Occurrence of IMP-8, IMP-10, and IMP-13 metallo-β-lactamases located on class 1 integrons and other extended-spectrum β-lactamases in bacterial isolates from Tunisian rivers
Occurrence of IMP-8, IMP-10, and IMP-13 metallo-β-lactamases located on class 1 integrons and other extended-spectrum β-lactamases in bacterial isolates from Tunisian rivers
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DOI：
10.3109/00365548.2012.717712
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发表时间：
2013-02-01
影响因子：
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通讯作者：
Correia, Antonio
中科院分区：
文献类型：
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作者：
Chouchani, Chedly;Marrakchi, Rim;Correia, Antonio
背景资料：水体中的抗生素耐药菌已被广泛调查，但很少有研究确定河流沃茨中抗生素耐药菌的多样性。本研究旨在调查突尼斯污染河流细菌分离株的耐药性起源。方法：在这项研究中，从突尼斯北部的2条污染河流中获得128株对β-内酰胺类抗生素耐药的菌株。使用Phoenix表型标准鉴定分离株。通过PCR扩增和测序研究bla（TEM）、bla（SHV）、bla（CTX-M）、bla（CMY）、bla（Vim）和bla（IMP）的发生情况，并通过比较XbaI脉冲场凝胶电泳（PFGE）图谱分析16株IMP产生的肺炎克雷伯菌的遗传相关性。结果如下：使用Phoenix表型标准，鉴定了不同属的细菌，其具有不同的流行率和对不同抗生素的不同最小抑菌浓度。证实了bla（TEM）、bla（SHV）、bla（CTXM）、bla（CMY）、bla（Vim）和bla（IMP）基因的存在。对bla（IMP）基因上游和下游的DNA序列进行测定，发现所有IMP编码基因构成第一类整合子的第一个盒，其次是编码氨基糖苷类耐药的aacA基因盒。PFGE图谱的比较显示，只有2个菌株是克隆的，其他14个菌株显示独特的图谱。超广谱β-内酰胺酶（ESBL）基因以bla（CTX-M）基因为主，其次为bla（TEM）基因。结论：在受污染的河水中发现了高度多样化的产ESBL细菌和金属β-内酰胺酶，特别是bla（IMP），这对通过河流环境在社区中传播耐药细菌的潜在性提出了警告。
Background: Antibiotic-resistant bacteria have been surveyed widely in water bodies, but few studies have determined the diversity of antibiotic-resistant bacteria in river waters. This study was undertaken to investigate the origin of resistance among polluted river bacterial isolates in Tunisia. Methods: In this study 128 isolates resistant to beta-lactam antibiotics were obtained from 2 polluted rivers in the north of Tunisia. Isolates were identified using Phoenix phenotyping criteria. The occurrence of bla(TEM), bla(SHV), bla(CTX-M), bla(CMY), bla(VIM), and bla(IMP) was studied by polymerase chain reaction (PCR) amplification and sequencing, and the genetic relatedness of the 16 IMP-producing Klebsiella pneumoniae isolates was analyzed by comparison of XbaI pulsed-field gel electrophoresis (PFGE) profiles. Results: Using Phoenix phenotyping criteria, diverse genera of bacteria were identified with different rates of prevalence and with different minimum inhibitory concentrations against different antibiotics. The occurrence of bla(TEM), bla(SHV), bla(CTXM), bla(CMY), bla(VIM), and bla(IMP) genes was confirmed. The DNA sequences upstream and downstream of bla(IMP) genes were determined, revealing that all IMP-encoding genes constituted the first cassette of class 1 integrons, followed by aacA gene cassettes encoding aminoglycoside resistance. Comparison of PFGE profiles showed that only 2 of the isolates were clonal, the other 14 displaying unique profiles. The bla(CTX-M) gene was the most dominant of the extended-spectrum beta-lactamase (ESBL) genes, while the bla(TEM) gene was the second-most dominant. Conclusion: The discovery of highly diverse ESBL-producing bacteria and metallo-beta-lactamases, particularly bla(IMP), in polluted river water raises alarms with regard to the potential dissemination of antibiotic-resistant bacteria in communities through river environments.