Catalase expression, katG, and MIC of isoniazid for Mycobacterium tuberculosis isolates from São Paulo, Brazil.
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.
Ferrazoli
L
L
Setor de Micobacterias, Instituto Adolfo Lutz, São Paulo, Brazil.
Palaci
M
M
Telles
M A
MA
Ueki
S Y
SY
Kritski
A
A
Marques
L R
LR
Ferreira
O C
OC
Riley
L W
LW
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
D001426:Bacterial Proteins; D017931:DNA Primers; D010544:Peroxidases; D002374:Catalase; C076136:catalase HPI; D007538:Isoniazid