Fluoroquinolone resistance in atypical pneumococci and oral streptococci: evidence of horizontal gene transfer of fluoroquinolone resistance determinants from Streptococcus pneumoniae.

ABSTRACT: Atypical strains, presumed to be pneumococcus, with ciprofloxacin MICs of > or =4.0 microg/ml and unique sequence variations within the quinolone resistance-determining regions (QRDRs) of the gyrase and topoisomerase genes in comparison with the Streptococcus pneumoniae R6 strain, were examined. These strains were reidentified using phenotypic methods, including detection of optochin susceptibility, bile solubility, and agglutination by serotype-specific antisera, and genotypic methods, including detection of pneumolysin and autolysin genes by PCR, 16S rRNA sequencing, and multilocus sequence typing (MLST). The analysis based on concatenated sequences of the six MLST loci distinguished the "atypical" strains from pneumococci, and these strains clustered closely with S. mitis. However, all

SUBMITTER: Ip M 

PROVIDER: S-EPMC1932522 | biostudies-literature | 2007 Aug

REPOSITORIES: biostudies-literature