利奈唑胺耐药粪肠球菌感染患者临床分离株与定植株同源性分析

目的研究1例患者体内利奈唑胺(LZD)耐药粪肠球菌临床分离株与定植株同源性特点。方法对1例肺部感染患者分离的10株粪肠球菌(其中2株分离自尿标本,8株分离自粪便标本)进行细菌耐药分析,并通过脉冲场凝胶电泳(PFGE)确定粪肠球菌之间的同源性。结果患者进行LZD治疗前后,尿标本分离出的2株粪肠球菌均为LZD耐药株(MIC值分别为8 mg/mL,16 mg/mL),粪便中培养挑取的8株(治疗前6株,治疗后2株),其中LZD敏感4株,中介2株,耐药2株(MIC值波动在0.25~12 mg/mL)。通过PFGE分型检测提示10株粪肠球菌具有同源性。结论该例患者泌尿道和肠道检出的粪肠球菌具有同源性,提示LZD耐药肠球菌可能长期定植于患者体内,并可能发生移位导致耐药细菌感染。

Homology analysis of clinically isolated and colonized linezolid resistant Enterococcus faecalis strains from a patient

ObjectiveTo study the homology characteristics of clinicaly isolated and colonized linezolid（LZD） resistant Enterococcus faecalis (E. faecalis ) strains from a patient.MethodsTen E. faecalis strains (2 were isolated from urine specimens and 8 were from stool specimens) isolated from a patient with pulmonary infection were performed antimicrobial susceptibility testing, homology of E. faecalis was determined by pulsed field gel electrophoresis (PFGE).ResultsBefore and after patients received LZD therapy, 2 E. faecalis strains isolated form urine specimens were both resistant to LZD (MICs: 8 mg/mL, 16 mg/mL, respectively), among 8 strains from stool specimens (6 were isolated before therapy, and 2 were isolated after therapy), LZD susceptible, intermediate, and resistant strains were 4, 2, and 2 respectively（MICs: 0.25-12 mg/mL）. 10 strains of E. faecalis were homologous by PFGE typing. ConclusionIn this case, the detection of E. faecalis from urinary tract and intestinal tract is homologous, which suggested that LZD resistant Enterococcus may be colonized in vivo for a long time, and may be shift to cause bacterial infection.