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Anaerobe 15 (2009) 177
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Anaerobe
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The detection of Dichelobacter nodosus and Fusobacterium necrophorum fromfootrot lesions in New Zealand goats
Detection of both Fusobacterium necrophorum (F. necrophorum)and Dichelobacter nodosus (D. nodosus) has been shown to be highlyassociated with under-running footrot in sheep [1]. Footrot in goatsis considered a similar disease to sheep and D. nodosus has beenreported as an agent causing footrot in goats [2]. Using a previouslydescribed PCR diagnostic method [1] we undertook an experimentto see if F. necrophorum was associated with footrot in New Zealandgoats, as has been shown in sheep [1].
Swabs were taken from the skin-horn junction of healthy goats(n¼ 20) and goats with under-running footrot (n¼ 24). Oncereturned, swabs were stored at �80 �C, until DNA was extractedand a single fimA and ltkA PCR was performed as previouslydescribed [1].
Neither D. nodosus nor F. necrophorum was detected on the 20swabs taken from healthy goats. In contrast, 62.5% (15/24) of swabsfrom goats with under-running footrot tested positive for D. nodo-sus and 33.3% (8/24) swabs were positive for F. necrophorum. WhenF. necrophorum was detected on a swab, D. nodosus was alsodetected on 87.5% (7/8) of the swabs. D. nodosus was detected on53.3% (8/15) of swabs without any F. necrophorum being detectable.A previously described [1] log linear model was used to analyse thisdata. Detection of D. nodosus was found to be highly associated withunder-running footrot (P< 0.0005), as was detection of F. necropho-rum (P< 0.002). D. nodosus and F. necrophorum also tended to bedetected together, rather than singularly (P< 0.039).
These findings are similar to those presented previously forsheep with footrot [1]. However, it is notable that a large portionof swabs were negative for both D. nodosus and F. necrophorum.This would suggest either that the PCRs used lacked sensitivityand/or were inhibited by other compounds extracted from theswab, or that the sampling procedure was not contacting the organ-isms present. We consider the latter argument more likely, giventhat the skin–horn junction of the hoof was sampled rather thanfootrot lesions, which are variable in both location and accessibility.While sampling of this region was considered to be more consistentin practice, the swabs used may have failed to come in contact withthe expected microflora.
It was also observed that there was a high number of swabs withonly D. nodosus being detectable (8/15) compared to F. necrophorum
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(1/8). This was in contrast with footrot in sheep where D. nodosusand F. necrophorum were detected in similar proportions usingsimilar PCR technologies [1]. This supports the argument that thefailure to detect the organisms on some hooves is a function ofthe sampling procedure used, or that footrot is actually a differentdisease in goats.
Acknowledgements
We would like to thank the participating New Zealand Goatfarmers and the Lincoln University Gene-Marker Laboratory. Thiswork has been funded by the Struthers Scholarship, the InglebyCompany Limited Pastoral Scholarship and the Hellaby IndigenousGrasslands Research Trust.
References
[1] Bennett G, Hickford JGH, Sedcole R, Zhou H. Dichelobacter nodosus, Fusobacte-rium necrophorum and the epidemiology of footrot. Anaerobe 2009;15(4):173–6.
[2] Claxton PD, O’Grady KC. Footrot in goats and characterisation of caprine isolatesof Bacteroides nodosus. In: Stewart DJ, Peterson JE, McKern NM, Emery DL,editors. Footrot in ruminants. Proceedings of a workshop, Melbourne 1985.Sydney: CSIRO Division of Animal Health and Australian Wool Corporation;1986. p. 119–23.
Grant BennettAyla van Loenen
Huitong ZhouRichard Sedcole
Jon Hickford*
Agriculture and Life Sciences Division,Lincoln University, Lincoln 7647, New Zealand
� Corresponding author. Tel.: þ64 3 325 2811;fax: þ64 3 325 3851.
E-mail address: [email protected] (J. Hickford)
19 December 2008
Available online 25 February 2009
