2006--2011年60株血感染金黄色葡萄球菌毒素及耐药基因分析

Analysis of the Antimicrobial-Resistant Gene and Virulence Gene Carried by Staphylococcus Aureus Collected from Bloodstream Infections in Tianjin:2006-2011

目的了解2006—2011年临床分离的60株血感染金黄色葡萄球菌的耐药情况及毒素基因和耐药基因的流行情况。方法 VITEK2-compact全自动细菌鉴定仪及配套鉴定卡、药敏卡对细菌进行鉴定及药敏试验;头孢西丁纸片扩散法筛选耐甲氧西林金黄色葡萄球菌(MRSA);应用聚合酶链反应(PCR)检测mecA、耐消毒剂基因(qacA)、杀白细胞素基因(pvl)、肠毒素基因(sea、seb、sec1、sed、see)及中毒休克综合征毒素-1基因(tst)。结果 60株金黄色葡萄球菌对青霉素的耐药率最高(91.7%),其次为红霉素(65.0%)、克林霉素(65.0%)、庆大霉素(40.0%)。未发现万古霉素、利奈唑胺、替加环素耐药菌株。其中携带耐药基因mecA13株(21.7%)、qacA3株(5.0%)、检出毒素基因pvl4株(6.7%)、肠毒素基因sea20株(33.3%)、seb3株(5.0%)、sec9株(15.0%)及sed7株(11.7%),未检出see及tst。结论血感染的金黄色葡萄球菌对青霉素、红霉素、克林霉素、庆大霉素耐药率高,同时携带多种毒素及耐药基因,临床应加强毒素及耐药基因检测。

Objective To investigate resistance profile, antimicrobial-resistant genes and virulence genes carried by 60 staphylococcus aureus collected from bloodstream infections in General Hospital of Tianjin Medical University from 2006 to 2011. Methods The bacteria identification and the antimicrobial susceptibility test were conducted by VITEK-2 com- pact automatic system. Methicillin resistant staphylococcus aureus （MRSA） were screened by disk diffusion method with cefoxitin. The polymerase chain reaction （PCR） was used to detect genes of mecA, qacA, pvl, sea, seb, secl, sed, see and TSST-1. Results The resistance rates of 60 isolates to penicillin, erythromycin, clindamycin and gentamicin were 91.7%, 65.0%; 65.0% and 40.0%, respectively. All of the isolates were susceptible to vancomycin, linezolid, and tigecycline. Among the 60 isolates, the positive rates of mecA and qacA werel3 （21.7%） and 3（5.0%） respectively. The positive rates ofpvl, sea, seb, sec and sed were 4 （6.7%）, 20（33.3%）, 3 （5%）, 9 （15.0%） and 7 （11.7%）. Both see and tst were negative in all strains. Conclusion The resistance rates of staphylococcus aureus collected from bloodstream infections were high to penicillin, erythromycin, clindamyein and gentamicin. The various toxin and the antimicrobial-resistant genes were positive in staphylococcus aureus. We should pay attention to the detection of the antimicrobialesistant gene and virulence gene.