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

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。

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

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.