Distribution of 13-Valent Pneumococcal Conjugate Vaccine Streptococcus pneumoniae Serotypes in US Adults Aged ≥50 Years With Community-Acquired Pneumonia

Background. Streptococcus pneumoniae causes a substantial proportion of community-acquired pneumonia (CAP) and healthcare-associated pneumonia (HCAP) in the United States. Limited data are available regarding the pneumococcal serotypes causing CAP and HCAP. Methods. Adults aged >= 50 years presenting to participating US hospitals with radiographically confirmed pneumonia between February 2010 and September 2011 were screened for inclusion. S. pneumoniae was identified using microbiological cultures, BinaxNOW (R) S. pneumoniae assay, or urine antigen detection (UAD) assay capable of detecting 13-valent pneumococcal conjugate vaccine (PCV13)-associated serotypes. Results. Among 710 subjects enrolled, the median age was 65.4 years; 54.2% of subjects were male, 22.4% of radiographically confirmed pneumonia cases were considered HCAP, and 96.6% of subjects were hospitalized. S. pneumoniae was detected in 98 subjects (13.8%) by any test, and PCV13-associated serotype(s) were identified by UAD in 78 (11.0%). Serotype 19A was most prevalent, followed by 7F/A, 3, and 5. Serotypes associated with 7-valent pneumococcal conjugate vaccine (PCV7) accounted for 25% of UAD-positive isolates. Conclusions. Pneumococcal serotypes causing noninvasive pneumonia in adults may differ significantly from those causing invasive disease, with PCV7-associated serotypes overrepresented. Serotype 5, rarely seen in contemporary surveillance of invasive disease in the United States, substantially contributed to the observed cases of S. pneumoniae-positive CAP or HCAP.