1444. Trends in Antimicrobial Non-susceptibility of PCV13-Type Streptococcus pneumoniae Pneumonia in Adults in the United States During 2009–2017

Abstract

BackgroundThe routine use of 13-valent pneumococcal conjugate vaccination (PCV13) was implemented in children in 2010 and in adults (≥65 years of age) in 2014 in the United States. Trends in rates of penicillin G (PEN) antimicrobial nonsusceptibility (NS) for PCV13-type S. pneumoniae from adult pneumonia patients were assessed by age group.MethodsIsolates were consecutively collected from pneumonia patients in 105 US sites in 40 states during 2009–2017. Isolates were identified by biochemical algorithms and/or PCR; susceptibility testing and interpretation used CLSI Methods. The cpsB sequence was obtained by PCR or whole-genome sequencing for serotype (ST) determinations. Multiplex PCR and/or Quellung reactions were also performed, as needed.ResultsOf 7,254 analyzed S. pneumoniae isolates, 63.6 and 36.4% were obtained from pneumonia patients aged 18–64 and ≥65 years, respectively. S. pneumoniae recovered from both age groups (18–64 and ≥65 years of age) showed a reduction in PEN-NS rates (from 12.9–14.5% in 2009 to 2.8–4.3% in 2017). The PEN-NS rates among PCV13 STs from both age groups rose to 37.7–39.9% from 2009 to 2011, decreasing in subsequent years (2012–2017) to 11.8–16.4% (Figure 1). Similar results were observed for PEN-NS rates against the STs included in PCV13 but not PCV7 (Figure 2). PEN-NS rates against PCV13 and PCV13-non-PCV7 STs from patients age 18–64 years plateaued or increased in 2015–2017, while PCV13 and PCV13-non-PCV7 STs from patients age ≥65 years declined continuously after 2012.ConclusionThe decrease in PEN-NS rates among PCV13 and PCV13-non-PCV7 STs may be associated with the herd effect from PCV13 vaccination in children, an effect that may have occurred as early as 2 years after PCV13 implementation. The modest differences in PEN-NS trends between age groups during 2015–2017 may reflect the US recommendation to directly vaccinate adults age ≥65 but not 18–64 years; however, this hypothesis requires further data for confirmation. Disclosures R. E. Mendes, T. B. Doyle, L. N. Woosley, R. K. Flamm, Pfizer Inc: Research Contractor, Research support. J. A. Suaya, Pfizer: Employee and Shareholder, Benefits and stock and Salary. B. D. Gessner, Pfizer Inc.: Employee and Shareholder, Salary. R. E. Isturiz, Pfizer, Inc: Employee and Shareholder, Salary and Stock & Stock Options.