STUDIES ON ENDOTOXINS OF ERWINIA HERBICOLA AND THEIR BIOLOGICAL-ACTIVITY

Abstract

The endotoxin (lipopolysaccharide [LPS]) preparations were extracted from 10 strains of E. herbicola isolated from the air of grain mills and from human and animal sources. These preparations had true endotoxic properties: lethality for mice, ability to produce primary inflammatory lesions in rabbit skin and ability to predispose rabbit skin for the local Shwartzman reaction. Endotoxins obtained from 5 E. herbicola isolates were highly toxic and had mouse LD50 values from 0.23-0.50 mg. The preparations derived from the remaining 5 strains were less potent with LD50 values from 0.96-2.83 mg. The endotoxins of E. herbicola caused primary skin lesions (edema and/or erythema) in rabbits in the mean threshold doses (SLD50) of 1.33-5.94 .mu.g and had the ability to predispose rabbit skin for the local Shwartzman reaction in the mean threshold doses (SPD50) of 2.97-95.0 .mu.g. The endotoxic properties of the E. herbicola preparations were similar to those of simultaneously tested enterobacterial LS. The results of the mouse toxicity tests were positively correlated with those of the rabbit skin tests. In the additional tests the single preparations of E. herbicola showed 2 other endotoxic properties: ability to produce hemorrhagic lesions in rabbit skin after mixing with epinephrine and lethal effect on chick embryos. A preliminary chemical analysis of trichloroacetic acid extracts of E. herbicola revealed low N and high carbohydrate contents; the common monosaccharides reported in literature for endotoxins of various gram-negative bacteria were present. The significance of the presence of endotoxins in the ubiquitous E. herbicola rods is discussed, particularly with respect to occupational health hazard resulting from inhalation of vegetable dusts containing these organisms.