不同人群肠道携带耐万古霉素肠球菌的研究

Study on Vancomycin-resistant Enterococci Carried by Intestinal Tract in Different People Groups

摘要:

调查住院病人、门诊病人和正常人粪便中耐万古霉素肠球菌的携带率及其耐药表型、基因型和同源性, 为临床预防和治疗选药提供依据。根据CLSI指南做药敏试验, 用PCR法检测万古霉素耐药基因, 用重复基因外回文序列-聚合酶链反应(REP-PCR)进行同源性分析。从住院病人肠道中分离出31株(20.67 %)耐万古霉素肠球菌, 其中22株VRE为VanA基因型, 9株VIE为VanC1基因型。22株VRE同源性分析, A型有19株, 其中A1型4株, A2型6株, A3型4株, A4型3株, A5型2株。B型、C型、D型各1株。9株VIE中有3对菌株分别有100%同源性。门诊病人分离出4株VIE(4%), 为VanC1型, 其中两株有100%同源性。正常人中分离出11株(27.5%)VIE, 8株为VanC1型, 3株为VanC2型; 11株VIE同源性分析, 以A型为主, A1型有1株, A2型有2株, A3型有1株, A4型有1株, D1、D2、D3型各有1株, B、C、E型各有1株。2株住院病人VIE与2株门诊病人VIE有100%同源性, 另外2株住院病人VIE与1株门诊病人VIE有100%同源性。他们与正常人分离的VIE同源性低。22株VRE对万古霉素的MIC值>512 μg/mL, 16株VIE对万古霉素的MIC值为16 μg/mL。8株VIE对万古霉素MIC值为8 μg/mL。可见住院病人肠道中VRE携带率高, 是医院感染的危险因素, 46株耐万古霉素肠球菌的耐药表型与耐药基因型一致; 耐万古霉素肠球菌对多种抗菌药物耐药; 部分菌株有较高的同源性。

Abstract:

To investigate the rate of carriage, the phenotype, the genotype and homology in stool specimen from outpatients, inpatients and health adult for prevention and guiding the clinical treatment. According to CLSI’s guideline, antimicrobial susceptibility tests were performed; To detect vancomycin resistant gene by PCR; To analyze the homology by REP-PCR method. The vancomycin resistant carriage rate in intestinal tract of inpatients was 20.67%. All 22 isolates harbored VanA genotype; 9 isolates harbored VanC1 genotype. The homology in 22 vancomycin resistant enterococci was mostly type A, which was divided into A1-A5 subtypes, and they had high homology. Type A had 19 isolates. Of all, type A1 had 4 isolates; type A2 had 6 isolates; type A3 had 4 isolates; type A4 had 3 isolates; type A5 had 2 isolates. Type B、C、D had no subtypes. Three pairs of isolates had 100% homologies. There were 4 isolates (4%) separated from outpatients. All were vanC1 types. Two were likely to be the same isolate. There were 11 isolates (27.5%) separated from health adults. Of all, 8 isolates were VanC1, and the others were vanC2. The homology in 11 VIE was mostly type A, which was divided into A1-A4 subtypes. Type A1 had 1 isolate; type A2 had 2 isolates; type A3 had 1 isolate; type A4 had 1 isolate. Type D1、D2、D3 was 1 isolate separately. Type B、C、E had no subtypes. Two VIE from inpatients and two from outpatients had 100% homologies. The other two VIE from inpatients and two from outpatients had 100 homologies, too. They had low homology with the isolates from health adults.Minimum inhibitory concentration (MIC) of 22 VRE to vancomycin were > 512μg/mL; MIC of 16 VIE to vancomycin were 16μg/mL; MIC of 8 VIE to vancomycin were 8μg/mL. It is a risk factor for hospital infection that VRE carriage of inpatients in intestinal tract is high. There is 100% agreement between phenotypes and genotypes in 46 vancomycin resistance enterococci. VRE are multiresistant. Part isolates have high homology.