Nasopharyngeal Carriage and Serotype Distribution of Streptococcus pneumoniae in Elderly: A Cross-sectional Study in Turkey

Objective: The incidence and mortality of invasive pneumococcal disease are much higher in people over 65 years compared to the general population. The incidence of the disease and the distribution of serotypes changed with the spread of childhood conjugate pneumococcal vaccines and the use of vaccines in the adult age group. Nasopharyngeal carriage is an important stage in the disease pathogenesis. In this study, we aimed to determine the pneumococcal carriage prevalence and serotype distribution in adults aged >_ 65 years living in a nursing home.Materials and Methods: The nasopharyngeal swabs were taken from >_ 65 years old people living in Narlidere Nursing Home. The specimens were cultured and pneumococci were isolated according to colony appearance, optochin sensitivity and solubility in bile salts. Pneumococcal serotypes were identified using the capsule swelling reaction.Results: Pneumococcus was isolated in 10 of 341 subjects and the pneumococcal carriage prevalence was 2.9%. Advanced age, immunocompromised status and chronic renal failure were associated with pneumococcal carriage. In multivariate model, having immunocompromised status was significantly associated with carriage. Serotypes/serogroups of pneumococci were 7F, 23F, 10, 11, 15. 17, 20 and 33. The 13 valent conjugated pneumococcal vaccine serotype carriage prevalence was 0.6%.Conclusion: Although pneumococcal colonization in older people is uncommon, most of the isolated serotypes are not PCV13 serotypes. The monitoring of pneumococcal serotypes can offer useful information about the circulation of this pathogen among older people and the potential protective effect of pneumococcal vaccines.