Department of Microbiology, Faculty of Medicine, Kuwait University, Kuwait.
Indian J Med Res. 2012 May;135(5):756-62.
BACKGROUND & OBJECTIVES: Frequency of resistance-conferring mutations vary among isoniazid- and ethambutol-resistant Mycobacterium tuberculosis isolates obtained from patients of various ethnic groups. This study was aimed to determine the occurrence of specific rpoB mutations in rifampicin-resistant M. tuberculosis isolates from tuberculosis patients of various ethnic groups in Kuwait.
Rifampicin-resistant M. tuberculosis isolates (n=119) from South Asian (n=55), Southeast Asian (n=23), Middle Eastern (n=39) and other (n=2) patients and 107 rifampicin-susceptible isolates were tested. Mutations in rpoB were detected by DNA sequencing. Polymorphisms at katG463 and gyrA95 were detected by PCR-RFLP for genetic group assignment.
None of rifampicin-susceptible but 116 of 119 rifampicin-resistant isolates showed rpoB mutation(s). Mutations among isolates from South Asian patients were distributed at rpoB516 (20%), rpoB526 (24%) and rpoB531 (27%) while 78 and 51 per cent of isolates from Southeast Asian and Middle Eastern patients, respectively, contained a mutated rpoB531. All isolates with rpoB N-terminal and cluster II mutations were obtained from Middle Eastern and South Asian patients. Most isolates from South Asian (84%) and Southeast Asian (70%) patients belonged to genetic group I while nearly all remaining isolates belonged to genetic group II. Isolates from Middle Eastern patients were distributed among genetic group I (46%), genetic group II (33%) and genetic group III (21%).
INTERPRETATION & CONCLUSIONS: The occurrence of specific rpoB mutations varied considerably in rifampicin-resistant M. tuberculosis isolates obtained from patients of different ethnic groups within the same country. The present data have important implications for designing region-specific rapid methods for detecting majority of rifampicin-resistant strains.
在来自不同种族结核病患者的异烟肼和乙胺丁醇耐药分枝杆菌分离株中，耐药相关突变的频率存在差异。本研究旨在确定科威特不同种族结核病患者的利福平耐药分枝杆菌分离株中 rpoB 特定突变的发生情况。
检测了来自南亚（n=55）、东南亚（n=23）、中东（n=39）和其他（n=2）患者的 119 株利福平耐药分枝杆菌分离株（n=119）和 107 株利福平敏感分离株。通过 DNA 测序检测 rpoB 突变。通过 PCR-RFLP 检测 katG463 和 gyrA95 多态性，用于遗传群分配。
119 株利福平耐药分离株中，除 107 株利福平敏感分离株外，其余均存在 rpoB 突变（s）。南亚患者分离株的突变分布在 rpoB516（20%）、rpoB526（24%）和 rpoB531（27%），而东南亚和中东患者分离株中 78%和 51%分别含有突变 rpoB531。所有 rpoB N 端和簇 II 突变的分离株均来自中东和南亚患者。来自南亚（84%）和东南亚（70%）患者的大多数分离株属于遗传群 I，而其余几乎所有分离株均属于遗传群 II。中东患者的分离株分布在遗传群 I（46%）、遗传群 II（33%）和遗传群 III（21%）。
在同一国家不同种族的结核病患者中，获得的利福平耐药分枝杆菌分离株中特定 rpoB 突变的发生情况差异很大。这些数据对于设计针对大多数利福平耐药株的特定地区快速检测方法具有重要意义。
