西安市与上海市百日咳鲍特菌对大环内酯类抗生素的耐药性、耐药相关分子特征及多位点抗原序列分型的比较研究

Comparison of macrolide resistance, molecular characteristics and MAST types of Bordetella pertussis collected from Xi’an and Shanghai

目的 比较西安市与上海市临床分离百日咳鲍特菌对大环内酯类抗生素的耐药性、耐药相关分子特征及多位点抗原序列分型(MAST)特征,为改进我国百日咳的防治和疫苗策略提供参考。方法 采用E-test法检测2018年至2019年西安市和上海市临床分离百日咳鲍特菌对红霉素、阿奇霉素、克拉霉素的耐药性;采用PCR法检测可水平转移的耐药基因与耐药相关突变位点;采用MAST方法对菌株进行分型,比较两市菌株耐药性的差异及抗原序列型别构成比的差异。结果 本研究共分离出百日咳菌株60株,其中西安市34株,上海市26株。西安市与上海市临床分离百日咳鲍特菌对大环内酯类抗生素的耐药性存在统计学差异(χ^(2)=13.650,P<0.001)。两市菌株MAST分型型别构成比也存在统计学差异(χ^(2)=18.642,P<0.001),西安市菌株以prn1/ptxP1/ptxA1/fim3-1/fim2-1型别为主,而上海市prn1/ptxP1/ptxA1/fim3-1/fim2-1与prn2/ptxP3/ptxA1/fim3-1/fim2-1型别几乎各占一半。两市所有耐药株均检出A2047G位点突变,所有敏感株均未检出该突变;耐药基因中,部分耐药株检出甲基化酶基因ermA和ermB,未检出其他耐药基因;所有敏感株均未发现耐药基因和位点突变。结论 西安市与上海市临床分离百日咳鲍特菌对大环内酯类抗生素的耐药性存在差异,两市菌株MAST型别分布亦存在差异,应进一步加强中国百日咳菌株耐药性和基因型演变的监测。

Objective To compare the macrolide resistance, molecular characteristics and multilocus antigen sequence typing(MAST) of Bordetella pertussis(Bp) collected from Xi’an and Shanghai so as to provide reference for prevention of pertussis and optimize vaccination strategies. Methods Erythromycin, azithromycin and clarithromycin susceptibility of clinical isolates collected from Xi’an and Shanghai during 2018 and 2019 were determined by E-test. PCR was used to detect the drug-resistant genes and mutation sites. MAST was employed to do molecular typing for the strains. The differences in macrolide resistance and MAST types between Xi’an and Shanghai were compared. Results Totally 34 strains from Xi’an and 26 strains from Shanghai were isolated. There were differences between Xi’an and Shanghai in the macrolide resistance(χ^(2)=13.650,P<0.001).The composition ratio of MAST types of pertussis strains was also different between Xi’an and Shanghai(χ^(2)=18.642,P<0.001)in that the prn1/ptxP1/ptxA1/fim3-1/fim2-1 strains dominated in Xi’an,while the prn1/ptxP1/ptxA1/fim3-1/fim2-1 and prn2/ptxP3/ptxA1/fim3-1/fim2-1 were almost half and half in Shanghai.A2047G site mutation was detected in all the macrolide-resistant strains,but not in all sensitive strains.Methylase genes ermA and ermB were detected in some macrolide-resistant strains.No other macrolide-resistant genes were found in resistant strains and no mutation or drug resistance gene was found in all the susceptible strains.Conclusion Differences existed between Xi’an and Shanghai in the macrolide resistance and MAST types of Bordetella pertussis strains.Further monitoring of Bordetella pertussis in China is required to better understand the resistance and evolution of the pathogen.