title: Variations in the occurrence of specific rpoB mutations in rifampicin-resistant Mycobacterium tuberculosis isolates from patients of different ethnic groups in Kuwait.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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%).
  
  
  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.
authors: Department of Microbiology, Faculty of Medicine, Kuwait University, Kuwait.
authors: Suhail
authors: S
authors: Ahmad
authors: Noura M
authors: NM
authors: Al-Mutairi
authors: Eiman
authors: E
authors: Mokaddas
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D001426:Bacterial Proteins / Q000235:genetics*; D012321:DNA-Directed RNA Polymerases; D005006:Ethnicity / Q000235:genetics; D006801:Humans; D007730:Kuwait; D009154:Mutation; D009169:Mycobacterium tuberculosis / Q000235:genetics* / Q000472:pathogenicity; D012293:Rifampin / Q000627:therapeutic use; D017422:Sequence Analysis, DNA; D018088:Tuberculosis, Multidrug-Resistant / Q000188:drug therapy / Q000208:ethnology / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; C505805:rpoB protein, Mycobacterium tuberculosis; D012321:DNA-Directed RNA Polymerases; D012293:Rifampin