背景:耐多药结核病(MDR-TB)已成为全球主要的公共卫生问题。一线和二线药物靶标如katG的突变,inhA,rpoB,rrs,eis,gyra,gyrB与耐药有关。监测耐多药结核病患者群体中的主要突变对于监测和设计未来的治疗方案至关重要。本研究旨在表征印度东部人群中结核分枝杆菌(MTB)杆菌的MDR分离株中的基因突变,该突变对二线抗结核药物具有耐药性。
方法:这项横断面研究是在微生物学系进行的,英迪拉·甘地医学科学研究所,巴特那,比哈尔邦,在结核病示范和培训中心,阿甘宽,巴特那该研究共招募了3270名怀疑患有MDR-TB的患者。两份痰样本,一个在现场,早上收集每位患者的另一个,并通过Gene-Xpert检验诊断为利福平敏感(RS)/利福平耐药(RR/MDR)TB。150个RS-TB样品和150个RR/MDR-TB样品被考虑用于线探针测定(LPA)。使用Genotype®MTBDRPlusver2.0对RS样品进行一线LPA,并且使用Genotype®MTBDRslver2.0对RR/MDR样品进行二线LPA考虑。使用Ziehl-Neelsen染色法对所有痰样品进行痰涂片显微镜检查。统计分析是使用社会科学统计软件包(SPSS)26.0版(IBMCorp.Armonk,纽约)和R(4.1版;R核心团队2021)。
结果:在本研究中,在3270名患者中,我们在235例患者中检测到RR/MDR-TB(7.19%),812例患者的RS-TB(24.83%),其余患者MTB阴性(2223,67.98%)。在测试的150例RR/MDR-TB痰样本中,在41个样品中观察到对氟喹诺酮(FQ)的抗性。由于gyrA基因突变,所选择的患者主要具有FQ抗性(97.56%,n=40)与gyrB基因突变(2.44%,n=1)。我们在密码子94(MUT3C(D94G)中观察到>60%的gyrA基因突变,MUT3A(D94A),和MUT3D(D94H)。此外,我们在考虑的MTB患者人群中,在gyrA基因的密码子90和91中发现了突变MUT1(A90V)和MUT2(S91P).
结论:鉴定的基因可以进一步验证,以被视为治疗靶标。但更多的治疗方法和先进的策略应应用于MTB的管理。
BACKGROUND: Multi-drug-resistant tuberculosis (MDR-TB) has become a major public health concern globally. Mutations in first- and second-line drug targets such as katG, inhA, rpoB, rrs, eis, gyrA, and
gyrB have been associated with drug resistance. Monitoring predominant mutations in the MDR-TB patient population is essential to monitor and devise future therapeutic regimes. The present study is aimed to characterize genetic mutations in MDR isolates of Mycobacterium tuberculosis (MTB) bacilli conferring resistance to a second-line anti-tuberculosis drug in the Eastern Indian population.
METHODS: This cross-sectional study was conducted in the Department of Microbiology, Indira Gandhi Institute of Medical Sciences, Patna, Bihar, and in the Tuberculosis Demonstration & Training Centre, Agamkuan, Patna. A total of 3270 patients suspected to have MDR-TB were recruited in the study. Two sputum samples, one on the spot, and the other in the morning were collected from each patient and the diagnosis of rifampicin-sensitive (RS)/rifampicin-resistant (RR/MDR) TB was done by Gene-Xpert test. One hundred fifty RS-TB samples and 150 RR/MDR-TB samples were considered for line probe assay (LPA). RS samples were subjected to first-line LPA using Genotype® MTBDR Plus ver 2.0 and RR/MDR samples were considered for second-line LPA using Genotype® MTBDRsl ver 2.0. All sputum samples were subjected to sputum smear microscopy using the Ziehl-Neelsen staining method. Statistical analysis was done using Statistical Package for Social Sciences (SPSS) version 26.0 (IBM Corp. Armonk, NY) and R (version 4.1; R Core Team 2021).
RESULTS: In the present study, out of 3270 patients, we detected RR/MDR-TB in 235 patients (7.19%), RS-TB in 812 patients (24.83%), the rest of the patients negative for MTB (2223, 67.98%). Out of 150 RR/MDR-TB sputum samples tested, resistance to fluoroquinolone (FQ) was observed in 41 samples. The selected patients had predominantly FQ resistance due to the gyrA gene mutations (97.56%, n=40) compared to the
gyrB gene mutations (2.44%, n=1). We observed >60% of the mutations in the gyrA gene in codon 94 (MUT3C (D94G), MUT3A (D94A), and MUT3D (D94H). In addition, we found the mutations MUT1 (A90V) and MUT2 (S91P) in the codons 90 and 91 of the gyrA gene in the considered MTB patient population.
CONCLUSIONS: The identified genes can be further validated to be considered as therapeutic targets, but more therapeutics and advanced strategies should be applied in the management of MTB.