GENETIC RELATEDNESS AMONGST INTESTINAL SPIROCHETES ISOLATED FROM RATSAND BIRDS

Multilocus enzyme electrophoresis was used to determine genetic relati onships amongst 32 intestinal spirochaetes (Serpulina spp.) isolated f rom rats (17), rheas (7), chickens (4), ducks (2), a swan (1) and a fl amingo (1). The strains were divided into 20 electrophoretic types (ET s), with a mean genetic diversity per locus of 0.62. The results were compared with those previously published for porcine intestinal spiroc haetes. One strain from a healthy rat, and three rhea strains which we re recovered from cases of necrotizing typhlitis, were grouped in the same ETs as certain porcine strains of Serpulina hyodysenteriae. The r hea strains could be differentiated from these by pulsed-field gel ele ctrophoresis. Fifteen of the rat strains were genetically and phenotyp ically closely related. In contrast the avian strains were genetically more heterogeneous, with pathogenic isolates located in three differe nt genetic groups.