Streptococcus pneumoniae carriage in school children

Abstract

Purpose. To investigate the serotype distribution, clonal structure and antimicrobial resistance of pneumococci isolated from schoolchildren.Materials and methods. During the period from 2012 to 2018 we examined 498 healthy school children aged 6 to 17 years. Oropharyngeal swab was taken from each child for culture, after that all S. pneumoniae strains were genotyped for serotype and ST-type deduction (PCR and sequencing, respectively). Antimicrobial resistance was also determined.Results. Pneumococcal culture was positive in 10.6 % of children. S. pneumoniae isolates belonged to seven serogroups and seven serotypes. Serogroup 6 and serotype 19F strains (15.1% each), and serogroup 9 strains (13.2%) were the most prevalent. S. pneumoniae33FA/37 and 3 (9.4 and 5.7%), serogroups 15 and 18 (7.6 and 5.7%), and 10A serotype (3.8%) were determined at a lower frequency. 20 detected ST-types belonged to 14 clonal complexes (CCs); CC156, CC447, and CC320 were predominant. 1.9% of isolates were penicillin-resistant; 13.2% – macrolide-, clindamycin-, and tetracycline-resistant. S. pneumoniae antibiotic resistant strains belonged to multidrug-resistant CCs 320, 315, and 156.Conclusion. S. pneumoniae prevalence in school children is not high. Pneumococcal population is characterized by serotype and clonal diversity including ‘invasive’ serotypes and genotypes. Most of strains are susceptible to antimicrobials.