A retrospective analysis of 111 cases of pneumococcal pneumonia: clinical features and prognostic factors.

OBJECTIVE Streptococcus pneumoniae is an important and common pathogen of acute pneumonia. The urinary pneumococcal antigen test has been increasingly used for the diagnosis of pneumococcal pneumonia, but there have been few studies on pneumococcal pneumonia after this test became prevalent. The present study was conducted to characterize the clinical features of pneumococcal pneumonia after the introduction of the urinary antigen test. METHODS We retrospectively analyzed 111 cases from 105 patients with pneumococcal pneumonia in our hospital between 2007 and 2010, and collected data regarding background characteristics, laboratory data, isolated bacteria, and clinical courses. RESULTS The cases analysed included 77 of community-acquired pneumonia (CAP), 21 of healthcare-associated pneumonia (HCAP), and 13 of hospital-acquired pneumonia (HAP). Penicillin-resistant Streptococcus pneumoniae was isolated in 12.5 and 55.6% of non-HAP and HAP cases, respectively. When the cases were divided into 5 groups according to A-DROP scores (0, 1, 2, 3 and 4 points), critical events occurred at 0, 0, 8.7, 15.4, and 75.0% in groups of cases of 0, 1, 2, 3, and 4 points, respectively. Similarly, critical events occurred at 66.7, 4.7, 3.8, and 9.1% in groups of cases according to WBC counts of <4,000, 4,000-9,999, 10,000-19,999, and ≥20,000 cells/µL, respectively. CONCLUSION Most of the pneumococcal pneumonia cases occurred as CAP and were treated successfully. HAP cases were frequently penicillin resistant. Elevated A-DROP scores and decreased WBC counts were found to be predictive of critical events.