Emergence of OXA-carbapenemase- and 16S rRNA methylase-producing international clones of Acinetobacter baumannii in Norway
Emergence of OXA-carbapenemase- and 16S rRNA methylase-producing international clones of Acinetobacter baumannii in Norway
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DOI：
10.1099/jmm.0.028340-0
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发表时间：
2011-04-01
影响因子：
3
通讯作者：
Samuelsen, Orjan
中科院分区：
文献类型：
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作者：
Karah, Nabil;Haldorsen, Bjorg;Samuelsen, Orjan
本研究旨在调查2004年至2009年在挪威获得的11株耐碳青霉烯类临床分离鲍曼不动杆菌的分子流行病学和耐药性特征。有趣的是，所有的分离株都与最近在挪威境外住院有关。采用多位点序列分型(MLST)、国际主要克隆多重聚合酶链式反应分析、BLA(OXA-51)样变异体分型和PFGE等方法对流行状况进行调查。用聚合酶链式反应和测序的方法分析了菌株的耐药特性，包括编码OXA碳青霉烯酶和编码16S rRNA甲基酶的基因和1类整合子的出现情况。7株菌株含有BLA(OXA-66)，分别属于MLST克隆复合体CC2(P)(巴斯德研究所方案)、CC92(B)(Bartual方案)和国际克隆II，其中1株含有BLAA(OXA-69)，属于CC1(P)、CC109(B)和国际克隆I，2株属于序列群9，可能是国际克隆I的一个亚群，1株属于序列群4，为新的国际克隆。所有分离株均含有获得性OXA-碳青霉烯酶编码基因：Bla(OXA-23)样蛋白(n=9)、Bla(OXA-24)样蛋白(n=1)和Bla(OXA-58)样蛋白(n=1)。4株对氨基糖苷类高度耐药的菌株含有编码16S rRNA甲基酶的arma基因。检测到具有6个不同可变区的1类整合子。基因盒序列分析表明，4个氨基糖苷(aacA4、aac(6‘)Im、aadA1和aacC1)、2个氯霉素(catB8和cm1A5)、1个β-内酰胺酶(bla(OXA-20))和1个利福平(arr-2)耐药基因存在不同组合。总之，产生OXA碳青霉烯酶和16S rRNA甲基酶的鲍曼不动杆菌菌株在挪威的出现与国际克隆I和II的全球分布以及新的国际克隆的出现有关。
This study was designed to investigate the molecular epidemiology and antibiotic-resistance characteristics of 11 carbapenem-resistant clinical isolates of Acinetobacter baumannii obtained in Norway between 2004 and 2009. Interestingly, all the isolates were linked with recent hospitalization outside Norway. The epidemiological status was investigated by multilocus sequence typing (MLST), multiplex PCR assays for major international clones, typing of bla(OXA-51)-like variants and PFGE. The genotypic-resistance characteristics, including the occurrence of OXA-carbapenemase-encoding and 16S rRNA methylase-encoding genes and class 1 integrons, were investigated by PCR assays and sequencing. Seven isolates were found to harbour bla(OXA-66) and belong to MLST clonal complexes (CCs) CC2(P) (Pasteur Institute scheme) and CC92(B) (Bartual scheme), and international clone II. One isolate harboured bla(OXA-69), and belonged to CC1(P), CC109(B) and international clone I. Two isolates belonged to sequence group 9, probably a subgroup of international clone I, and one isolate belonged to sequence group 4, a proposed novel international clone. All isolates contained an acquired OXA-carbapenemase-encoding gene: bla(OXA-23)-like (n=9), bla(OXA-24)-like (n=1) and bla(OXA-58)-like (n=1). Four isolates with high-level aminoglycoside-resistance contained the 16S rRNA methylase-encoding armA gene. Class 1 integrons with six different variable regions were detected. Sequence analysis of gene cassettes identified four aminoglycoside (aacA4, aac(6') Im, aadA1 and aacC1), two chloramphenicol (catB8 and cm1A5), one beta-lactamase (bla(OXA-20)) and one rifampicin (arr-2) resistance gene in various combinations. In conclusion, the occurrence of A. baumannii isolates producing OXA carbapenemase and 16S rRNA methylase in Norway was related to the worldwide distribution of international clones I and II, and the emergence of novel international clones.