Molecular Bacteriology Laboratory, Pasteur Institute of Morocco, 1 Place Louis Pasteur, 20360 Casablanca, Morocco.
Microb Pathog. 2013 Aug-Sep;61-62:16-22. doi: 10.1016/j.micpath.2013.04.010. Epub 2013 May 2.
This study was designed to characterize extended-spectrum-β-lactamases (ESBL) produced by Escherichia coli isolates causing community urinary tract infections over a 2-year period (2010 and 2011) in a Moroccan large geographical region. Molecular characterization was done by using PCR and sequencing of the β-lactamases genes and plasmid-mediated quinolone resistance determinants. Among 1174 isolates, 49 (4.1%) were ESBL producers. The blaCTx-M-15 (n = 31) was the most frequent ESBL gene detected, followed by blaCTx-M-1 (n = 5), blaSHV-12 (n = 6), blaPER-2 (n = 3), then blaTEM-3, blaTEM-20, blaTEM-158, blaSHV-27, blaSHV-28, blaSHV-36, blaSHV-125, blaCTx-M-14 and blaCTx-M-27 with one isolate for each. The non-ESBL genes detected were blaTEM-70 (n = 1), blaTEM-176 (n = 1), blaTEM-104 (n = 6), blaTEM-1 (n = 15) and blaOxA-1 (n = 12). Plasmid mediated AmpC β-lactamases genes; blaACT-5 (n = 1), blaDHA-1(n = 2) and blaCMY-2 (n = 4) were detected in seven isolates (14.2%). The blaOxA-48 (n = 1) and blaIMP-1 (n = 1) carbapenemases genes were detected among five carbapenem-resistant E. coli. Five isolates (10.2%) harboured qnr genes, qnrB1 (n = 3), qnrB2 (n = 1) and qnrS1 (n = 1) type were detected. Thirty isolates (61.2%) were positive for aac(6')-Ib-cr gene. The class 1 integron was detected in twenty two (44.8%) isolates. Phylogenetic grouping revealed that 22 (44.8%) isolates belonged to group A, while 15 (30.6%), 11 (22.4%) and 1 (2%) belonged to B2, D and B1. Results of conjugation experiments indicated that blaCTx-M-15, blaTEM-1, blaOxA-1, aac(6')-Ib-cr and qnrB1 genes were co-transferred and that these genes were carried by a conjugative plasmid of high molecular weight. The results of this work reports the genetic diversity of ESBL genes, with the CTX-M-15 enzyme being the most common among ESBL-producing E. coli in Moroccan community.
本研究旨在描述 2010 年至 2011 年摩洛哥一个大地理区域社区尿路感染中大肠埃希菌分离株产生的超广谱β-内酰胺酶（ESBL）。通过使用 PCR 和β-内酰胺酶基因和质粒介导的喹诺酮耐药决定因素的测序进行分子特征描述。在 1174 株分离株中，有 49 株（4.1%）为 ESBL 产酶菌。检测到的最常见的 ESBL 基因是 blaCTX-M-15（n=31），其次是 blaCTX-M-1（n=5）、blaSHV-12（n=6）、blaPER-2（n=3），然后是 blaTEM-3、blaTEM-20、blaTEM-158、blaSHV-27、blaSHV-28、blaSHV-36、blaSHV-125、blaCTX-M-14 和 blaCTX-M-27，每种基因各有 1 株分离株。检测到的非 ESBL 基因有 blaTEM-70（n=1）、blaTEM-176（n=1）、blaTEM-104（n=6）、blaTEM-1（n=15）和 blaOxA-1（n=12）。在 7 株（14.2%）分离株中检测到blaACT-5（n=1）、blaDHA-1（n=2）和 blaCMY-2（n=4）质粒介导的 AmpC β-内酰胺酶基因。blaOxA-48（n=1）和 blaIMP-1（n=1）碳青霉烯酶基因在 5 株耐碳青霉烯类大肠埃希菌中检测到。5 株（10.2%）分离株携带 qnr 基因，检测到 qnrB1（n=3）、qnrB2（n=1）和 qnrS1（n=1）型。30 株（61.2%）分离株对 aac(6')-Ib-cr 基因呈阳性。22 株（44.8%）分离株检测到类 1 整合子。系统发育群集显示 22 株（44.8%）分离株属于 A 群，而 15 株（30.6%）、11 株（22.4%）和 1 株（2%）属于 B2、D 和 B1。接合实验结果表明，blaCTX-M-15、blaTEM-1、blaOxA-1、aac(6')-Ib-cr 和 qnrB1 基因共同转移，这些基因由高分子量的接合质粒携带。这项工作的结果报告了 ESBL 基因的遗传多样性，CTX-M-15 酶是摩洛哥社区大肠埃希菌中产 ESBL 酶的最常见酶。
