d-ribose utilisation differentiates porcine Brachyspira pilosicoli from other porcine Brachyspira species

d-ribose utilisation was studied in 60 Brachyspira pilosicoli strains and 35 strains of other Brachyspira species, the majority of which were of porcine origin. Utilisation of d-ribose was demonstrated indirectly by measuring the reduction in pH of densely inoculated tryptone–peptone broth supplemented with 7% foetal calf serum and 1% d-ribose. Among B. pilosicoli strains, the mean reduction in pH units was 1.72 (range 0.95–2.28) in broth with d-ribose and 0.27 (range 0.10–0.40) in sugar-free control broth. For Brachyspira strains other than B. pilosicoli, the corresponding reductions in pH units were 0.37 (range 0.12–0.49) and 0.37 (range 0.15–0.58). In conclusion, porcine B. pilosicoli can be differentiated from other porcine Brachyspira species by a test for d-ribose utilisation.