Molecular surveillance of macrolide, tetracycline and quinolone resistancemechanisms in 1191 clinical European Streptococcus pneumoniae isolates

Streptococcus pneumoniae isolates (n = 1191) were collected during a 1997-1 999 European surveillance study. In addition to susceptibility data, a mole cular epidemiological survey of their mechanisms of resistance to macrolide s, tetracyclines, and quinolones was provided. Of the isolates tested, 72.6 % were penicillin-susceptible, 19.9% penicillin-intermediate and 7.5% penic illin-resistant. There was an obvious relationship between resistance to pe nicillin and resistance to erythromycin (19% of all isolates), clindamycin (14%) and tetracycline (23%). Only one isolate was resistant to levofloxaci n. Seventy-three percent of the European S. pneumoniae isolates resistant t o erythromycin (n = 229) carried the erm(B) gene, while the remaining 27% p ossessed the mef(A) gene. No mutations were detected in 23S rRNA or in ribo somal proteins L4 and L22. All tetracycline-resistant isolates (n = 277) ca rried the tet(M) gene; none carried the tet(O) gene. Classical mutations in gyrA (Ser 81-Phe or Tyr) and parC (Ser 79-Phe and Asp 83-Asn) and efflux c ontributed to the decreased quinolone susceptibility. This study of recent European S. pneumoniae isolates can be used to recognize any changes in sus ceptibility patterns and resistance mechanisms that may occur in the future . (C) 2001 Elsevier Science B.V. and International Society of Chemotherapy. All rights reserved.