Comparison of drug resistance genotypes between Beijing and non-Beijing family strains of Mycobacterium tuberculosis in Korea.

Abstract The frequency of resistance genotypes among Beijing and non-Beijing strains was compared using a reverse blot hybridization assay to detect mutations within genes associated with rifampicin ( rpoB ) and isoniazid ( katG , inhA , and ahpC ) resistance. Of the 743 Mycobacterium tuberculosis isolates, 569 (77%) belonged to Beijing family. The proportion of Beijing strains was significantly higher among MDR-TB isolates than among drug-susceptible strains (82% vs. 72%, p rpoB gene revealed significantly lower rates of the Ser531Leu mutation rate among Beijing vs. non-Beijing MDR-TB strains (41% vs. 66%, p katG gene was more common among Beijing vs. non-Beijing family strains (65% vs. 50%, p inhA gene was lower among Beijing strains compared with non-Beijing strains (14% vs. 25%, p Significant differences in mutation rates in the rpoB , katG , and inhA genes between Beijing strains and non-Beijing strains could explain discrepancies in mutation rates of genotypes in different countries. Reverse hybridization was useful for rapid detection of isoniazid and rifampicin resistant strains.