广州地区耐喹诺酮结核分枝杆菌gyr基因突变特点

MUTATION CHARACTERIZATION OF GYR GENE IN QUINOLONE RESISTANT MYCOBACTERIUM TUBERCULOSIS CLINICAL ISOLATES FEOM GUANGZHOU CITY

目的分析广州地区耐喹诺酮结核分枝杆菌临床菌株的gyr基因突变特点,为进一步研究结核分枝杆菌耐喹诺酮类药物的分子机理提供地区性资料。方法采用绝对浓度法测定结核分枝杆菌对左氧氟沙星的敏感性,应用DNA直接测序法检测结核分枝杆菌gyr基因的突变情况。结果23株左氧氟沙星耐药株中,15株存在gyrA基因突变,突变率为65.2%,突变位点包括89位、90位、91位和94位;1株存在gyrB基因突变,突变率为4.3%,突变位点为511位。结论广州地区耐喹诺酮结核分枝杆菌临床菌株的gyr基因突变情况与其它地区存在差异。

Objective To analyze the characteristics of gyr gene mutations of quinolond resistant Mycobacterium tuberculosis clinical isolates from Guangzhou city and provide some basic information for the study on molecular mechanism of quinolone resistance. Methods Susceptibility to levofloxacin was determined by absolute concentration method and mutations of gyr gene were detected by DNA direct sequencing. Results Of 23 levofloxacin resistant Mycobacterium tuberculosis clinical isolates, 15 mutated at condon 89,90,91 or 94 of gyrA gene whose mutation rate is 65.2% and 1 mutated at condon 511 of gyrB whose mutation rate is 4. 3%. Conclusion Gyr gene mutations have some differences between quinolone resistant Mycobacterium tuberculosis clinical isolates from Guangzhou city and those from other areas.