>, despite the two isolates belonging to different species.</div></div><div><h3>Conclusions</h3><div>Our findings demonstrate that the carriage of <em>bla</em>_VIM-2 on a novel ∼44 kb untypable plasmid in <em>P. asiatica</em> L2126 could facilitate horizontal gene transfer of carbapenem resistance. The plasmid’s high homology to one previously identified in <em>P. monteilii</em> suggests that it has the potential for intra-genus dissemination, posing a significant threat to the spread of carbapenem resistance.</div></div>","PeriodicalId":15936,"journal":{"name":"Journal of global antimicrobial resistance","volume":"45 ","pages":"Pages 173-175"},"PeriodicalIF":3.2,"publicationDate":"2025-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145191761","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}