Background: Heptavalent pneumococcal vaccine which included pneumococcal serotypes 4, 6B, 9V,14, 18C, 19F and 23F has been regularly used and is effective on preventing invasive pneumococcal infection. This study aimed to determine vaccine-related serotype distribution in nasopharyngeal carrier and healthy children under five years old.
Materials and methods: In this cross-sectional study from September 2010 to September 2011, 363 nasopharyngeal specimens were collected from healthy children in day care centers. In positive cultures of streptococcus pneumoniae (S. pneumonia) distribution, serotypes were detected by Multiplex polymerase chain reaction (PCR). Electrophoresis of PCR products was used for detection of serotypes of S. pneumoniae.
Results: The carrier rate of S. pneumoniae was 29.5% with 95% confidence interval as 24.8- 34.5%. Electrophoresis of PCR products for detection of serotypes of S. pneumonia revealed 430, 220, 753, 189, 573, 304, and 384 bp (s) for 4, 6B, 9V, 14, 18C, 19F, and 23F serotypes of S. pneumoniae, respectively. The frequency of 23F, 6B, 19F, and 18C serotypes were 43%, 34%, 18%, and 5% respectively, but other serotypes (4, 9V and 14) were not detected.
Conclusion: Based on the 30% carrier rate and high prevalence of most of heptavalent pneumococcal conjugate vaccine serotypes in our study, this vaccine should be used for prevention of invasive infection in Iranian children.
Keywords: Electrophoresis; Heptavalent pneumococcal conjugate vaccine; PCR product; Streptococcus pneumoniae.