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

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

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。

Objective To study the homology characteristics of clinicaly isolated and colonized linezolid（LZD）-resistant Enterococcus faecalis （E.faecalis） strains from a patient.Methods Ten 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）.Results Before 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.Conclusion In 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.