利福平耐药结核分枝杆菌对A组抗结核药物的耐药性研究

Study on the resistance of rifampicin-resistant Mycobacterium tuberculosis to anti-tuberculosis drugs in group A

目的总结利福平耐药结核分枝杆菌(MTB)对A组抗结核药物的耐药性。方法本研究为回顾性研究,收集2016—2021年北京市结核病防治系统(简称北京结防系统,包括区结核病防治机构和区级结核病定点医疗机构)疑似耐多药肺结核患者分离培养阳性菌株,经MPB64抗原检测试验鉴定为MTB的菌株1226例,经比例法药敏检测利福平(RFP)和异烟肼(INH)的耐药情况,筛选出利福平耐药结核病(RR-TB)患者菌株,用微孔板法检测左氧氟沙星(LFX)、莫西沙星(MFX)、贝达喹啉(BDQ)、利奈唑胺(LZD)的耐药性。总结4种A组抗结核药物的耐药率、耐药水平和最低抑菌浓度(MIC)分布情况,分析RR-TB、耐多药结核病(MDR-TB)、准广泛耐药结核病(pre-XDR-TB)、广泛耐药结核病(XDR-TB)4类耐药肺结核患者不同特征的分布差异、LFX、MFX交叉耐药、耐BDQ和耐LZD菌株耐药谱以及RR-TB患者治疗转归情况。计数资料采用率或构成比表示,组间和组内采用χ^(2)检验,以P<0.05为差异有统计学意义。结果1226例疑似耐多药肺结核患者中RR/MDR/pre-XDR/XDR-TB患者检出率分别为20.8%(255/1226)、15.2%(186/1226)、5.7%(70/1226)、0.5%(6/1226)例;在年龄和初复治情况分布差异均有统计学意义(χ^(2)=14.95,P=0.020;χ^(2)=15.91,P=0.001);在RR-TB患者菌株中LFX、MFX、BDQ和LZD耐药率分别为27.5%(70/255)、27.5%(70/255)、0.4%(1/255)、2.4%(6/255);LFX、MFX和LZD敏感菌MIC主要集中在0.25 mg/L,BDQ敏感菌MIC主要集中在0.03 mg/L;同时对LFX和MFX均耐药的菌株有25.1%(64/255),单耐LFX和单耐MFX菌株均为6例,呈不完全双向交叉耐药;研究检出1株耐BDQ菌株,6株耐LZD菌株;RR-TB患者治疗成功率为74.4%(151/203),含LFX的方案中耐药和敏感患者治疗转归差异有统计学意义(Fisher′s精确检验,P=0.012)。结论利福平耐药MTB氟喹诺酮类药物(LFX和MFX)耐药形势严峻;LFX和MFX呈不完全双向交叉耐药;抗结核新药BDQ和LZD目前耐药率不高,有广阔的临床应用前景;加强耐药检测将有助于进一步提高治疗成功率。

Objective To summarize the resistance of rifampicin-resistant Mycobacterium tuberculosis to anti-tuberculosis drugs in group A.Methods In the retrospective study,a total of 1226 clinical isolates from suspected multidrug-resistant pulmonary tuberculosis patients in Beijing TB control system from 2016 to 2021 were identified as Mycobacterium tuberculosis(MTB)strains by MPB64 antigen detection test.Rifampicin-resistant tuberculosis(RR-TB)strains were screened by the phenotypic drug susceptibility using the proportion method.The drug susceptibilities of Levofloxacin(LFX),Moxifloxacin(MFX),Bedaquiline(BDQ)and Linezolid(LZD)were detected by the phenotypic drug susceptibility with microplate method.The drug resistance rate,drug resistance level and minimum inhibitory concentration(MIC)distribution of four anti-tuberculosis drugs in group A were analyzed.We calculated the demographic distribution of RR-TB,multidrug-resistant tuberculosis(MDR-TB),pre-extensively drug resistant tuberculosis(pre-XDR-TB),extensively drug resistant tuberculosis(XDR-TB)patients and the cross resistance of LFX and MFX,then summarized the drug-resistance spectrum of BDQ-resistant and LZD-resistant strains and the treatment outcome of RR-TB patients.Measurement data were expressed as rate or composition ratio,χ^(2)test was used between and within groups,and P<0.05 was considered statistically significant.Results Among the 1226 suspected multidrug-resistant pulmonary tuberculosis patients,the detection rates of RR/MDR/pre-XDR/XDR-TB patients were 20.8%(255/1226),15.2%(186/1226),5.7%(70/1226),0.5%(6/1226),respectively.There were statistically significant differences in the distribution of patients with the four types of drug resistance in terms of age and treatment history(χ^(2)=14.95,P=0.020;χ^(2)=15.91,P=0.001).The drug resistance rates of LFX,MFX,BDQ and LZD in RR-TB patients were 27.5%(70/255),27.5%(70/255),0.4%(1/255)and 2.4%(6/255),respectively.The MICs of LFX,MFX and LZD-susceptible MTB were mainly at 0.25 mg/L,and the MIC of BDQ-susceptible MTB was mainly concentrated at 0.03 mg/L.25.1%(64/255)of the RR MTB were resistant to both LFX and MFX,and 6 strains were resistant to LFX or MFX,showing incomplete two-way cross resistance.One BDQ-resistant strain and six LZD-resistant strains were detected.The treatment success rate of RR-TB patients was 74.4%(151/203),and there were statistically significant differences in treatment outcomes between resistant and sensitive patients on the LFX-containing treatment regimen(Fisher′s exact test,P=0.012).Conclusions The prevalence of fluoroquinolones(LFX and MFX)resistance in rifampicin-resistant MTB is very serious.LFX and MFX show incomplete bidirectional cross-resistance.BDQ and LZD have the most promising future in the treatment of MDR-TB.Improve drug-resistance testing will help to further improve the success rate of treatment.