Studies on endotoxin of Erwinia herbicola and their biological activity.

The endotoxin (lipopolysaccharide) preparations were extracted by the BOIVIN method from 10 strains of Erwinia herbicola isolated from the air of grain mills and from human and animal sources. It was found in assays for biological activity that these preparations had true endotoxic properties: lethality for mice, ability to produce primary inflammatory lesions in rabbit skin and ability to prepare rabbit skin for the local SHWARTZMAN reaction. Endotoxins obtained from five E. herbicola isolates were highly toxic and had mouse LD50 values ranging from 0.23 to 0.50 mg. The reparations derived from the remaining five strains were less potent with LD50 values ranging from 0.96 to 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 to 5.94 mug and had the ability to prepare the rabbit skin for the local SHWARTZMAN reaction in the mean threshold does (SPD50) of 2.97 to 95.0 mug. The endotoxic properties of the E. herbicola preparations were similar to those of simultaneously tested enterobacterial lipopolysaccharides. 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 two other endotoxic properties: ability to produce hemorrhagic lesions in rabbit skin after mixing with epinephrine and lethal effect on chick embryo. A preliminary chemical analysis of the trichloroacetic extracts of E. herbicola revealed low nitrogen and high carbohydrate contents as well as the presence of the common monosaccharides, reported in literature for endotoxins of various gram-negative bacteria. 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.