[In vitro susceptibility to antibiotics and the most common Streptococcus pneumoniae serotypes: a multicenter study].

The susceptibility and serotypes of 211 strains of Streptococcus pneumoniae collected from 12 Spanish hospitals in December 2003 were studied. Susceptibility tests for eight antibiotics were carried out by E-test, and the serotype classification was carried out using pneumococcus antiserum from the Copenhagen Statens Serum Institute. Overall, the most frequent serotypes were 19 (12.2%); 6 (10.7%); 23 (10.2%); 3 (8.1%); 9 (6.6%); 14 (6.1%); and 29 (5.1%). In blood, the most frequent were 19 (16.6%) and 14 (11.9%), and 8.6% were nontypable. Under NCCLS (M7-A5) criteria, 55.6% of the strains were susceptible to penicillin (MIC < or =0.06 mg/l) and 7.9% showed high resistance (MIC > or =2 mg/l). Susceptibility to other antibiotics was 98% to moxifloxacin; 97.1% to levofloxacin; 94.6% to amoxicillin-clavulanic acid; 71.2% to cefuroxime; 84.4% to ceftriaxone; and 63.1% to clarithromycin and azithromycin. Only 13.3% of the strains showed susceptibility to the antibiotics tested. The greatest percentage of strains resistant to other antibiotics was found among the strains resistant to penicillin. Nine resistant phenotypes were detected.