乳酶生生产菌株的鉴定及耐药谱的分析

Identification and drug-resistance spectrum of a lactasin-producing strain

目的对乳酶生生产用菌株粪肠球菌(Enterococcus faecalis)140623株进行全面系统鉴定,检测该菌株耐药谱,为临床用药安全性提供参考。方法利用传统生化、API生化鉴定系统及16S rRNA序列测定对乳酶生生产用菌株粪肠球菌140623株及标准菌株粪肠球菌32222株进行鉴定,利用琼脂扩散纸片法检测其对临床常用10类21种抗生素的敏感性,并免疫小鼠进行菌株毒性试验。结果粪肠球菌140623株为屎肠球菌(Enterococcus faecium);耐药谱显示该菌株对四环素类、氯霉素敏感,对醣肽类中度敏感,对青霉素类、头孢菌素类、喹诺酮类、氨基糖甙类、大环内脂类、单环β-内酰胺类、碳青霉烯类抗生素及磺胺耐药;全部小鼠健康存活,符合"微生态活菌制品"菌种毒性试验要求。结论标准物质目录中标示为"供乳酶生生产用菌株粪肠球菌140623"应为屎肠球菌140623株。对其耐药谱的研究可为临床联合用药及对该菌株的质量控制提供参考。

Objective To systemically identify Enterococcus faecalis strain 140623, a lactasin- producing strain, and de- termine its drug-resistance spectrum to provide a reference for safety in clinic. Methods E. faecalis strain 140623 for production of lactasin and standard strain 32222 were identified by traditional biochemical culture, API biochemical iden- tification system and 16S rRNA sequencing, of which the sensitivities to 21 kinds of antibiotics belonging to 10 classes were analyzed by agar diffusion test, and the toxicities were tested in mice. Results Strain 140623 was identified as E. faecium. Drug-resistance spectrum showed that the strain was sensitive to tetracyclines and chloromycetin, moderately sensitive to carbohydrate peptide, and resistant to penicillins, cephalosporins, quinolones, aminoglycosides, macrolide, Beta-lactam, carbapenems and sulfanilamide. All the mice survived the toxicity test, which met the requirements for toxi- city test on probiotics. Conclusion The nomenclature of strain for production of lactasin in List of Standard Substance should be revised from Enterococcus faecalis 140623 to Enterococcus faecium 140623, and the study on its drug-resis- tance spectrum provided a reference for combined application in clinic and quality control of the strain.