title: Characterization of rpoB mutations in rifampin-resistant Mycobacterium tuberculosis isolates from the Middle East.
abstract: The nature and frequency of mutations in the rpoB gene of rifampin-resistant clinical Mycobacterium tuberculosis isolates vary considerably according to geographical locations. There is no information on the prevalence of specific mutations in clinical M. tuberculosis strains isolated from patients in Middle-Eastern countries. In this study, 13 rifampin-resistant and 6 susceptible clinical M. tuberculosis isolates were tested for identification and characterization of mutations in the rpoB gene by INNO-LiPA Rif. TB kit and DNA sequencing of the PCR amplified target DNA. The kit identified all six susceptible strains as rifampin-sensitive and the DNA sequence of the amplified rpoB gene in the target region matched perfectly with the wild-type sequence. The kit identified 12 resistant isolates as rifampin-resistant with specific detection of mutations in 8 isolates while one of the rifampin-resistant strain was identified as rifampin-susceptible. DNA sequencing confirmed these results and, in addition, led to the specific detection of mutations in 4 rifampin-resistant isolates in which specific base changes within the target region could not be determined by the INNO-LiPA Rif. TB kit. The majority (8 of 13) of resistant isolates involved base changes at codon 531 of the rpoB gene. Mutations at codon position 531 within the rpoB gene have also been reported in majority of rifampin-resistant strains from Greece and St. Petersburg, Russia but not from other geographical locations.
authors.affiliation: Department of Microbiology, Faculty of Medicine, Kuwait University, P.O. Box 24923, Safat 13110, Kuwait. suhail_ah@hsc.kuniv.edu.kw
authors.forename: S
authors.initials: S
authors.lastname: Ahmad
authors.forename: G F
authors.initials: GF
authors.lastname: Araj
authors.forename: P K
authors.initials: PK
authors.lastname: Akbar
authors.forename: E
authors.initials: E
authors.lastname: Fares
authors.forename: T D
authors.initials: TD
authors.lastname: Chugh
authors.forename: A S
authors.initials: AS
authors.lastname: Mustafa
mesh_terms: D000904:Antibiotics, Antitubercular / Q000494:pharmacology*; D001483:Base Sequence; D012321:DNA-Directed RNA Polymerases / Q000235:genetics*; D004352:Drug Resistance, Microbial / Q000235:genetics; D005798:Genes, Bacterial; D006801:Humans; D015336:Molecular Probe Techniques; D008969:Molecular Sequence Data; D009154:Mutation; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000235:genetics; D016133:Polymerase Chain Reaction; D012293:Rifampin / Q000494:pharmacology*; D017422:Sequence Analysis, DNA; D014397:Tuberculosis, Pulmonary / Q000382:microbiology
chemical_list: D000904:Antibiotics, Antitubercular; D012321:DNA-Directed RNA Polymerases; C105078:RNA polymerase beta subunit; D012293:Rifampin