Abstract
A 74-year-old woman with a history of pure red cell aplasia and hypogammaglobulinemia developed pneumonia. A urine antigen test and sputum subculture on buffered charcoal yeast extract (BCYE)α agar were positive for Legionella pneumophila. Serological testing identified L. pneumophila serogroup 2. An aerobic blood culture also became positive on day 5; its subculture on BCYEα agar revealed the same pathogen, but that on blood agar revealed Helicobacter cinaedi. We thus diagnosed her with bacteremia caused by both pathogens. Hence, in cases of H. cinaedi bacteremia along with pneumonia, the screening of other pathogens including L. pneumophila is needed.