我国607株不同宿主来源弯曲菌耐药基因簇aadE-sat4-aphA-3分布分析

Distribution of aminoglycoside resistance gene cluster aad E-sat4-aph A-3 in 607 Campylobacter isolates from different sources in China

目的了解不同宿主来源弯曲菌对氨基糖苷类抗生素的耐药现状,确定耐药菌株中氨基糖苷类耐药基因簇aadE-sat4-aph A-3的分布,并初步了解耐药菌株的菌型特征。方法利用琼脂稀释法分析不同宿主来源菌株针对链霉素最小抑菌浓度(MIC),对耐药的221株菌通过聚合酶链反应筛查氨基糖苷类耐药基因簇aad E-sat4-aph A-3的分布情况。选取不同来源共100株耐药菌株进行多位点序列分型分析并进行聚类分析,获得耐药菌株的菌型特征及遗传相关性。结果 607株弯曲菌中共筛查到221株(36.41%)链霉素耐药株(MIC≥4μg/ml),其中腹泻患者来源菌株耐药率33.33%(78/234)、鸡来源菌株耐药率35.14%(123/350)、猪来源菌株耐药率86.96%(20/23)。空肠弯曲菌耐药率14.37%(51/355),结肠弯曲菌耐药率67.46%(170/252)。24株(10.86%)链霉素耐药弯曲菌中筛查到aad E-sat4-aph A-3耐药基因簇,分别来自腹泻患者14株、鸡4株、猪6株。100株耐药菌株共分为58种ST序列型。结论结肠弯曲菌链霉素耐药率明显高于空肠弯曲菌,猪源弯曲菌耐药率显著高于人源和鸡源,空肠弯曲菌与结肠弯曲菌中均筛查到aad E-sat4-aph A-3耐药基因簇。

Objective To investigate the aminoglycoside resistance of Campylobacter isolated from different sources in China and the distribution of the aminoglycoside resistance gene cluster aadE-sat4-aphA-3 in the resistant isolates and the genotype of the resistant isolates. Methods Agar dilution method was used to analyze the minimum inhibitory concentration （MIC） of the isolates from different sources. The distribution of the aadE-sat4.aphA-3 gene cluster in streptomycin resistant Campylobacter isolates were detected by using PCR. Multilocus sequence typing was conducted to analyze the genotypes of the resistant isolates. Results Among 607 strains of Campylobacter isolated, 221 were streptomycin resistant （MIC ≥4 μg/ml）. The resistant rates of the isolates from diarrhea patients, chickens and pigs were 33.33%, 35.14% and 86.96%, respectively. The resistant rates of Campylobacterjejuni and Campylobacter coli were 14. 37% and 67. 46% respectively. The aadE-sat4-aphA-3 gene cluster was detected in 24 streptomycin resistant isolates （ 10. 86% ）, in which 14 were from diarrhea patients, 4 were from chickens and 6 were from pigs. Among 100 streptomycin resistant isolates from different sources, 58 sequence types were detected, and ST 1464 was the most common sequence type. Conclusion The streptomycin resistant rate of C. coli was significantly higher than that of C. jejuni, and the resistant rate of Campylobacter isolated from pigs was higher than that of the isolates from diarrhea patients and chickens. The aadE-sat4-aphA-3 gene cluster was detected in both C. jejuni and C. coli.