Serotypes distribution and antibiotic susceptibility of Streptococcus pneumoniae strains: five-year surveillance results of post-PCV-13.

Abstract

Background: Approximately 100 capsular serotypes of S. pneumonia have been identified according to the composition of their capsular polysaccharides, currently available vaccines do not cover many of these. Pneumococcal vaccination serotype coverage is essential for preventing noninvasive and invasive illnesses as well as asymptomatic carriage. We aimed to determine the serotype distribution and antimicrobial susceptibility pattern of pneumococcal clinical isolates in this study. We also analyzed the serotype coverage rates of PCV13, which is applied in the NIP, and PCV-15 and PCV20, which have been introduced recently.

Methods: This study is a retrospective surveillance of pneumococcal infections including invasive pneumococcal isolates (IPIs) and non-invasive pneumococcal isolates (non-IPIs).

Results: A total of 420 isolates from 356 different patients aged 0-89 years were enrolled in the study. A total of 420 pneumococcal isolates were serotyped and 26 different serotypes were detected. Serotype 19 F was the most prevalent serotype (n = 96, 22.8%), followed by 6 A/B (n = 55, 13.1%), 23 F (n = 49, 11.6%), 3 (n = 22, 5.2%) and 19 A (n = 16, 3.8%).

Conclusions: Surveillance studies of pneumococcal diseases are critical to investigating current serotype distributions, antibiotic resistance status, and frequency of IPD cases. Considering the increasing antibiotic resistance rates of S. pneumoniae, it is necessary to provide protective immunization by switching to more comprehensive PCV vaccines rather than treatment.

Clinical trial number: Not applicable.