Quantitative Studies on Some of the Gram‐negative Anaerobic Bacteria in the Pig Alimentary Tract

摘要

Summary.A medium suitable for isolating some groups of Gram‐negative anaerobic bacteria from the pig alimentary tract is described. Colony counts were made of Gram‐negative anaerobes in the gut of pigs varying in age from 1 day to 6 months. The generaBacteroides, Veillonella, SphaerophorusandPeptostreptococcuswere recognized on the basis of morphology. TheBacteroidesspp. were of two morphological types: a coccobacillus, present only in pigs up to 18 days of age and a bacillus, present in all the pigs with the exception of those between the ages of 43 and 67 days. Veillonellae were absent from the gut of pigs up to 11 days of age and thereafter were usually the predominant anaerobic flora.Sphaerophorusspp. were not isolated until the pigs reached 43 days of age. Peptostreptococci were isolated only occasiona