A comparative study of spirochaetes from the porcine alimentary tract

Abstract

SUMMARYStrains ofTreponema hyodysenteriaecapable of inducing swine dysentery in specific pathogen-free pigs were compared with other spirochaetes from the porcine alimentary tract by biochemical and serological tests and by electrophoresis of their proteins. Carbohydrate fermentation and esculin hydrolysis were similar in all the spirochaetes. Indole was produced byT. hyodysenteriaeand by some of the other spirochaetes. Analysis of the fatty acids produced from glucose showed a difference betweenT. hyodysenteriaeand other spirochaetes only in the amount ofn-butyric acid produced. The indirect fluorescent antibody test showed extensive cross-reactions between all the spirochaetes unless antisera were first absorbed. A microtitre agglutination test and a growth-inhibition test were both more specific; strains ofT. hyodysenteriaecould be distinguished from the other spirochaetes using unabsorbed sera. Both tests revealed some antigenic heterogeneity among strains ofT. hyodysenteriae. The cell proteins of a single strain ofT. hyodysenteriaegave an electrophoretic pattern distinct from those of the other spirochaetes.Two of the six spirochaetes not associated with swine dysentery, PWS/B and PWS/C, were indistinguishable serologically and electrophoretically. The other four strains were serologically distinct from one another and from PWS/B and PWS/C. Only two of these spirochaetes were examined electrophoretically, but each gave a different pattern from PWS/B and PWS/C. The diversity observed among spirochaetes not associated with swine dysentery indicates that their suggested inclusion in a single species,T. innocens, may prove to be unjustified.