agar and Dysentery

A method has been developed for separating Serpulina hyodysenteriae, a large spirochete and the causative agent of swine dysentery (SD), from other fecal anaerobic bacteria in rectal and colonic swabs. This was done by cutting the blood agar in parallel cuts and streaking perpendicular to the cuts in the center of the petri dish. Migration of S. hyodysenteriae from the central streak was apparent by the presence of strong beta-hemolysis along the edges of the cuts. If only S. hyodysenteriae migrated in the cut, they migrated to the end of the cut. However, if both motile bacteria and S. hyodysenteriae migrated in the cut, the motile bacteria migrated to the end of the cut where they formed colonies and the S. hyodysenteriae located along the edges of the cut between the colonies of motile bacteria and the central streak. Although motile bacteria were present where S. hyodysenteriae located, the growth of the motile bacteria was partially inhibited since they rarely formed visible colonies and were low in number. The cut in the agar was thought to improve traction for the serpentine movement of the S. hyodysenteriae and for the flagellar movement of the motile bacteria. Use of sliced blood agar was superior to conventionally streaked blood agar in that (i) it was easier to see strong beta-hemolysis on sliced agar; (ii) frequently, a confirmatory diagnosis could be made using only one petri dish with sliced agar, thereby saving time and media; (iii) S. hyodysenteriae could sometimes be isolated free of other bacteria; and (iv) sliced agar was more effective in isolating S. hyodysenteriae from swine with chronic diarrhea and nondiarrhetic carriers of SD in which the shedding of S. hyodysenteriae was low.

Topics: Agar; Animals; Bacteriological Techniques; Brachyspira hyodysenteriae; Colon; Dysentery; Evaluation Studies as Topic; Hemolysis; Rectum; Spirochaetales Infections; Swine; Swine Diseases

Optimal culture conditions in artificial nutritive media were determined for a defined avirulent strain of Treponema hyodysenteriae and for four field strains of treponemas in pigs with clinical dysentery. The treponemas were isolated with the use of milliporous filters with pores of 0.3 micrometer in diameter, which were located on the surface of blood agar. No significant difference in the influence of equine, bovine or sheep blood on the growth of treponemas was determined. The commercial amount of glucose in the used media, 2.0 to 2.5 g per 1,000 ml, was quite sufficient for the growth of the treponemas and it was not necessary to increase the amount. After reaching the optimal rate of growth the oxidoreduction potential was diminished by adding cystein or cystein hydrochloride and placing the Petri dishes with the media, prior to inoculation, into an anaerobic medium filled with hydrogen. The suitable composition of the culture atmosphere created in a special anaerostat comprised 0.4 to 1.0% carbon dioxide and the rest being hydrogen. Treponemas grew on the blood agar in zones with very slight hemolysis without forming separated colonies.

Topics: Agar; Animals; Blood; Culture Media; Dysentery; Horses; Intestine, Large; Sheep; Swine; Swine Diseases; Treponema

Topics: Agar; Antigens; Bacterial Infections; Dysentery; Precipitin Tests; Research; Shigella dysenteriae

Topics: Agar; Bacillus; Dysentery; Dysentery, Bacillary; Lacticaseibacillus casei; Yeast, Dried