摘要目的 分析整合子类型、耐药基因盒在志贺菌中的分布及其与耐药性之间的关系.方法 采用最低抑菌浓度(M IC)测定志贺菌药物敏感性,PCR扩增Ⅰ、Ⅱ和Ⅲ类整合子及其耐药基因盒,限制性内切酶及DNA测序确定各基因序列.结果 在分离的62株志贺菌中,57株存在多重耐药现象,占91.9％.在多重耐药株中,Ⅰ类、Ⅱ类整合子基因阳性株分别为52和55株,分别占91.2％和96.5％(其中仅含Ⅰ类整合子2株,仅含Ⅱ类5株,Ⅰ类、Ⅱ类整合子均含的50株).未检测到Ⅲ类整合子基因.典型Ⅰ类整合子8株,耐药基因盒为dfrV和dfrA 17 aadA5;非典型Ⅰ类整合子44株,耐药基因盒均为blaOXA0-aadA1.6株福氏志贺菌中存在典型和非典型Ⅰ类整合子共存现象.Ⅱ类整合子耐药基因盒均为dfrA1sat1-aadA1.结论 本研究分离的志贺菌存在严重多重耐药,多重耐药株中普遍携带非典型Ⅰ类整合子和Ⅱ类整合子的耐药基因盒,部分菌株存在典型和非典型Ⅰ类整合子共存现象.

abstractsObjective To analyze the distribution of class 1,2 and 3 integrons and their gene cassettes,and to explore its relationship with drug resistance in Shigella.Methods Antimicrobial susceptibility was detected by minimal inhibitory concentration (MIC) method.All the genes of integrons and gene cassettes were amplified by polymerase chain reaction (PCR).The amplicons were identified by amplified fragment length polymorphism (AFLP) and sequencing.Results Fifty seven multi-drug resistant strains were identified from a total of 62 Shigella strains (91.9％).Among multi drug resistant strains,52 strains carried integrons of class 1 (91.2 ％) and 55 strains carried integrons of class 2 (96.5％).Only 2 strains carried class 1 integrons alone,5 strains carried class 2 integrons alone and 50 strains had both class 1 and class 2 integrons.Class 3 integrons were not detected.The gene cassettes of typical class 1 integrons,dfrV and dfrA17-aadA5,were detected in 6 strains and 2 strains,respectively.Atypical class 1 integrons with gene cassettes blaOxA30 aadA1 were detected in 44 strains.The typical and atypical class 1 integrons coexisted in 6 Shigella flexneri strains.Gene cassettes for class 2 integrons were dfrA1 sat1-aadA1.Conclusions The multi-drug resistant Shigella strains are widely distributed in Ji'nan,and the atypical class 1 integrons and class 2 integrons are common in these strains.Coexistence of the two integrons is observed in some of the strains.