Characterisation of Dichelobacter nodosus and detection of Fusobacterium necrophorum and Treponema spp. in sheep with different clinical manifestations of footrot

• Published in: Veterinary microbiology 2015-08, Vol.179 (1-2), p.82-90
• Main Authors: Frosth, Sara, König, Ulrika, Nyman, Ann-Kristin, Pringle, Märit, Aspán, Anna
• Format: Article
• Language: English
• Subjects: Animals; Bacterial Proteins - genetics; Dichelobacter nodosus; Dichelobacter nodosus - genetics; Dichelobacter nodosus - immunology; Dichelobacter nodosus - isolation & purification; Foot Rot - microbiology; Foot Rot - pathology; Fusobacterium Infections - microbiology; Fusobacterium Infections - pathology; Fusobacterium Infections - veterinary; Fusobacterium necrophorum; Fusobacterium necrophorum - genetics; Fusobacterium necrophorum - isolation & purification; Gram-Negative Bacterial Infections - microbiology; Gram-Negative Bacterial Infections - pathology; Gram-Negative Bacterial Infections - veterinary; Ovine footrot; Pathobiology; Patobiologi; Serogroup; Sheep; Sheep Diseases - microbiology; Sheep Diseases - pathology; Treponema - genetics; Treponema - isolation & purification; Treponema spp; Treponemal Infections - microbiology; Treponemal Infections - pathology; Treponemal Infections - veterinary; Virulence
• ISSN: 0378-1135; 1873-2542; 1873-2542
• DOI: 10.1016/j.vetmic.2015.02.034

•D. nodosus and F. necrophorum were more commonly found in feet with footrot than in healthy feet.•Treponema spp. was common in both flocks and feet with and without footrot.•The majority of D. nodosus detected was benign and of six different serogroups.•Virulent D. nodosus was only detected in a single flock.•A significant association was found between feet with severe footrot lesions and the aprV2 gene. The aim of this study was to determine the proportion of Dichelobacter nodosus, Fusobacterium necrophorum and Treponema spp. in sheep with different clinical manifestations of footrot compared to healthy sheep both at flock and individual level. The second aim was to characterise D. nodosus with respect to virulence, presence of intA gene and the serogroups. Swab samples (n=1000) from footrot-affected (n=10) and healthy flocks (n=10) were analysed for the presence of D. nodosus, F. necrophorum and Treponema spp. by real-time PCR and culturing (D. nodosus only). Dichelobacter nodosus isolates (n=78) and positive swabs (n=474) were analysed by real-time PCR for the aprV2/B2 and the intA genes and by PCR for the fimA gene (isolates only). D. nodosus was more commonly found in flocks affected with footrot than in clinically healthy flocks. A significant association was found between feet with severe footrot lesions and the aprV2 gene and between feet with moderate or no lesions and the aprB2 gene, respectively. F. necrophorum was more commonly found in flocks with footrot lesions than in flocks without lesions. No significant association was found between sheep flocks affected with footrot and findings of Treponema spp. or the intA gene. Benign D. nodosus of six different serogroups was detected in twelve flocks and virulent D. nodosus of serogroup G in one. In conclusion, D. nodosus and F. necrophorum were more commonly found in feet with footrot than in healthy feet. The majority of D. nodosus detected was benign, while virulent D. nodosus was only detected in a single flock.