Penicillin Resistance in Nasopharyngeal Streptococcus pneumoniae among Children with Sickle Cell Disease Immunized with 7-Valent Pneumococcal Conjugate Vaccine

Abstract

To assess the prevalence, the antimicrobials resistance and to identify risk factors of nasopharyngeal colonization by Streptococcus pneumoniae in children with sickle cell disease (SCD) using prophylactic penicillin and immunized with 7-valent pneumococcal conjugate vaccine. A total of 424 swabs were collected from the nasopharynx in 216 children with SCD and 109 samples from the control group, both from 2 to 60 months age range. Isolation and identification of pneumococci followed standard procedures. Minimum inhibitory concentration (MIC) for penicillin was determined by the E-test method. Prevalence of nasopharyngeal colonization by pneumococci in children with SCD was 17%, and 11% in the control group. The risk factors for increased colonization in children with SCD were the presence of more than five people at home, daycare/school attendance and low prophylaxis compliance. The prevalence of strains with penicillin resistance was 57.5% in patients with SCD and 25% in the control group. Conclusions: Prevalence of pneumococci nasopharyngeal colonization was similar among the study groups. Prophylactic use of penicillin may have increased the prevalence of resistant strains. The vaccine did not decrease the colonization with penicillin resistant strains.