MOLECULAR DETECTION AND SEROTYPING OF STREPTOCOCCUS PNEUMONIAE IN MENINGITIS SUSPECTED CHILDREN IN 2014-2018, BOJNURD, IRAN. WHICH TYPE OF VACCINE IS MORE SUITABLE FOR THIS REGION

Background and Aim:To date, we know more than 90 Streptococcus pneumoniae capsular serotypes based on their polysaccharide component. The prevalence of these serotypes is varied based on geographical area and presumable vaccination program. Owing to the lack of regular vaccination programs for S. pneumoniae in infants in developing countries, serotyping of the prevalent isolates can be useful in true vaccine selection.Methods:All suspected Cerebro Spinal Fluid (CSF) samples for bacterial meningitis in Imam Reza Hospital- Bojnurd were collected during 2014-2018. Because of a high rate of false negative culture results, we used PCR Method for detection of lytA and psaA genes of S. pneumoniae and also modified Marrimon’s Multiplex PCR method for serotyping of this bacteria.Results:106 of 901 samples were positive for S. pneumoniae using PCR while 92 cases were positive with conventional methods. Serotyping was performed using modified Marrimon’s Multiplex PCR method. Serotypes 23F, 19F, 1, 14, 19A and serogroup 6 were the most common types in our samples. serogroups 18 (C), 15(A/F/B/C), 9(A/V), 7(A/F), 11(A/D/F) and 22(A/F) were also detected in our isolates. 2.8% of samples were non-typable.Conclusion:In last two years, some serogroups including 9(A/V), 15(A/F), 7(A/F), 1, 11(A/D/F), 22(A/F) have been increased in our samples. Based on results, it seems that the PCV-13 is the best candidate for the coverage of our common serotypes of meningitis-related S. pneumoniae strains. This vaccine covers 77.13% of our common serotypes. The results of this study will help the design of an appropriate vaccination program for this region.

Keywords:

Streptococcus pneumoniae , capsule , polysaccharide , serotype , molecular , Vaccine