title: Catalase expression, katG, and MIC of isoniazid for Mycobacterium tuberculosis isolates from São Paulo, Brazil.
abstract: The MIC of isoniazid, peroxidase-catalase expression, and the presence of the katG gene for 102 Mycobacterium tuberculosis isolates from patients in São Paulo were compared. Fifty-three isoniazid-resistant and 49 isoniazid-sensitive isolates were analyzed by polymerase chain reaction (PCR) for the presence of katG sequences. All isoniazid-sensitive and 43 (81%) isoniazid-resistant isolates expressed catalase (P = .001). None of isoniazid-sensitive and 4 (7%) of 53 isoniazid-resistant isolates lacked katG sequences. Among 6 isolates with MICs > 50 micrograms/mL, 5 (83%) did not express catalase and 2 lacked katG sequences; only 1 had complete gene deletion shown by Southern blot analysis. These findings indicate a correlation between loss of catalase and isoniazid resistance among highly resistant isolates, but these isolates were a small proportion of resistant clinical M. tuberculosis isolates from São Paulo.
authors.affiliation: Setor de Micobacterias, Instituto Adolfo Lutz, São Paulo, Brazil.
authors.forename: L
authors.initials: L
authors.lastname: Ferrazoli
authors.forename: M
authors.initials: M
authors.lastname: Palaci
authors.forename: M A
authors.initials: MA
authors.lastname: Telles
authors.forename: S Y
authors.initials: SY
authors.lastname: Ueki
authors.forename: A
authors.initials: A
authors.lastname: Kritski
authors.forename: L R
authors.initials: LR
authors.lastname: Marques
authors.forename: O C
authors.initials: OC
authors.lastname: Ferreira
authors.forename: L W
authors.initials: LW
authors.lastname: Riley
mesh_terms: D001426:Bacterial Proteins; D001483:Base Sequence; D015139:Blotting, Southern; D001938:Brazil; D002374:Catalase / Q000235:genetics*; D017931:DNA Primers; D004352:Drug Resistance, Microbial; D005798:Genes, Bacterial; D006801:Humans; D007538:Isoniazid / Q000494:pharmacology*; D008969:Molecular Sequence Data; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification; D010544:Peroxidases / Q000235:genetics*; D016133:Polymerase Chain Reaction; D014397:Tuberculosis, Pulmonary / Q000382:microbiology
chemical_list: D001426:Bacterial Proteins; D017931:DNA Primers; D010544:Peroxidases; D002374:Catalase; C076136:catalase HPI; D007538:Isoniazid