Methods: We examined the molecular epidemiology of the most common serotypes among children and adults cared for at two medical centers in the Kansas City region in 2010-2013. Streptococcus pneumoniaeisolates from children with invasive and noninvasive disease and adults with IPD were serotyped using type-specific antisera and observation of the Quellung reaction. The most frequent serotypes shared among children and adults were selected for pulsed-field gel electrophoresis (PFGE) analysis.
Results: A total of 379 (79 adult and 318 pediatric) S. pneumoniaeisolates were serotyped. PFGE analysis was conducted on 147 isolates of the most common serotypes shared among children and adults. PCV13-related isolates included serotypes/serogroups 3 (N=20), 7 (N=26), 19A (N=29), and 23 (N=13). Analyzed nonvaccine serotypes/serogroups were 15 (N=20), 22 (N=11), 33 (N=15), and 35 (N=13). Phylogenetic analysis revealed 20 clusters with 86% or greater genetic relatedness. Serotypes/serogroups 3, 7, 22, 33, and 35 formed individual closely related clusters that comprised 85% or more of their representative isolates. In contrast, serotypes/serogroups 15, 23, and 19A were more genetically diverse.
Conclusion: Although nonvaccine serotype pneumococcal disease has emerged, PCV13-related pneumococcal disease persists. In the Kansas City region, pneumococcal isolates within serotypes/serogroups 3, 7, 22, 33, and 35 are genetically closely related. With the changing seroepidemiology of pneumococcal disease, continued surveillance is needed to learn whether PCV13-induced antibody pressure may lead to further serotype shifts or changing epitopes in existing serotypes.
Actavis: Grant Investigator , Research grant
GSK: Grant Investigator , Research grant
F. Merino, Pfizer: Grant Investigator , Research grant
E. Atwood, None
R. Horvat, IBT Laboratory: Consultant and Speaker's Bureau , Consulting fee
M. J. Tort, Pfizer: Employee , Salary
A. Mcdaniel, Pfizer: Employee , Salary
A. James, None
R. Goering, None