A preliminary study of the molecular epidemiology of Brachyspira hyodysenteriaeisolates in Australia

摘要

Swine dysentery (SD) is a mucohaemorrhagic colitis of grower-finisher pigs. Affected pigs have faeces ranging from soft, yellow-grey to mucoid, bloody diarrhoea. Swine dysentery is one of the most economically significant enteric diseases of pigs in Australia due to its effect on growth rate, feed efficiency, mortality and the associated medication control costs. The classical causative agent is a strongly beta-haemolytic anaerobic intestinal spirochaete Brachyspira hyodysenteriae. Diagnosis of SD requires bacterial isolation and (or) identification using polymerase chain reaction (PCR). A number of PCR methods have been described for identifying B. hyodysenteriae. In this study, a multiplex PCR for B. hyodysenteriae, B. pilosicoli, L. intracellularis and Salmonella spp. including primers described by Elder et al. (1997) was compared with the PCR targeting N ADH oxidase (nox) as described by La et al. (2006). Multi-locus sequence typing (MLST) was used to determine the relatedncss of the B. hyodysenteriae isolates (La etal. 2009). The hypothesis was that isolates that were test-negative using the multiplex PCR but test-positive using the simple PCR were related but different to those positive on both PCR tests.