Serotype Distribution among Streptococcus pneumoniae Isolates in Puerto Rico

S. pneumoniae infections remain a significant cause of morbidity and mortality despite vaccine availability. Limited information exists about current pneumococcal serotypes transmission in Puerto Rico. Our study aimed to describe the serotype distribution of S. pneumoniae isolates in Puerto Rico and its patients' demographic characteristics.

This prospective laboratory-based observational study from 25 hospitals in Puerto Rico (April 2021-July 2023) collected specimens positive for S. pneumoniae and serotyped them using the Pneumotest-Latex assay and the Quellung reaction tests. A summary of the distribution of S. pneumoniae isolates is presented.

Nineteen specimens were received from sterile (8/19, 42.1%), and non-sterile sites (11/19, 57.9%). All sterile specimens were isolated from blood samples. Most specimens came from male patients (16/19, 84.2%), the median age was 67 years (range: 8 months to 87 years) and came from different geographic regions. Thirteen serotypes were identified: 3 ( two patients), 6A (two patients), 11C, 11D, 15A, 15C, 19A (two patients), 19B, 19C (two patients ), 19F (two patients ), 22A, 34 (two patients ), and 35. Of these, nine (69.2%) were not covered in PPSV23 and PCV13 (available vaccines being used prior and by the time of specimen collection period), three (23%) were covered by both PPSV23, and PCV13, and one (8%) by PCV13 only.

Our findings highlight the importance of continuous surveillance to detect early serotype changes, ongoing vaccination to avoid preventable infections and complications, and pursuing new higher-valency vaccines with broad serotype coverage to address the evolving pneumococcal disease epidemiology.