Nasopharyngeal carriage of Streptococcus pneumoniae

Objective. To determine nasopharyngeal carriage rate and prevalent serogroups/types (SGT) of S. pneumoniae in healthy children, assess their antimicrobial susceptibility and its implications over the heptavalent pneumococcal conjugate vaccine. Methods. 200 healthy children aged between 3 months and 3 years attending Pediatric OPD at Sir Ganga Ram Hospital, New Delhi were studied. A nasopharyngeal swab was collected from each child which was processed to isolate Streptococcus pneumoniae. Serotyping was performed by the Quellung reaction. Antimicrobial susceptibility patterns were determined by disk diffusion and E test methods. Results. S. pneumoniae carriage rate was 6.5%. Isolates belonged to serotypes 1, 6, 14 and 19, of which serotype 19 was the most common. None of the strains were totally resistant to penicillin though 2 (15.4%) were intermediately resistant. Overall, 84.6% of the isolates belonged to the strains covered by the heptavalent pneumococcal vaccine. Conclusion. The heptavalent conjugate vaccine covers most isolated strains, but since the number of strains is very small, it is suggested that there is need for further studies in different regions to assess the usefulness of this vaccine.