Spontaneous rifampicin-resistant (RFM(R)) mutants were isolated from Bacillus subtilis 168 cultivated in the presence or absence of oxygen. By DNA sequencing, the mutations were located within Cluster I of the rpoB gene encoding the β subunit of RNA polymerase. The spectrum of RFM(R) rpoB mutations isolated from B. subtilis cells grown anaerobically differed from aerobically grown cells, not on...

To investigate the possibility that the unusual dominant rifampicin-resistance characteristic of the rifd18 allele of E. coli rpoB is due to a secondary, regulatory mutation, we have determined the nucleotide sequence of a 1.1 Kbp wild-type DNA fragment, including the transcriptional attenuator and translational start-site of rpoB. We have also re-investigated the previously published sequences...

Mutations of the rpoB gene conferring resistance to rifampin were analyzed in 40 methicillin-resistant Staphylococcus aureus isolates obtained from six countries. Interestingly, the majority of clinical isolates showed multiple mutations within rpoB. The amino acid substitution 481His-->Asn was the most prevalent one, capable of conferring low-level resistance on its own. Cross-resistance to ri...

although mycoplasma equigenitalium has been implicated in equine reproductive problems, its prevalence is largely unexplored due to the lack of specific diagnostic tests. to address this limitation, the authors developed and optimized species-specific primer pairs that target m. eguigenitalium rpob (rna polymerase b subunit) gene sequences. the specificity of the pcr assay developed in this stu...

INTRODUCTION Tuberculosis remains the leading causes of death worldwide with frequencies of mutations in rifampicin and isoniazid resistant Mycobacterium tuberculosis isolates varying according to geographical location. There is limited information in Zimbabwe on specific antibiotic resistance gene mutation patterns in MTB and hence, increased rate of discordant results and mortality due to ina...

A recent article described rpoB mutations in 18 rifampinresistant variants of Legionella spp. (4). One of these 18 strains, isolate 8749, an in vitro-generated high-level rifampin-resistant (MIC $ 256 mg/ml) variant of K26, a susceptible clinical Legionella bozemanii isolate, was shown to harbor no codon exchange in the cluster I rpoB 69-bp hot spot, the DNA region investigated. Besides codon e...

Fourteen meningococcal strains were selected towards rifampicin resistance in a stepwise manner in vitro; final MICs were between 8 and >256 microg ml(-1). Sequence analysis of a 295 bp subgenic fragment of the RNA polymerase beta-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...