中国防痨杂志2024，Vol.46Issue(8)：942-950,9.DOI:10.19982/j.issn.1000-6621.20240133
利福平耐药结核分枝杆菌对氟喹诺酮类药物表型耐药与其基因突变的一致性研究
Consistency between phenotypic resistance to fluoroquinolones and genetic mutations in rifampicin resistant Mycobacterium tuberculosis strains
摘要
Abstract
Objective:To elucidate the mutation profiles of fluoroquinolones(FQs)resistance genes in Mycobacterium tuberculosis(MTB)and to analyze the correlation between specific genetic mutations and the minimum inhibitory concentrations(MICs)of FQs.Methods:Positive strains isolated and cultured from rifampicin-resistant tuberculosis(RR-TB)patients,who were admitted to tuberculosis prevention and control institutions and designated hospitals in Beijing between 2016 and 2021,were selected for drug sensitivity testing using the microplate method.The MICs of levofloxacin(Lfx)and moxifloxacin(Mfx)for these RR-MTB strains were determined and summarized.Concurrently,first-generation sequencing was performed.The relationship between the mutation characteristics of the gyrA and gyrB genes,which were associated with FQs resistance,and the MICs of FQs was analyzed.Phenotypic drug sensitivity testing(pDST)results were used as a reference standard to evaluate the performance of genotypic drug sensitivity testing(gDST)in detecting FQs resistance.Additionally,the reasons for discrepancies between phenotypic and genotypic resistance in RR-MTB strains were investigated.Results:Among the 303 RR-MTB strains analyzed,the pDST resistance rate to FQs was 27.7％(84/303),and the detection rate of gyrA gene mutations was 25.1％(76/303).No gyrB gene mutations were detected.Using pDST results as the reference standard,the sensitivity and specificity of gDST for detecting FQ resistance in RR-MTB were 84.5％(71/84;95％CI:74.6％-91.2％)and 97.7％(214/219;95％CI:94.5％-99.1％),respectively.There were 25 strains with inconsistent results between the two methods,resulting in an inconsistency rate of 8.3％(25/303).The MIC of FQs-resistant strains was predominantly 2 μg/ml,with the most common mutation site located at codon 94(53.9％,41/76).The gyrA gene mutations at codons 88 and 94 were completely consistent with pDST resistance,while the consistency rates of pDST resistance at codons 90 and 91 were 95.8％(23/24)and 3/5,respectively.The mutation at position 88 was linked to resistance to Lfx in pDST and high-level resistance to Mfx.The mutation at codon 90,predominantly an alanine-to-valine substitution(92.3％,24/26),resulted in MICs at the critical concentrations for Lfx(1 μg/ml)and Mfx(0.25 μg/ml).The aspartic acid mutation at codon 94 was associated with high-level resistance to Lfx and Mfx when mutated to asparagine(1/1).Additionally,this aspartic acid mutation,when altered to tyrosine,was linked to resistance to Lfx(1/1)and high-level resistance to Mfx(1/1).Conclusion:The primary mechanism of FQs resistance in RR-MTB in Beijing is attributed to mutations in the gyrA gene.Different gyrA mutations are indicative of varying levels of FQs resistance.The concordance between pDST and gDST for detecting FQs resistance in RR-MTB is high.Consequently,gDST can be implemented early to identify FQs resistance in RR-TB patients,facilitating the clinical development of effective treatment plans.关键词
分枝杆菌,结核/荧光喹诺酮类/微生物敏感性试验/DNA突变分析/抗药性,细菌Key words
Mycobacterium tuberculosis/Fluoroquinolones/Microbial sensitivity tests/DNA mutational analysis/Drug resistance,bacterial分类
医药卫生引用本文复制引用
于兰,陈双双,王嫩寒,田丽丽,赵琰枫,樊瑞芳,刘海灿,李传友,代小伟..利福平耐药结核分枝杆菌对氟喹诺酮类药物表型耐药与其基因突变的一致性研究[J].中国防痨杂志,2024,46(8):942-950,9.基金项目
Beijing Center for Disease Prevention and Control Research and cultivation program(2023-KYJH-03) 北京市疾病预防控制中心科研培育专项(2023-KYJH-03) （2023-KYJH-03）
