2707. Non 13-Valent Pneumococcal Conjugate Vaccine Serotypes Predominate as Causes of Pneumococcal Otitis Media in Children

BACKGROUND: Pneumococcal acute otitis media (AOM) in children due to vaccine-related serotypes (ST) has declined after the introduction of the 13-valent pneumococcal conjugate vaccine (PCV13), although some serotypes, such has 3, 19A and 19F have persisted. Among non-vaccine serotypes, 35B has been shown to contribute substantially to both OM and invasive infections. This study describes the current epidemiology of pneumococcal OM isolates obtained from the U S Pediatric Multicenter Pneumococcal Surveillance Group (USPMPSG). METHODS: From the USPMPSG database, we collected data from patients <18 years of age with pneumococcal OM isolates from 2014 to 2018. Analysis included demographics, immunization status, antimicrobial susceptibility data and serotype. Statistical comparisons included Fisher’s exact and Wilcoxon rank-sum tests. RESULTS: A total of 494 patients with isolates were identified within the time period from 5 children’s hospitals. Median age was 1.7 years (range 0–17.6) and 299 (60.5%) were male; 176 (35.7%) had an underlying condition. Thirty-two patients had received no dose of either PCV7 or PCV13. Thirty-five serotypes were identified (3 isolates were non-typeable), of which 6 serotypes [35B (16.8%), 3 (9.5%), 15A (7.9%), 15B (7.9%), 23B (7.9%) and 21 (6.1%)] caused more than half of the total OM infections (figure). Ninety (18.2%) isolates were of PCV13 serotypes. Twenty-five of 476 (5.3%) isolates had a penicillin MIC>2 µg/mL. These were of serotypes 11A, 15A/C, 19A/F, 35B and NT; 10/455 (2.2%) isolates had ceftriaxone MIC>1 µg/mL and were of ST 3, 15A, 19A/F and 35B. CONCLUSION: Most pneumococcal OM were caused by non-PCV13 serotypes. Serotype 35B remained the most common serotype among pneumococcal isolates recovered from ear drainage or middle ear cultures. The low proportion of penicillin-resistant isolates along with the increasing proportion of AOM cases being due to non-pneumococcal isolates supports the consideration to switch routine antibiotic treatment for AOM to standard dose amoxicillin-clavulanate from high dose amoxicillin in PCV13 immunized children (Pediatr Infect Dis J 2018;37:1255–1257). [Image: see text] DISCLOSURES: All authors: No reported disclosures.