Escherichia coli ST224 and IncF/blaCTX-M-55 plasmids drive resistance to extended-spectrum cephalosporins in poultry flocks in Parana, Brazil.

Resistant Enterobacterales of avian intestinal origin can contaminate carcasses during broiler processing and thereby spread through the human food chain. This study aimed at assessing the prevalence, diversity and genomic characteristics of ESBL/AmpC Enterobacterales in poultry flocks from different farms and cities in the state of Paraná, Brazil. Enterobacterales isolated from cloacal samples were subjected to antimicrobial susceptibility testing (AST). ESBL/AmpC isolates were whole-genome sequenced and subjected to S1-nuclease pulsed-field gel electrophoresis (S1-PFGE) followed by Southern blotting to determine the location of resistant genes on plasmids. A surprisingly high proportion of E. coli (40.6 %) collected on non-selective plates presented an ESBL/AmpC phenotype. Multidrug resistance was statistically not higher in ESBL/AmpC E. coli having the potential to be Avian Pathogenic (APEC-like) compared to non-APEC-like ESBL/AmpC E. coli isolates. Resistance to antibiotics not authorized for use in poultry in the State of Paraná was observed, suggesting that antimicrobial resistance (AMR) is co-selected by the use of veterinary-licensed antibiotics. Phylogenetic analyzes revealed the presence of identical or highly similar ESBL/AmpC E. coli clones on farms distant up to 100 km of each other; this strongly suggests that the centralization and verticalization of the poultry industry can facilitate the spread of resistant bacteria among different farms, companies, and cities. The molecular characterization of clones and plasmids proved the dominance of the ST224 E. coli lineage and the IncF/blaCTX-M-55 plasmid, possibly indicating the emergence of successful clones and plasmids adapted to the chicken host. Our data contribute to the epidemiological tracking of resistance mechanisms in Enterobacterales from poultry and to knowledge for further One Health studies to control the spread of resistant bacteria from food animals to humans.

Salivary, serum, and abomasal mucus IgA as an immune correlate of protection against Haemonchus contortus infection in naturally infected lambs.

This study aimed to evaluate salivary, serum, and abomasal mucus IgA levels in lambs naturally infected with Haemonchus contortus. Thirty-seven crossbred lambs (½ Texel or ½ Ile de France) with an average age of 193 days were evaluated for 56 days after grazing on a contaminated pasture. Fecal samples were collected every 7 days to evaluate the EPG. Blood and saliva samples were collected for IgA measurement every 14 days. On D56, 29 animals were killed for parasite counting and IgA quantification in the abomasal mucus. Salivary, serum, and abomasal mucus IgA were measured by ELISA using third-stage larvae antigens. Salivary and mucus IgA were not correlated, but D14 salivary IgA correlated with EPG on D28 (r = -0.37) and D56 (r = -0.36); D28 salivary IgA correlated with D49 (r = -0.40) and D56 EPG (r = -0.44). Abomasal mucus IgA negatively correlated with EPG from D28 to D56 (r varied from _0.51 to -0.62) and with the counts of all parasitic stages (-0.60 to -0.67). The lambs were classified as susceptible (S) or resistant (R) according to EPG (D56 EPG and cumulative EPG) or IgA (salivary, serum, and mucus IgA). Based on D56 EPG and cumulative EPG, resistant lambs had higher D14 salivary IgA, mucus IgA, and total worm counts. For evaluations based on IgA levels, the EPG of S and R animals differed, indicating that IgA was an immune correlate of protection against natural infection with Haemonchus sp., mainly in the saliva sample of D14.

Relevance of antibodies against the Chicken Anaemia Virus.

Chicken Infectious Anaemia (CIA) Virus (CAV) inhibits the function of multiple immune compartments. Mortality due to clinical infection is controlled in broilers by passive immunization derived from vaccinated breeders. Therefore, serological tests are often used in chicks to determine maternally-derived antibodies (MDA). We used a vaccine overdose-induced model of CIA. The model replicated the most common features of the disease. This model was used to determine the role of MDA in the protection of chicks. Hatchlings were tested for anti-CAV titers by ELISA and were sorted into groups based on antibody levels. SPF chicks were used as a no-antibody control. Lower specific antibody levels seemed to facilitate viral entry into the thymus, but viral levels, CD4+ and CD8+ counts, thymus architecture, and haematocrit were preserved by MDA, regardless of its levels. Levels of MDA are not correlated with protection from CIA, but are important for the progression CAV infection.

Microalgae Schizochytrium sp. as a source of docosahexaenoic acid (DHA): Effects on diet digestibility, oxidation and palatability and on immunity and inflammatory indices in dogs.

The objective of this study was to evaluate the effects of the microalgae Schizochytrium sp., as a dietary source of docosahexaenoic acid (DHA), on diet palatability, coefficients of total tract apparent digestibility (CTTAD) of nutrients and metabolizable energy (ME), blood variables and indicators of immunity in dogs. We also evaluated oxidative stability. Two diets containing 0 and 0.4% of microalgae Schizochytrium sp. were evaluated in three experiments. On Experiment I the palatability of diets containing 0% versus 0.4% microalgae was compared. In Experiment II test diets were offered for 30 days to determine digestibility, fecal characteristics, and blood parameters. In Experiment III, the oxidative stability of diets containing microalgae versus anchovy oil was evaluated. There was a higher intake ratio of the diet containing microalgae (p < .05). The ME and CTTAD of nutrients increased (p < .05), except for ether extract after acid hydrolysis, with the inclusion of the microalgae in diet. The amount of monocytes and phagocytic granulocytes was higher (p < .05) in dogs fed 0.4% microalgae. There was greater oxidative stability for the sample containing microalgae. The addition of 0.4% microalgae presented high palatability, increased phagocytic cell numbers, and demonstrated oxidative stability superior to anchovy oil.

Flow cytometric immune profiling of specific-pathogen-free chickens before and after infectious challenges.

Broilers and layer chickens have been intensively selected for production parameters. This selection has affected immune capacity. Consequently, the fine-tuning of immune responses is becoming important for maximum productivity. Flow cytometry is a recurrent technology used for the immunophenotyping of birds. Studies, however, have focused on the mechanism of specific diseases or have used animals whose immunological condition could be biased-by vaccination or environmental stressors, for example. The aim of this study was to evaluate the immune status of specific-pathogen-free birds across different age ranges to characterize the natural changes that occur over time. Additionally, specific-pathogen-free chickens were challenged with four infectious agents, allowing identification of the subpopulations of peripheral blood immune cells that are consistently altered under various conditions. Several lymphocyte subsets vary naturally with aging, so the interpretation of results using animals of different age ranges must proceed with care. Parameters such as CD8(+)CD28(-), CD8αα(+), CD4(+)CD8(+), and CD8(+)TCRVß1(+) have been shown to be valuable in understanding immune changes during disease. The use of these data allows a determination of the consistency of cytometric parameters under various conditions, which should ease the interpretation of immunophenotyping and the future application of cytometric analysis in the poultry industry.

Infecção por scrapie via intranasal ou inalatória: uma breve revisão / Infección por scrapie vía intranasal o inhalación: una brave revisión / Scrapie infection via intranasal or inhalatory pathway: a brief review

O scrapie é uma doença neurodegenerativa fatal, pertencente ao grupo das encefalopatias espongiformes transmissíveis. Já foi detectada no Brasil, e o Paraná é o estado com maior número de animais afetados, já possuindo casos autóctones. Sabe-se que a transmissão horizontal é essencial para a perpetuação da doença, mas as rotas de transmissão não estão bem estabelecidas. Conhecer as vias de transmissão é o requisito básico para que se desenvolva um programa de controle e erradicação da doença baseado em evidências. Diversas vias já foram propostas como meios de entrada do agente causal príon. Entretanto, avanços recentes nesse campo, unidos com informações recorrentes na literatura fornecem indícios que a via intranasal ou a via inalatória podem representar uma porta de entrada para os príons na transmissão lateral do scrapie em ovinos e caprinos.

Scrapie is a fatal neurodegenerative disease, belonging to the group of transmissible spongiform encefalopathies. It has already been detected in Brazil, and Paraná is the state with the highest number of affected animals, presenting autochthonous cases. It is known that horizontal transmission is essential for the disease perpetuation, but the transmission pathways are not well established. Knowing them is the basic requirement to develop a control and eradication program of the disease based on evidence. Several pathways have been proposed for the transmission of the causative agents, prions. However, recent advances in this and information from the literature provide evidence that intranasal or inhalatory pathway might represent a route for prions in lateral transmission of scrapie in ovines and caprines.

El scrapie es una enfermedad neurodegenerativa fatal, perteneciente al grupo de las encefalopatías espongiformes transmisibles. Ya se ha detectado en Brasil, y el Paraná es el estado con mayor número de animales afectados, teniendo casos autóctonas. Se sabe que la transmisión horizontal es esencial para la perpetuación de la enfermedad, pero las rutas de transmisión no están bien establecidas. Conocer las vías de transmisión es el requisito básico para que se desarrolle un programa de control y erradicación de la enfermedad basado en evidencias. Diversas vías ya fueron propuestas como medios de entrada del agente causal prion. Sin embargo, avanzos recientes en ese campo, unidos con informaciones recurrentes en la literatura fornecen indicios que la vía intranasal o la vía inhaladora pueden representar una puerta de entrada para los priones en la transmisión lateral del scrapie en ovinos y caprinos.