In-vivo evaluation of pathogenicity and antimicrobial profile susceptibility from Escherichia coli samples isolated from commercial layer hens / Avaliação da patogenicidade in vivo e do perfil de resistência antimicrobiana de amostras de Escherichia coli isoladas de galinhas de postura comercial

Antimicrobial sensitivity and pathogenicity level of 90 strains of Escherichia coli isolated from livers and intestines from commercial layer hens presenting diarrhea were analyzed. To evaluate the antimicrobial susceptibility, all samples were subjected to antimicrobial susceptibility testing using 11 commercial drugs. The results have showed none of the strains was susceptible to all antibiotics tested. All samples showed resistance to two or more drugs. According to the mortality rate of the birds, the in-vivo pathogenicity test classifies the strains into four classes: high, intermediate, low and nonpathogenic. The test has showed 23 (25.5%) of the samples were highly pathogenic, 21 (23.3%) of intermediate pathogenicity, 23 (25.5%) low pathogenic, and 23 (25.5%) nonpathogenic. When the results of the classes of pathogenicity from isolates have been associated with antimicrobial susceptibility, nonpathogenic strains were less sensitive to the antibiotic ampicillin and increased sensitive to streptomycin antimicrobial compared to the others classes of pathogenic. Nonpathogenic strains showed resistance to many antimicrobials, an alert for poultry, since these bacteria might acquire the virulence genes and infect birds, others animals and even human beings.(AU)

Foram verificados a sensibilidade antimicrobiana e o índice de patogenicidade de 90 amostras de Escherichia coli isoladas do fígado e do intestino de pintainhas de postura comercial com diarreia. Para avaliar a sensibilidade antimicrobiana, todas as amostras foram submetidas ao teste de susceptibilidade antimicrobiana por meio de 11 drogas comerciais. Os resultados demonstraram que nenhuma das estirpes foi sensível a todos os antimicrobianos testados. Todas as amostras apontaram resistência a duas ou mais drogas. De acordo com o índice de mortalidade das aves, o teste de patogenicidade in vivo classificou as estirpes em quatro classes: alta, intermediária, baixa e não patogênica. O teste revelou que 23 (25,5%) das amostras foram de alta patogenicidade, 21 (23,3%) de patogenicidade intermediária, 23 (25,5%) de baixa patogenicidade e 23 (25,5%) não patogênicas. Quando os resultados das classes de patogenicidade dos isolados foram associados à sensibilidade antimicrobiana, estirpes não patogênicas apresentaram menor sensibilidade ao antimicrobiano ampicilina e maior sensibilidade ao antimicrobiano estreptomicina, quando comparadas com as estirpes das demais classes de patogenicidade. Estirpes não patogênicas exibiram resistência a vários antimicrobianos, representando um alerta para a avicultura, uma vez que essas bactérias podem adquirir genes de virulência e, assim, infectar aves, outros animais e até mesmo o seres humanos.(AU)

In-vivo evaluation of pathogenicity and antimicrobial profile susceptibility from Escherichia coli samples isolated from commercial layer hens / Avaliação da patogenicidade in vivo e do perfil de resistência antimicrobiana de amostras de Escherichia coli isoladas de galinhas de postura comercial

Antimicrobial sensitivity and pathogenicity level of 90 strains of Escherichia coli isolated from livers and intestines from commercial layer hens presenting diarrhea were analyzed. To evaluate the antimicrobial susceptibility, all samples were subjected to antimicrobial susceptibility testing using 11 commercial drugs. The results have showed none of the strains was susceptible to all antibiotics tested. All samples showed resistance to two or more drugs. According to the mortality rate of the birds, the in-vivo pathogenicity test classifies the strains into four classes: high, intermediate, low and nonpathogenic. The test has showed 23 (25.5%) of the samples were highly pathogenic, 21 (23.3%) of intermediate pathogenicity, 23 (25.5%) low pathogenic, and 23 (25.5%) nonpathogenic. When the results of the classes of pathogenicity from isolates have been associated with antimicrobial susceptibility, nonpathogenic strains were less sensitive to the antibiotic ampicillin and increased sensitive to streptomycin antimicrobial compared to the others classes of pathogenic. Nonpathogenic strains showed resistance to many antimicrobials, an alert for poultry, since these bacteria might acquire the virulence genes and infect birds, others animals and even human beings.(AU)

Foram verificados a sensibilidade antimicrobiana e o índice de patogenicidade de 90 amostras de Escherichia coli isoladas do fígado e do intestino de pintainhas de postura comercial com diarreia. Para avaliar a sensibilidade antimicrobiana, todas as amostras foram submetidas ao teste de susceptibilidade antimicrobiana por meio de 11 drogas comerciais. Os resultados demonstraram que nenhuma das estirpes foi sensível a todos os antimicrobianos testados. Todas as amostras apontaram resistência a duas ou mais drogas. De acordo com o índice de mortalidade das aves, o teste de patogenicidade in vivo classificou as estirpes em quatro classes: alta, intermediária, baixa e não patogênica. O teste revelou que 23 (25,5%) das amostras foram de alta patogenicidade, 21 (23,3%) de patogenicidade intermediária, 23 (25,5%) de baixa patogenicidade e 23 (25,5%) não patogênicas. Quando os resultados das classes de patogenicidade dos isolados foram associados à sensibilidade antimicrobiana, estirpes não patogênicas apresentaram menor sensibilidade ao antimicrobiano ampicilina e maior sensibilidade ao antimicrobiano estreptomicina, quando comparadas com as estirpes das demais classes de patogenicidade. Estirpes não patogênicas exibiram resistência a vários antimicrobianos, representando um alerta para a avicultura, uma vez que essas bactérias podem adquirir genes de virulência e, assim, infectar aves, outros animais e até mesmo o seres humanos.(AU)

Análise da textura de músculos submetidos à fixação em formaldeído e conservação em solução de benzoato de sódio 0, 5% e ácido acético 0, 5% / Tenderness analysis of muscles fixed in formaldehyde and kept in 0, 5% sodium benzoate and 0, 5% acetic acid solution

Background: Tissue texture, or tenderness, may be checked-out by analyzing the force necessary to cause muscle fibers rupture (shearing force) and the result is expressed in kilogram-force (kgf). The aim of this paper was to analyze the texture of broiler chicken breast muscles fixed in a 10% formaldehyde solution and kept in a 0.5% sodium benzoate and 0.5% acetic acid solution up to 180 days so any alteration regarding resistance and the best moment for dissection could be described. Materials, Methods & Results: Forty chicken breasts were used and muscle texture was analyzed by the shearing force whose values were correspondent to the maximum force necessary to chisel the samples. Eight of 40 breasts were taken as a control group (fresh muscles). The remaining breast muscles were fixed in a 4% formaldehyde solution and kept in plastic containers with this solution during seven days and, then, eight breasts went through texture analysis. The 24 remaining breasts were set in plastic containers with 0.5% sodium benzoate and 0.5% acetic acid solution. The texture analyses were taken out at 30, 90 and 180 days of conservation, and eight breasts were used in each time. The shearing force was obtained for each sample and, just before cutting, muscles were washed in running water for 24 h so the excess of the conservation agent could be removed. Data were submitted to statistical analysis by the 5% Tukey's test. The average shearing force of the control, formaldehyde and 30-day sodium benzoate and acetic acid groups differed among them and from the 90-day and 180-day of sodium benzoate and acetic acid groups. The average shearing forces of the two last groups did not statistically differ among them. Discussion: The longer the muscles were kept in the sodium benzoate and acetic acid solutions, the more they became soft, and the shearing force decreased from 21.46 Kgf (seven days of conservation) to 19.20 Kgf (30 days), 17.23 Kgf (90 days) and 16.32 Kgf (180 days) not reaching, however, values from 8.97 to 15.31 Kgf, as described in chicken breasts conserved in 96oGL ethylic alcohol. The average shearing force of chicken breasts conserved in sodium benzoate and acetic acid progressively decreased during 180 days of conservation, when it reached a value of 16.32 Kgf, similar to the value of 15.32 Kgf of chicken breasts conserved for 45 days in formaldehyde. By the seventh day of conservation in 10% formaldehyde, samples presented an average shearing force of 21.46 Kgf, which was higher than the 15.33 Kgf of chicken breasts conserved during 45 days or the 14.74 to 17.37 Kgf of the same tissue kept up to a year in formaldehyde solution. It was concluded that conservation of breast broiler chickens fixed in formaldehyde and conserved in sodium benzoate and acetic acid made them softer through within 180 days, resulting in a better structure malleability and suggesting that dissection of anatomical muscle pieces may occur in an easier way in this moment. Although the sodium benzoate and acetic acid effect in texture of broiler chicken muscle tissue fixed in formaldehyde has been studied, it is believed that, due this great tissue homogeneity, these data might be taken or used as basis to similar studies in other species.

Análise da textura de músculos peitorais submetidos à fixação e conservação em álcool / Tenderness analysis of muscles fixed and kept in alcohol

A textura, ou maciez, pode ser avaliada pela mensuração da força necessária para ocorrer o cisalhamento das fibras musculares. Objetivou-se, nesse trabalho, a análise da textura de músculos submetidos à fixação e conservação em álcool, ao longo de um ano, mediante uso de um aparelho analisador de textura. Foram utilizados 48 peitos de frangos jovens, pesados, fixados e conservados em álcool etílico 96° GL. As análises foram realizadas após 15, 30, 90, 180 e 360 dias de conservação, além do grupo controle de músculos frescos. Os valores da força de cisalhamento dos diferentes grupos aumentaram progressivamente de 3,38 (grupo controle) até 15,31 Kgf (180 dias), caindo para 9,53 Kgf após 360 dias. Concluiu-se que quando músculos são submetidos à fixação e conservação em álcool 96° GL, ocorre diminuição da maciez, tornando-os quase cinco vezes mais rígidos ao corte após seis meses, e três vezes mais rígidos após um ano. Sugere-se que a dissecção de peças anatômicas musculares ocorra até 90 dias após fixação e conservação em álcool 96° GL ou ao redor de um ano nesse agente conservante, pois há menor rigidez tissular nesses períodos. Embora se tenha estudado o efeito do álcool na textura de tecido muscular de aves, acredita-se que, devido à grande homogeneidade tissular neste caso, tais dados possam ser extrapolados ou servir de base para estudos similares em outras espécies.(AU)

Texture, or tenderness, may be evaluated by measuring the force necessary to cause rupture of muscle fibers. The aim of this paper was to analyze the texture of muscles fixed and kept in alcohol, throughout a year, by using a texture analyzer. Forty eight poultry breasts were weighted, fixed and kept in a 96° GL ethylic alcohol solution. Analyses were performed at 15, 30, 90, 180 and 360 days of conservation, besides the one of the control group of fresh breasts. Values of shear forces of different groups increased progressively from 3.38 (control group) to 15.31 Kgf (180 days), decreasing to 9.53Kgf after 360 days. It was concluded that when muscles are fixed and kept in ethylic alcohol 96° GL the tenderness is decreased, becoming almost five times harder during the first six months and three times harder after a year. It is suggested that muscle anatomic pieces dissection occurs up to 90 days after fixation and conservation in 96° GL alcohol or around 1 year on this conservation product because there is smaller muscle stiffness in these times. Although the alcohol effect in texture of poultry muscle tissue has being studied in this paper, it is believed that, due this great tissue homogeneity, these data might be taken or being basis to similar studies in other species.(AU)

Avaliação de substâncias desinfetantes utilizadas na água de tanques de pré-resfriamento de abatedouro avícola

Durante o abate de aves, substâncias desinfetantes podem ser adicionadas à água dos tanques de pré-resfriamento com o propósito de reduzir a contaminação microbiana. O presente estudo teve como objetivo avaliar a eficiência de cinco desinfetantes sobre a redução da população de micro-organismos indicadores de qualidade em carcaças de frangos de corte e sobre Salmonella Enteritidis (SE) na presença e ausência de matéria orgânica. Para isso foram realizados dois experimentos. No primeiro, carcaças de frango foram imersas em recipientes contendo desinfetantes e posteriormente, análises microbiológicas para estimativa de micro-organismos indicadores foram realizadas. Ao todo, para cada desinfetante, 21 carcaças foram analisadas. No experimento 2, a ação dos desinfetantes sobre uma estirpe SE foi avaliada por meio de teste ?in vitro?. Os resultados revelaram que o dióxido de cloro e o hipoclorito de sódio não reduziram as contagens de micro-organismos indicadores nas carcaças. Por outro lado, produtos a base de ácido peracético, cloreto de alquil benzil dimetil amônia e clorito de sódio acidificado diminuíram as contagens de coliformes totais e termotolerantes, sendo que o primeiro também reduziu o número de micro-organimos psicrotróficos. Todos os desinfetantes foram eficientes na redução da contagem de SE apenas na ausência de matéria orgânica. Ao que tudo indica, a redução de matéria orgânica em tanques de pré-resfriamento contendo tais soluções poderia ajudar na diminuição da contaminação de carcaças por Salmonella spp. O ácido peracético bem como o clorito de sódio acidificado poderiam ser recomendados futuramente para serem utilizados em tanques de pré-resfriamento

During the poultry slaughter process antimicrobial products can be added in water immersion chilling tanks in order to reduce microbial contamination. The present study aimed to evaluating the efficacy of five antimicrobials in decreasing the population of food quality indicator microorganisms and Salmonella Enteritidis (SE) in presence and absence of organic matter. In order to this, two experiments were carried out. Firstly, broiler carcasses were immersed in containers with 5 different disinfectant substances and subsequently examined for estimating microorganism indicators. The action of each of substance was assessed in 21 carcasses. In experiment 2, the action of disinfectants against SE was evaluated by "in vitro" test. The results showed that chlorine dioxide and sodium hypochlorite did not reduce the counts of microorganisms in the carcass. On the other hand, peracetic acid, alkyl dimethyl benzyl ammonium and acidified sodium chlorite reduced the counts of total and faecal coliforms. Peracetic acid was also able to decrease the number of psychrotrophic microorganisms. All products were effective in reducing SE counts only in the absence of organic matter. Therefore, it is possible to suggest that reduction of organic matter in water tanks containing antimicrobial agents could help decreasing carcass contamination by Salmonella spp. Peracetic acid and acidified sodium chlorite could be recommended for use in water immersion chilling tanks in future