Legionella pneumophila serogroup 9: a cause of human pneumonia

Ann Intern Med. 1984 Aug;101(2):196-8. doi: 10.7326/0003-4819-101-2-196.


A new serogroup of Legionella pneumophila was isolated from bronchoscopic washings and an open-lung biopsy specimen of a patient from California with pneumonia. A serologically identical isolate was obtained from tap water of a hospital ward in the Netherlands, and a fatal case of pneumonia in a patient from Virginia was shown retrospectively to have been caused by this new organism. The type strain of what is now serogroup 9 of L. pneumophila is IN-23-G1-C2 (American Type Culture Collection no. 35289). Disease caused by L. pneumophila serogroup 9 is not apparently different from that caused by other L. pneumophila serogroups.

Publication types

  • Case Reports
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Agglutination Tests
  • Bacterial Infections / microbiology*
  • Bacteriological Techniques
  • Female
  • Fluorescent Antibody Technique
  • Humans
  • Legionella / classification*
  • Legionella / isolation & purification
  • Legionnaires' Disease / microbiology
  • Male
  • Middle Aged
  • Pneumonia / microbiology*
  • Serotyping
  • Water Microbiology