RESUMO
In the equine carbohydrate overload model of acute laminitis, disease progression is associated with changes in bacteria found in the cecum. To date, research has focused on changes in specific Gram-positive bacteria in this portion of the intestinal tract. Metagenomic methods are now available making it possible to interrogate microbial communities using animal protocols that sufficiently power a study. In this study, the microbiota in cecal fluid collected from control, non-laminitic horses (n=8) and from horses with early-stage acute laminitis induced with either oligofructan (n=6) or cornstarch (n=6) were profiled. The microbiota were identified based on sequencing the V4 hypervariable region of the 16S rRNA gene. The results of the study show that the relative abundance of Lactobacillus sp. and Streptococcus sp. increased significantly (p<0.05) following OF and CS infusion. Other significant changes included an increase (p<0.05) in relative abundance of Veillonella sp. and Serratia sp., two potentially pathogenic, Gram-negative bacteria. Significant decreases in the relative abundance of presumptive normal flora were detected as well. Although changes in cecal microbiota described in this communication are from a pilot study, it is hypothesized that an overgrowth of pathogenic Gram-negative bacteria develops and contributes to enterocolitis, pyrexia and lameness in the carbohydrate overload model of acute laminitis.
Assuntos
Infecções Bacterianas/veterinária , Ceco/microbiologia , Doenças do Pé/veterinária , Doenças dos Cavalos/microbiologia , Microbiota , RNA Ribossômico 16S/genética , Doença Aguda , Animais , Infecções Bacterianas/patologia , Ceco/patologia , Carboidratos da Dieta/farmacologia , Doenças do Pé/etiologia , Doenças do Pé/patologia , Genes de RNAr , Doenças dos Cavalos/etiologia , Doenças dos Cavalos/patologia , Cavalos , Lactobacillus/genética , Coxeadura Animal/etiologia , Coxeadura Animal/microbiologia , Coxeadura Animal/patologia , Serratia/genética , Streptococcus/classificação , Streptococcus/genética , Veillonella/genéticaRESUMO
Carbohydrate overload models of equine acute laminitis are used to study the development of lameness. It is hypothesized that a diet-induced shift in cecal bacterial communities contributes to the development of the pro-inflammatory state that progresses to laminar failure. It is proposed that vasoactive amines, protease activators and endotoxin, all bacterial derived bioactive metabolites, play a role in disease development. Questions regarding the oral bioavailability of many of the bacterial derived bioactive metabolites remain. This study evaluates the possibility that a carbohydrate-induced overgrowth of potentially pathogenic cecal bacteria occurs and that bacterial translocation contributes toward the development of the pro-inflammatory state. Two groups of mixed-breed horses were used, those with laminitis induced by cornstarch (n=6) or oligofructan (n=6) and non-laminitic controls (n=8). Cecal fluid and tissue homogenates of extra-intestinal sites including the laminae were used to enumerate Gram-negative and -positive bacteria. Horses that developed Obel grade2 lameness, revealed a significant overgrowth of potentially pathogenic Gram-positive and Gram-negative intestinal bacteria within the cecal fluid. Although colonization of extra-intestinal sites with potentially pathogenic bacteria was not detected, results of this study indicate that cecal/colonic lymphadenopathy and eosinophilia develop in horses progressing to lameness. It is hypothesized that the pro-inflammatory state in carbohydrate overload models of equine acute laminitis is driven by an immune response to the rapid overgrowth of Gram-positive and Gram-negative cecal bacterial communities in the gut. Further equine research is indicated to study the immunological response, involving the lymphatic system that develops in the model.
Assuntos
Bactérias , Ceco/microbiologia , Colo/microbiologia , Doenças do Pé/veterinária , Doenças dos Cavalos/microbiologia , Coxeadura Animal/microbiologia , Animais , Infecções Bacterianas/veterinária , Carga Bacteriana , Endotoxinas/metabolismo , Doenças do Pé/microbiologia , Doenças do Pé/patologia , Frutanos , Casco e Garras/metabolismo , Casco e Garras/patologia , Doenças dos Cavalos/imunologia , Doenças dos Cavalos/patologia , Cavalos , Inflamação/veterinária , Coxeadura Animal/induzido quimicamente , Coxeadura Animal/imunologia , Coxeadura Animal/patologia , Linfonodos/imunologia , Linfonodos/microbiologia , Linfonodos/patologia , AmidoRESUMO
A common sequella of chronic laminitis in horses is repeated abscesses with variable lameness and drainage. It is unclear whether the exudate represents the debridement phase of a non-septic inflammatory process involving clearance of laminar tissue damaged during the acute episode of laminitis, or a response to a microbial infection developed by ascent of microbes from the environment to the tissue via the white line. The objective of this study was to evaluate the possibility that an undiagnosed microbial infection in laminar tissue is present in laminar tissue collected from chronically laminitic horses without an active hoof abscess. Methods to collect laminar tissue, aseptically, from control (non-laminitic) horses and those with chronic/recurrent laminitis are described. Laminae homogenates were evaluated for the presence of bacteria. Bacteria were identified using biochemical tests and sequencing of 16S rRNA and virulence genes. Laminae from chronically laminitic horses revealed 100-fold higher levels (P=0.002) of bacteria compared to control, non-laminitic horses. Although environmental organisms were identified, potential pathogens were identified. Included were Gram positive bacteria, Brevibacterium luteolum, coagulase-negative Staphylococcus spp. as well as Gram negative bacteria, enterohemorrhagic Escherichia coli and Alcaligenes faecalis. Further research is warranted to evaluate the role of bacteria in equine chronic laminitis.
Assuntos
Infecções Bacterianas/microbiologia , Infecções Bacterianas/patologia , Fenômenos Fisiológicos Bacterianos , Doenças do Pé/veterinária , Casco e Garras/microbiologia , Doenças dos Cavalos/microbiologia , Doenças dos Cavalos/patologia , Animais , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Carga Bacteriana , Brevibacterium/classificação , Brevibacterium/genética , Feminino , Doenças do Pé/microbiologia , Doenças do Pé/patologia , Cavalos , Masculino , Dados de Sequência Molecular , Filogenia , RNA Ribossômico 16S/genéticaAssuntos
Membro Posterior/diagnóstico por imagem , Doenças dos Cavalos/tratamento farmacológico , Cavalos/lesões , Luxação Patelar/veterinária , Animais , Anti-Inflamatórios/uso terapêutico , Membro Posterior/patologia , Masculino , Luxação Patelar/diagnóstico por imagem , Luxação Patelar/terapia , RadiografiaRESUMO
ANIMAL STUDIED: A 6-year-old, pregnant female llama experienced a 6-month history of epiphora, buphthalmos, and acute loss of vision in the left eye. The condition was unresponsive to topical antimicrobial and anti-inflammatory therapy and progressed to corneal rupture. PROCEDURES: Transpalpebral enucleation was performed and an intraorbital silicone prosthesis was implanted. The eye was fixed in formalin and processed according to routine paraffin technique. Sections of a mass were immunohistochemically prepared routinely and stained for glial fibrillary acidic protein (GFAP), S-antigen, and rhodopsin. RESULTS: Gross, histopathologic, and immunohistochemical analysis revealed a retinal tumor consistent with a retinoblastoma. The neoplastic tissue formed Flexner-Wintersteiner and Homer-Wright rosettes, originated from the retina, and demonstrated photoreceptor differentiation with S-antigen and rhodopsin expression. Neoplastic cells were negative for GFAP. Four years after enucleation, the llama showed no signs of recurrent neoplasia. CONCLUSIONS: This report describes the diagnosis and successful treatment of the first known retinoblastoma in a llama.