A distinct bacterial dysbiosis associated skin inflammation in ovine footrot

Abstract

Ovine footrot is a highly prevalent bacterial disease caused by Dichelobacter nodosus and characterised by the separation of the hoof horn from the underlying skin. The role of innate immune molecules and other bacterial communities in the development of footrot lesions remains unclear. This study shows a significant association between the high expression of IL1β and high D. nodosus load in footrot samples. Investigation of the microbial population identified distinct bacterial populations in the different disease stages and also depending on the level of inflammation. Treponema (34%), Mycoplasma (29%) and Porphyromonas (15%) were the most abundant genera associated with high levels of inflammation in footrot. In contrast, Acinetobacter (25%), Corynebacteria (17%) and Flavobacterium (17%) were the most abundant genera associated with high levels of inflammation in healthy feet. This demonstrates for the first time there is a distinct microbial community associated with footrot and high cytokine expression.

Detection and Serogrouping of Dichelobacter nodosus Infection by Use of Direct PCR from Lesion Swabs To Support Outbreak-Specific Vaccination for Virulent Footrot in Sheep

“…This may have been due to the physical characteristics of score 3 lesions rather than to the D. nodosus load; at the score 3 stage, the horn of the epidermis has begun to separate only recently, forming a small cavity that is relatively free of debris and of the necrotic material from which a noncontaminated specimen can be collected. Although the D. nodosus load was reported to be higher on feet with interdigital lesions than on feet with severe, underrun lesions (44,45,49), in those studies the specimens were collected from the interdigital skin rather than from the active margin of the lesion.…”

Peer Review #2 of "Novel inflammatory cell infiltration scoring system to investigate healthy and footrot affected ovine interdigital skin (v0.1)"

“…We have shown previously that mRNA expression of IL-1β, similar to inflammation scores, were comparable in healthy and footrot affected tissues in parallel samples from the same feet (Maboni et al 2017a). Here we analysed inflammatory scores, parakeratosis and presence of microabscesses in the context of IL-1β mRNA expression.…”

“…Preparation was as previously described (Maboni et al 2017a), in brief all samples were fixed using 10% (v/v) neutral buffered formalin; however to obtain optimal tissue integrity healthy biopsies were fixed for 48 hours at 4°C and footrot biopsies for 24 hours at room temperature (fixation and processing were optimised using two fixatives (10% v/v neutral buffered formalin verses 4% v/v paraformaldehyde), two incubation temperatures (room temperature verses 4°C) and two incubation times (24 hours verses 48 hours). An extended tissue processing protocol was used (60 minutes in dH 2 O, 4 hours in 50% ethanol, 4 hours in 70% ethanol, 16 hours in 90% ethanol, 4 hours in 100% ethanol, 4h in Xylene) followed by embedding into paraffin wax (2 hours, 60ºC).…”

Klaueninfektionen beim Schaf – Therapiemöglichkeiten in der tierärztlichen Praxis unter besonderer Berück sichtigung der Moderhinkebekämpfung

“…Der Versuch, Diagnosen per definitionem mit bestimmten Erregern zu verknüpfen, misslingt mit zunehmendem bakteriologischem Wissen. Fortlaufend steigt die Zahl der im Umfeld der Schafsklauen identifizierten Keime durch die Beschreibung neuer Bakterien und neuer Varianten bekannter Erreger (103,104), die zu der jeweiligen "microbial community" bei Klauenentzündungen gehören (61). Dabei ergeben sich mehr Fragen als Antworten in Bezug auf deren ätiologische Relevanz (23).…”