Abstract
Variability among 29 clinical and environmental strains of Legionella dumoffii was investigated by multilocus enzyme analysis by use of starch gel electrophoresis. Based on results of analysis at 20 enzyme loci, the strains were separated into five closely related electrophoretic types (ETs), which were clearly distinguished from 53 strains representing 53 ETs of L. pneumophila. DNA hybridization results (hydroxyapatite method, 60 and 75 degrees C) for representative strains confirmed that all L. dumoffii ETs were a single genetic species. Although multilocus enzyme analysis indicated that L. dumoffii was genetically a quite uniform species, sufficient variability existed to warrant electromorph fingerprinting for epidemiologic studies.