eThe present study investigated the in vitro and the in vivo interactions among azithromycin, clarithromycin, minocycline, and tigecycline against Pythium insidiosum. In vitro antimicrobial activities were determined by the broth microdilution method in accordance with CLSI document M38-A2, and the antibiotic interactions were assayed using the checkerboard MIC format. In vivo efficacy was determined using a rabbit infection model. The geometric mean MICs of azithromycin, clarithromycin, minocycline, and tigecycline against P. insidiosum were, respectively, 1.91, 1.38, 0.91, and 0.79 g/ml. By checkerboard testing, all combinations resulted in in vitro synergistic interactions (>60%). Antagonism was not observed. The in vivo studies showed that azithromycin (20 mg/kg/day twice daily) alone or in combination with minocycline (10 mg/kg/day twice daily) significantly decreased the fungal burden. This study demonstrates that azithromycin possesses potent curative efficacy against subcutaneous pythiosis in the rabbit model.

Paraffin-embedded fragments of bovine digital skin lesions were sectioned and stained with Warthin-Starry, haematoxylin and eosin, Grocott's methenamine silver and immunohistochemical techniques. Microorganisms observed in the silver-stained sections were classified into four major morphological groups. Spirochaetes were the most prevalent organisms, but bacillary and coccoid elements were also present in most sections. Immunohistochemical probing demonstrated that approximately 80 per cent, 46 per cent and 41 per cent of the digital and interdigital dermatitis sections stained positively with polyclonal antisera to Treponema pallidum, Campylobacter jejuni and Fusobacterium necrophorum, respectively. An unidentified branching filamentous organism (presumed to be an actinomycete) was consistently present in the sections of samples from mild interdigital lesions.

Foram examinadas amostras de fígado, rins, baço e linfonodos hepáticos, mesentéricos, retro-mandibulares, pré-escapulares e mediastínicos de 12 lotes em um total de 120 animais, envolvendo diferentes faixas etárias, todos oriundos do Estado de Mato Grosso. Os animais haviam sido mantidos em pastos onde Brachiaria decumbens e Brachiaria brizantha eram as forrageiras predominantes. Macroscopicamente o fígado desses animais mostrava coloração amarelada, mais evidente após 24 horas de fixação em formol a 10%. Nos linfonodos hepáticos e mesentéricos foram evidenciadas, na superfície de corte, estriações esbranquiçadas de forma radiada na cortical e medular com pequenas áreas brancas nodulares multifocais principalmente na medular. Em muitos casos, associado com essas áreas foram vistos focos de aspecto hemorrágico. Microscopicamente foram encontradas, no fígado, linfonodos hepáticos e mesentéricos, células com citoplasma espumoso, muitas das quais multinucleadas. Nos linfonodos hepáticos e mesentéricos estes infiltrados estavam associados a áreas de necrose e hemorragia. No fígado, as células de citoplasma espumoso estavam presentes em todo parênquima, de forma irregular, geralmente formando nódulos ao redor da veia centrolobular. Estas células não se coravam pelo ácido periódico de Schiff (PAS) e apenas fracamente na coloração de gordura pelo Oil Red O. Na ultra-estrutura as células de citoplasma espumoso apresentavam fendas, parcial ou totalmente delimitadas por membrana, que representam a imagem negativa de cristais, presentes também no citoplasma dos hepatócitos.

Abstract. Cholangiohepatopathy was induced in 5 lambs by oral administration of extracts from signal grass (Brachiaria decumbens) in Brazil. Grossly there were pale foci multifocally distributed throughout the hepatic parenchyma in 4 lambs. The microscopic changes, which were similar to those produced by other steroidal sapogenins-containing plants such as Tribulus terrestris and Panicum spp., included multifocal cholangitis, bile duct proliferation, and the presence of crystals in the biliary system. Sporadic outbreaks of photosensitization in ruminants grazing on signal grass (Brachiaria decumbens) have been reported. 9,21 Cases of photosensitization occurring on this grass in Brazil had formerly been ascribed to intoxication by sporidesmin from spores of the saprophytic fungus Pithomyces chartarum. 2,7,8 However, the potential importance of steroidal saponins present in B. decumbens has been established, suggesting that photosensitization by this grass belongs to the group of plant-induced hepatogenous photosensitizations, 9,21 which are also induced by Panicum spp., 3,10,19 Tribulus terrestris, 11,16 Agave lecheguilla, 4 and Narthecium ossifragum. 17 All of these plants contain steroidal saponins and have been associated with cholangitis and deposition of crystals in the biliary system, causing photosensitization in sheep. Furthermore, steroidal sapogenins have been isolated from bile and biliary crystals of sheep fed those plants. 4,10,16,17 The plant saponins are converted by ruminal metabolism into ␤-D-glucuronides of sapogenins, which in the presence of calcium may precipitate, forming the characteristic biliary crystals. 14,21 Diosgenin and yamogenin have been detected from B. decumbens samples and from a mixture of metabolites in the rumen of sheep grazed on B. decumbens. 6,12,14,20 The arguments against involvement of P. chartarum in most Brazilian outbreaks include the low density or even absence of spores and the failure of most fungal isolates to produce sporidesmin. 5,6,[13][14][15]21 Typical photosensitivity has been reproduced in sheep grazing pure pastures of B. decumbens with no detected P. chartarum spores. 6 The aim of the present study was to reproduce hepatic lesions and photosensitization in sheep by oral administration of fractionated extracts from B. decumbens, as has been done with T. terrestris, 11,16 A. lecheguilla, 18 and N. ossifragum. 1 Counts of P. chartarum spores 15 were performed on pasture samples of plant material used for extraction. Forty kilograms of air-dried samples of B. decumbens were powdered and extracted by maceration, using 80 liters ethanol for 7 days at room temperature. A second maceration was performed, and the extracts were mixed. The solvent was evaporated, and the residual alcoholic phase was suspended in water and partitioned with dichloromethane, yielding the dichloromethane and aqueous fractions. After concentration in vacuum and at low temperature (Ͻ55 C), those fractions resulted in 500 g and 1.6 kg of syrupy residues, respectively, which corresponde...

Abstract. An aflatoxicosis outbreak affected 65 dogs from 9 different farms after they were fed diets with cooked corn meal as a common ingredient. Of the dogs, 60 died. Numerous dogs died on additional farms, but those dogs were not included in the study. The farmers acquired the contaminated maize products, in the form of whole corn grain or as corn meal, from the same supplier. The corn product was mixed with meat that was left over from home or commercial rations to form corn polenta, which was fed to the dogs. Necropsy was performed on 3 dogs. Two of the dogs died after a few days of refusing food, showing anorexia, polydipsia, icteric mucous membranes, hematemesis, hematochezia, or melena, and bleeding of the skin, eye, ear, and mouth. The primary necropsy findings included jaundice, hemorrhages in several organs, and yellowish enlarged liver with enhanced lobular pattern. The dog that experienced chronic ascites had a yellowish liver with reduced volume, irregular surface, and increased consistency. The main histological findings included hepatocyte fatty degeneration, biliary duct hyperplasia, cholestasis and, in the chronic case, hepatic fibrosis. High-performance liquid chromatography analysis of the corn meal from 2 affected farms revealed 1,640 ppb and 1,770 ppb of aflatoxin B 1 , respectively. The current study demonstrates an additional way that dogs can be exposed to, poisoned, and killed by aflatoxin.