艰难梭菌临床分离株5年前后耐药性变化

Ribotyping and antimicrobial resistance patterns of Clostridium difficile during two periods with an interval of 5 years

目的了解艰难梭菌临床分离株5年前后核糖体分型和对常用抗菌药物耐药性的变化。方法分别收集复旦大学附属华山医院2007年8月至2008年7月和2012年8月至2013年7月艰难梭菌临床分离株,用琼脂稀释法测定甲硝唑等10种抗菌药物对艰难梭菌临床分离株的抗菌活性;PCR法检测艰难梭菌的毒素基因tcdA、tcdB、cdtA和cdtB;核糖体分型法对菌株进行分子分型。结果 2007年8月—2008年7月与2012年8月—2013年7月分别获得艰难梭菌产毒株74株和64株。5年前产毒株中A+B+和A-B+分别占66.2%和31.1%,二元毒素(A+B+CDT+)占2.7%;5年后A+B+和A-B+菌株分别占65.6%和34.4%。5年前细菌核糖体分型以017型最多见,占24.3%,5年后以H型(18.8%)最多见。所有临床分离株对甲硝唑和万古霉素均呈高度敏感,但对克林霉素、四环素和夫西地酸等多种抗菌药物的耐药率较5年前上升。对氟喹诺酮类、大环内酯类和林可酰胺类药物呈多重耐药的菌株从28.3%上升至32.8%。结论艰难梭菌临床分离株中A+B+菌株仍约占2/3,但核糖体分型由017型最多见转为以H型最多见。所有艰难梭菌菌株对甲硝唑和万古霉素均呈敏感,但对四环素等多种抗菌药物耐药率较5年前增高。

Objective To investigate the changing patterns of ribotypes and antimicrobial resistance of Clostridium difficile strains collected from Huashan Hospital of Fudan University after 5 years. Methods C. difficile isolates collected during the periods from August 2（107 to July 2008 and August 2（/12 to July 2013 were analyzed and compared for their antibiotic suscepti- bility patterns using agar dilution method. PCR ribotyping and real-time PCR were performed to detect tcdA, tcdB, ctdA, and cdtB genes. Results Seventy-four toxigenic C. difficile strains were collected during the period from August 2007 to July 2008 and and 64 strains were obtained from August 2012 to July 2013. Among the 74 strains,49 were toxin A＋ B＋ （66.2%）, 23 toxin A 13 ＋ （31.1）, and2 toxin A ＋ 13 ＋CDT ＋ （2.7）.The dominant PCR ribotype was 017 （24.3/00）. Five years later, 65.6 of the 64 strains belonged to toxin A＋ B＋ . PCR ribotype H （18.8） was the dominant clone. Both sets of strains were highly susceptible to metronidazole and vancomycin. However, the strains resistant to elindamyein, tetracycline and fusidic acid in- creased after 5 years. The strains resistant to multiple drugs including fluoroquinolones, macrolides and lincosamides increased from28.3o/00 to 32.8 after 5 years. Conclusions C. difficile A＋ B＋ strains still play a major role in CDI, accounting for about 2/3 of the isolates. PCR ribotype H has replaced 017 as the dominant clone. All the strains are still susceptible to metron- idazole and vancomycin,but the resistance to tetracycline and fu sidic acid gets higher than 5 years before.