High prevalence of children colonized with penicillin-resistant Streptococcus pneumoniae in public day-care centers.

Objectives: To investigate the prevalence of Streptococcus pneumoniae (pneumococci) in the nasopharynx of healthy children enrolled in public day-care centers of the municipality of Umuarama, state of Paraná, Brazil. The susceptibility of the pneumococcal strains to antimicrobial agents was also studied.

Methods: Nasopharyngeal specimens from 212 children were collected from April to October 2008. After the specimens were seeded in blood agar and incubated at 37 degrees C for 24-48 hours, the colonies suspected of belonging to S. pneumoniae were identified using alpha-hemolysis, optochin sensitivity, and bile solubility test. Penicillin susceptibility was investigated using the disk diffusion and dilution tests. Susceptibility to the other antimicrobial agents indicated for the treatment of pneumococcal infections was investigated using the disk diffusion test.

Results: The prevalence of nasopharyngeal pneumococci was 43.4% (92/212), with higher rates in children between 2 and 5 years old (p = 0.0005). There was no significant difference between sexes. Intermediate and full resistance to penicillin were found in 34.8 (32/92) and 22.8% (21/92) isolates, respectively. Sixty-seven strains (72.8%) were resistant to sulfamethoxazole-trimethoprim, eight (8.7%) were resistant to erythromycin, and six (6.5%) to tetracycline. One strain was resistant to clindamycin (1.1%) and another was resistant to chloramphenicol (1.1%). All strains were sensitive to levofloxacin, ofloxacin, rifampicin, telithromycin, linezolid, and vancomycin. Nine strains were considered multiresistant because they were resistant to three or more classes of antimicrobial agents.

Conclusions: The present study detected a high prevalence of healthy children colonized with penicillin-resistant S. pneumoniae strains who may be important reservoirs of this pathogen in the community.