›› 2015, Vol. 42 ›› Issue (5): 1274-1282.doi: 10.16431/j.cnki.1671-7236.2015.05.036

• 疾病防治 • 上一篇    下一篇

屎肠球菌新序列型ST989菌株的分离鉴定及多重耐药性分析

张芬芬1,2, 李学瑞2, 杨建设1   

  1. 1. 西北师范大学生命科学学院, 兰州 730070;
    2. 中国农业科学院兰州兽医研究所, 家畜疫病病原生物学国家重点实验室, 农业部草食动物疫病重点开放实验室, 兰州 730046
  • 修回日期:2015-03-13 出版日期:2015-05-20 发布日期:2015-06-02
  • 通讯作者: 杨建设 E-mail:yangjs@impcas.ac.cn
  • 作者简介:张芬芬(1990-),女,甘肃平凉人,硕士生,研究方向:辐射生物学、动物传染病及分子流行病学,E-mail:1046767776@qq.com
  • 基金资助:
    "国家重点基础研究计划(2008FY210200)"项目

Isolation,Identification and Multidrug-resistant Analysis of the New Sequence Type ST989 Strain of Enterococcus faecium

ZHANG Fen-fen1,2, LI Xue-rui2, YANG Jian-she1   

  1. 1. College of Life Science, Northwest Normal University, Lanzhou 730070, China;
    2. Key Laboratory of Grazing Animal Diseases of Ministry of Agriculture, State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, CAAS, Lanzhou 730046, China
  • Revised:2015-03-13 Online:2015-05-20 Published:2015-06-02

摘要: 试验从青海民和县某羊场致病性感染半月龄羔羊中分离出革兰氏阳性菌,感染羔羊临床症状有精神萎靡,采食减少,发病1~2 h后死亡。两只濒死羔羊剖检结果发现,其中一只出现肝脏肿大及肝包膜脱落,其余脏器无明显病理变化;另一只各脏器均未发现病理变化。分离病料,革兰氏染色发现,从病料中分离到的细菌均为革兰氏阳性球菌。对分离菌株进行Tuf基因PCR扩增,BLASTn比对结果显示与屎肠球菌AUS0085核苷酸序列相似性为99.8%,据此初步确定这些菌株为屎肠球菌。药敏试验结果表明,这些菌株可分为两类,第1类对β-内酰胺类、氨基糖苷类、大环内酯类、四环素类、喹诺酮类、利福霉素类抗生素及林可霉素和克林霉素耐药,对氯霉素和万古霉素敏感;第2类对β-内酰胺类、氨基糖苷类、四环素类、喹诺酮类、利福霉素类抗生素耐药,对红霉素和罗红霉素中度耐药,但对克拉霉素、阿奇霉素、克林霉素、林可霉素、氯霉素和万古霉素敏感。对第1类耐药性代表菌株lby1和第2类耐药性代表菌株lbg3进行多位点序列分析(MLST),结果发现这些菌株为一个屎肠球菌的新序列型,为ST989。系统进化树结果显示屎肠球菌lbg3与屎肠球菌ST468亲缘关系最近,致病力试验结果表明屎肠球菌lby1和lbg3均具有致病性。

关键词: 羔羊; 致死性感染; 多重耐药屎肠球菌; 致病性

Abstract: Gram-positive cocci were isolated from half a month diseased lambs with a fatal infection in a sheep farm in Minhe county, Qinghai province.The clinical symptoms observed were drooping, reduced feed intake, emaciated and fever.The infected lambs died several hours after the disease been observed.Necropsy of two dying lambs revealed that for one lamb, the liver was enlarged and capsule of the liver dropped, and other organs had no obvious changes;For the other one, the organs had no obvious changes.After gram staining, gram-positive cocci were observed from all the samples.Partial Tuf gene sequences of these isolates were amplified and sequenced for species identification, BLASTn conparison result revealed that they had the highest sequence similarity with that of Enterococcus faecium (E.faecium) AUS0085 (99.8%), we thus primarily confirmed that these strains belonged to E.faecium.Antimicrobial susceptibility test indicated that these strains could be divided into two classes.Class 1 was resistant to β-lactams, aminoglycosides, macrolides, tetracyclines, quinolones, rifamycins, lincomycin and clindamycin;Susceptible to chloromycetin and vancomycin.Class 2 was resistant to β-lactams, aminoglycosides, tetracyclines, quinolones, rifamycins;Intermediate resistance to erythromycin and roxithromycin;But susceptible to clarithromycin, azithromycin, clindamycin, lincomycin, chloromycetin and vancomycin.Multilocus sequence typing (MLST) based on seven housekeeping genes for E.faecium revealed that E.faecium lby1 strain in class 1 and E.faecium lbg3 strain in class 2 were defined as a new sequence type ST989.Phylogenetic tree analysis revealed the representative strain of these isolates, E.faecium lbg3, was clustered together with E.faecium ST468.The pathogenicity test revealed that E.faecium lby1 and lbg3 strains both had pathogenicity.

Key words: lamb; fatal infection; multidrug-resistant Enterococcus faecium; pathogenicity

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