Determination of antigenic relationships among legionellae and non-legionellae by direct fluorescent-antibody and immunodiffusion tests.
Six isolates, five from water samples and one from a human tracheal swab taken at autopsy, reacted strongly with working dilutions of Legionella fluorescent-antibody conjugates. Of these, two isolates of Pseudomonas fluorescens (EB and CDC93), one isolate of the Flavobacterium-Xanthomonas group (CDC65), and one isolate of P. alcaligenes (CDC11) reacted with Legionella pneumophila serogroup 1 conjugate. P. alcaligenes ABB 50 reacted with an L. pneumophila serogroup 3 conjugate and of P. maltophilia reacted with the L. micdadei conjugate. Antisera and labeled conjugates were prepared for these new cross-reacting isolates, and their relationships to the legionellae were examined by direct fluorescent-antibody and immunodiffusion tests. A nonreciprocal cross-reaction existed between L. micdadei and P. maltophilia and also between serogroups 3 of L. pneumophila and P. alcaligenes ABB50. Of the four isolates that reacted with serogroup 1 of L. pneumophila, P. fluorescens CDC93 had the strongest relationship, and the other three had only minor relationships. Although cross-reactivity among non-legionellae and legionellae has not been a major problem, these findings are relevant to the interpretation of direct fluorescent-antibody tests for detecting these bacteria.
D000942:Antigens, Bacterial / Q000032:analysis*; D003429:Cross Reactions; D005417:Flavobacterium / Q000276:immunology; D005455:Fluorescent Antibody Technique; D006801:Humans; D005779:Immunodiffusion; D007875:Legionella / Q000276:immunology*; D011549:Pseudomonas / Q000276:immunology*; D012703:Serotyping; D014132:Trachea / Q000382:microbiology; D014871:Water Microbiology; D014974:Xanthomonas / Q000276:immunology
D000942:Antigens, Bacterial