摘要目的 了解江苏地区宋内志贺菌中各类整合子的检出情况和携带耐药基因的种类.方法 收集2011年江苏省6座城市32株宋内志贺菌,纸片扩散法检测志贺菌对抗菌药物的敏感性,脉冲场凝胶电泳(PFGE)检测分子同源性,PCR-限制性片段长度多态性(RFLP)进行整合子检测和分类,联合RFLP和DNA测序技术分析整合子携带的耐药基因.结果 多重耐药宋内志贺菌的检出率为87.5％(28/32),对氨苄西林、萘啶酸和四环素的耐药率最高,均为87.5％,对诺氟沙星的耐药率为0.PFGE聚类分析结果发现,32株宋内志贺菌中,有3种为具有同源性的克隆,涉及31株菌,其中2株菌、5株菌和24株菌同源的各有1种克隆,分别在同一城市、两座和五座不同城市间传播.1类、2类和非典型1类整合子广泛分布于宋内志贺菌中,检出率分别为62.5％(20/32)、81.3％ (26/32)和21.9％(7/32),未检测到3类整合子.DNA测序发现1类整合子中携带aacA4-cmlA1和dfrA1-aadA1耐药基因盒;2类和非典型1类整合子可变区分别携带耐药基因盒dfrA1-sat1-aadA1和blaaxa-30-aadA1.结论 2011年江苏省内各城市间存在同源性一致的宋内志贺菌株的传播,且多重耐药情况普遍存在,整合子在宋内志贺菌中普遍存在.

abstractsObjective To investigate the resistance status of different integrons of Shigella sonnei (S.sonnei) and to analyze the distribution of resistant genes in integrons in Jiangsu Province.Methods A total of 32 strains of S.sonnei isolated from six cities of Jiangsu Province in 2011 were collected.The antibiotic susceptibility was tested by disk diffusion method.The molecular homology was analyzed by pulsed field gel electrophoresis (PFGE).The detection and classification of integrons were achieved by analyzing the positive polymerase chain reaction (PCR) products using restriction fragment length polymorphism (RFLP).RFLP and DNA sequencing were used to analyze the resistance genes in integrons.Results Multi-drug resistance (MDR) was detected in 28 (87.5％) S.sonnei strains.The resistant rates to ampicillin,nalidixic acid and tetracycline were highest (87.5％,respectively).However,it was sensitive to norfloxacin.PFGE analysis showed that there were 3 kinds of homologous clones involving 31 strains of the 32 S.sonnei strains.Among them,2,5 and 24 strains had the same clones,respectively.Accordingly,they spread within one,two and five different cities.The detection rates of class 1,class 2 and the atypical class 1 integrons in S.sonnei were 62.5％ (20/32),81.3％ (26/32) and 21.9％ (7/32),respectively,and no class 3 integron was detected.Sequence analysis of class 1 integron variable area revealed that it contained multiple resistant genes (aacA4-cmlA1 and dfrA1-aadA 1) ; dfrA1-sat 1-aadA 1 from class 2 integron and blara-30-aadA 1 from atypical class 1 integron were also identified.Conclusions In 2011,homologous S.sonnei strains spread among different cities in Jiangsu Province.MDR strains are prevalent and integrons are widespread which mediated the emergence of MDR strains.