Description of new mutations in the rpoB gene in rifampicin-resistant Neisseria meningitidis selected in vitro in a stepwise manner

Abstract

Fourteen meningococcal strains were selected towards rifampicin resistance in a stepwise manner in vitro; final MICs were between 8 and >256 μg ml−1. Sequence analysis of a 295 bp subgenic fragment of the RNA polymerase β-subunit (rpoB) gene from the original and the fully resistant strains revealed that, with one exception, the strain pairs differed by just one position in the deduced amino acid sequence. Transformation of a PCR-amplified subgenic rpoB fragment harbouring the mutated site into a susceptible strain demonstrated the resistance-conferring mechanism.