福建省结核分枝杆菌异烟肼耐药相关基因突变特征初步分析

Mutations of drug-resistance genes related to INH in Mycobacterium tuberculosis isolates in Fujian Province,China

目的了解福建省结核分枝杆菌异烟肼耐药相关基因的突变特征,为异烟肼耐药快速检测方法的建立提供一定的科学依据。方法对来源于福建省结核病耐药性监测30个监测点纳入的75株耐多药和10株全敏感结核分枝杆菌分离株,进行katG、inhA、oxyR-ahpC基因片段PCR扩增并测序分析,用RD105缺失基因检测法进行北京家族基因型鉴定,使用卡方检验分析相关性。结果 10株全敏感株未检测到突变。75株耐多药结核分枝杆菌检测到72株katG、inhA、oxyR-ahpC发生单一或联合基因突变,突变率为96.0%(72/75)。其中,65株(86.7%,65/75)发生katG突变,涉及5个位点,最常见位点突变的密码子是315,突变率为82.7%(62/75),最常见突变形式为Ser315Thr(77.3%,58/75);8株(10.7%,8/75)发生inhA突变,突变形式均为C(-15)T;5株(6.7%,5/75)发生oxyR-ahpC突变,突变形式为C(-39)T或C(-46)A。katG、inhA和oxyR-ahpC在北京家族基因型菌株和非北京家族基因型菌株中的突变率分别为83.9%(47/56)、12.5%(7/56)、7.1%(4/56)和94.7%(18/19)、5.3%(1/19)、5.3%(1/19),差异无统计学意义(P值分别为0.23、0.38、0.78)。结论福建省结核分枝杆菌异烟肼耐药性相关基因突变绝大多数发生在katG、inhA和oxyR-ahpC基因位点,且以katG突变为主。初步分析显示北京家族基因型菌株流行与异烟肼耐药基因突变特征无关。

The characteristics of the mutations of drug-resistance genes related to INH in drug resistant Mycobacteriurn tuberculosis （M. tb） isolates in Fujian Province, China was analyzed in this study, and molecular evidence for fast diagnosis method for INH resistant M. tb was provided. Seventy-five multi-drug resistant （MDR） M. tb isolates and 10 pan-susceptible isolates were chosen from 30 survey sites, the katG, inhA and occyR-ahpC genes of these isolates were detected by PCR and followed by sequencing. All these isolates were identified Beijing family genotype by RD105 deletion test, and Chi-square test was used to analyze the relation. No mutation was detected in 10 pan-susceptible isolates. Mutations of katG, inhA or o：ryR- ahpC were detected in seventy-two isolates out of 75 MDR M. tb. The total rate of mutation was 96.0% （72/75）. Among them, katG mutation was detected in sixty-five isolates. There were 5 sites involved in katG mutation, in which codon 315 （82.7%, 62/75） was the most frequency mutation site （Ser315Thr, 77.3%, 58/75）. The inhA mutation was detected in 8 isolates（10.7%,8/75）, and the mutation form was C（-15）T. The oxyR-ahpC mutation was detected in five isolates （6.7%, 5/75）, and the mutation form wasC（-39）T or C（-46）A. There was no significant association between Beijing {amily genotype isolates and the mutations in katG, inhA or oxyR-ahpC （P value was 0.23, 0.38 and 0.78 respectively）. Our data showed that detection on the mutations of katG, inhA and oxyR-ahpC has important value to diagnosis the INH resistant of M. tb, and to provide evidence for developing tools for rapid diagnosis of INH resistant MDR M. tb in Fujian Province. The Beijing family genotype isolates were prevalent in Fujian, but there was no related to the mutations of drug resistant genes related to INH.