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Levofloxacin-resistant invasive Streptococcus pneumoniae in the United States: evidence for clonal spread and the impact of conjugate pneumococcal vaccine.
- Source :
-
Antimicrobial agents and chemotherapy [Antimicrob Agents Chemother] 2004 Sep; Vol. 48 (9), pp. 3491-7. - Publication Year :
- 2004
-
Abstract
- The emergence of fluoroquinolone resistance in sterile-site isolates of Streptococcus pneumoniae is documented in this study characterizing all invasive levofloxacin-resistant (MIC, > or = 8 mg/liter) S. pneumoniae isolates (n = 50) obtained from the Centers for Disease Control and Prevention Active Bacterial Core Surveillance from 1998 to 2002. Resistance among all isolates increased from 0.1% in 1998 to 0.6% in 2001 (P = 0.008) but decreased to 0.4% in 2002, while resistance among vaccine serotypes continued to increase from 0.3% in 1998 to 1.0% in 2002, suggesting that fluoroquinolones continue to exert selective pressure on these vaccine serotypes. Only 22% of resistant isolates were not covered by the conjugate vaccine serogroups. Multilocus sequence typing revealed that 58% of resistant strains were related to five international clones identified by the Pneumococcal Molecular Epidemiology Network, with the Spain(23F)-1 clone being most frequent (16% of all isolates). Thirty-six percent of the isolates were coresistant to penicillin, 44% were coresistant to macrolides, and 28% were multiresistant to penicillin, macrolides, and fluoroquinolones. Fifty percent of the isolates were resistant to any three drug classes. Ninety-four percent of the isolates had multiple mutations in the quinolone resistance-determining regions of the gyrA, gyrB, parC, and parE genes. In 16% of the isolates, there was evidence of an active efflux mechanism. An unusual isolate was found that showed only a single parE mutation and for which the ciprofloxacin MIC was lower (2 mg/liter) than that of levofloxacin (8 mg/liter). Our results suggest that invasive pneumococcal isolates resistant to levofloxacin in the United States show considerable evidence of multiple resistance and of clonal spread.
- Subjects :
- Anti-Bacterial Agents metabolism
Drug Resistance, Bacterial
Electrophoresis, Gel, Pulsed-Field
Genes, Bacterial genetics
Humans
Microbial Sensitivity Tests
Molecular Sequence Data
Multigene Family
Mutation genetics
Ofloxacin metabolism
Pneumococcal Infections prevention & control
Population Surveillance
Reverse Transcriptase Polymerase Chain Reaction
Serotyping
Streptococcus pneumoniae genetics
Streptococcus pneumoniae metabolism
United States epidemiology
Vaccines, Conjugate
Anti-Bacterial Agents pharmacology
Levofloxacin
Ofloxacin pharmacology
Pneumococcal Infections epidemiology
Pneumococcal Infections microbiology
Pneumococcal Vaccines therapeutic use
Streptococcus pneumoniae drug effects
Subjects
Details
- Language :
- English
- ISSN :
- 0066-4804
- Volume :
- 48
- Issue :
- 9
- Database :
- MEDLINE
- Journal :
- Antimicrobial agents and chemotherapy
- Publication Type :
- Academic Journal
- Accession number :
- 15328116
- Full Text :
- https://doi.org/10.1128/AAC.48.9.3491-3497.2004