title: "Endotoxicity" of the Legionnaires' disease bacterium.
abstract: The Legionnaires' disease (LD) bacterium is a gram-negative organism whose "endotoxicity" appears to differ in several respects from the classic endotoxicity generally associated with gram-negative bacteria. Discrepancies were noted between the high activity of LD bacteria in gelating limulus lysate in vitro and their low pyrogenicity in rabbits. Further in-vivo biologic tests indicated that LD bacteria were relatively weak in "endotoxicity". Analysis of LD bacterial cells and in their cellular fractions by gas-liquid chromatography indicated that LD bacteria did not contain hydroxy fatty acids commonly associated with lipid A of endotoxin. The branched-chain fatty acids that were characteristic of LD bacteria were associated with the cell envelope, and were readily extracted into organic solvents without prior saponification. The presence of 2-keto-3-deoxyoctonate in LD bacteria and cell extracts was detected by a microassay method but remains to be confirmed with gas-liquid chromatography and mass spectrometry. The active principle "endotoxicity" in LD bacteria may be a new type of bacterial lipopolysaccharide.
mesh_terms: D000818:Animals; D001419:Bacteria / Q000032:analysis / Q000187:drug effects / Q000472:pathogenicity*; D002210:Caprylates / Q000032:analysis; D004731:Endotoxins / Q000032:analysis* / Q000633:toxicity; D007877:Legionnaires' Disease / Q000382:microbiology*; D008033:Limulus Test; D008070:Lipopolysaccharides / Q000032:analysis; D008297:Male; D051379:Mice; D011112:Polymyxin B / Q000494:pharmacology; D011817:Rabbits
chemical_list: D002210:Caprylates; D004731:Endotoxins; D008070:Lipopolysaccharides; D011112:Polymyxin B