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 1 226 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,χ2 test was used between and within groups, and P<0.05 was considered statistically significant. Results: Among the 1 226 suspected multidrug-resistant pulmonary tuberculosis patients, the detection rates of RR/MDR/pre-XDR/XDR-TB patients were 20.8%(255/1 226), 15.2%(186/1 226), 5.7%(70/1 226), 0.5%(6/1 226), 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 (χ2=14.95, P=0.020;χ2=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.
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1 226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χ2检验，以P<0.05为差异有统计学意义。 结果： 1 226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%（255/1 226）、15.2%（186/1 226）、5.7%（70/1 226）、0.5%（6/1 226）例；在年龄和初复治情况分布差异均有统计学意义（χ2=14.95，P=0.020；χ2=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。.