International Health Management Associates, Inc., Schaumburg, IL 60173, USA.
J Antimicrob Chemother. 2011 Sep;66(9):1992-7. doi: 10.1093/jac/dkr240. Epub 2011 Jun 14.
To investigate the β-lactamase background of ertapenem non-susceptible isolates for the presence of the most commonly detected carbapenemase genes, bla(KPC), bla(OXA-48) and bla(VIM), and the newly described bla(NDM-1).
Two hundred and thirty-five ertapenem-non-susceptible (MIC ≥ 0.5 mg/L) isolates of Enterobacteriaceae from the worldwide Study for Monitoring Antimicrobial Resistance Trends (SMART) 2009 programme were screened using a multiplex PCR for the presence of bla(KPC), bla(OXA-48), bla(VIM) and bla(NDM-1) genes. Extended-spectrum β-lactamase (ESBL) and AmpC genes (bla(ESBL) and bla(AmpC)) were identified using the Check-MDR CT101 microarray. DNA sequencing was performed to identify the bla(ESBL), bla(KPC) and bla(NDM-1) genes. Molecular typing was also performed to genetically characterize these isolates.
Sixty-six isolates (28%) had a carbapenemase gene, with bla(NDM-1) identified in 33 isolates including 2 isolates carrying both bla(NDM-1) and bla(OXA-48); other carbapenemase genes found included bla(KPC) (n = 23), bla(VIM) (n = 7) and bla(OXA-48) (n = 3). All bla(NDM-1)-carrying isolates were from patients in India and comprised five different species. With the exception of one isolate carrying only bla(NDM-1), all bla(NDM-1) carbapenemase-possessing isolates carried additional β-lactamases in various combinations: bla(ESBL) and bla(AmpC) (n = 18); bla(ESBL) (n = 10); bla(ESBL), bla(AmpC) and bla(OXA-48) (n = 2); and bla(AmpC) (n = 2). Except for bla(OXA-48)-carrying isolates, novel multilocus sequence types or enterobacterial repetitive intergenic consensus PCR patterns were observed along with clonal dissemination within and among sites.
A range of carbapenemase genes, associated with diverse ESBLs and/or AmpC backgrounds, were found among Enterobacteriaceae isolated during the study. Many of these ertapenem non-susceptible strains were clonally related and carried various combinations of β-lactamases.
调查厄他培南不敏感分离株的β-内酰胺酶背景，以检测最常见的碳青霉烯酶基因，如 bla(KPC)、bla(OXA-48)和 bla(VIM)，以及新发现的 bla(NDM-1)。
采用多重 PCR 方法对来自全球监测抗菌药物耐药性趋势（SMART）2009 项目的 235 株厄他培南不敏感（MIC≥0.5mg/L）肠杆菌科分离株进行 bla(KPC)、bla(OXA-48)、bla(VIM)和 bla(NDM-1)基因检测。采用 Check-MDR CT101 微阵列检测超广谱β-内酰胺酶（ESBL）和 AmpC 基因（bla(ESBL)和 bla(AmpC)）。对 bla(ESBL)、bla(KPC)和 bla(NDM-1)基因进行 DNA 测序鉴定。采用分子分型方法对这些分离株进行遗传特征分析。
66 株（28%）携带碳青霉烯酶基因，其中 33 株携带 bla(NDM-1)，包括 2 株同时携带 bla(NDM-1)和 bla(OXA-48)；其他碳青霉烯酶基因包括 bla(KPC)（n=23）、bla(VIM)（n=7）和 bla(OXA-48)（n=3）。所有携带 bla(NDM-1)的分离株均来自印度患者，包括 5 个不同的种属。除 1 株仅携带 bla(NDM-1)外，所有携带 bla(NDM-1)碳青霉烯酶的分离株均携带不同组合的其他β-内酰胺酶：bla(ESBL)和 bla(AmpC)（n=18）；bla(ESBL)（n=10）；bla(ESBL)、bla(AmpC)和 bla(OXA-48)（n=2）；以及 bla(AmpC)（n=2）。除携带 bla(OXA-48)的分离株外，还观察到新的多位点序列类型或肠杆菌重复基因间保守序列 PCR 模式，且在不同地点之间存在克隆传播。
在本研究期间，肠杆菌科分离株中存在多种碳青霉烯酶基因，与不同的 ESBLs 和/或 AmpC 背景相关。许多厄他培南不敏感菌株具有克隆相关性，并携带各种组合的β-内酰胺酶。
