Extensive diversity in New Zealand Dichelobacter nodosus strains from infected sheep and goats

Footrot is a contagious bacterial disease of ruminants spread by the Gram-n egative, anaerobic organism, Dichelobacter nodosus. It is endemic in New Ze aland and throughout sheep and goat farming regions of the world. Using the polymerase chain reaction (PCR) to amplify fragments of the fimbrial gene fimA), D. nodosus was detected in 14 hoof scrapings, sampled from six farmi ng regions within New Zealand. DNA sequencing revealed 15 strains covering eight serogroups on the New Zealand farms. The predominant serogroup was B which contained six strains, followed by serogroups F, H and G. No strains from serogroups D and I were detected in this investigation. Eleven out of the 15 D. nodosus strains had fimbriae sequences different to those previou sly reported and the presence of multiple strains on a single hoof was comm on (86% samples). Individual sheep from the same farm, or the same paddock, were often infected by a different range of strains, which suggests a host role in mediating footrot infection. (C) 2000 Elsevier Science B.V. All ri ghts reserved.