医院感染金黄色葡萄球菌的流行与耐药机制

Antibiotic Resistance and Molecular Epidemiology Profile of Staphylococcus aureus in Hospital-acquired Infection

目的对医院感染金黄色葡萄球菌进行基因分型,研究流行菌株的传播及其耐药的分子机制,以控制医院感染的发生。方法对分离的21株金黄色葡萄球菌进行RAPD分型,并进行mecA、gyrA、grlA基因分析,研究其耐药机制。结果21株金黄色葡萄球菌根据RAPD带型可分为3型,其中Ⅰ型12株,是医院感染的主要流行株;在临床分离的17株金黄色葡萄球菌中14株对甲氧西林和喹诺酮类均耐药;在耐药株中除1株(13064)外,其余菌株均检测出mecA基因;14株耐药株中均存在gyrA和(或)grlA突变;gyrA突变点为gyrA 84位TCA→TTA,gylA突变点为grlA80位TCC→TTC。结论RAPD基因分型技术简便快捷,可为医院感染金黄色葡萄球菌准确分型,是分子流行病学研究的有效方法;医院医院感染的金黄色葡萄球菌流行株主要为Ⅰ型,有可能经飞沫传播;17株临床分离株中14株存在多重耐药,并有相应的基因变异。

OBJECTIVE To identify the pop strain of Staphylococcus aureus hospital acquired infection by random amplification of polymorphic DNA（RAPD）, and to study the molecular mechanism of antibiotic resistance, so as to reduce the occurrence of drug resistance and infection acquired in hospital. METHODS 1. DNA from 21 strains of S. aureus were extracted by the phenol-chloroform method and analyzed by using arbitrary primer polymerase chain reaction （AP-PCR）. 2. Amplifying mecA, GyrA and GrlA by PCR, and testing the variation of these genes by using Hinf I -digested analysis. RESULTS Twenty one S. aureus strains were divided into 3 genetic types. Type I is the pop strain in our hospital which including 12 strains. Fourteen from 17 clinical stains were resistant to meticillin and quinolones, of which 13 strains had mecA except isolate 13064. And they all had variation in GyrA and/or GrlA. CONCLUSIONS RAPD provides markers for the typing of clinical strains and is suitable for molecular epidemiologic studies with high type ability, powerful discrimination, simplicity and rapidness. Type I is the pop S. aureus strain in hospital-acquired infection of our hospital. The majority of these strains are multiresistant to meticillin, quinolones and other antibiotics.