Barguigua Abouddihaj, Zerouali Khalid, Katfy Khalid, El Otmani Fatima, Timinouni Mohammed, Elmdaghri Naima
Molecular Bacteriology Laboratory, Pasteur Institute of Morocco, Casablanca, Morocco; Microbiology, Health and Environment Team, Department of Biology, Faculty of Sciences, Chouaib Doukkali University, El Jadida, Morocco.
University Hospital Center Ibn Rochd, Casablanca, Morocco; Faculty of Medicine and Pharmacy, University Hassan II, Casablanca, Morocco.
Infect Genet Evol. 2015 Apr;31:142-8. doi: 10.1016/j.meegid.2015.01.010. Epub 2015 Jan 22.
The purpose of this investigation was to determine the prevalence and the characteristics of carbapenemase-producing Klebsiellapneumoniae isolates recovered from various clinical specimens in the university hospital of Casablanca, in Morocco. We conducted a prospective study on a total of 166 K. pneumoniae isolates collected from June to August 2011. The strains suspected to carry carbapenemase showed reduced susceptibility to imipenem or ertapenem. The PCR and a sequencing strategy were used to identify carbapenemases, expended spectrum β-lactamases (ESBL), plasmid-mediated AmpC β-lactamases, plasmid mediated quinolone resistance and aminoglycoside resistance determinants. The clonal relationships between isolates were analyzed by pulsed field gel electrophoresis (PFGE). Among the 166 K. pneumoniae isolates studied, 11 (6%) were carbapenemases producers, 9 of which harbored blaOXA-48 and 2 were positive for blaNDM-1. All carbapenemase-producing K. pneumoniae were also ESBL producers and the blaCTX-M-15 was the most frequent ESBL gene detected (n=9), blaCTX-M-28 and blaSHV-28 were also encountered in one isolate each. The K.pneumoniae isolates carried also non-ESBL genes blaTEM-1 (n=9), blaSHV-1 (n=8) and blaOXA-1 (n=3). Five isolates harbored qnr genes, qnrS1 (n=3) and qnrB1 (n=2) variants. Six isolates were positive for aac(6')-Ib-cr gene and two for aac(3)-II gene. The class 1 integron was detected in five isolates. PFGE has revealed the presence of a clonal dissemination in our hospital. The results of conjugation experiments indicated that blaOXA-48+blaCTX-M-15, blaOXA-48+blaCTX-M-28, blaNDM-1+blaCTX-M-15+blaTEM-1+blaOXA-1+qnrS1+aac(6')-Ib-cr and blaNDM-1+blaCTX-M-15+blaTEM-1+qnrB1+aac(6')-Ib-cr genes were co-transferred and that these genes were carried by a conjugative plasmid of high molecular weight.
本研究的目的是确定从摩洛哥卡萨布兰卡大学医院的各种临床标本中分离出的产碳青霉烯酶肺炎克雷伯菌的流行情况和特征。我们对2011年6月至8月收集的总共166株肺炎克雷伯菌进行了前瞻性研究。疑似携带碳青霉烯酶的菌株对亚胺培南或厄他培南的敏感性降低。采用聚合酶链反应（PCR）和测序策略来鉴定碳青霉烯酶、超广谱β-内酰胺酶（ESBL）、质粒介导的AmpCβ-内酰胺酶、质粒介导的喹诺酮耐药性和氨基糖苷类耐药性决定簇。通过脉冲场凝胶电泳（PFGE）分析分离株之间的克隆关系。在所研究的166株肺炎克雷伯菌分离株中，11株（6%）为碳青霉烯酶产生菌，其中9株携带blaOXA-48，2株blaNDM-1呈阳性。所有产碳青霉烯酶的肺炎克雷伯菌也是ESBL产生菌，blaCTX-M-15是检测到的最常见的ESBL基因（n = 9），在一株分离株中还分别检测到blaCTX-M-28和blaSHV-28。肺炎克雷伯菌分离株还携带非ESBL基因blaTEM-1（n = 9）、blaSHV-1（n = 8）和blaOXA-1（n = 3）。五株分离株携带qnr基因，分别为qnrS1（n = 3）和qnrB1（n = 2）变体。六株分离株aac(6')-Ib-cr基因呈阳性，两株aac(3)-II基因呈阳性。在五株分离株中检测到1类整合子。PFGE显示在我们医院存在克隆传播。接合实验结果表明，blaOXA-48+blaCTX-M-15、blaOXA-48+blaCTX-M-28、blaNDM-1+blaCTX-M-15+blaTEM-1+blaOXA-1+qnrS1+aac(6')-Ib-cr和blaNDM-1+blaCTX-M-15+blaTEM-1+qnrB1+aac(6')-Ib-cr基因可共同转移，且这些基因由高分子量的接合质粒携带。
