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.

Molecular characterization of virulence genes cctA, nanA, and fliC in Clostridium chauvoei from Rio Grande do Sul and São Paulo State, Brazil / Caracterização molecular dos genes de virulência cctA, nanA e fliC em Clostridium chauvoei isolados no Rio Grande do Sul e São Paulo, Brasil

ABSTRACT: Clostridium chauvoei toxin A (CctA), neuraminidase (NanA), and flagellin (FliC) proteins contribute to the pathogenicity of Clostridium chauvoei, the causative agent of blackleg in cattle. The aim of this study was to analyze the genetic variability of cctA, nanA, and fliC genes in C. chauvoei isolates from the Rio Grande do Sul and São Paulo state- Brazil, during different sampling periods. The presence of these genes was verified through PCR amplification and partial gene sequencing of 17 strains. Alignment of PCR amplicons combined with bioinformatics analysis was used in an attempt to study the variability across C. chauvoei solates. The similarity among the partial sequences of cctA and nanA genes was 100%. The sequencing of fliC revealed three different paralog alleles of flagellin, and two strains were seen to be polymorphic, with amino acid alterations in the predicted protein. Overall, this study indicates that strains of C. chauvoei isolated in Brazil are highly conserved with respect to the virulence factors evaluated.

RESUMO: Toxina A de Clostridium chauvoei (CctA), neuraminidase (NanA) e flagelina (FliC) são proteínas que contribuem para a patogenicidade de Clostridium chauvoei, o agente causador do carbúnculo sintomático em bovinos. O objetivo deste estudo foi analisar a variabilidade genética dos genes cctA, nanA, e fliC em C. chauvoei isolados em diferentes períodos no Rio Grande do Sul e São Paulo. A presença destes genes foi verificada pela amplificação dos produtos da PCR e sequenciamento parcial dos genes de 17 cepas. Os alinhamentos da amplificação dos produtos da PCR combinados com a análise de bioinformática foram utilizados na tentativa de avaliar a variabilidade dos genes entre os isolados de C. chauvoei. A similaridade do sequenciamento parcial dos genes cctA e nanA foi 100%. O sequenciamento do fliC revelou três alelos paralogos diferentes de flagelina e duas cepas mostraram polimorfismos, causando alterações na sequência de aminoácidos. As cepas de C. chauvoei isoladas no Brasil mostraram-se altamente conservadas em relação aos fatores de virulência avaliados neste estudo.

Acute myonecrosis in horse caused by Clostridium novyi type A

The objective of this study was to describe the first report involving a case of equine acute myonecrosis caused by C. novyi type A with an emphasis on clinical signs, the pathological and bacteriological analysis, and molecular identification of the microorganisms as the key of the definitive diagnosis.

Stability evaluation of propolis topical bases for veterinary use

This study aimed to evaluate and select different dermatological bases incorporated with propolis for veterinary use as well as to analyze the chemical compounds of the propolis hydroalcoholic extract by LC-MS/MS. Thus, formulations were submitted to accelerated stability tests under different temperatures and to mechanical stress, and evaluated for the appearance, color, odor, pH, viscosity, spreadability, and the mean size of the dispersed globules from the internal phase during a period of three months. The creamy gel formulation showed satisfactory results for all the evaluated items with an excellent capability to incorporate the hydroalcoholic extract of propolis associated to the maintenance of its physicochemical properties. The propolis used in this study had been shown to possess antibacterial and antifungal in vitro activity against the main microorganisms responsible for such diseases. Therefore, the propolis creamy gel described here could be a promising formulation for use in the veterinary medicine.