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.

Culturable Microbial Population From the Upper Respiratory Tract of 1,010 Clinically Healthy Horses in Southern Brazil.

Microbiological diagnosis of equine respiratory infections is essential for disease management. However, reliable diagnosis can be a challenge due to colonization of the upper respiratory tract (URT) by a diverse microbial population, and because there is a lack of studies with samples from healthy animals. Aiming to guide adequate URT culture, this work reports culturable microbial population from the URT of 1,010 apparently healthy horses from 341 farms in Southern Brazil and identifies the putative presence of pathogenic microorganisms. Nasal swabs were cultured in 5% blood agar, and the isolates were phenotypically identified to genus level. A diverse respiratory microbial population was found, mostly composed of Gram-positive bacteria, including Staphylococcus spp., Bacillus spp., Streptococcus spp. and Corynebacterium spp. The microbiological profile from the nasal cavity of 911 horses was described, with the five most common profiles being: (1) Staphylococcus sp. + Gram-negative bacilli (12.67%), (2) Staphylococcus sp. in pure culture (12.47%), (3) Staphylococcus sp. + Bacillus sp. (10.10%), (4) Gram-negative bacilli in pure culture (6.93%), and (5) Staphylococcus sp. + Bacillus sp. + Gram-negative bacilli (6.73%). Streptococcus equi equi and Rhodococcus equi were detected in 34 horses (3.37%), demonstrating the presence of pathogenic bacteria along with commensal microorganisms in apparently healthy animals. The disclosed data may guide and facilitate microbiological diagnosis of URT infection in horses. The significant presence of Gram-negative bacilli was evidenced, as well as the occurrence of relevant pathogens, such as S. equi equi and R. equi, thus helping to improve diagnosis and antimicrobial therapy.

Diagnosis of blackleg from cattle tissue impregnated in common filter paper / Diagnóstico de carbúnculo sintomático a partir de papel filtro comum impregnado com tecido bovino

ABSTRACT: Blackleg, an acute myonecrosis caused by Clostridium chauvoei, is usually underdiagnosed since the rapid transport of adequate samples for laboratory testing is difficult. This study tested a direct polymerase chain reaction (PCR) technique using common filter paper impregnated with cattle tissue samples obtained from animals suspected with blackleg. Twenty-five samples, belonging to eleven animals from Rio Grande do Sul State, Brazil, were analyzed. The direct PCR technique identified eight positive animals corroborating with results from microbiological culture. Skeletal muscle was the most common tissue type used in this study and when the animal was positive the pathogen was always detected in this tissue. Storage time of the impregnated filter paper at room temperature did not prove to be a limiting factor for the quality of the results indicating that this procedure can be carried out in the field and samples be sent in regular mail. Our results suggested that direct PCR of common filter paper impregnated with cattle tissue is a practical and economical alternative for the diagnosis of blackleg.

RESUMO: Carbúnculo sintomático, uma mionecrose aguda causada por Clostridium chauvoei, costuma ser subdiagnosticada, pois o transporte rápido de amostras adequadas para exames laboratoriais é complicado. O objetivo deste estudo foi testar a técnica de reação em cadeia da polimerase (PCR) direta, utilizando papel filtro comum impregnado com amostras de tecido bovino obtidas de animais suspeitos de carbúnculo sintomático. Foram analisadas 25 amostras, pertencentes a onze animais do estado do Rio Grande do Sul, Brasil. A técnica de PCR direta identificou oito animais positivos, corroborando com os resultados da cultura microbiológica. O músculo esquelético foi o tecido mais utilizado neste estudo e quando o animal foi positivo, o patógeno sempre foi detectado neste tecido. O tempo de armazenamento do papel filtro impregnado, à temperatura ambiente, não se mostrou um fator limitante para a qualidade dos resultados, indicando que esse procedimento pode ser realizado no local e as amostras enviadas por correio normal. Nossos resultados sugerem que a PCR direta usando papel filtro comum impregnado com tecido bovino é uma alternativa prática e econômica para o diagnóstico de carbúnculo sintomático.

Antigenic characterization of Moraxella bovis, Moraxella bovoculi and Moraxella ovis strains with potential use in vaccines.

Moraxella bovis is historically known as the primary agent of infectious bovine keratoconjunctivitis (IBK). However, Moraxella bovoculi and Moraxella ovis are also reported to be involved in the pathogenesis of IBK, therefore, these three species should be included in the development of a new vaccine with a broad-spectrum protection against the disease natural challenge. In this study we investigated the antigenic properties of clinical isolates and reference strains of M. bovis, M. bovoculi and M. ovis using a novel in vitro approach for vaccine evaluation based on two techniques, flow cytometry and western blotting (WB). Here, we demonstrated that rabbit antisera produced against reference M. bovis strain and commercial bacterin showed low number of IgG with capacity to recognize a panel of heterologous strains composed by M. bovoculi and M. ovis. On the other hand, the antisera generated against two clinical isolates of M. ovis (Mov2 and Mov3) presented high cross-reactivity levels against all M. ovis and M. bovis strains evaluated. Similarly, the antisera against Mbv3 (clinical isolate of M. bovoculi) had high levels of IgG associated on the surface of all M. bovoculi strains and most of the M. ovis strains analyzed. The WB analysis demonstrated that Moraxella spp. has multiple immunogenic antigens and most of them are shared between the three species. Based on the cross-reactivity analysis and considering the relative number of IgGs associated on the bacterial surface, we suggest that a multivalent vaccine including Mbv3, Mov2 and Mov3 strains may provide a strong and broad protection against all strains involved in IBK outbreaks.

Temporal profile of antimicrobial resistance exhibited by strains of Staphylococcus spp. isolated from cases of bovine mastitis for 20 years (1992-2011) / Perfil temporal da resistência antimicrobiana exibido por cepas de Staphylococcus spp. isoladas de casos de mastite bovina durante 20 anos (1992-2011)

Records of in vitro susceptibility tests performed between 1992 and 2011 were retrospectively reviewed in order to evaluate the dynamic profiles of possible changes in antimicrobial resistance of Staphylococcus spp. isolated from milk samples of cows with mastitis during two decades. The results of 2,430 isolates tested by disk diffusion technique for susceptibility to oxacillin, penicillin, ampicillin, cephalexin, norfloxacin, tetracycline, sulfazotrim, gentamicin, and neomycin were analysed. Comparisons were performed between the percentages of resistance to antimicrobials and their classes and also between the decades studied. Additionally, the possible tendency or changes in the behaviour of these pathogens against the major drugs used in the last two decades were evaluated using regression analysis. The highest rates of resistance (P<0.0001) were observed for the beta-lactams (34.3%), with exception of cephalexin (6.9%), and for the tetracyclines (28%). Similar resistance rates (7.6% to 15.7%) were observed among the other drugs. Regression analysis showed a reduction in resistance to penicillin and ampicillin throughout the period, whilst for oxacillin and neomycin a decrease in the resistance was observed during the first decade, followed by an increase. A trend towards decreased resistance was found for sulfazotrim, whereas for the other antimicrobials no decrease was observed. The results indicated no trend towards increased resistance for most antimicrobials tested. Nevertheless, it is necessary to monitor the resistance patterns of these pathogens in order to save these drugs as a therapeutic reserve.

Os registros de resultados de testes de suscetibilidade in vitro realizados no período de 1992 a 2011 foram revisados, retrospectivamente, a fim de avaliar a dinâmica de possíveis mudanças dos perfis de resistência de isolados de Staphylococcus spp., oriundos de amostras de leite de vacas com mastite ao longo do tempo. Os resultados de 2430 isolados testados pela técnica de difusão em disco para oxacilina, penicilina, ampicilina, cefalexina, norfloxacina, tetraciclina, sulfazotrim, gentamicina e neomicina foram analisados. Comparações entre as médias de resistência para os antimicrobianos e suas respectivas classes e em relação ao período analisado foram estabelecidas. O comportamento da resistência para cada antimicrobiano foi avaliado por meio de análise de regressão. As maiores taxas de resistência (P<0,0001) foram observadas para os betalactâmicos (34,3%), com exceção da cefalexina (6,9%), e tetraciclina (28%). Frente aos demais fármacos, os isolados apresentaram médias de resistência semelhantes entre si (de 7,6% a 15,7%). A análise de regressão demonstrou redução da resistência para penicilina e ampicilina ao longo do período analisado. Para a oxacilina e a neomicina, houve um decréscimo da resistência dos micro-organismos testados durante a primeira década; entretanto, houve um aumento no segundo período. Em relação ao sulfazotrim, foi verificada uma tendência à diminuição da resistência dos isolados, ao passo que, para os demais antimicrobianos, nenhum comportamento foi destacado. Os resultados não indicaram tendência de aumento da resistência dos isolados de Staphylococcus spp. para a maioria dos antimicrobianos testados. Contudo, é necessário monitorar os padrões de resistência destes patógenos, a fim de que estes fármacos sejam preservados para garantir uma reserva terapêutica.