OBJECTIVES: Pneumococcal Diseases (PD) are vaccine-preventable conditions caused by Streptococcus pneumoniae. Despite the availability of pneumococcal conjugated vaccines (PCVs) and the pneumococcal polysaccharide vaccine (PPSV23), developed to cover the most prevalent pneumococcal serotypes, PD are still an important cause of morbidity and mortality. However, there is limited information about current pneumococcal serotypes distribution in Puerto Rico. This study aimed to determine the serotype distribution of S. pneumoniae isolates in Puerto Rico and to describe the patient´s demographic characteristics.

METHODS: This was a prospective laboratory-based observational and descriptive study. S. pneumoniae isolates from sterile and non-sterile sites were collected from patients six weeks or older from 25 hospitals located in all regions in Puerto Rico. Recruitment period was from April 2020 to July 2023. Serotypes were identified using antigen-antibody reactions in agglutination and capsule swelling test (Quellung). The distribution of S. pneumoniae isolates was summarized using frequencies and percentages.

RESULTS: Nineteen specimens were collected from sterile (n:8, 42.1%), and non-sterile sites (n:11, 57.9%). All sterile specimens were isolated from blood samples. Most specimens came from male patients (n:16, 84.2%). Patient’s median age was 67 years (range: 8 months to 87 years). No geographical cluster was found for any serotype. Thirteen serotypes were identified: 3 (2), 6A (2), 11C, 11D, 15A, 15C, 19A (2), 19B, 19C (2), 19F (2), 22A, 34 (2), and 35. Of these, ten (76,9%) were not covered by any available vaccine, two (15,4%) were covered by PPSV23 and PCVs (13, 15 and 20 valent), and one (7.6%) by just PCVs

CONCLUSIONS: The majority of serotypes identified were not included in any available pneumococcal vaccine. These findings support the need to establish surveillance of circulating S. Pneumoniae serotypes in Puerto Rico and the development of new vaccines to address the changing epidemiology of pneumococcal disease.