北京市复治结核病患者非北京基因型菌株谱系及耐药分析

目的 了解北京市复治结核病患者非北京基因型菌株谱系及耐药情况,为复治非北京基因型结核病患者有效防治提供科学依据。方法 采用RD105基因缺失法对复治患者所分离的结核分枝杆菌（Mycobacterium tuberculosis, MTB）进行检测,筛查出非北京基因型菌株,使用可变数目串联重复序列基因分型实验分析非北京基因型菌株的遗传特征,再使用比例法药敏实验及全基因组测序分析其耐药情况。结果 134例复治结核病患者所分离的MTB中,北京基因型为 125例（93.3%）,非北京基因型为9例（6.7%）。9例非北京基因型MTB呈现9种不同的基因型,均不成簇,为独特型。9例非北京基因型MTB均为谱系4,其中,亚谱系L4.4有4株,亚谱系L4.5有5株。耐药预测结果显示,9例非北京基因型中,6例为全敏感菌株（66.7%）,1例单耐异烟肼,耐药突变位点为ahpC_c.-48G>A,1例同时耐异烟肼与乙硫异烟胺, 耐药突变位点为fabG1_c.-15C>T,1例单耐氟喹诺酮,耐药突变位点为gyrA_p.Asp94Asn与gyrA_p.Ala90Val。全基因组测序预测耐药结果与比例法药敏结果完全一致。结论 复治结核病患者非北京基因型菌株主要为谱系4,呈明显的多态性。耐药突变位点均为常见突变位点。

Analysis of non-Beijing genotype strain lineage and drug resistance in retreated tuberculosis patients in Beijing

Objective To investigate the lineage and drug resistance of non-Beijing genotype strains in retreated tuberculosis patients in Beijing, and to provide scientific basis for effective prevention and control. Methods The RD105 gene deletion method was used to detect the Mycobacterium tuberculosis (MTB) isolated from retreatment patients, and the non-Beijing genotype strains were screened out. The genetic characteristics of non-Beijing genotype strains were analyzed by variable number tandem repeat genotyping test, and drug resistance was analyzed by proportional drug susceptibility test and whole genome sequencing. Results Totally 125 (93.3%) MTB isolates from 134 retreatment tuberculosis patients were Beijing genotype, and 9 (6.7%) were non-Beijing genotype. The 9 non-Beijing genotype strains presented 9 different genotypes, all of which were not clustered and were unique. The 9 non-Beijing genotype strains were all lineage 4, including 4 strains in sublineage L4.4 and 5 strains in sublineage L4.5. The prediction results of drug resistance showed that 6 cases were fully sensitive strains (66.7%, 6/9). One case was single resistant to isoniazid, and the mutation site of resistance was ahpC_c.-48G>A. One case was resistant to both isoniazid and ethionamide, and the mutation site of resistance was fabG1_c.-15C>T. One case was single resistant to fluoroquinolone, and the resistant mutation sites were gyrA_p.Asp94Asn and gyrA_p.Ala90Val. The prediction of drug resistance by whole genome sequencing was consistent with that by proportional method. Conclusions The non-Beijing genotype strains of retreated tuberculosis patients were mainly lineage 4, showing obvious polymorphism. The resistance mutation sites were common mutation sites.