Susceptibilities to telithromycin and six other agents and prevalence of macrolide resistance due to L4 ribosomal protein mutation among 992 Pneumococci from 10 central and Eastern European countries.

The macrolide and levofloxacin susceptibilities of 992 isolates of Streptococcus pneumoniae from clinical specimens collected in 1999 and 2000 were determined in 10 centers in Central and Eastern European countries. The prevalences of penicillin G-intermediate (MICs, 0.125 to 1 μg/ml) and penicillin-resistant (MICs, ≤2 μg/ml) Streptococcus pneumoniae isolates were 14.3 and 16.6%, respectively. The MICs at which 50% of isolates are inhibited (MIC50s) and the MIC90s of telithromycin were 0.016 and 0.06 μg/ml, respectively; those of erythromycin were 0.06 and >64 μg/ml, respectively; those of azithromycin were 0.125 and >64 μg/ml, respectively; those of clarithromycin were 0.03 and >64 μg/ml, respectively; and those of clindamycin were 0.06 and >64 μg/ml, respectively. Erythromycin resistance was found in 180 S. pneumoniae isolates (18.1%); the highest prevalence of erythromycin-resistant S. pneumoniae was observed in Hungary (35.5%). Among erythromycin-resistant S. pneumoniae isolates, strains harboring erm(B) genes (125 strains [69.4%]) were found to be predominant over strains with mef(E) genes (25 strains [13.4%]), L4 protein mutations (28 strains [15.6%]), and erm(A) genes (2 strains [1.1%]). Similar pulsed-field gel electrophoresis patterns suggested that some strains containing L4 mutations from the Slovak Republic, Bulgaria, and Latvia were clonally related. Of nine strains highly resistant to levofloxacin (MICs, >8 μg/ml) six were isolated from Zagreb, Croatia. Telithromycin at ≤0.5 μg/ml was active against 99.8% of S. pneumoniae isolates tested and may be useful for the treatment of respiratory tract infections caused by macrolide-resistant S. pneumoniae isolates.