肠球菌临床耐药性分析及耐药基因vanM在屎肠球菌中的检测

目的了解肠球菌临床分离株耐药性及vanM基因在屎肠球菌的分布情况,为临床合理用药及探讨耐药机制提供依据.方法采用VITEK60全自动微生物分析仪对肠球菌进行鉴定及药敏试验,按NCCLS/CLSI标准判断并统计分析结果;PCR法检测耐万古霉素、替考拉宁菌株中的耐药基因vanM,并对阳性基因进行测序,分析耐药基因与耐药性的关系.结果临床分离肠球菌共506株,其中屎肠球菌277株,粪肠球菌229株.尿液标本来源比例最高,为167株（33%）;粪便标本114株（22.5%）;痰液标本78株（15.4%）;胆汁标本57株（11.3%）;脓液标本54株（10.7%）;其他来源36株（7.1%）.药敏结果显示：肠球菌对大部分临床抗菌药高度耐药,屎肠球菌对β-内酰胺类抗菌药物（氨苄西林）、喹诺酮类（左氧氟沙星）、糖肽类（万古霉素、替考拉宁）的耐药率明显高于粪肠球菌（P〈0.05）.vanM基因在耐万古霉素菌株中的检出率为100%,耐替考拉宁菌株检出率为90%.结论屎肠球菌可引起临床各类感染,屎肠球菌对大多数抗生素的耐药率明显高于粪肠球菌,且呈多重耐药趋势.vanM基因可能在糖肽类药物万古霉素、替考拉宁耐药机制中发挥重要作用.

Analysis on Enterococcal Clinical Resistance and Detection of New Resistance Gene vanM in Enterococcus faecium

Objective To investigate the antibiotic resistance of isolated Enterococcus spp. and the distribution of gene vanM in Enterococcus faecium. Methods VITEK60 automatic microorganism analyzer was used to conduct identification of Enterococci and drug sensitive test,and the results were calculated and analyzed according to the standard of NCCLS/CLSI;Glycopeptide drug resistance gene vanM was detected by PCR and the sequence of positive gene was measured for analyzing the relationship between the resistance gene and the resistance. Results 506 Enterococcus isolates, there were 277 isolates of Enterococcus faecium and 299 isolates of Enterococcus faecalis. The sample resources included urine 167（33. 0%）,stool 114（22. 5%）,sputum 78（15. 4%）,bile 57 （11.3%）,pus 54（10. 7%） and others 36（7. 1%） respectively. The drug sensitive test results showed that Enterococcus had a high antibiotic resistance to most antibiotics;the resistance rate of Enterococcus faecium toβ-lactams（ampicillin）,quinolones（levofloxacin） and glycopeptide（vancomycin and teicoplanin） antibiotics was significantly higher than that of Enterococcus faecalis（P〈0. 05）;the detectable rate of vanM fragment was 100%and that of teicoplanin-resistant isolates was 90%. Conclusions Enterococcus faecium can cause all kinds of clinical infection and its resistant rate is significantly higher than that of Enterococcus faecalis,showing a multiple drug resistance trend. vanM gene may play an important role in the resistance mechanisms to glycopeptide antibiotics,vancomycin and teicoplanin.