Anaerobic respiration of fumarate as a differential test betweenCampylobacter fetus andCampylobacter jejuni

The effect of formate and of various electron acceptors—fumarate, aspartate, or nitrate—on the growth of 36 catalase-producingCampylobacter strains was quantitatively investigated in a semisynthetic medium, under aerobic (5% oxygen, 10% carbon dioxide, 85% nitrogen) or anaerobic (10% carbon dioxide, 90% nitrogen) conditions. Under anaerobic conditions, 24 strains ofC. jejuni failed to grow, or grew poorly, in the presence of fumarate, whereas ten strains ofC. fetus subsp.fetus and two strains ofC. fetus subsp.venerealis grew abundantly, rather better than under aerobic conditions. The quantitative differences of growth yields were very significant between the two species with fumarate, but less pronounced with aspartate or nitrate. The activity of fumarate-reductase inC. fetus was substantiated by identification of relevant metabolites by gas liquid chromatography and by mass spectrometry. The anaerobic fumarate respiration in the genusCampylobacter has taxonomic implications.