High Prevalence of the ermB Gene among Erythromycin-Resistant Streptococcus pneumoniae Isolates in Germany during the Winter of 2000-2001 and In Vitro Activity of Telithromycin

Of 595 isolates of Streptococcus pneumoniae from outpatients with respiratory tract infections, collected from 17 microbiology laboratories, 14.1 % were resistant to erythromycin. Eighty-three erythromycin-resistant iso-lates were genetically analyzed, 83.1 % of which harbored the ermB gene. Only four isolates (4.8%) harbored the mefA gene. Telithromycin exhibited potent activity against all isolates. The two most common mechanisms of macrolide resistance among Streptococcus pneumoniae isolates are efflux of the drug mediated by a transport protein encoded by the mefA (subclass mefE) gene and target-site modification due to a methylase encoded by the ermB gene (subclass ermAM) (15, 20). Isolates harboring the mefA gene display low-level resistance to 14- and 15-membered-ring macrolides, whereas isolates with the ermB genotype display high-level resistance to all macrolides, linco-samides, and group B streptogramins (2, 6, 15). Telithromycin, the first compound of the ketolide class, is highly active against pneumococcal isolates, including both ermB- and mefA-mediated macrolide-resistant isolates (4, 7