Antibiotic susceptibility patterns and serotypes of antibiotic resistant and/or invasive Streptococcus pneumoniae strains circulating in Italy

Antibiotic susceptibility patterns and serotypes of 397 Streptococcus pneum oniae recovered from 1994 to 1998 in Italy have been determined. This colle ction included 229 penicillin- and/or erythromycin-resistant strains and 16 8 isolates responsible for invasive infections. Among penicillin-resistant pneumococci, the most prevalent serotype was 23F, followed by 19F and 9V, w hile among erythromycin-resistant but penicillin-susceptible strains seroty pe 6B was predominant followed by 19A, 14, 19F, 15A, 15B, and 23F. The most common invasive serotypes were 6B, 19F, 23F, 3, 4, 14, 20, 15B, and 9N. Th e currently available 23-valent pneumococcal vaccine could cover 91% of non invasive penicillin- and/or erythromycin-resistant strains, 84% of pneumoco cci isolated from sterile sites, and 83% of invasive antibiotic-resistant S . pneumoniae. Penicillin-resistant pneumococci also showed reduced suscepti bility to other antimicrobial compounds. Against invasive pneumococci, amox icillin, cefotaxime, ceftriaxone, imipenem, vancomycin, and rifampin were 1 00% effective. Penicillin, chloramphenicol, erythromycin, tetracycline, and co-trimoxazole resistance was 1.8%, 9.5%, 15.5%, 18.5%, and 21.4%, respect ively.