RESUMEN
Digital dermatitis (DD) is one of the main causes of lameness in dairy cattle worldwide, and it is frequently reported in high-yielding, free stall dairy herds from regions with a temperate climate. However, DD is also observed with high prevalence in grazing cattle with a low milk yield in tropical regions. To clarify whether these differences have an impact on the etiology of the disease, we studied DD lesions from all year round grazing cattle of mixed breed in Brazil using high-throughput 16S rRNA gene sequencing and fluorescent in situ hybridization. The study included samples from 66 skin lesions and 5 healthy skins collected from five farms. Both techniques showed Treponema spp. to be the most abundant bacteria, present in all but one of the samples with minimal epidermal alterations. We identified eleven different Treponema strains belonging to the six major phylotypes of Treponema which have all previously been identified in DD lesions. Furthermore, we identify Dichelobacter nodosus in DD lesions by gene sequencing and also by fluorescent in situ hybridization in almost half of biopsy specimens in areas with mild epithelial damage and together with Treponema. The present data support the hypothesis that Treponema constitutes the main pathogen responsible for DD, independent of the environment and region where cows are kept, and it further suggests D. nodosus as another potentially important pathogen.
Asunto(s)
Crianza de Animales Domésticos/métodos , Enfermedades de los Bovinos/microbiología , Dichelobacter nodosus/patogenicidad , Dermatitis Digital/microbiología , Infecciones por Bacterias Gramnegativas/veterinaria , Infecciones por Treponema/veterinaria , Animales , Biopsia , Brasil/epidemiología , Bovinos , Enfermedades de los Bovinos/epidemiología , Enfermedades de los Bovinos/patología , ADN Bacteriano/genética , ADN Bacteriano/aislamiento & purificación , Dichelobacter nodosus/genética , Dichelobacter nodosus/aislamiento & purificación , Dermatitis Digital/epidemiología , Dermatitis Digital/patología , Conducta Alimentaria , Femenino , Infecciones por Bacterias Gramnegativas/epidemiología , Infecciones por Bacterias Gramnegativas/microbiología , Infecciones por Bacterias Gramnegativas/patología , Herbivoria , Hibridación Fluorescente in Situ , Cojera Animal/epidemiología , Cojera Animal/microbiología , Cojera Animal/patología , Ribotipificación , Treponema/genética , Treponema/aislamiento & purificación , Infecciones por Treponema/epidemiología , Infecciones por Treponema/microbiología , Infecciones por Treponema/patologíaRESUMEN
Background: Pododermatitis or footrot is an infectious disease that affects the hoof and interdigital tissue of sheep causing lameness. The disease is caused by the interaction of the agent Dichelobacter nodosus and symbiotic bacteria in the complex environment of the epidermal tissues of the hoof and host immune system. D. nodosus is not able to invadehealthy hooves, so the infection is preceded by colonization of the interdigital skin by Fuso bacterium necrophorum. The aim of this research was to perform the isolation andcharacterization of D. nodosus in sheep farms of different municipalities of Bahia, obtaining the serogroups present in each herd.Materials, Methods & Results: The study was carried out in nine sheep farms from eight municipalities in the state of Bahia. All farms presented history of foot diseases. A total of 620 animals were observed, 140 of which were examined for lameness. To collect the contents of the lesions, sterile swabs were introduced into tubes containing sterile Thorley transport medium under refrigeration at 8°C and sent for laboratory analysis. Subsequently, each swab collected was seeded in two Petri dishes containing 4% hoof agar medium and incubated in anaerobic at 37°C for 96 hours. The purified samples were seeded on 2% hoof agar and incubated under the same conditions as above. The colonies were identified by the morphological characteristic and Gram staining. The DNA was extracted and stored at -20°C until its use in PCR, for identification and classification of D. nodosus in serogroups (A-I). In the nine farms visited were found animals with clinical signs of infectious pododermatitis. After processing, there was success of isolation in 39 samples (41%), confirming the presence of D. nodosus in all municipalities evaluated.[...]
Asunto(s)
Animales , Dichelobacter nodosus/aislamiento & purificación , Ovinos/microbiología , Panadizo Interdigital/epidemiología , Reacción en Cadena de la Polimerasa/métodos , Reacción en Cadena de la Polimerasa/veterinariaRESUMEN
Background: Pododermatitis or footrot is an infectious disease that affects the hoof and interdigital tissue of sheep causing lameness. The disease is caused by the interaction of the agent Dichelobacter nodosus and symbiotic bacteria in the complex environment of the epidermal tissues of the hoof and host immune system. D. nodosus is not able to invadehealthy hooves, so the infection is preceded by colonization of the interdigital skin by Fuso bacterium necrophorum. The aim of this research was to perform the isolation andcharacterization of D. nodosus in sheep farms of different municipalities of Bahia, obtaining the serogroups present in each herd.Materials, Methods & Results: The study was carried out in nine sheep farms from eight municipalities in the state of Bahia. All farms presented history of foot diseases. A total of 620 animals were observed, 140 of which were examined for lameness. To collect the contents of the lesions, sterile swabs were introduced into tubes containing sterile Thorley transport medium under refrigeration at 8°C and sent for laboratory analysis. Subsequently, each swab collected was seeded in two Petri dishes containing 4% hoof agar medium and incubated in anaerobic at 37°C for 96 hours. The purified samples were seeded on 2% hoof agar and incubated under the same conditions as above. The colonies were identified by the morphological characteristic and Gram staining. The DNA was extracted and stored at -20°C until its use in PCR, for identification and classification of D. nodosus in serogroups (A-I). In the nine farms visited were found animals with clinical signs of infectious pododermatitis. After processing, there was success of isolation in 39 samples (41%), confirming the presence of D. nodosus in all municipalities evaluated.[...](AU)