Serotype 19A is the most common streptococcus pneumoniae isolate in children with chronic sinusitis

Background: The introduction of the heptavalent pneumococcal conjugate vaccine has altered the epidemiology of acute otitis media and invasive pneumococcal disease in children. However, sparse data regarding pediatric sinusitis are available since the licensure of pneumococcal conjugate vaccine. In this study, sinus cultures which grew Streptococcus pneumoniae at Texas Children's Hospital were evaluated with regard to pneumococcal serotype, antimicrobial susceptibility, and frequency of coinfecting organisms. Methods: S. pneumoniae isolates from sinus cultures were identified from January 1, 2007 to July 31, 2008. A retrospective chart review was performed and information including age, ethnicity, gender, and comorbidities was collected. Isolates were serotyped and their susceptibility to oral penicillin, cefotaxime, erythromycin, clindamycin, and trimethoprim-sulfamethoxazole was determined. Results: During the study period, 24 pneumococcal isolates were recovered from endoscopic sinus surgery cultures; 23 isolates were nonvaccine serotypes. Serotype 19A accounted for 50% of isolates. Eleven of the 12 serotype 19A isolates were nonsusceptible to oral penicillin as compared with 6 isolates of the other serotypes. Five of 12 serotype 19A isolates were nonsusceptible to cefotaxime; in comparison, all of the other serotypes were susceptible to cefotaxime. One third of the 19A isolates were nonsusceptible to all 5 antimicrobials tested. Other organisms were coisolated in 87% of cases. Conclusions: Serotype 19A has become the most common pneumococcal serotype isolated from chronic or recurrent pneumococcal sinusitis in children at Texas Children's Hospital. Serotype 19A isolates have high rates of antimicrobial resistance and are frequently isolated along with multiple other organisms.