REP-PCR对医护人员鼻腔中鲍曼不动杆菌分离株的溯源分析

REP-PCR analysis of the sources of Acinetobacter baumannii isolated the nasal cavities of medical personnel

目的对医护人员鼻腔中的鲍曼不动杆菌进行分离鉴定,对其来源和传播途径进行分析。方法用棉拭子采集10名医护人员和10名非医护人员(大学生)鼻腔样品,分离鉴定非重复鲍曼不动杆菌,采用K-B法检测其对13种常用抗生素的敏感性;利用多重PCR扩增OXA型碳青霉烯酶耐药基因;应用基因外重复回文序列REP-PCR对分离株进行分子多样性分析。结果共分离19株鲍曼不动杆菌,其中分离自医护人员鼻腔12株,分离自非医护人员鼻腔7株。K-B法检测Ab的耐药性,医护人员鼻腔分离株对环丙沙星(CIP)、亚胺硫霉素(IPM)、头孢曲松(CRO)、环磷酰胺(CTX)和新诺明(SXT)耐药率均≥41.7%,非医护人员分离株耐药率均≤3%;耐药基因检测19株菌中都携带OXA-51基因,且医护人员鼻腔分离株携带OXA-23菌株数多于非医护人员鼻腔分离株。另外两种未检出耐药基因(OXA-24和OXA-58)。REP-PCR显示,医护人员鼻腔分离株、非医护人员鼻腔分离株Ab的8种基因型(A-H)中同源性≥90%的有33株菌,占94.29%(33/35)。结论鲍曼不动杆菌不仅能通过直接接触传播,也可能存在气源性传播途径。

Objectives The aims of this study were to isolate and identify Acinetobacter baumannii from the nasal cavities of hospital personnel and to analyze its origin and route of transmission. Methods Cotton swabs were used to take nasal swabs from 10 hospital personnel and 10 college students,and 19 strains of non-repetitive A.Baumannii were isolated and identified.The susceptibility of the isolates to 13 commonly used antibiotics was determined using the Kirby-Bauer（K-B）method.Genes encoding OXA carbapenemases that confer drug resistance were amplified with multiplex PCR.The molecular diversity of the isolates was analyzed using repetitive extragenic palindromic PCR（REP-PCR）. ResultsIn total,19 strains of A.baumannii were isolated in this study;12of these strains were isolated from medical personnel and 7were isolated from non-medical personnel.The drug resistance of A.Baumannii indicated that isolates from the nasal cavities of medical personnel had resistance to ciprofloxacin,imipenem,ceftriaxone,cyclophosphamide,and sulfamethoxazole greater than or equal to 41.7% while strains isolated from non-medical personnel had resistance of 3% or less.Detection of drug resistance genes revealed that all 19 of the A.baumannii strains carried the OXA-51 gene.Strains carrying the OXA-23 gene were more frequently isolated from hospital personnel than from non-hospital personnel.Other drug resistance genes（OXA-24 and OXA-58）were not detected.REP-PCR indicated that strains of A.baumannii isolated from the nasal cavities of medical personnel and strains isolated from the nasal cavities of non-medical personnel had a similarity of 90% or more to 33 of 35strains（94.29%）in 8genotypes（A-H）. Conclusion A.baumannii can be transmitted through direct contact as well as through the air.