Levofloxacin-Resistant Invasive Streptococcus pneumoniae in the United States: Evidence for Clonal Spread and the Impact of Conjugate Pneumococcal Vaccine

摘要: The emergence of fluoroquinolone resistance in sterile-site isolates Streptococcus pneumoniae is documented this study characterizing all invasive levofloxacin-resistant (MIC, > or = 8 mg/liter) S. (n 50) obtained from the Centers for Disease Control and Prevention Active Bacterial Core Surveillance 1998 to 2002. Resistance among increased 0.1% 0.6% 2001 (P 0.008) but decreased 0.4% 2002, while vaccine serotypes continued increase 0.3% 1.0% suggesting that fluoroquinolones continue exert selective pressure on these serotypes. Only 22% resistant were not covered by conjugate serogroups. Multilocus sequence typing revealed 58% strains related five international clones identified Pneumococcal Molecular Epidemiology Network, with Spain(23F)-1 clone being most frequent (16% isolates). Thirty-six percent coresistant penicillin, 44% macrolides, 28% multiresistant fluoroquinolones. Fifty any three drug classes. Ninety-four had multiple mutations quinolone resistance-determining regions gyrA, gyrB, parC, parE genes. In 16% isolates, there was evidence an active efflux mechanism. An unusual isolate found showed only a single mutation which ciprofloxacin MIC lower (2 than levofloxacin (8 mg/liter). Our results suggest pneumococcal United States show considerable clonal spread.