新生儿重症监护室5例早产儿肠球菌感染的鉴定及同源性分析

目的对北京协和医院新生儿重症监护室(neonatal intensive care units,NICU)早产儿定植和感染部位、环境及益生菌中分离出的肠球菌进行菌种鉴定及同源性分析。方法收集2017年6月1—10日NICU及益生菌制剂中分离出的肠球菌共11株,用基质辅助激光解吸电离飞行时间质谱(MALDI-TOF MS)进行菌种鉴定,采用微量肉汤稀释法测定临床常用抗菌药物的最低抑菌浓度(MIC),用多位点序列分型(MLST)及脉冲场凝胶电泳(PFGE)进行菌株同源性分析。结果 11株菌均为粪肠球菌,对氨苄西林、万古霉素、替考拉宁、呋喃妥因、氯霉素、左氧氟沙星、利奈唑胺等抗菌药物均表现为敏感,仅1株菌对四环素和红霉素耐药。11株粪肠球菌经PFGE分为a-d 4个克隆群,MLST分型分别为ST624、ST25、ST40及ST16,PFGE与MLST分型结果一致。结论此次NICU早产儿粪肠球菌定植或感染可能与益生菌制剂的使用及物表定植的粪肠球菌相关。

Identification and homology analysis of Enterococcus isolated from 5 premature babies in NICU

Objective To identify and analyze the homology of Enterococcus strains isolated from Enterococcus infection or colonization in premature babies, the environment and probiotics. Methods The 11 strains of Enterococcus were collected from NICU and probiotics during June 1 to 10 in 2017 in Peking Union Medical College Hospital, identfied by MALDI-TOF MS. The antimicrobial susceptibility test were performed by microdilution broth method. The homology was analyzed by multilocus sequence typing(MLST) and pulsed-field gel electrophoreses(PFGE). Results Based on the identification of MALDI-TOF MS, all of the 11 strians were Enterococcus faecalis. Antimicrobial susceptibility test showed that all of the strains were seneitive to ampicillin, vancomycin, teicoplanin, nitrofurantoin, chloramphenicol, levofloxacin and linezolid. Only 1 strain was resistant to tetracycline and erythromycin. PFGE showed that the 11 strains can be divided into 4 groups of cloning(a-d), MLST showed 4 groups,ST624, ST25, ST40 and ST16, the two methods were consistent. Conclusion The Enterococcus faecalis colonization or infection in premature babies in neonatal intensive care unit may be associated with Enterococcus faecalis isolated from probiotic and object surface.