Rifampin and Rifabutin Resistance Mechanism in Helicobacter pylori

Eighty-one clinical isolates of Helicobacter pylori showed no resistance to rifampin (MIC range, 0.032 to 2 μg/ml; MIC at which 50% of isolates are inhibited [MIC(50)], 0.25 μg/ml). The MIC(50) of rifabutin was 0.008 μg/ml (n = 16). All resistant laboratory mutants of H. pylori ATCC 43504 showed amino acid exchanges in codons 524 to 545 or codon 585 of the rpoB gene, corresponding to the gene sequences from Mycobacterium tuberculosis and Escherichia coli.