Abstract
Implementation of molecular serotype-specific characterization for Streptococcus pneumoniae
APHA 2022 Annual Meeting and Expo
Streptococcus pneumoniae (S. pneumoniae) is a commensal human pathogen that is typically present in the upper respiratory tract of the host. The high burden of pneumococcal disease is mainly observed in elderly individuals, especially with underlying comorbidities causing substantially high mortality rates. Since the introduction of pneumococcal conjugate vaccines (PCV7 & PCV13), the incidence of disease caused by S. pneumoniae has decreased. Invasive infections caused by PCV13-targeted serotypes are still a major public health concern, however, due to documented antibiotic resistance in certain serotypes. The Quellung reaction remains the gold standard for serotyping, which is dependent on culture, microscopy and rabbit antisera to visualize capsule swelling. The primary limitations of this assay are that it is not suitable as a high throughput assay, and it lacks specificity for certain serotypes. The University of Louisville Infectious Diseases Laboratory (IDL) implemented the Centers for Disease Control and Prevention (CDC) protocol to develop the real-time PCR for the molecular serotyping-specific characterization of S. pneumoniae that proved to be highly sensitive, specific, and reproducible on isolates of S. pneumoniae. The overall aim for the development of this molecular serotyping assay for S. pneumoniae is to improve the timely diagnosis of pneumococcal disease with serotype identification. This assay will provide a better understanding of geographical distribution and shifts in the prevalence of pneumococcal disease over time. Ultimately, the data will aid in surveillance efforts for vaccine optimization and development, yielding a clearer picture of pneumococcal vaccines on disease burden.