OBJECTIVE To determine the mechanism of rifampicin resistance in Streptococcus pneumoniae in Taiwan. METHODS Rifampicin resistance was investigated with respect to the rpoB gene in 23 invasive S. pneumoniae isolates collected from 1996 to 2001. PCR and molecular typing were used for genetic and epidemiological analyses. Transformation was used to determine the functional gene for resistance. ...

High-level methicillin-resistant Staphylococcus aureus (MRSA) isolates show rapid evolution of rifampicin resistance, forcing reliance upon expensive and often inferior antibiotics to manage these infections. Accordingly, this study was conducted to: 1) evaluate the level of multidrug resistance among hospital-associated MRSA isolates from Chennai, India; 2) determine their rifampicin resistanc...

The thermosensitivity of the Escherichia coli dnaR130 mutant in initiation of DNA replication was suppressed by a spontaneous rifampin resistance mutation in rpoB, the gene for the beta subunit of RNA polymerase. Among the dnaR-suppressing rpoB alleles obtained was rpoB22, which was able to suppress the thermosensitivity of the dnaA46 or dnaA167 mutant, but not that of the dnaA5 mutant, in init...

INTRODUCTION It is perceived wisdom that within the host macrophage, Mycobacterium tuberculosis frequently encounters oxidative stress. Exposure of bacteria to reactive oxygen intermediates can have a mutagenic effect on the DNA. Various mutations are thought to arise as a consequence, including the oxidation of guanine residues, leading to G?C-->T?A substitution, and oxidation of cytosine resu...

The temporal change of phenotypes during the adaptive process remains largely unexplored, as do the genetic changes that affect these phenotypic changes. Here we focused on three mutations that rose to high frequency in the early stages of adaptation within 12 Escherichia coli populations subjected to thermal stress (42 °C). All the mutations were in the rpoB gene, which encodes the RNA polymer...

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...

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...

Rifampin is the most potent drug used in the treatment of disease due to Mycobacterium kansasii. A 69-bp fragment of rpoB, the gene that encodes the beta subunit of the bacterial RNA polymerase, was sequenced and found to be identical in five rifampin-susceptible clinical isolates of M. kansasii. This sequence showed 87% homology with the Mycobacterium tuberculosis gene, with an identical deduc...