Asymptomatic nasopharingeal carrying of Streptococcus pneumoniae in preschool children

Introduction. Despite the availability of modern, effective antibiotics and vaccines, up to 825 000 children under five years of age worldwide suffer from severe pneumococcal infection every year. Aim. To study the prevalence and manifestation of asymptomatic carriage of St. pneumoniae in unvaccinated preschool children. Materials and methods. The study design was a prospective cohort study that began before the inclusion of pneumococcal vaccination in the National Preventive Vaccination Calendar of Uzbekistan (2015). The microbiota of the nasopharynx was studied in 236 practically healthy children, of which children attending preschool, from 3 to 5 years old – 143 (60.6%), unorganized children from 1.5 to 3 years old – 93 (39.4%). According to standard methods, a bacteriological analysis (bacterial culture) was carried out to detect St. pneumoniae in a nasopharynx smear. Results and discussion. Asymptomatic nasopharyngeal carriage of St. pneumoniae was detected in 40.7% of those observed, which was higher than the detection rate of H. influenzae – 22.0% (52/236), as well as Moraxella catarrhalis – 13.6% (32/236), and in children attending kindergartens, the detection rate was two times higher (50.4% versus 25.8%), compared to unorganized children. According to two-year observations, a more aggressive effect of pathogens was noted in young children (unorganized children). Repeated episodes of pneumonia were noted in 29.2%, which is 5.2 times more than in children from the second age group (5.6%). The data obtained indicate a high incidence of children under three years of age with St. pneumoniae carriage. Conclusion. Among unvaccinated children under five years of age, asymptomatic nasopharyngeal carriage of St. pneumoniae was 40.7%, and the transition of asymptomatic carriage to invasive respiratory diseases reached 97.9%, which indicates the need for family doctors to organize and conduct effective vaccination of children before their admission to preschool institutions.