Background & objectives: Streptococcus pneumoniae is  one of the major causes of vaccine - preventable diseases worldwide. Current pneumococcal vaccines consist of serotype specific capsular polysaccharide antigen and do not offer full clinical protection against pneumococcal diseases. Due to such limitations, a new generation of protein-based pneumococcal vaccines is being developed. The objective of this study was to determine the distribution of gens encoding five protein antigens including pneumococcal histidine triad D and E (phtD, phtE), rlr- regulated gene A (rrgA), Autolysin (lytA) and Pneumococcal surface protein C (pcpC) among pneumococcal isolates collected from nasopharyngeal specimens in healthy children.

Methods: A total of 43 pneumococcal isolates were collected from nasopharyngeal specimens of healthy children attending the kindergartens in Ardabil province. The strains were identified using optochin susceptibility and bile solubility testes and further confirmed by amplification of capsular polysaccharide A gene (cpsA). PCR was used for screening the presence of pcpC, phtD, phtE, rrgA and lytA genes.

Results: 81.4 % of isolates were found to contain at least one of the tested genes. lytA, pcpC, phtE, phtD and rrgA were detected in 70, 60, 39.5, 35 and 25.5 percent of isolates, respectively. The results showed that the genes were not distributed consistently among the isolates and for obtaining a full coverage pneumococcal vaccine, multiple choices of these antigens should be included.