印度河流及污水处理厂中对超广谱头孢菌素耐药或对碳青霉烯类耐药的大肠杆菌分离株中抗菌药物耐药性决定因素的分布及相互关系
Distribution and Relationships of Antimicrobial Resistance Determinants among Extended-Spectrum-Cephalosporin-Resistant or Carbapenem-Resistant Escherichia coli Isolates from Rivers and Sewage Treatment Plants in India.
作者信息
Akiba Masato, Sekizuka Tsuyoshi, Yamashita Akifumi, Kuroda Makoto, Fujii Yuki, Murata Misato, Lee Ken-Ichi, Joshua Derrick Ian, Balakrishna Keshava, Bairy Indira, Subramanian Kaushik, Krishnan Padma, Munuswamy Natesan, Sinha Ravindra K, Iwata Taketoshi, Kusumoto Masahiro, Guruge Keerthi S
机构信息
Bacterial and Parasitic Disease Research Division, National Institute of Animal Health, National Agriculture and Food Research Organization, Ibaraki, Japan Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Osaka, Japan
Pathogen Genomics Center, National Institute of Infectious Diseases, Tokyo, Japan.
出版信息
Antimicrob Agents Chemother. 2016 Apr 22;60(5):2972-80. doi: 10.1128/AAC.01950-15. Print 2016 May.
To determine the distribution and relationship of antimicrobial resistance determinants among extended-spectrum-cephalosporin (ESC)-resistant or carbapenem-resistant Escherichia coli isolates from the aquatic environment in India, water samples were collected from rivers or sewage treatment plants in five Indian states. A total of 446 E. coli isolates were randomly obtained. Resistance to ESC and/or carbapenem was observed in 169 (37.9%) E. coli isolates, which were further analyzed. These isolates showed resistance to numerous antimicrobials; more than half of the isolates exhibited resistance to eight or more antimicrobials. The blaNDM gene was detected in 14/21 carbapenem-resistant E. coli isolates: blaNDM-1 in 2 isolates, blaNDM-5 in 7 isolates, and blaNDM-7 in 5 isolates. The blaCTX-M gene was detected in 112 isolates (66.3%): blaCTX-M-15 in 108 isolates and blaCTX-M-55 in 4 isolates. We extracted 49 plasmids from selected isolates, and their whole-genome sequences were determined. Fifty resistance genes were detected, and 11 different combinations of replicon types were observed among the 49 plasmids. The network analysis results suggested that the plasmids sharing replicon types tended to form a community, which is based on the predicted gene similarity among the plasmids. Four communities each containing from 4 to 17 plasmids were observed. Three of the four communities contained plasmids detected in different Indian states, suggesting that the interstate dissemination of ancestor plasmids has already occurred. Comparison of the DNA sequences of the blaNDM-positive plasmids detected in this study with known sequences of related plasmids suggested that various mutation events facilitated the evolution of the plasmids and that plasmids with similar genetic backgrounds have widely disseminated in India.
为了确定印度水生环境中对超广谱头孢菌素（ESC）耐药或对碳青霉烯耐药的大肠杆菌分离株中抗菌药物耐药决定因素的分布及关系，从印度五个邦的河流或污水处理厂采集了水样。共随机获得446株大肠杆菌分离株。在169株（37.9%）大肠杆菌分离株中观察到对ESC和/或碳青霉烯的耐药性，并对这些分离株进行了进一步分析。这些分离株对多种抗菌药物耐药；超过一半的分离株对八种或更多种抗菌药物耐药。在21株碳青霉烯耐药的大肠杆菌分离株中检测到blaNDM基因：2株为blaNDM - 1，7株为blaNDM - 5，5株为blaNDM - 7。在112株分离株（66.3%）中检测到blaCTX - M基因：108株为blaCTX - M - 15，4株为blaCTX - M - 55。我们从选定的分离株中提取了49个质粒，并测定了它们的全基因组序列。检测到50个耐药基因，在49个质粒中观察到11种不同的复制子类型组合。网络分析结果表明，共享复制子类型的质粒倾向于形成一个群落，这是基于质粒之间预测的基因相似性。观察到四个群落，每个群落包含4至17个质粒。四个群落中的三个包含在印度不同邦检测到的质粒，这表明祖先质粒已经在不同邦之间传播。将本研究中检测到的blaNDM阳性质粒的DNA序列与相关质粒的已知序列进行比较，结果表明各种突变事件促进了质粒的进化，并且具有相似遗传背景的质粒已在印度广泛传播。
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