Pleural Infections: A 9-Year Review of Bacteriology, Case Characteristics and Mortality

Background: Despite advances in medical therapies, pleural infections remain a common disease. The characteristics of this disease seem to change over time, with alterations in patient characteristics and bacteriology. The purpose of this study was to provide a retrospective descriptive analysis of pleural infections during a 9-year period. Methods: We performed a single-center retrospective review of all culture-positive pleural infections between January 2000 and December 2008. The primary outcome was assessment of long-term survival and associated independent risk factors affecting survival. Length of survival was determined using the Social Security Death Index. Case characteristics and bacteriology were reviewed for descriptive analysis. Results: During a 9-year period, 187 culture-positive pleural infections were identified. Review of bacteriology revealed gram-positive cocci as the predominate organisms, most commonly Streptococcus and Staphylococcus. Anaerobes were found in 9.1% of the cases. Independent risk factors associated with risk of death based on multivariable survival analysis were age older than 65, cirrhosis and past and present malignancy. The hospital mortality was 10.7%, and the 1-year, 3-year and 5-year estimated survival rates were 73.8%, 63.3% and 60.6%, respectively. Conclusions: Pleural infections continue to remain a major health problem and carry significant morbidly and mortality. The importance of Staphylococcus aureus in this population has yet to be fully examined, and although potentially underestimated in this study, anaerobic infections remain a common pathogen.