Background: Streptococcus pneumoniae, as an important human pathogen, is a leading cause of serious infections (e.g., sepsis, pneumonia and meningitis). Nasopharyngeal colonization is often the first step in the development of pneumococcal infections. The aim of this study was to determine the prevalence of S. pneumoniae serotypes in the nasopharynx of students in Kashan and its related risk factors.

Materials and Methods: This cross-sectional study was conducted on 1289 students in Kashan from November 2011 to December 2012. Demographic and clinical data were collected from patients using a questionnaire. Samples were cultured on a selective media. Moreover, S. pneumoniae strains were identified using gram staining, detecting alpha hemolysis, catalase, optochin susceptibility and bile solubility tests.

Results: One-hundred eighty one out of 1289 (14%) students were carriers for nasopharyngeal S. pneumoniae. There was a significant correlation between sex, age, previous respiratory infections, asthma, runny nose and previous hospitalization with an increased rate of the pneumococcal carriers.

Conclusion: According to the high prevalence of pneumococcal carriers and a significant correlation between increased rates of colonization and sex, age, previous respiratory infections, asthma, runny nose and previous hospitalization, applying preventive strategies such as student vaccination seems to be necessary.