Genotypic characterization of macrolide-resistant strains of Streptococcus pneumoniae isolated in Quebec, Canada, and in vitro activity of ABT-773 and telithromycin

• Published in: Journal of antimicrobial chemotherapy 2002-09, Vol.50 (3), p.403-406
• Main Authors: Weiss, K., Guilbault, C., Cortes, L., Restieri, C., Low, D. E.
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Anti-Bacterial Agents - pharmacology; Child; Drug Resistance, Bacterial; Erythromycin - analogs & derivatives; Erythromycin - pharmacology; Female; Genes, Bacterial - genetics; Genotype; Humans; Ketolides; Macrolides; Male; Microbial Sensitivity Tests; Pneumococcal Infections - drug therapy; Pneumococcal Infections - epidemiology; Pneumococcal Infections - microbiology; Quebec - epidemiology; Streptococcus pneumoniae - drug effects; Streptococcus pneumoniae - genetics; Streptococcus pneumoniae - isolation & purification
• ISSN: 0305-7453; 1460-2091; 1460-2091
• DOI: 10.1093/jac/dkf146

Increasing resistance of Streptococcus pneumoniae to macrolides represents a challenge for clinicians. New ketolides have an enhanced activity against macrolide-resistant strains. Four hundred and seventy-four strains of S. pneumoniae were collected during the 2000–2001 season in Quebec through a surveillance network. Macrolide resistance was 20.2%, and significantly higher in non-invasive strains versus invasive ones (22.4% versus 14.8%), and in children (30%) versus adults (14.8%). For susceptible strains, MIC90s of ABT-773 and telithromycin were 0.008 and 0.015 mg/L. Among the 96 macrolide-resistant strains, 56 (58%) were erm(B), 35 (37%) carried the mef(A) gene, four were carrying both genes and one none. ABT-773 and telithromycin were very active against all these resistant strains irrespective of the resistance mechanism, with MIC90s of 0.25 and 0.5 mg/L, respectively.