The prevalence of circulating <i>S. pneumoniae</i> serotypes in people older than 18 years: healthy carriers, patients with acute otitis media, community-acquired pneumonia, and invasive pneumococcal infections (epidemiological study «SPECTRUM»)
Objective. To estimate the prevalence of S. pneumoniae serotypes in adults aged of 18 years and older, including healthy carriers and patients with acute otitis media (AOM), community-acquired pneumonia (CAP) and invasive pneumococcal infection (IPI). Materials and methods. A total of 230 isolates of S. pneumoniae from 10 centers were included in the study from 01.06.2019 to 01.10.2019. Re-identification and typing using real-time PCR with 22 primer pairs were performed in the central laboratory (Institute of Antimicrobial Chemotherapy, Russia). Results. In healthy nasopharyngeal carriers (n = 31), the following serotypes of S. pneumoniae were detected: 19F (29.0%), 6А/В (22.6%), 3 (16.1%), 11A/D and 23F (9.7% each), 14 (3.2%); PCV-13 and PPV-23 covered 80.6% and 90.3% of those serotypes, respectively. In patients with AOM (n = 18), serotypes were: 3 (16.7%), 11A/D and 6A/B (11.1% each), 19А, 19F, 23F, 7A/F (5.6% each); PCV-13 and PPV-23 covered 50% and 61.1% of those serotypes, respectively. Among 166 isolates from patients with CAP, the following serotypes were detected: 3 (12.0%), 19F and 6A/B (10.2% each), 14 and 11A/D (5.4% each), 9N/L (4.2%), 18 and 22A/F (2.4% each), 19A and 23F (1.8% each), 33A/33F/37 and 9V/A (1.2% each), 4 (0.6%), non-vaccine serotypes (41.0%); PCV-13 and PPV-23 covered 45.6% and 58.8% of those serotypes, respectively. Isolates from patients with IPI (n = 15) belonged to the following serotypes: 3 (26.7%), 12F, 23F and 9N/L (13.3% each), 4 (6.7%), non-vaccine serotypes - 4 isolates (26.7%); PCV-13 and PPV-23 covered 46.7% and 73.3% of those serotypes, respectively. Conclusions. The majority of S. pneumoniae serotypes in adult population in Russia are included in PPV-23, but not in PCV-13 (primarily due to serotype 11A/D). There was a high PCV-13 and PPV-23 coverage of serotypes from healthy nasopharyngeal carriers. PPV-23 covered more than 60% of clinical isolates, whereas PCV-13 covered no more than 50% (AOM - 50.0%, CAP - 45.6%, IPI - 46.7%), thus indicating a potentially lower efficacy of PCV-13 in adult population.