Increasing telithromycin resistance among Streptococcus pyogenes in

mycin (MIC 0.5) was determined by CLSI broth microdilution. Changes in resistance over time and the relationship of resistance to antimicrobial use (European Surveillance of Antimicrobial Consumption data) were assessed. Telithromycin-resistant isolates were characterized by PFGE to determine genetic relatedness and by PCR to detect mef(A), erm(A) and erm(B). Results: The erythromycin resistance rate during 2004–05 (11.6%) was similar to 2002–03 (10.4%). The proportion of macrolide-resistant isolates with the constitutive MLSB phenotype increased from 29.3% (2002–03) to 45.7 % (2004–05). Telithromycin resistance increased from 1.8 % in 2002–03 to 5.2 % in 2004–05. For Western Europe, associations of telithromycin and erythromycin resistance, respectively, were found with azithromycin use (R25 0.52 and 0.60), clarithromycin use (R2 5 0.76 and 0.85) and total macrolide/lincosamide use (R25 0.75 and 0.69). For Eastern Europe, associations of antimicrobial use with resistance were not apparent. The 162 telithromycin-resistant isolates comprised 42 PFGE pat-terns with 68.5 % in eight major PFGE groups. The erm(B) gene was detected in 155 of the 162 telithro-mycin-resistant isolates. Conclusions: Significant increases in telithromycin resistance occurred from 2002–03 to 2004–05 i