Antimicrobial susceptibility and serotypes of nasopharyngeal Streptococcus pneumoniae in children with pneumonia and in children attending day-care centres in Fortaleza, Brazil

Abstract

The susceptibility of nasopharyngeal Streptococcus pneumoniae to eight antibiotics was studied in 482 children under 5 years of age with community-acquired pneumonia and in 429 healthy pneumococci carriers in Fortaleza, Brazil. Serotyping of strains with pooled and type-specific antisera was also performed. Overall, S. pneumoniae was isolated from 499/911 (55%) children. The carriage rate in children attending day-care centres was higher (72%) than in children with pneumonia (50%) (P<0.001). MIC determination in 441 strains revealed 45% to be intermediate penicillin-resistant and 4% high penicillin-resistant strains. Resistance rates to co-trimoxazole and erythromycin were 42 and 23%, respectively. Serotyping of 211 penicillin-resistant and 58 randomly selected penicillin-susceptible isolates showed that 78% of the strains belonged to paediatric serogroups 6, 14, 19 and 23 (86% of the penicillin-resistant and 51% of the penicillin-susceptible strains, P=0.001). Resistance rates of S. pneumoniae to penicillin and co-trimoxazole in Fortaleza were higher than previously reported in Brazil and associated with paediatric serogroups 6, 14, 19 and 23.