Prospective, population-based surveillance of the burden of Streptococcus pneumoniae in community-acquired pneumonia in older adults, Chrzanów County, Poland, 2010 to 2012.

INTRODUCTION Community-acquired pneumonia (CAP) caused by Streptococcus pneumoniae is a substantial cause of morbidity and mortality among older adults. This study estimated incidences of CAP, chest x-ray-confirmed CAP (CXR+CAP), S pneumonia- positive CAP, S pneumonia-positive CXR+CAP, and S. pneumoniae serotype distribution among 46,000 at-risk adults aged ≥ 50 years residing in Chrzanów County, Poland. MATERIAL AND METHODS From January 2010 to January 2012, all facilities providing ambulatory and inpatient care enrolled all consenting resident patients with suspicion of CAP. Chest x-rays, urine, blood, and sputum samples were analyzed. Annualized incidence rates were determined. Presence of S pneumonia-positive CAP and/or S. pneumoniae serotype distribution was determined using the urine antigen detection assay (capable of detecting the serotypes in the 13-valent pneumococcal conjugate vaccine [PCV13]), BinaxNOW®, and/or microbiology cultures. RESULTS Among 5055 enrolled patients, 1195 (23.7%) were diagnosed with CAP and 1166 (23.4%) had CXR+CAP. S. pneumoniae was detected in 144 (12.1%) and 131 (11.2%) patients from the CAP and CXR+CAP cohorts, respectively. Annualized incidence rates of CAP, CXR+CAP, S pneumonia-positive CAP, and S. pneumonia-positive CXR+CAP were 12.8, 12.5, 1.6, and 1.4 per 1000 residents, respectively. Among CXR+CAP patients, 39.7% were aged 50 to 64 years and 60.3% were aged ≥ 65 years. Incidence rates generally increased with age. The most common serotypes in S. pneumoniae-positive CXR+CAP patients were 3 (n = 15), 23F (n = 10), 18C (n = 9), and 9V (n = 6). CONCLUSIONS CAP due to PCV13 serotypes is a source of morbidity among adults >50 years and may be reduced by greater access to pneumococcal vaccines.