西安市结核病患者耐药情况及耐药菌株基因突变现状

Drug resistance of tuberculosis patients and gene mutation of drug-resistant strains in Xi'an

目的了解西安市结核病患者耐药情况,以及对常用抗结核药耐药的结核分枝杆菌(MTB)的相关耐药基因突变特征进行分析。方法对2020年1—12月西安市结核病定点医院上报的痰涂片阳性结核病患者的痰样本进行分离培养,对鉴定为MTB阳性的菌株样本进行药敏试验,并利用全基因组测序(WGS)对耐药菌株的耐药相关基因突变特征进行分析。结果共鉴定出892例MTB阳性患者,其中初治患者758例,复治患者134例;耐药209例,总耐药率23.43%;单耐药(MR-TB)、多耐药(PDR-TB)、耐多药(MDR-TB)、广泛耐药(XDR-TB)和利福平耐药(RR-TB)率分别为10.43%、2.47%、4.60%、0.45%和6.28%。复治患者的耐药率(31.34%)明显高于初治患者(22.03%);且2组耐药患者MR-TB、PDR-TB、MDR-TB、XDR-TB和RR-TB所占比例的差异均有统计学意义(均P<0.05)。209例MTB耐药菌株对常用抗结核药品的耐药相关基因突变主要为81株katG(77.14%,异烟肼)、54株rpoB(96.43%,利福平)、49株rpsL(84.48%,链霉素)、24株embB(88.89%,乙胺丁醇)、17株pncA(89.47%,吡嗪酰胺)、10株gyrA(90.91%,氧氟沙星)、18株rss(94.74%,二线注射类抗结核药物)。其中相关耐药基因突变位点频率最高的分别为katG S315T(72株)、rpsL K43R(42株)、rss A1401G(23株)、rpoB S531L(19株)、embB M306V(13株)和rpoB H526D(11株)。结论西安市结核病患者对常用抗结核药具有较高的耐药性,耐药菌株基因突变以katG、rpoB、rpsL、embB和pncA等基因突变为主,且主要发生在katG S315T、rpsL K43R等高频突变位点,针对上述突变特征开发敏感、特异的快速分子检测方法具有理论可行性。

Objective To understand the drug resistance of tuberculosis patients in Xi'an,and to analyze the mutation characteristics of drug-resistant genes related to Mycobacterium tuberculosis(MTB)that are resistant to commonly anti-tuberculosis drugs.Methods The sputum samples of tuberculosis patients with positive sputum smears reported by tuberculosis-designated hospitals in Xi'an from January to December 2020 were isolated and cultured,and the samples identified as MTB-positive strains were tested for drug sensitivity,and the mutation characteristics of drug-resistant related genes of drug-resistant strains were analyzed by whole genome sequencing(WGS).Results A total of 892 MTB-positive patients were identified,including 758 newly treated patients and 134 retreated patients;209 cases were drug-resistant,and the total drug resistance rate was 23.43%;The rates of monodrug resistant tuberculosis(MR-TB),poly-drug resistant tuberculosis(PDR-TB),multidrug-resistant tuberculosis(MDR-TB),extensive drug-resistant tuberculosis(XDR-TB),and rifampicin-resistant tuberculosis(RR-TB)were 10.43%,2.47%,4.60%,0.45%,and 6.28%,respectively.The drug resistance rate of retreated patients(31.34%)was significantly higher than that of newly treated patients(22.03%);The proportion of MR-TB,PDR-TB,MDR-TB,XDR-TB,and RR-TB in drug-resistant patients of the two groups was statistically significant(all P<0.05).Among 209 MTB-resistant strains,the mutations of resistance-related genes to commonly used anti-tuberculosis drugs were 81 strains of katG(77.14%,isoniazid),54 strains of rpoB(96.43%,rifampicin),49 strains of rpsL(84.48%,streptomycin),24 strains of embB(88.89%,ethambutol),17 strains of pncA(89.47%,pyrazinamide),10 strains of gyrA(90.91%,ofloxacin),and 18 strains of rss(94.74%,second-line injection type anti-tuberculosis drugs).Among them,katG S315T(72 strains),rpsL K43R(42 strains),rss A1401G(23 strains),rpoB S531L(19 strains),embB M306V(13 strains),and rpoB H526D(11 strains)had the highest mutation frequency of related drug resistance genes.Conclusions Tuberculosis patients in Xi'an are highly resistant to commonly used anti-tuberculosis drugs.The gene mutations of drug-resistant strains are mainly katG,rpoB,rpsL,embB,and pncA,and mainly occur at high-frequency mutation sites such as katG S315T and rpsL K43R.It is theoretically feasible to develop sensitive and specific rapid molecular detection methods based on the above mutation characteristics.