title: High prevalence of KatG Ser315Thr substitution among isoniazid-resistant Mycobacterium tuberculosis clinical isolates from northwestern Russia, 1996 to 2001.
abstract: A total of 204 isoniazid (INH)-resistant strains of Mycobacterium tuberculosis isolated from different patients in the northwestern region of Russia from 1996 to 2001 were screened by a PCR-restriction fragment length polymorphism (RFLP) assay. This assay uses HapII cleavage of an amplified fragment of the katG gene to detect the transversion 315AGC-->ACC (Ser-->Thr), which is associated with INH resistance. This analysis revealed a 93.6% prevalence of the katG S315T mutation in strains from patients with both newly and previously diagnosed cases of tuberculosis (TB). This mutation was not found in any of 57 INH-susceptible isolates included in the study. The specificity of the assay was 100%; all isolates that contained the S315T mutation were classified as resistant by a culture-based susceptibility testing method. The Beijing genotype, defined by IS6110-RFLP analysis and the spacer oligonucleotide typing (spoligotyping) method, was found in 60.3% of the INH-resistant strains studied. The katG S315T shift was more prevalent among Beijing genotype strains than among non-Beijing genotype strains: 97.8 versus 84.6%, respectively, for all isolates, including those from patients with new and previously diagnosed cases, isolated from 1999 to 2001 and 100.0 versus 86.5%, respectively, for isolates from patients with new cases isolated from 1996 to 2001. The design of this PCR-RFLP assay allows the rapid and unambiguous identification of the katG 315ACC mutant allele. The simplicity of the assay permits its implementation into routine practice in clinical microbiology laboratories in regions with a high incidence of TB where this mutation is predominant, including northwestern Russia.
authors.affiliation: Laboratory of Molecular Microbiology, St. Petersburg Pasteur Institute, St. Petersburg, Russia. miv@IM4520.spb.edu
authors.forename: Igor
authors.initials: I
authors.lastname: Mokrousov
authors.forename: Olga
authors.initials: O
authors.lastname: Narvskaya
authors.forename: Tatiana
authors.initials: T
authors.lastname: Otten
authors.forename: Elena
authors.initials: E
authors.lastname: Limeschenko
authors.forename: Lidia
authors.initials: L
authors.lastname: Steklova
authors.forename: Boris
authors.initials: B
authors.lastname: Vyshnevskiy
mesh_terms: D000293:Adolescent; D000328:Adult; D019943:Amino Acid Substitution; D000995:Antitubercular Agents / Q000494:pharmacology*; D001426:Bacterial Proteins; D004269:DNA, Bacterial / Q000032:analysis; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D006801:Humans; D007538:Isoniazid / Q000494:pharmacology*; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000145:classification / Q000187:drug effects* / Q000302:isolation & purification; D010544:Peroxidases / Q000235:genetics*; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D015995:Prevalence; D012426:Russia / Q000453:epidemiology; D012694:Serine; D013912:Threonine; D014397:Tuberculosis, Pulmonary / Q000453:epidemiology / Q000382:microbiology
chemical_list: D000995:Antitubercular Agents; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D013912:Threonine; D012694:Serine; D010544:Peroxidases; C076136:catalase HPI; D007538:Isoniazid