A Newly Identified Bacterium Phenotypically Resembling, but Genetically Distinct from, Legionella pneumophila: An Isolate in a Case of Pneumonia

Abstract

A bacterium with growth characteristics similar to, but genetically distinct from, L. pneumophila or WIGA (a rickettsia-like agent) was obtained from a postmorten lung specimen of a patient with fatal atypical pneumonia at the M.D. Anderson Hospital and Tumor Institute in Houston, Texas [USA]. This bacterium and WIGA have essentially the same cellular fatty acid composition, which is distinct from that of L. pneumophila. DNA-relatedness studies show that the isolate from Texas is only about 10% related to L. pneumophila and WIGA and may represent a new species. This new bacterium should be considered in selecting laboratory procedures in the diagnosis of atypical pneumonia.