志贺菌属非典型1类整合子与耐多药关系

Atypical class 1 integron and multi-drug resistance in Shigella spp.

目的研究志贺菌属中非典型1类整合子的分布及其与耐多药性的关系。方法对实验室保存的90株志贺菌属进行8种抗生素药敏实验,针对非典型1类整合子的耐药基因盒区域设计引物进行聚合酶链反应(PCR)扩增和限制性片段长度多态性(RFLP)分析,对代表性菌株进行测序分析。结果 90株志贺菌属中有86株(95.6%)对≥3种抗生素耐药;有66株(73.3%)对氨苄青霉素(AMP)、四环素(TET)和氯霉素(CHL)联合耐药;非典型1类整合子分布于65株(72.2%)志贺菌属中;RFLP分析结果表明,所有酶切产物的带型均一,测序分析发现序列为blaoxa-30-aadA1;非典型1类整合子阳性菌株对AMP-TET-CHL联合耐药率(81.5%)高于阴性菌株(52.0%),经双侧χ2检验发现差异有统计学意义(P<0.05)。结论志贺菌属非典型1类整合子阳性与其对AMP-TET-CHL联合耐药有关,可能参与耐多药性的形成。

Objective To investigate the distribution of atypical class 1 integron and its relationship to multi-drug resistance in Shigella spp.Methods Susceptibility test of 8 antimicrobials was determined in 90 Shigella strains.PCR and restriction fragment length polymorphism（RFLP） analysis of atypical class 1 integron were applied to all strains.PCR production of representative isolate was selected for sequencing analysis.Results High prevalence of multi-drug resistance（86/90,95.6%） was found.Of all isolates,66（73.3%）were resistant to ampicillin,tetracycline,and chloramphenicol and 65（72.2%）had atypical class 1 integron.RFLP analysis revealed the identical profile and gene cassettes blaoxa-30-aadA1.The multi-resistant rate to ampicillin,tetracycline and chloramphenicol was significantly higher in the isolates positive of atypical class 1 integron than in those of negative isolates（P0.05）.Conclusion Atypical class 1 integron is related to the multiple resistance to ampicillin,tetracycline and chloramphenicol and may play a role in the emergence of multi-drug resistance in Shigella spp.