摘要
参照CLSI推荐的肉汤微量稀释法检测了46株猪链球菌对8种抗生素的耐药性,采用PCR方法检测其大环内酯类耐药基因的分布情况,并用脉冲场凝胶电泳(PFGE)分型方法分析大环内酯类抗生素耐药株和敏感株的遗传差异性。试验结果显示:46株猪链球菌对四环素的耐药率达到100%,对头孢喹肟、红霉素、泰乐菌素、替米考星、阿奇霉素和氨苄西林的耐药率分别为43.48%、34.78%、26.09%、23.91%、15.22%和2.17%,所有猪链球菌对氟苯尼考表现为敏感或中介。46株猪链球菌中有34.78%(16/46)的菌株携带大环内酯类耐药基因,均表现出对大环内酯类抗生素耐药。其中12株携带ermB基因,菌株为MLSB耐药表型,是大环内酯类耐药的主要方式;4株携带mefA基因,菌株为M型耐药表型。PFGE指纹图谱显示16株ermB或mefA耐药株的图谱不一致,存在明显的遗传差异性。结果提示猪链球菌对抗生素的耐药性较高,大环内酯类耐药基因在猪链球菌中广泛存在,其中以ermB介导的核糖体23S rRNA甲基化占主导地位,其次是mefA介导的药物外排系统。这些耐药菌株分属不同的克隆株,推测耐药基因ermB可能通过移动基因元件的水平转移而广泛传播。
The aim of the study is to analyse the macrolides resistant rate and the genetic diversity of Streptococcus suis clinical isolates as well as the possible mode of the transmission of macrolide resistance genes.The broth microdilution method was used to detect the antimicrobial sensitivity of eight antibiotics against 46 S.suis.PCR was used to detect the macrolide resistance genes ermA/B/C,mefA and msrD.And genotyping was carried out by pulsed-field gel electrophoresis(PFGE).The results showed that S.suis was resistant to tetracycline,cefquinome,erythromycin,azithromycin,tylosin,tilmicosin and ampicillin with the different rate of 100%,43.48%,34.78%,15.22%,26.09%,23.91% and 2.17%,respectively.Fourty-six strains were not resistant to florfenicol.Macrolide resistance gene ermB was detected in 12 strains and mefA was found in 4 strains.PFGE typing result implied that the isolates represented a wide variety of genetic difference.The study indicates that there is a high resistant rate to macrolide due to the acquirement of ermB and mefA resistant genes in S.suis.The genomic polymorphism of the macrolide resistant strains is more apparent than that of the sensitive strains,which indicates the possible transmission mode of the resistance is horizontal way,but not clone spread.
出处
《南京农业大学学报》
CAS
CSCD
北大核心
2013年第4期105-110,共6页
Journal of Nanjing Agricultural University
基金
江苏省自然科学基金项目(BK2012771)
国家自然科学基金项目(30972220)
中央高校基本科研业务费专项资金项目(6J0396)
