First identification and characterisation of in pigs in Hong Kong.

Swine dysentery (SD) is an important endemic disease of pigs throughout the world. The most common aetiological agent is the anaerobic intestinal spirochaete The related spirochaete causes a milder form of colitis. We report the first isolation of and from a pig farm in Hong Kong. Faecal samples containing mucus or fresh blood were collected from the ground where finisher pigs had just been loaded into a truck for transport to the abattoir. The samples were subjected to selective anaerobic culture and PCR for and , and two isolates of both species were obtained. The isolates showed clinical resistance to tylosin and lincomycin, whilst the isolates were resistant to tylosin and showed intermediate susceptibility to lincomycin. The isolates were subjected to multilocus sequence typing and a single previously undescribed sequence type (ST250) was identified. Disease was not recorded in other pigs on the farm, but it may have been masked by the use of antimicrobials. Further work is required to examine the distribution of these two pathogens in this and other farms in Hong Kong and in adjoining mainland China.