Development of macrolide-resistance and comparative activity of telithromycin in streptococci in Austria, 1996-2002.

The increase detected in macrolide resistance in streptococci in various parts of the world has brought into question the usefulness of macrolides as first line therapy for respiratory tract infections. In a nationwide study, a total of 3012 Streptococcus pneumoniae and 499 Streptococcus pyogenes isolates were collected from 1996 to 2002 and tested for their susceptibility to penicillin, azithromycin, clarithromycin and telithromycin (2002 only). Penicillin-intermediate and -resistant isolates of S. pneumoniae comprised 4.9% (2.9 and 2.0%, respectively) of all isolates in 1996; macrolide resistance was also comparatively low at 3.2%. In the following years the rate of penicillin-resistant pneumococci increased steadily, reaching the 10% mark in 2002. A similar trend was recorded for the macrolides. No penicillin-resistant strain of S. pyogenes was found during the observation period. The prevalence of macrolide-resistance in S. pyogenes climbed from 4.7% in 1996 to the present rate of 7.2% (clarithromycin) and 9.4% (azithromycin). Telithromycin showed excellent activity against both S. pneumoniae and S. pyogenes with 99.8 and 100% strains sensitive, respectively.