江西地区鲍曼不动杆菌NDM-1及其他碳青霉烯酶基因检测研究

NDM-1 gene and other carbapenemase genes in Acinetobacter baumannii in Jiangxi area

目的了解江西地区耐碳青霉烯类鲍曼不动杆菌(CRAB)NDM-1及其他碳青霉烯酶基因携带情况,为预防和控制医院感染提供实验室依据。方法收集2015年1月—2016年6月江西地区3所三级甲等医院临床标本分离的CRAB共64株,采用K-B法测定其对常用抗菌药物的敏感性,采用改良Hodge试验和EDTA协同试验筛查CRAB产碳青霉烯酶和金属酶的情况,采用聚合酶链反应(PCR)检测碳青霉烯酶基因,对产NDM-1的鲍曼不动杆菌进行接合试验。结果 CRAB对氨苄西林/舒巴坦、环丙沙星、庆大霉素、左氧氟沙星耐药率高达95.31%、98.44%、90.63%、54.69%。CRAB菌株改良Hodge试验阳性率为76.56%,EDTA协同试验阳性率为96.88%。PCR扩增结果显示,87.50%(56株)的CRAB携带OXA-23、VIM-1基因,18.75%(12株)携带SIM基因,3.13%(2株)携带OXA-24基因,26.56%(17株)携带NDM-1基因。携带NDM-1基因的CRAB均来自于南昌大学第一附属医院,其中64.70%(11/17)表现为泛耐药。接合试验结果显示,携带NDM-1基因的菌株可将NDM-1基因传递给受体菌大肠埃希菌J53,使其获得对亚胺培南的耐药性。结论该地区临床分离的CRAB耐药率高,碳青霉烯酶基因以OXA-23、VIM-1基因型为主,检出NDM-1基因阳性CRAB,NDM-1基因可能存在医院内的克隆传播,应尽快采取有效措施预防和控制NDM-1基因阳性CRAB的传播。

ObjectiveTo understand the carriage of NDM1 and other carbapenemases in carbapenemresistant Acinetobacter baumannii（CRAB） in Jiangxi area, and provide laboratory basis for the prevention and control of healthcareassociated infection （HAI）. MethodsSixtyfour strains of CRAB isolated from clinical specimens from 3 tertiary firstclass hospitals in Jiangxi area from January 2015 to June 2016 were collected, susceptibility to commonly used antimicrobial agents were detected with KirbyBauer method. Carbapenemases and metalloenzyme in CRAB were screened with modified Hodge test and EDTAdisk synergy test respectively, carbapenems gene was detected by polymerase chain reaction （PCR）, NDM1producing Acinetobacter baumannii （A. baumannii） were performed conjugation test.ResultsThe resistance rates of CRAB to ampicillin/sulbactam, ciprofloxacin, gentamicin, and levofloxacin were up to 95.31%, 98.44%, 90.63%, and 54.69% respectively. The positive rates of modified Hodge test and EDTAdisk synergy test were 76.56% and 96.88% respectively. PCR amplification result showed that 87.50%（n=56） of CRAB carried OXA23 and VIM1 genes,18.75%（n=12）carried SIM, 3.13%（n=2）carried OXA-24,and 26.56%（n=17） carried NDM1. CRAB carrying NDM1 gene were all from The First Affiliated Hospital of Nanchang University, 64.70%（11/17）of which were pandrugresistant strains. Conjugation test result showed that NDM1producing strains could transfer NDM1 gene to recipient strain Escherichia coli J53, then acquired resistance to imipenem. ConclusionAntimicrobial resistance rates of clinically isolated CRAB in this area are high, OXA23 and VIM1 genes are the main carbapenemase genes, NDM1 gene positive CRAB is detected, and there may be a clonal spread of NDM1 gene in hospital, effective measures should be taken as soon as possible to prevent and control the spread of NDM1 positive CRAB.