Isolated pneumococcal bacteremia: Patients referred for infectious diseases consultation from 1999 to 2010

Background: Streptococcus pneumoniae (pneumococcus) commonly causes pneumonia, otitis media, and meningitis in both children and adults. Isolated pneumococcal bacteremia with no identifiable source is rare and is not a well-described entity in the medical literature. Methods: We performed a retrospective cohort study among approximately 4000 patients seen from 1999 to February 2010 by one infectious disease physician at our community teaching hospital and analyzed the patients with a diagnosis of isolated pneumococcal bacteremia. RESULTS: We found that among the approximately 4000 patients seen during the study period, only 7 patients had isolated pneumococcal bacteremia without manifestation of focal infection in any organ. Patients of African American descent, of male sex, aged older than 60 years, and with a body mass index of more than 25 kg/m² were more frequently infected than others. None of the patients smoked cigarettes, drank alcohol, or used any illicit drugs. Conclusions: Although infections with S. pneumoniae are seen on a daily basis in every hospital in the United States, isolated bacteremia with this organism is rare. We did not find an association with previously reported risk factors such as malignancies, systemic lupus erythematosus, or others.