Serotypes of respiratory tract isolates of Streptococcus pneumoniae from Jamaican children

Abstract

Background: Data are lacking on the pneumococcal serotypes present in many developing regions, including the Caribbean. We examined the serotypes of nasopharyngeal (NP) isolates of pneumococci obtained from Jamaican children. Methods: We obtained NP samples from children seen in the Emergency Department at the Bustamante Children's Hospital. The samples were transported to Canada for isolation and serotyping of pneumococci. Results: We obtained 94 isolates from 276 children; median age 3.4 years. The majority (57%) had symptoms of acute respiratory infection at the time of sampling. The main serotypes carried were 6B (20.5%), 19F (14.5%), and 14 (8.4%). Non-typable isolates accounted for 10.8% of the isolates. Fifty-nine per cent of the serotypes were present among the 11 being considered for candidate pneumococcal conjugate vaccines (95% CI 48–70%); the corresponding proportion present in the recently licensed 7-valent vaccine was 57% (95% CI 45–67%). A significant proportion of the serotypes found is absent from those to be included in future conjugate vaccines (P<0.0001; reference=85% expected serotype representation). Less than 5% of isolates were non-susceptible to penicillin (3.2%), cefotaxime-ceftriaxone (3.2%) and cefuroxime (3.2%), while 8.4% and 1.1% of isolates were resistant to trimethoprim-sulfamethoxazole and erythromycin respectively. There were three isolates with resistance to two or more classes of drug. These isolates were all resistant to penicillin (MIC 2 μg/mL); the serotypes were 14, 23F, and 19F. Conclusion: A significant proportion of the serotypes found is absent from those to be included in future conjugate vaccines.