[Investigation of drug-resistance to rifampin and rpoB gene sequence analysis of Mycobacterium abscessus].
OBJECTIVE
To observe the resistance of Mycobacterium abscessus to rifampin and to investigate if there is any mutation of rpoB gene in strains with high minimal inhibitory concentration (MIC).


METHODS
Mycobacterium abscessus was identified with both biochemical methods and PCR-RFLP. The MICs of rifampin to all the clinical strains and the type strain ATCC19977 were determined. DNA sequences were obtained from a 1272 bp fragment of the rpoB gene from either low or high rifampin MIC strains using PCR amplification.


RESULTS
Only one strain had low MICs of 4 microg/ml. MICs of all the other 14 strains, as well as the type stain were above 128-256 microg/ml. Although there were some differences in nucleotide sequence of rpoB gene, all strains had the same amino acid sequence without any mutations.


CONCLUSIONS
Mycobacterium abscessus showed a high resistance to rifampin. Mutations of rpoB gene do not seem to be the responsible mechanism.
Sha
Wei
W
Department of Tuberculosis, Pneumology Hospital, Shanghai 200433, China.
Weng
Xin-hua
XH
Xiao
He-ping
HP
He
Guo-jun
GJ
D000904:Antibiotics, Antitubercular / Q000494:pharmacology*; D012321:DNA-Directed RNA Polymerases / Q000235:genetics*; D024881:Drug Resistance, Bacterial; D016926:Mycobacterium chelonae / Q000187:drug effects* / Q000235:genetics; D012293:Rifampin / Q000494:pharmacology*
D000904:Antibiotics, Antitubercular; D012321:DNA-Directed RNA Polymerases; C105078:RNA polymerase beta subunit; D012293:Rifampin