Pneumococci isolated from children in community-based practice differ from isolates identified by population and laboratory-based invasive disease surveillance.

BACKGROUND:Characterizing strains causing noninvasive and invasive pneumococcal disease (IPD) may inform the impact of new pneumococcal conjugate vaccines (PCVs). METHODS:During 2011-2019, among children aged 6-36 months, pneumococcal serotype distribution and antibiotic non-susceptibility of nasopharyngeal and middle ear fluid (MEF) isolates collected at onset of acute otitis media (AOM) in Rochester, New York were compared with IPD isolates from Active Bacterial Core surveillance (ABCs) across 10 U.S. sites. RESULTS:From Rochester, 400 (nasopharyngeal) and 156 (MEF) pneumococcal isolates were collected from 259 children. From ABCs, 907 sterile-site isolates were collected from 896 children. Non-PCV serotypes 35B and 21 were more frequent among the Rochester AOM cases, while serotypes 3, 19A, 22F, 33F, 10A, and 12F contained in PCVs were more frequent among ABCs IPD cases. The proportion of antibiotic non-susceptible pneumococcal isolates was generally more common among IPD cases. In 2015-2019, serotype 35B emerged as the most common serotype associated with multiclass antibiotic non-susceptibility for both the Rochester AOM and ABCs IPD cases. CONCLUSIONS:Pneumococcal isolates from children in Rochester with AOM differ in serotype distribution and antibiotic susceptibility compared to IPD cases identified through U.S. surveillance. Non-PCV serotype 35B emerged as a common cause of AOM and IPD.