猪链球菌2型多重耐药菌株的人工诱导  

In vitro induction of multidrug resistant strains of Streptococcus suis serotype 2

作　　者：胡弘历[1] 姚杰[1] 顾昊旻 黄珊[1] 邹曜宇[1] 王丽平[1] 

机构地区：[1]南京农业大学动物医学院,江苏南京210095

出　　处：《畜牧与兽医》2011年第6期27-30,共4页Animal Husbandry & Veterinary Medicine

基　　金：国家自然基金项目(30972220);江苏省高等学校大学生实践创新计划项目(JSS0908)

摘　　要：采用6种常用抗菌药物对临床分离的38株猪链球菌2型进行敏感性检测,从中选择3株对红霉素和环丙沙星敏感的菌株,采用体外递增药物浓度的方法分别诱导成对红霉素和环丙沙星耐药的菌株,按临床检验标准委员会(CLSI)推荐的方法测定了红霉素和环丙沙星对同一亲本的敏感株和诱导耐药株的体外最小抑菌浓度(MIC),并测定在外排泵抑制剂利血平存在的情况下敏感株和诱导耐药株的MIC变化情况。微量稀释法测定的MIC结果显示:在所选的6种抗生素中,氟苯尼考和氨苄西林对临床分离的38株猪链球菌的作用最好,抑菌率都为100%,红霉素及环丙沙星有一定作用,耐药率分别达39.5%(15/38)和28.9%(11/38),而磺胺间甲氧嘧啶、四环素的抑菌效果最差,耐药率达100%。浓度递增法成功诱导了猪链球菌2型菌株对红霉素和环丙沙星耐药性,其MIC值分别由0.001 8 mg/L上升至128 mg/L。在外排泵抑制剂利血平存在的情况下,抗菌药物对部分猪链球菌2型菌株的MIC值下降。结果提示:逐步增加药物浓度可以诱导猪链球菌2型菌株对红霉素和环丙沙星的耐药性,而且猪链球菌2型菌株耐药性的产生可能与耐药性相关的主动外排机制有关。Six drugs were used to perform the antimicrobial susceptibility test in 38 strains of Streptococcus suis serotype 2 （ SS2 ）. Three parent strains of SS2 were chosen for stepwise exposure to increasing levels of erythroein and eiprofloxaein followed by selection of resistant mutants. Clinical categorization of isolates as susceptible or resistant was based on minimal inhibitory concentration （MIC） interpretative standards of the Clinical Laboratory Standards Institute （CLSI）. Reselloine was used to determine the effect of efflux pump inhibitor on the MICs of erythroein and ciprofloxaein against susceptible and induced resistant strains of the same parents. The result of MICs tested by microdilution indicated that resistance to sulfamonomethoxine and tetracycline （100%） was most frequent, and then erythromyein （39.5%）, ciprofloxacin （28.9%）. However, 100% strains were susceptible to florfenieol and ampieillin. The MICs of muhidrug resistant strains induced in vitro reached 128 mg/L from the initial 0. 001 8 mg/L, and the MICs of erythromycin and ciprofloxacin against some resistant strains were decreased to different degree when reserpine was used. The study indicated that stepwise inereasing eoneentration of erythromyein and ciprofloxacin can easily select resistant strains of SS2 and the active efflux pumps may play an important role in drug resistant mechanisms.

关 键 词：猪链球菌2型 微量稀释法 体外人工诱导 外排泵抑制剂 

分 类 号：S852.6[农业科学—基础兽医学]