A Gram-negative Sporing Bacterium from the Rumen

Abstract

REPORTS in the literature of Gram-negative sporing bacteria are comparatively rare, although recently three have been mentioned^1–3, two from the rumen contents of cattle or sheep. We have obtained some Gram-negative sporing organisms during investigation of rumen bacteria. Three isolations were obtained from Gram-negative rods of the genera Bacteroides and Butyrivibrio ⁴ which had been isolated at different times from the rumens of sheep or cattle using a strictly anaerobic technique, based on that of Hungate⁵, with either xylose or xylan as carbohydrate. Sporing forms were first noted on reculturing freeze-dried cultures. It seemed unlikely that the sporing bacteria were airborne contaminants, and although they were, under some conditions, very similar in morphology to the Bacteroides and Butyrivibrio spp. their properties always differed from these bacteria even after continued anaerobic culturing.