Protothecosis in Veterinary Medicine: a minireview.

Protothecosis is an important infection caused by Prototheca spp., an alga that affect humans and animals. Prototheca spp. infections determine losses of production and quality of life for the affected animals. In this disease, prevention and early diagnosis are essential to avoid the spread of the agent to susceptible hosts. This review aimed to assemble the reported cases of protothecosis in Veterinary Medicine, highlighting Prototheca species involved in the infections, the main animal species affected, as well as the clinical manifestations, diagnosis, and treatment. Our findings showed that protothecosis has been reported in various domestic and wild animal species, presenting diverse clinical manifestations, including mastitis in cows, respiratory manifestations in goats and cats, and a wide range of clinical signs in dogs. The clinical diagnosis and treatment of Prototheca spp. infections are difficult and infected animals are frequently discarded or euthanized. Due to the importance of this infection, protothecosis must be considered an important differential diagnosis in routine clinical Veterinary Medicine.

Biogenic silver nanoparticle (Bio-AgNP) has an antibacterial effect against carbapenem-resistant Acinetobacter baumannii with synergism and additivity when combined with polymyxin B.

AIMS: Carbapenem-resistant Acinetobacter baumannii represents a public health problem, and the search for new antibacterial drugs has become a priority. Here, we investigate the antibacterial activity of biogenic silver nanoparticles (Bio-AgNPs) synthesized by Fusarium oxysporum, used alone or in combination with polymyxin B against carbapenem-resistant A. baumannii. METHODS AND RESULTS: In this study, ATCC® 19606™ strain and four carbapenem-resistant A. baumannii strains were used. The antibacterial activity of Bio-AgNPs and its synergism with polymyxin B were determined using broth microdilution, checkboard methods and time-kill assays. The integrity of the bacterial cell membrane was monitored by protein leakage assay. In addition, the cytotoxicity in the VERO mammalian cell line was also evaluated, and the selectivity index was calculated. Bio-AgNPs have an antibacterial activity with MIC and MBC ranging from 0.460 to 1.870 µg/ml. The combination of polymyxin B and Bio-AgNPs presents synergy against four of the five strains tested and additivity against one strain in the checkerboard assay. Considering the time of cell death, Bio-AgNPs killed all carbapenem-resistant isolates and ATCC® 19606™ within 1 h. When combined, Bio-AgNPs presented 16-fold reduction of the polymyxin B MIC and showed a decrease in terms of viable A. baumannii cells in 4 h of treatment, with synergic and additive effects. Protein leakage was observed with increasing concentrations for Bio-AgNPs treatments. Additionally, Bio-AgNP and polymyxin B showed dose-dependent cytotoxicity against mammalian VERO cells and combined the cytotoxicity which was significantly reduced and presented a greater pharmacological safety. CONCLUSIONS: The results presented here indicate that Bio-AgNPs in combination with polymyxin B could represent a good alternative in the treatment of carbapenem-resistant A. baumannii. SIGNIFICANCE AND IMPACT OF STUDY: This study demonstrates the synergic effect between Bio-AgNPs and polymyxin B on carbapenem-resistant A. baumannii strains.

Leukoencephalomalacia in horses associated with immature corn consumption / Surto de leucoencefalomalacia em equinos associado ao consumo de milho verde

ABSTRACT: Horse leukoencephalomalacia (ELEM) is a disease caused by the ingestion of mycotoxins (fumonisins) produced by fungi of the genus Fusarium that infect corn and/or its byproducts. This disease has been described by ingestion of mature corn with humidity above 15% at temperatures below 20°C. The aim of this paper was to report an outbreak of leukoencephalomalacia in horses fed with immature corn. Two horses out of three showed neurological signs approximately seven days after eating immature corn in its reproductive phase (R2, milky grains). Corn was harvested and administered directly to the animals, with no storage. Deaths occurred approximately 24 hours after the onset of clinical signs. Grossly, there were multifocal dark red to brown areas in the white matter of the telencephalon and hyppocampus and thalamus. Histologically, there was edema and hemorrhage in several areas of the telencephalon white matter, which corresponded to dark red to brown areas observed in the macroscopy. There was also foci of malacia with presence of reactive astrocytes with abundant eosinophilic cytoplasm and inflammatory cells. Diffuse capillary wall degeneration and endothelial cell swelling were also observed. Two ppm of fumonisin were detected by immunoaffinity column method (VICAM) in the immature corn sample. The water activity in this cereal, when the grain is still milky, is 0.98 and can predispose it to growth of mycotoxin-producing fungi. In the present case, fumonisin was found in milky grains in the beginning of the reproductive phase (R2), which suggested that even immature corn may be infected by Fusarium spp. and should not be administered to horses.

RESUMO: A leucoencefalomalácia dos equinos (ELEM) é uma doença causada pela ingestão de micotoxinas (fumonisinas) produzidas por fungos do gênero Fusarium que infectam o milho e/ou seus subprodutos. A doença tem sido descrita pela ingestão de milho maduro com umidade acima de 15% em temperatura ambiente abaixo de 20°C. O objetivo deste trabalho foi relatar um surto de leucoencefalomacia em equinos alimentados com milho verde. Dois equinos de três animais apresentaram sinais clínicos neurológicos aproximadamente sete dias após iniciarem a ingestão de milho verde na fase reprodutiva (R2, grãos leitosos) com palha e talos, colhido no máximo 24 horas antes de ser administrado. A morte ocorreu aproximadamente 24 horas após o início dos sinais clínicos. Macroscopicamente havia no sistema nervoso central áreas multifocais acinzentadas e amareladas na substância branca do telencéfalo, no hipocampo e no tálamo. Histologicamente observou-se edema e hemorragia em diversas áreas da substância branca do telencéfalo, que correspondiam às áreas acinzentadas observadas na macroscopia. Havia, também, próximo as áreas hemorrágicas, focos de malacia com presença de astrócitos reativos com abundante citoplasma eosinophilico e algumas células inflamatórias. Degeneração das paredes dos capilares e tumefação das células endoteliais também foram observadas. Na análise da amostra de milho pelo método de colunas de imunoafinidade (VICAM) foram detectados 2ppm de fumonisina. A atividade de água neste cereal, quando o grão ainda está leitoso, é de 0,98, o que predispõe ao crescimento de fungos produtores de micotoxinas. No presente caso fumonisina foi encontrada nos grãos leitosos no início da fase reprodutiva (R2), o que sugere que mesmo o milho ainda imaturo pode estar infectado por Fusarium spp. e não deve, também, ser administrado aos equinos.