[Relationship between catalase activity, KatG gene and isoniazid-resistance in M. tuberculosis].
OBJECTIVE
To investigate the relationship between catalase activity, KatG gene, gene mutation and INH-resistance in M. tuberculosis.


METHODS
Catalase activities in 58 M. tuberculosis isolates were tested, and KatG gene mutations were detected further by PCR-SSCP.


RESULTS
None of INH-sensitive isolates lacked KatG sequences and all expressed catalase. 8(25%) INH-resistant isolates did not express catalase and 3(10%) lacked KatG gene, most of which were strains of high levels of resistance (MIC > 50 micrograms/ml). 8 INH-resistant isolates were analyzed further by PCR-SSCP and all were found to have KatG gene mutation.


CONCLUSIONS
These findings indicated that lacking of catalase activity and KatG gene deletion occurred mainly in those highly INH-resistant strains, gene mutation other than complete deletion of KatG gene may be the major mechanism of INH-resistance.
Shenzheng Municipal Longgang Central Hospital, Shenzhen 518116.
X
X
Wang
Q
Q
Han
B
B
Liang
D000995:Antitubercular Agents / Q000494:pharmacology; D002374:Catalase / Q000378:metabolism*; D004352:Drug Resistance, Microbial; D005798:Genes, Bacterial / Q000235:genetics*; D007538:Isoniazid / Q000494:pharmacology*; D009169:Mycobacterium tuberculosis / Q000201:enzymology / Q000235:genetics; D017354:Point Mutation
D000995:Antitubercular Agents; D002374:Catalase; D007538:Isoniazid