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目的分析浙江省结核杆菌临床分离株gyrA基因喹诺酮耐药决定区(QRDR)突变与氧氟沙星耐药的相关性。方法鉴定392株结核杆菌临床菌株并检测对利福平、异烟肼、链霉素、乙胺丁醇及氧氟沙星的药物敏感性,PCR法分别扩增30株氧氟沙星敏感株和52株氧氟沙星耐药株的gyrA基因片段并测序。结果临床菌株对氧氟沙星耐药率为13.3%(52/392)。39株氧氟沙星耐药株gyrA基因编码的90、91和94位氨基酸存在突变,有31株发生Asp94Gly/Asn/Ala/His/Tyr突变为最常见(59.6%),12株发生Ala90Val/Lys突变,3株发生Ser91Pro/Trp突变(其中Ser91Trp为首次报道),7株存在双突变。有1株敏感株gyrA基因扩增片段中存在Asp94Asn突变。所有测序菌株都存在Ser95Thr突变。结论结核杆菌gyrA基因QRDR突变与氧氟沙星耐药密切相关。
Objective To analyze the relationship between the quinolone resistance - determining region (QRDR) mutation of gyrA gene and ofloxacin resistance in clinical isolates of Mycobacterium tuberculosis in Zhejiang Province. Methods 392 strains of Mycobacterium tuberculosis were identified and their susceptibility to rifampicin, isoniazid, streptomycin, ethambutol and ofloxacin was tested. PCR was used to amplify 30 sensitive samples of ofloxacin And gyrA gene fragment of 52 ofloxacin resistant strains were obtained and sequenced. Results The resistance rate of clinical isolates to ofloxacin was 13.3% (52/392). Of the 39 isolates containing ofloxacin, there were mutations in the amino acids 90, 91 and 94 encoded by the gyrA gene. Among them, 31 mutations occurred in Asp94Gly / Asn / Ala / His / Tyr and the most common mutation was 59.6% Lys mutation, Ser91Pro / Trp mutation occurred in 3 strains (Ser91Trp was first reported), and 7 strains had double mutation. There was a Asp94Asn mutation in the gyrA gene amplified fragment of a sensitive strain. Ser95Thr mutation was found in all the sequencing strains. Conclusion Mycobacterium tuberculosis gyrA gene QRDR mutation is closely related to ofloxacin resistance.