河南省胞内分枝杆菌临床分离株耐药特征及基因分型

Drug resistance and genotyping of Mycobacterium intracellulare clinical isolates in Henan Province

目的:分析河南省胞内分枝杆菌临床分离株的耐药及基因分型。方法:收集68株2019年河南省部分地市结核病专科医院痰标本分离的胞内分枝杆菌,采用微孔板法测定其对16种药物的敏感性,用16位点VNTR方法进行基因分型,并用BioNumerics软件对分型数据进行聚类分析。结果:68株对克拉霉素、利福布汀和甲氧苄啶/磺胺甲恶唑的耐药率分别为11.76%(8/68)、5.88%(4/68)、8.82%(6/68)。克拉霉素、利福布汀和甲氧苄啶/磺胺甲恶唑的抑制50%胞内分枝杆菌的最低抑菌浓度(MIC 50)和MIC 90分别为2和32 mg/L、0.5和2 mg/L以及0.25/4.75和2/38 mg/L。16位点VNTR将68株分为45个基因型,包括来自11个簇的34株和34个独特模式的分离株,Hunter-Gaston分辨力指数为0.978。成簇菌株利奈唑胺和阿米卡星耐药率高于非成簇菌株(58.82%vs 23.53%;44.12%vs 14.71%)(P<0.05)。结论:克拉霉素、利福布汀和甲氧苄啶/磺胺甲恶唑等对河南省胞内分枝杆菌临床分离株具有较好的抗菌活性。VNTR分型方法对胞内分枝杆菌具有较好的分型能力。成簇菌株中利奈唑胺和阿米卡星的耐药率高于非成簇菌株。

Aim:To investigate the drug resistance and genotyping results of Mycobacterium intracellulare clinical isolates in Henan Province.Methods:Sixty-eight Mycobacterium intracellulare isolated from sputum samples in 2019 at tuberculosis hospitals in some prefectures in Henan Province were collected.The minimum inhibitory concentration(MIC)of 16 drugs against Mycobacterium intracellulare isolates was determined by broth microdilution assay.Genotyping was carried out by the 16-loci VNTR method and data were analyzed by the BioNumerics software.Results:The drug resistance rates of Mycobacterium intracellulare isolates to clarithromycin,rifambutin and trimethoprim/sulfamethoxazole were 11.76%(8/68),5.88%(4/68)and 8.82%(6/68),respectively.MIC 50 and MIC 90 of clarithromycin,rifambutin and trimethoprim/sulfamethoxazole were 2 and 32 mg/L,0.5 and 2 mg/L,0.25/4.75 and 2/38 mg/L.Sixty-eight isolates were divided into 45 different genotypes by the 16-loci VNTR method,including 34 isolates from 11 clusters and 34 isolates with unique patterns.The HGDI index was 0.978.The drug resistance rates of linezolid(58.82%vs 23.53%)and amikacin(44.12%vs 14.71%)in 34 clustered isolates were significantly higher than those of 34 non-clustered isolates(P<0.05).Conclusion:Clarithromycin,rifambutin and trimethoprim/sulfamethoxazole have good antibacterial activity against Mycobacterium intracellulare isolates in Henan Province in vitro.The 16-loci VNTR typing showed a highly discriminatory power.The drug resistance rates of linezolid and amikacin in clustered isolates are higher than those of non-clustered isolates.