Distribution of the stx1 and stx2 genes in Escherichia coli isolated from milk cattle according to season, age, and production scale in southwestern region of Goiás, Brazil / Distribuição dos genes stx1 e stx2 em Escherichia coli isoladas de bovinos de leite de acordo com a estação, idade e escala de produção na região sudoeste de Goiás, Brasil

This study determined the distribution of stx1 and stx2 genes in Escherichia coli isolated from dairy herds with regard to animal age, season, and farm production-scale, and analyzed the phylogenetic distribution of the groups A, B1, B2, and D of 276 isolates of bovine feces Shiga toxin-producing E. coli (STEC). The stx1 profile was the most common, detected in 20.4% (202/990) of the isolates, followed by stx2 (4.54%, 45/990) and stx1+stx2 (2.92%, 29/990). The stx1 gene was detected more frequently in calves than in adult animals. In the dry season (winter), the presence of stx1+stx2 profile in cattle feces was higher than in the rainy season (summer), while no significant changes were observed between seasons for the stx1 and stx2 profiles. The most predominant phylogenetic groups in adult animals were B1, A, and D, while groups A and B1 prevailed in calves. Our data highlight the importance of identifying STEC reservoirs, since 7.5% of the tested isolates were positive for stx2, the main profile responsible for the hemolytic-uremic syndrome (HUS). Moreover, these microorganisms are adapted to survive even in hostile environments and can contaminate the food production chain, posing a significant risk to consumers of animal products.(AU)

Esse estudo determinou a distribuição dos genes stx1 e stx2 em Escherichia coli isolados de rebanhos leiteiros em relação a idade, estação e produção, e analisaram a distribuição filogenética dos grupos A, B1, B2 e D de 276 E. coli produtoras de toxina Shiga (STEC). O perfil stx1 foi mais comum, detectado em 20,4% (202/990) dos isolados, seguido de stx2 (4,54%, 45/990) e stx1+stx2 (2,92%, 29/990). O gene stx1 foi detectado mais frequentemente em bezerros que animais adultos. No período de seca (inverno), a presença do perfil stx1+stx2 nas fezes dos bovinos foi mais prevalente que no período chuvoso (verão), apesar de não haver diferença significativa entre estações para os perfis stx1 e stx2. Os grupos filogenéticos mais predominantes em animais adultos foram B1, A e D, enquanto grupos A e B2 prevaleceram em bezerros. Nossos dados enfatizam a importância de se detectar reservatórios de STEC já que 7,5% dos isolados testados foram positivos para stx2, o perfil mais prevalente em casos de síndrome hemolítica-urêmica. Ademais, esses microorganismos são adaptados à sobreviver em ambientes hostis e contaminam a cadeia alimentar, levando a risco significativo para consumidores de alimentos de origem animal.(AU)

Serum γ - glutamyltransferase activity as an indicator of chronic liver injury in cattle with no clinical signs / γ - glutamiltransferase como indicador de lesão hepática crônica em bovinos sem sinais clínicos

This study aimed to determine the power of the serum aspartate aminotransferase (AST) and gamma-glutamyltransferasase (GGT) activities and of the albumin and cholesterol dosages for detecting hepatic histopathological injuries. A total of 220 healthy male Nelore cattle that had been extensively bred were evaluated. Blood and liver samples were collected on the day of slaughter for biochemical and histopathological tests. The results showed that the sensitivity to AST, GGT, albumin, and cholesterol tests were respectively 22.4%, 22.4%, 36%, and 37.2%.

Determinou-se a capacidade da dosagem das atividades séricas da aspartato aminotransferase (AST) e gama-glutamiltransferase (GGT) e das dosagens de albumina e de colesterol para a detecção de lesões histopatológicas hepáticas. Foram avaliados 220 bovinos, machos da raça Nelore, criados de forma extensiva. Amostras de sangue e de fígado foram coletadas para a realização dos testes histopatológicos e bioquímicos no dia do abate. Os resultados mostraram que a sensibilidade dos testes de AST, GGT, albumina e colesterol foram, respectivamente, de 22,4%, 22,4%, 36%, e 37,2%. A especificidade dos testes AST, GGT, albumina e colesterol foram, respectivamente, de 78,8%, 90,4%, 75,6% e 68,3%.

Detection of a resistance gradient to Passion fruit woodiness virus and selection of 'yellow' passion fruit plants under field conditions.

Productivity of 'yellow' passion fruit (Passiflora edulis Sims. f. flavicarpa O. Deg.) is reduced by infection with Cowpea aphid-borne mosaic virus (CABMV). We examined resistance in 72 yellow passion fruit plants grown from open-pollinated commercial seed. Plants were mechanically inoculated with CABMV virus and maintained in the field in order to select contrasting genotypes for resistance. Isolates were obtained from symptomatic leaves of yellow passion fruit plants from field production in Livramento de Nossa Senhora, Bahia state and were characterized by sequencing the viral coat protein gene. Severity of leaf symptoms of the disease, evaluated through a global leaf disease index, was measured during the eighth month of growth. Morpho-agronomic variables of fruit were evaluated from months 10 to 12. Significant linear regressions between the quantification of the leaf symptoms and the morpho-agronomic characteristics related to productivity were detected (5.17%

Virulence markers and serotypes of Shiga toxin-producing Escherichia coli, isolated from cattle in Rio Grande do Sul, Brazil.

AIMS: To determine the prevalence of Shiga toxin-producing Escherichia coli (STEC) and serotypes and virulence markers of the STEC isolates from beef and dairy cattle in Rio Grande do Sul, Brazil. METHODS AND RESULTS: Faecal samples from beef cattle were collected at slaughterhouses. The isolates were submitted to colony hybridization assay with specific DNA probes for stx1, stx2 and eae genes, and serotyped for the identification of O and H antigens. Thirty-nine per cent of beef cattle surveyed harboured at least one STEC strain. Among the distinct serotypes identified, 10 were shared by both beef and dairy cattle. Most of the strains isolated harboured stx2. Genotypic and phenotypic profiles allowed the identification of 34 and 31 STEC strains, isolated from beef and dairy cattle, respectively. Serotypes O10:H14, O15:H21, O96:H21, O119:H4, O124:H11, O128:H21, O137:H-, O141:H19, O159:H42, O160:H2 and O177:H11, identified in this study, have not been previously reported as STEC isolated from cattle. CONCLUSIONS: Cattle are an important reservoir of STEC strains associated with human diseases in South America. SIGNIFICANCE AND IMPACT OF THE STUDY: Determining the prevalence, genotypic profile and serotypes of STEC strains isolated from cattle enables the prediction of possible risk for public health.