Journal of global antimicrobial resistance最新文献

{"title":"Emergence of Acinetobacter towneri harbouring a novel plasmid with blaNDM-1 and tet(X7) from hospital wastewater in the Philippines","authors":"Zoe Mallonga ,&nbsp;Maho Tokuda ,&nbsp;Rin Yamazaki ,&nbsp;Shunta Tsuruga ,&nbsp;Isana Nogami ,&nbsp;Yuka Sato ,&nbsp;Ann Gelanie Tarrayo ,&nbsp;Rolly Fuentes ,&nbsp;Richard Parilla ,&nbsp;Kazuhide Kimbara ,&nbsp;Masato Suzuki ,&nbsp;Masaki Shintani","doi":"10.1016/j.jgar.2025.01.017","DOIUrl":"10.1016/j.jgar.2025.01.017","url":null,"abstract":"<div><h3>Objectives</h3><div>The clinical effectiveness of carbapenem and tigecycline, which are last-resort antimicrobials used to treat multidrug-resistant bacterial infections<em>,</em> faces challenges due to emerging plasmid-borne resistance mechanisms, including the enzymatic inactivation of antimicrobials. Here, we investigate and report the co-occurrence of <em>bla</em>_NDM-1 and <em>tet</em>(X7) genes in an <em>Acinetobacter towneri</em> isolate from hospital wastewater in the Philippines.</div></div><div><h3>Methods</h3><div>An <em>A. towneri</em> isolate PT23-B2 was obtained from a hospital wastewater treatment plant in Tacloban, Philippines in 2023. Whole-genome sequencing of PT23-B2 was performed and antimicrobial resistance genes (ARGs), plasmids, and mobile genetic elements were detected using custom sequence databases.</div></div><div><h3>Results</h3><div>Whole-genome sequencing analysis of <em>A. towneri</em> PT23-B2 resulted in the complete genome sequence consisting of one chromosome and five putative plasmids. One of the five plasmids identified, the 134-kb plasmid named pPT23-B2_1 (of which replicon was classified as R3-T45 or GR31), contained multiple ARGs, including <em>bla</em>_NDM-1 and <em>tet</em>(X7). The <em>bla</em>_NDM-1 was flanked by IS<em>Aba125</em>, and <em>tet</em>(X7) was associated with one IS<em>26</em> family insertion sequence (IS), indicating probable transpositions into the plasmid via these mobile genetic elements. Antimicrobial susceptibility tests showed that PT23-B2 is resistant to tigecycline, in addition to meropenem.</div></div><div><h3>Conclusions</h3><div>This is the first report on an environmental bacterial isolate from the Philippines harbouring both carbapenem-resistance gene (<em>bla</em>_NDM-1) and tigecycline-resistance gene [<em>tet</em>(X7)]. This study highlights the potential dissemination of clinically important ARGs, such as <em>bla</em>_NDM and <em>tet</em>(X), in environmental reservoirs, necessitating continuous monitoring and urgent intervention strategies.</div></div>","PeriodicalId":15936,"journal":{"name":"Journal of global antimicrobial resistance","volume":"41 ","pages":"Pages 287-289"},"PeriodicalIF":3.7,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143255693","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Treatment outcomes and key factors contributing to unfavourable outcomes among isoniazid-resistant pulmonary tuberculosis patients in Shanghai, China","authors":"Wenjing Xiao ,&nbsp;Jing Chen ,&nbsp;Lixin Rao ,&nbsp;Xiao Xiao ,&nbsp;Xubin Zheng ,&nbsp;Zheyuan Wu ,&nbsp;Xin Shen","doi":"10.1016/j.jgar.2025.02.003","DOIUrl":"10.1016/j.jgar.2025.02.003","url":null,"abstract":"<div><h3>Objective</h3><div>Given that more than 1 million people annually develop isoniazid-resistant tuberculosis (Hr-TB), the issue of Hr-TB may go unnoticed. However, limited studies have focused on the clinical treatment of Hr-TB in China, particularly regarding treatment outcomes and influencing factors. This study aimed to evaluate the treatment outcomes of Hr-TB patients in Shanghai from 2018 to 2021 and analyse the influencing factors, including demographic characteristics, clinical features, and treatment-related factors.</div></div><div><h3>Methods</h3><div>This study retrospectively reviewed the medical records of Hr-TB patients registered in the TB management information system from 2018 to 2021. Differences in demographic characteristics, clinical information, and treatment outcomes were evaluated. Multivariable logistic regression was used to identify risk factors associated with unfavourable outcomes.</div></div><div><h3>Results</h3><div>A total of 664 patients with Hr-TB were included in the analysis. A total of 84 cases (12.7%) had unfavourable outcomes. Only 318 (47.9%) Hr-TB patients used regimens containing fluoroquinolones. Adverse events occurred in 127 cases (19.1%), of which 12 cases (1.81%) discontinued treatment due to adverse events. There was statistically significant difference in the occurrence of adverse events between the different treatment regimens (<em>P</em> &lt; 0.001). Multivariable logistic regression showed that older age (adjusted odds ratio = 6.13, 95% confidence intervals [CI] = 1.24–30.24, <em>P</em> = 0.026), use of injectable agents (adjusted odds ratio = 3.75, 95% CI = 1.29–10.94, <em>P</em> = 0.016), and treatment duration (95% CI = 21.85–1487.61, <em>P</em> &lt; 0.001) were risk factors for unfavourable treatment outcomes.</div></div><div><h3>Conclusions</h3><div>Unfavourable outcomes were more frequent among older patients and those receiving injectable agents among Hr-TB patients in Shanghai, a low-endemic region for TB. This emphasizes the need for timely diagnosis and optimized treatment strategies for isoniazid-resistant tuberculosis.</div></div>","PeriodicalId":15936,"journal":{"name":"Journal of global antimicrobial resistance","volume":"42 ","pages":"Pages 177-186"},"PeriodicalIF":3.7,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143537235","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Combined dual β-lactams and diazabicyclooctane β-lactamase inhibitor is highly effective against Mycobacterium abscessus species in vitro","authors":"Kana Misawa ,&nbsp;Tomoyasu Nishimura ,&nbsp;Maiko Yoshikawa ,&nbsp;Rina Shimamura ,&nbsp;Shoko Kashimura ,&nbsp;Yuki Enoki ,&nbsp;Kazuaki Taguchi ,&nbsp;Kazuaki Matsumoto ,&nbsp;Naoki Hasegawa","doi":"10.1016/j.jgar.2025.02.015","DOIUrl":"10.1016/j.jgar.2025.02.015","url":null,"abstract":"<div><h3>Objective</h3><div><em>Mycobacterium abscessus</em> pulmonary disease is a refractory infectious disease. Developing an effective treatment is urgent as the number of patients infected with <em>M. abscessus</em> species (MABS) is increasing worldwide. We previously reported that nacubactam, a diazabicyclooctane (DBO) β-lactamase inhibitor, could inhibit MABS β-lactamase. Few reports have indicated that dual β-lactams are effective with a DBO β-lactamase inhibitor against MABS. The objective of this study was to determine which dual β-lactams have high antibacterial activity against MABS in the presence and absence of nacubactam.</div></div><div><h3>Methods</h3><div>Antimicrobial susceptibility tests were conducted through a checkerboard assay of 27 β-lactams using the broth microdilution method for three subspecies-type strains and 20 clinical isolates of MABS. The number of intracellular and extracellular bacteria was measured using human macrophages infected with <em>M. abscessus</em> treated with effective combinations confirmed in susceptibility tests.</div></div><div><h3>Results</h3><div>In antimicrobial susceptibility tests, 91 combinations of dual β-lactams with nacubactam exhibited synergistic effects on <em>M. abscessus</em> JCM13569. Among them, the combination of cefazolin, cefotiam, cefoxitin, or cefuroxime with imipenem and nacubactam exhibited highly synergistic effects, resulting in low MICs against MABS clinical isolates. Without nacubactam, the combination of imipenem and cefoxitin showed the lowest MIC. In experiments using human macrophages infected with <em>M. abscessus</em>, these dual β-lactam combinations reduced the number of intracellular and extracellular bacteria compared with those of single β-lactams.</div></div><div><h3>Conclusions</h3><div>The combination of cefazolin, cefotiam, cefoxitin, or cefuroxime with imipenem and nacubactam was highly effective against MABS. Without nacubactam, the combination of cefoxitin and imipenem was effective.</div></div>","PeriodicalId":15936,"journal":{"name":"Journal of global antimicrobial resistance","volume":"42 ","pages":"Pages 142-150"},"PeriodicalIF":3.7,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143523624","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spread of the Fosfomycin resistance fosA3 gene via the IS26 mobile element between plasmids and the chromosome of carbapenem-resistant Escherichia coli in China","authors":"Ying Zhang ,&nbsp;Chuanxin Yang ,&nbsp;Jiayao Yao ,&nbsp;Longjie Zhou ,&nbsp;Xiaofan Zhang ,&nbsp;Huan Wang ,&nbsp;Lijuan Liu ,&nbsp;Yuexing Tu ,&nbsp;Xi Li","doi":"10.1016/j.jgar.2025.02.011","DOIUrl":"10.1016/j.jgar.2025.02.011","url":null,"abstract":"<div><h3>Objective</h3><div>This study investigated <em>fosA3</em>-positive strains selected from carbapenem-resistant <em>Escherichia coli</em> (CREC) and further characterized them through genomic and phenotypic analyses.</div></div><div><h3>Methods</h3><div><em>fosA3-</em>positive CREC strains were subjected to agar dilution. Whole-genome sequencing (WGS) was used to identify molecular mechanisms of fosfomycin resistance and to investigate plasmid structure characteristics through comparative analysis. Conjugative transfer experiments were used to evaluate plasmid transfer ability, followed by plasmid stability assessment. Growth rate analysis evaluated the fitness costs of transconjugants. Phylogenetic analysis was performed on <em>fosA3</em>-positive CREC strains. Furthermore, analysis of <em>fos</em> genes carrying <em>E. coli</em> sequence types (STs) from the NCBI database explored the evolution and spread of fosfomycin resistance.</div></div><div><h3>Results</h3><div>Between 2016 and 2023, a total of 11.23% CREC strains (10/89) carrying <em>fosA3</em> were collected from a hospital for further analysis. These ten <em>fosA3</em>-positive strains were also resistant to fluoroquinolones and ceftazidime-avibactam. The <em>fosA3</em> gene was located within a similar genetic background (IS<em>26</em>-<em>fosA3</em>–1811bp-IS<em>26</em>) on plasmids or chromosomes. The <em>fosA3</em>-carrying IncFII(pHN7A8)-IncX3 cointegrate plasmid pEC00–2–145k was transferable, with fitness cost of 20% to host. Furthermore, three of ten <em>fosA3</em>-positive CREC strains belonged to ST156. Analysis of <em>fos</em> genes carrying <em>E. coli</em> strains from China in the NCBI database identified ST156 (5.39%, 147/2,725) and ST167 (5.21%, 142/2,725) as predominant STs.</div></div><div><h3>Conclusions</h3><div>This study revealed <em>fosA3</em> in CREC strains was associated with IS<em>26</em> and spreads fosfomycin resistance through horizontal transfer, occurring both on chromosomes and plasmids. The first <em>fosA3</em>-carrying cointegrate plasmid pHN7A8-IncX3-type in <em>E. coli</em> isolates was reported, highlighting a new route of fosfomycin resistance spread. Additionally, notable diversity of ST among <em>fosA3</em>-carrying <em>E. coli</em> strains highlights complexity of fosfomycin resistance dissemination and the importance of surveillance and control measures.</div></div>","PeriodicalId":15936,"journal":{"name":"Journal of global antimicrobial resistance","volume":"42 ","pages":"Pages 80-87"},"PeriodicalIF":3.7,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143483397","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Surveillance and Genomic Characterisation of Colistin-Resistant Gram-Negative Bacteria in the Drains of High-Risk Hospital Units","authors":"Giuseppe Fleres ,&nbsp;Alessia Mirabile ,&nbsp;Mariëtte Lokate ,&nbsp;John W.A. Rossen ,&nbsp;Natacha Couto ,&nbsp;Alexander W. Friedrich ,&nbsp;Silvia García-Cobos","doi":"10.1016/j.jgar.2025.02.012","DOIUrl":"10.1016/j.jgar.2025.02.012","url":null,"abstract":"<div><h3>Objective</h3><div>The health care water environment, including sinks and drainage systems, can be a long-term reservoir of nosocomial pathogens. In this study, we aimed to investigate the presence of colistin-resistant Gram-negative (ColR-GN) bacteria in humid compartments of high-risk hospital units at the University Medical Center Groningen, The Netherlands.</div></div><div><h3>Methods</h3><div>Environmental sampling was conducted in sink and shower drains of high-risk hospital units, and colistin MICs were determined using broth microdilution. Whole-genome sequencing was performed to investigate the presence of mobile colistin resistance (<em>mcr</em>) genes, chromosomal point mutations and gene alterations linked to colistin resistance.</div></div><div><h3>Results</h3><div>ColR-GN bacteria were detected in all investigated units, with <em>Enterobacter</em> spp. being the most abundant genus. Twelve isolates exhibited colistin resistance (MIC &gt;2 mg/L), including <em>Enterobacter cloacae</em> complex (n = 11) and <em>Klebsiella pneumoniae</em> (n = 1). Chromosomal mutations in genes involved in lipopolysaccharide structure modifications were the main mechanisms contributing to colistin resistance in <em>Enterobacter</em> spp. and <em>Klebsiella</em> spp. (91.6%, 11/12). Additionally, two <em>Enterobacter kobei</em> isolates harboured mobile colistin resistance genes, <em>mcr-4.3</em> and <em>mcr-9.1</em>.</div></div><div><h3>Conclusions</h3><div>The presence and persistence of bacterial ColR-GN clones in the sink and shower drains of high-risk hospital units highlights the importance of monitoring such environments for antibiotic-resistant bacteria to identify reservoirs and prevent further spread.</div></div>","PeriodicalId":15936,"journal":{"name":"Journal of global antimicrobial resistance","volume":"42 ","pages":"Pages 127-134"},"PeriodicalIF":3.7,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143492252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Emergence of mcr-8.2-mediated colistin resistance in Klebsiella pneumoniae isolated from pediatric diarrhea cases in southern Vietnam","authors":"Nga Thi Le ,&nbsp;Phuong Hoai Hoang ,&nbsp;Quynh Nguyen ,&nbsp;Minh Nhat Ha Truong ,&nbsp;Chinh Van Dang ,&nbsp;Tinh Huu Ho ,&nbsp;Phuc Le Hoang ,&nbsp;Dinh Quang Truong ,&nbsp;Ha Thi Thanh Nguyen ,&nbsp;Chuong Van Le ,&nbsp;Trang Thi Phuong Phan","doi":"10.1016/j.jgar.2025.02.007","DOIUrl":"10.1016/j.jgar.2025.02.007","url":null,"abstract":"<div><h3>Background</h3><div>Colistin resistance poses a growing global challenge, particularly in low- and middle-income countries where antibiotic misuse is prevalent. This study investigates the prevalence of colistin resistance in <em>Klebsiella</em> spp. and characterizes the genetic features of resistant isolates, focusing on the <em>mcr-8.2</em> gene identified in a <em>Klebsiella pneumoniae</em> isolate from pediatric diarrheal cases in southern Vietnam.</div></div><div><h3>Methods</h3><div>Stool samples were collected from 500 pediatric patients (aged 0–5 years) hospitalized with diarrhea in two tertiary hospitals in Ho Chi Minh City between March and September 2022. Samples were cultured on Violet Red Bile Glucose Agar, then presumptive <em>Klebsiella</em> spp. colonies were selected, purified on nutrient agar, and identified using MALDI-TOF MS. Colistin resistance was determined via minimum inhibitory concentration testing, and the presence of <em>mcr</em> genes was confirmed through polymerase chain reaction. Whole-genome sequencing was performed on the <em>Klebsiella pneumoniae</em> strain harboring <em>mcr-8.2</em> to elucidate resistance mechanisms. Strain characterization was performed using multi-locus sequence typing, while conjugation experiments assessed horizontal gene transfer potential.</div></div><div><h3>Results</h3><div>Among 121 <em>Klebsiella</em> spp. isolates, 49 (40.5%) were resistant to colistin. The <em>mcr-1</em> gene was detected in 31 isolates (25.6%), whereas the <em>mcr-8</em> was identified in a single isolate (0.8%), with a colistin MIC of 16 µg/mL. Genomic analysis revealed 34 antibiotic resistance genes, including <em>mcr-8.2</em> and multiple β-lactamase genes, alongside plasmid types IncFIB and IncFII. Chromosomal mutations in <em>phoP, phoQ</em>, and <em>lpxM</em> were also implicated in colistin resistance.</div></div><div><h3>Conclusions</h3><div>This study documents the emergence of <em>mcr-8.2</em>-mediated colistin resistance in K<em>. pneumoniae</em> from pediatric diarrhea in Vietnam and highlights a high prevalence of multidrug resistance in <em>Klebsiella</em> spp.. Continuous surveillance of <em>mcr</em> genes and novel therapeutic strategies are urgently needed.</div></div>","PeriodicalId":15936,"journal":{"name":"Journal of global antimicrobial resistance","volume":"42 ","pages":"Pages 120-126"},"PeriodicalIF":3.7,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143483344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Second-line drug resistance among multidrug-resistant tuberculosis patients in Ethiopia: A laboratory-based surveillance","authors":"Getu Diriba ,&nbsp;Ayinalem Alemu ,&nbsp;Bazezew Yenew ,&nbsp;Betselot Zerihun Ayano ,&nbsp;Michael Hailu ,&nbsp;Bedo Buta ,&nbsp;Amanuel Wondimu ,&nbsp;Zigba Tefera ,&nbsp;Abyot Meaza ,&nbsp;Getachew Seid ,&nbsp;Muluwork Getahun ,&nbsp;Biniyam Dagne ,&nbsp;Hilina Mollalign ,&nbsp;Yeshiwork Abebaw ,&nbsp;Melak Getu ,&nbsp;Mengistu Tadesse ,&nbsp;Tegegn Belhu ,&nbsp;Ephrem Alemu ,&nbsp;Minilik Demissie ,&nbsp;Ashenafi Erresso ,&nbsp;Gemechu Tadesse","doi":"10.1016/j.jgar.2025.02.014","DOIUrl":"10.1016/j.jgar.2025.02.014","url":null,"abstract":"<div><h3>Objectives</h3><div>To estimate the proportion of second-line anti-tuberculosis drug resistance among multidrug-resistant tuberculosis (MDR-TB) patients in Ethiopia.</div></div><div><h3>Methodology</h3><div>A laboratory-based prospective cross-sectional study was conducted at the National Tuberculosis Reference Laboratory (NTRL), Ethiopia, from February 2022 to July 2024. Phenotypic drug susceptibility testing (pDST) assessed resistance to various second-line antituberculosis drugs. The collected data were entered into Microsoft Excel 2016 and imported into Statistical Package for Social Sciences (SPSS) version 23 for descriptive analysis.</div></div><div><h3>Result</h3><div>Of 468 MDR-TB patients, 262 were new, and 206 were previously treated cases. Pre-extensively drug-resistant tuberculosis (pre-XDR-TB) was identified in four (1.52%) new cases and seven (3.40%) previously treated cases. Extensively drug-resistant tuberculosis (XDR-TB) was detected in three (1.15%) new cases and two (0.97%) previously treated cases. Overall, 11 (2.35%) cases were classified as pre-XDR-TB, and five (1.07%) as XDR-TB. Combined resistance to fluoroquinolones (FQs) and bedaquiline were detected in four cases (0.85%), comprising three new cases (1.15%) and one previously treated case (0.49%). Resistance to both FQs and linezolid was detected in a single previously treated case (0.49%) and acquired resistance to second-line drugs was identified in four cases.</div></div><div><h3>Conclusions</h3><div>Our study showed a prevalence of 2.35% for pre-XDR-TB and 1.07% for XDR-TB among MDR-TB cases, highlighting the importance of continuous surveillance and tailored treatment approaches to control the spread of drug-resistant TB (DR-TB) in Ethiopia. Future studies on MDR-TB surveillance should prioritize the integration of genomic surveillance into routine laboratory-based DR-TB monitoring systems to enhance early detection of resistance patterns, support targeted treatment strategies, and improve overall patient management efforts.</div></div>","PeriodicalId":15936,"journal":{"name":"Journal of global antimicrobial resistance","volume":"42 ","pages":"Pages 167-174"},"PeriodicalIF":3.7,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143483347","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Genetic determinants and phenotypic characteristics of heavy metal and biocide tolerance among multidrug-resistant and susceptible Gram-negative bacilli clinical isolates","authors":"Natália Columbaro Moreira ,&nbsp;Nathália Abichabki ,&nbsp;Joseane Cristina Ferreira ,&nbsp;Roberto Martinez ,&nbsp;Ana Lucia da Costa Darini ,&nbsp;Leonardo Neves Andrade","doi":"10.1016/j.jgar.2025.02.004","DOIUrl":"10.1016/j.jgar.2025.02.004","url":null,"abstract":"<div><div>Antimicrobial resistance is a major health care problem as well as a concern for global public health. As a result, the use of nonantibiotic antimicrobials, such as heavy metals and biocides, has increased in a bid to control the spread of antibiotic-resistant bacteria. Consequently, heavy metal tolerance genes (HMTGs) and biocide tolerance genes (BTGs) have been more frequently detected in Gram-negative bacilli. In this study, we searched for acquired HMTGs, BTGs, and antibiotic resistance genes (ARGs) and determined the MICs of common heavy metals and biocides in multidrug-resistant and susceptible Gram-negative bacilli clinical isolates. A high frequency of <em>sil</em>A and <em>pco</em>D genes was mainly detected among <em>Klebsiella</em> spp. and <em>Enterobacter cloacae</em> regardless of their susceptible profile. The <em>mer</em>A gene was also found in isolates carrying <em>sil</em>A/<em>pco</em>D genes. ARGs were detected in isolates that harboured <em>sil</em>A and/or <em>pco</em>D genes. BTGs (<em>qac</em>ΔE, <em>ydg</em>E, <em>ydg</em>F, <em>mdf</em>A, and <em>emr</em>E) were mostly detected in <em>Klebsiella pneumoniae</em> and <em>E. cloacae</em> isolates regardless of their susceptibility profile, and these isolates often co-harboured HMTGs and/or ARGs. Higher copper sulphate MIC values were obtained under aerobic conditions, regardless of the presence or absence of <em>pco</em>D and/or <em>sil</em>A genes. Nevertheless, in most isolates carrying <em>pco</em>D/<em>sil</em>A, higher copper sulphate MIC values were determined under anaerobic conditions. Regarding AgNO₃, no significant differences in MIC values were observed for isolates with or without the s<em>il</em>A gene. Our results show a broad distribution of HMTGs, BTGs, and ARGs in bacteria causing health care-associated infections, which could contribute to the co-selection of hospital pathogens resistant to multiple and diverse antimicrobials.</div></div>","PeriodicalId":15936,"journal":{"name":"Journal of global antimicrobial resistance","volume":"42 ","pages":"Pages 91-97"},"PeriodicalIF":3.7,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143472553","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multiple mechanisms drive linezolid resistance in clinical Enterococcus faecium isolates by increasing poxtA gene expression","authors":"Fernando Lázaro-Perona ,&nbsp;Paula Navarro-Carrera ,&nbsp;Iván Bloise ,&nbsp;Pablo Prieto-Casado ,&nbsp;Isabel García-Pérez ,&nbsp;Alberto Paradela ,&nbsp;Fernando Corrales ,&nbsp;Juana Cacho-Calvo ,&nbsp;Jesús Mingorance","doi":"10.1016/j.jgar.2025.02.005","DOIUrl":"10.1016/j.jgar.2025.02.005","url":null,"abstract":"<div><h3>Objectives</h3><div>The <em>poxtA</em> gene is a transferable linezolid-resistance gene that encodes an ATP-binding cassette F protein that prevents linezolid from inhibiting protein synthesis. In enterococci, the presence of the <em>poxtA</em> gene does not consistently imply resistance to linezolid. The objective of this work was to analyze the role of the <em>poxtA</em> gene in linezolid susceptibility in a cohort of five <em>poxtA⁺</em> clinical isolates of <em>Enterococcus faecium</em>.</div></div><div><h3>Methods</h3><div>Three of the isolates were linezolid-resistant and two were linezolid-susceptible. The genomes of all five isolates were sequenced using short and long read sequencing. The genomes were assembled to identify the location of the <em>poxtA</em> gene. The presence and relative amount of the PoxtA protein was determined with a proteomics approach.</div></div><div><h3>Results</h3><div>One of the linezolid-resistant isolates harbored a deletion in the <em>poxtA</em> gene promoter and a mutation in the ribosomal protein L4. Another exhibited two sets of tandem repeats of the <em>poxtA</em> gene within the chromosome, and the third displayed an increased copy number of the plasmid carrying the <em>poxtA</em> gene. Proteomic analysis detected the PoxtA protein and confirmed increased expression levels in the three resistant mutants. The highest expression was seen in the promoter deletion mutant.</div></div><div><h3>Conclusion</h3><div>The presence of the <em>poxtA</em> gene in clinical isolates of <em>E. faecium</em> does not imply resistance to linezolid, but it should be considered a significant risk factor for the development of resistance. Active molecular surveillance for intestinal <em>poxtA</em> gene carriers could be important to prevent dissemination.</div></div>","PeriodicalId":15936,"journal":{"name":"Journal of global antimicrobial resistance","volume":"42 ","pages":"Pages 113-119"},"PeriodicalIF":3.7,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143472269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The co-occurrence of tet(X4) and tmexCD2-toprJ2 mediated tigecycline resistance in Raoultella ornithinolytica","authors":"Weishuai Zhai ,&nbsp;Lu Liu ,&nbsp;Jijun Kang ,&nbsp;Mengjin Xiao ,&nbsp;Yiqing Wang ,&nbsp;Yao Wang ,&nbsp;Yingbo Shen ,&nbsp;Congming Wu ,&nbsp;Jianzhong Shen ,&nbsp;Yang Wang ,&nbsp;Dejun Liu","doi":"10.1016/j.jgar.2025.01.021","DOIUrl":"10.1016/j.jgar.2025.01.021","url":null,"abstract":"<div><h3>Objectives</h3><div>This study aimed to characterize the co-occurrence of the tigecycline resistance determinants <em>tet</em>(X4) and <em>tmexCD2-toprJ2</em> in a <em>Raoultella ornithinolytica</em> isolate collected from a pig rectal swab at the slaughterhouse.</div></div><div><h3>Methods</h3><div>The <em>R. ornithinolytica</em> isolate WS60 was subjected to antimicrobial susceptibility testing. Whole-genome sequencing (WGS) was performed to analyze the genetic features of the plasmids carrying <em>tet</em>(X4) and <em>tmexCD2-toprJ2</em>. Additionally, a conjugation assay was conducted to evaluate the transferability of these plasmids, followed by a 15-day stability test to assess the persistence of the two resistance determinants.</div></div><div><h3>Results</h3><div><em>R. ornithinolytica</em> WS60 exhibited high-level tigecycline resistance, with a minimum inhibitory concentration (MIC) of 32 μg/mL, and was also resistant to ampicillin, ampicillin-sulbactam, chloramphenicol, tetracycline, sulfamethoxazole-trimethoprim, florfenicol, and streptomycin. WGS analysis revealed that WS60 harbored three plasmids, including a 384,249-bp <em>tmexCD2-toprJ2</em>-carrying IncQ plasmid (pWS60–1) and a 78,159-bp <em>tet</em>(X4)-carrying IncFII plasmid (pWS60–2). Interestingly, pWS60–2 was identical to several plasmids found in <em>Klebsiella</em> spp<em>.</em> isolated from animals, animal-derived food, and humans. Moreover, pWS60–2 was successfully transferred to <em>Klebsiella</em> spp. via conjugation, whereas pWS60–1 failed to transfer. Notably, no significant fitness cost was observed in the transconjugants carrying pWS60–2. Additionally, a 15-day stability assay demonstrated that both resistance determinants were stably maintained in the bacterial population without significant loss, underscoring their persistence over time.</div></div><div><h3>Conclusions</h3><div>This is the first report of the co-occurrence of <em>tet</em>(X4) and <em>tmexCD2-toprJ2</em> in <em>R. ornithinolytica</em>. Enhanced surveillance in slaughterhouses, along with targeted interventions, should be implemented to mitigate the potential spread of mobile tigecycline resistance throughout the food production chain.</div></div>","PeriodicalId":15936,"journal":{"name":"Journal of global antimicrobial resistance","volume":"42 ","pages":"Pages 100-104"},"PeriodicalIF":3.7,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143472282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}