Comparative activity of telithromycin against macrolide-resistant isolates of Streptococcus pneumoniae: Results of two years of the PROTEKT surveillance study

The increase in resistance to macrolides has been linked with increasing use of these agents as empirical therapy for community-acquired respiratory tract infections (CARTIs). As part of the ongoing PROTEKT (Prospective Resistant Organism Tracking and Epidemiology for the Ketolide Telithromycin) surveillance program, over 7600 Streptococcus pneumoniae isolates were collected worldwide from 1999-2001 and evaluated for macrolide resistance. Globally, macrolide resistance was 31-33%, with considerable inter-country variation (71%). In Europe, France had the most resistant isolates (>53%). The highest rates of macrolide resistance were seen in 0-2 year olds. Co-resistance to clindamycin (64%) and all β-lactams (14-79%) was seen among macrolide-resistant isolates, but >99% of these isolates were susceptible to telithromycin, vancomycin and linezolid. There was considerable variation in the prevalence of erm(B) (56-64%) and mef(A) (30-35%): erm(B) was prevalent in Europe and mef(A) in North America. Globally, 5-7% isolates carried both mechanisms (erm(B)+mef(A)); of these, 47-65% were from South Korea. These double resistance isolates were >90% resistant to the β-lactams, except amoxicillin-clavulanate. Clindamycin was active against >98% mef(A) but poorly active against erm(B) and erm(B)+mef(A) isolates. Telithromycin, vancomycin and linezolid were highly active (>99.5%) across all three genotypes. Conclusions: In vitro, telithromycin, vancomycin and linezolid are highly active against antibiotic-resistant strains of S. pneumoniae. Telithromycin may be a useful therapeutic alternative to macrolides for the treatment of CARTIs.