Drug efflux and parC mutations are involved in fluoroquinolone resistance in viridans group streptococci.

ABSTRACT: Nine ciprofloxacin-resistant viridans group streptococci isolated from asymptomatic carriers were analyzed. Identification to the species level by using three different commercial systems and a PCR-based approach was inconsistent. The nucleotide sequences of fragments of the parC, parE, gyrA, and gyrB genes showed considerable intra- and interspecies variations, and these variations mainly involved silent mutations. Three isolates had changes in Ser-79 of ParC (to Phe or Tyr). Phenotypic characterization indicated that eight of the nine isolates had a putative efflux mechanism that would confer low-level resistance to ciprofloxacin.

SUBMITTER: Ferrandiz MJ 

PROVIDER: S-EPMC89512 | biostudies-literature | 1999 Oct

REPOSITORIES: biostudies-literature