NON-CULTURABLE LEGIONELLA-PNEUMOPHILA ASSOCIATED WITH ACANTHAMOEBA-CASTELLANII - DETECTION OF THE BACTERIUM USING DNA AMPLIFICATION AND HYBRIDIZATION

The intracellular localization of Legionella pneumophila serogroup 1 w ithin Acanthamoeba castellanii rendered the bacteria non-culturable on supplemented BCYE agar. DNA amplification, using two 19-mer primers, and hybridization using a 25-mer oligonucleotide probe, permitted dete ction of Leg. pneumophila in approximately 81% (29/36) of samples wher e the bacteria could not be detected using culture. A combination of c o-cultivation of samples with Leg. pneumophila-naive A. polyphaga or H artmannella vermiformis, incubation in a defined liquid medium or use of catalase indicated that approximately 31% (9/29) of the samples con tained Leg. pneumophila which were viable although not culturable.