中国黑龙江省东部地区耐碳青霉烯类肠杆菌科的分子特征及流行病学研究。
Molecular characterization and epidemiology of carbapenem non-susceptible Enterobacteriaceae isolated from the Eastern region of Heilongjiang Province, China.
机构信息
Department of Microbiology, the First Affiliated Hospital of Jiamusi University, Jiamusi, Heilongjiang, China.
Center for Disease Control and Prevention, Jiamusi, Heilongjiang, China.
出版信息
BMC Infect Dis. 2018 Aug 22;18(1):417. doi: 10.1186/s12879-018-3294-3.
BACKGROUND
The aim of this study was to elucidate the molecular epidemiology of carbapenem non-susceptible Enterobacteriaceae(CNSE) isolated in the Eastern region of Heilongjiang Province, China, and the mechanism of carbapenem resistance.
METHODS
A total of 53 CNSE isolates were collected in a grade-3 hospital in Heilongjiang province. Sensitivity to antibiotics was determined using the VITEK-2 Compact automatic system. The modified Hodge test (MHT) and modified carbapenem inactivation test (mCIM) were performed for phenotypic identification. Beta-lactamases gene were detected by Polymerase chain reaction(PCR) and DNA sequencing. The transfer of bla and bla was investigated through conjugation experiment. The clinical data of patients were retrospectively reviewed. Homology of Carbapenem-resistant Klebsiella pneumoniae(CRKP) was conducted by multilocus sequence typing (MLST).
RESULTS
CNSE were highly resistant to the majority of antimicrobial agents. The resistance rate was 100% for first, third, fourth generation cephalosporins and enzyme inhibitor compounds. Gentamicin and tobramycin recorded a resistance rate higher than 80%. Less than 30% resistance was detected for amikacin and levofloxacin. Among CNSE 52(98.1%) and 48(90.6%) of CNSE were positive for mCIM and MHT respectively. There were 42 positive bla genes, three bla genes, three bla genes, one bla gene, and six bla genes. Most isolates harbored multiple drug resistance gene, especially as related to extended-spectrum-β-lactamases, bla, bla and bla genes.The resistant gene was transferred into recipient Escherichia coli J53 through conjugation in 21.3% (10/47) of the strains. MLST revealed that ST76 (n = 36) was the most predominant clone, followed by ST896, ST323 and ST11. A new one ST 2946 was identity by this study.
CONCLUSION
The carbapenem resistance phenomenon is alarming and bla is the main resistant gene of CNSE in our hospital. This is the first report of an outbreak caused by bla positive K. pneumoniae ST76 in the Eastern region of Heilongjiang Province, China. Relevant departments should implement infection control and prevention measures to avoid further dissemination of the multi drug-resistant bacteria (MDR).
背景
本研究旨在阐明中国黑龙江省东部地区耐碳青霉烯肠杆菌科（CNSE）的分子流行病学及碳青霉烯类耐药机制。
方法
在黑龙江省一家 3 级医院共收集了 53 株 CNSE 分离株。采用 VITEK-2 Compact 自动系统测定抗生素敏感性。采用改良 Hodge 试验（MHT）和改良碳青霉烯灭活试验（mCIM）进行表型鉴定。采用聚合酶链反应（PCR）和 DNA 测序检测β-内酰胺酶基因。通过接合实验研究 bla 和 bla 的转移。通过回顾性分析患者的临床数据。采用多位点序列分型（MLST）对耐碳青霉烯肺炎克雷伯菌（CRKP）进行同源性分析。
结果
CNSE 对大多数抗菌药物高度耐药。第一代、第三代和第四代头孢菌素及酶抑制剂复合制剂的耐药率均为 100%。庆大霉素和妥布霉素的耐药率高于 80%。阿米卡星和左氧氟沙星的耐药率低于 30%。52（98.1%）和 48（90.6%）株 CNSE 对 mCIM 和 MHT 分别呈阳性。有 42 株携带 bla 基因，3 株携带 bla 基因，3 株携带 bla 基因，1 株携带 bla 基因，6 株携带 bla 基因。大多数分离株携带多种耐药基因，尤其是与超广谱β-内酰胺酶相关的 bla、bla 和 bla 基因。21.3%（10/47）的菌株通过接合将耐药基因转移到受体大肠杆菌 J53 中。MLST 显示 ST76（n=36）是最主要的克隆，其次是 ST896、ST323 和 ST11。本研究还发现了一个新的 ST2946。
结论
碳青霉烯类耐药现象令人警惕，本医院 CNSE 的主要耐药基因是 bla。这是中国黑龙江省东部地区首次报告 bla 阳性肺炎克雷伯菌 ST76 引起的暴发。相关部门应实施感染控制和预防措施，避免多重耐药菌（MDR）进一步传播。
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