Objectives - From July 1997 to June 1998, 15 microbiological laboratories, set up as a regional survey unit in Alsace, collected S. pneumoniae strains to assess their susceptibility to antibiotic agents.Method - The strains were isolated from various clinical samples (blood cultures, pulmonary samples, cerebrospinal fluid, otitis media).Results - 599 strains were collected and the prevalence of Pneumococci with a Decreased Susceptibility to Penicillin G (PDSP) reached 32.9% (197 strains, MIC > 0.06 mg/L) but included a very small percentage of high level resistance strains to penicillin G (10 strains with MIC > 1 mg/L). Amoxicillin and cefotaxime remained active (3 and 0 resistant strains, respectively). The percentage of DPSP was much higher in the isolates of children (45.3%) than in those of adults (28.2%). The PDSP were rather resistant to erythromycin (76.6%), cotrimoxazole (65.2%), and fosfomycin (18.4%). Among PDSP, the most prevalent serotypes were 23, 14, and 9.Conclusion - This epidemiological survey allowed to assess the local impact of pneumocaccal resistance to antibiotics thanks to extensive collection and study. (C) 2000 Editions scientifiques et medicales Elsevier SAS.