Classification of avian pathogenic Escherichia coli by a novel pathogenicity index based on an animal model

Background: Avian Pathogenic Escherichia coli is the main agent of colibacillosis, a systemic disease that causes considerable economic losses to the poultry industry. In vivo experiments are used to measure the ability of E. coli to be pathogenic. Generally, these experiments have proposed different criteria for results interpretation and did not take into account the death time. The aim of this study was to propose a new methodology for the classification of E. coli pathogenicity by the establishment of a pathogenicity index based in the lethality, death time and the ability of the strain to cause colibacillosis lesions in challenged animals. Materials, Methods & Results: A total of 293 isolates of E. coli were randomly selected to this study. The strains were isolated from cellulitis lesions, broiler bedding material or respiratory diseases and were previously confirmed through biochemical profile. The bacterial isolates were kept frozen at -20C. The strains were retrieved from stocks and cultured in brain-heart infusion broth overnight at 37C to obtain a final concentration of 109 UFC/mL. A total of 2940 one-dayold chicks from commercial breeding hens were randomly assigned to groups containing 10 animals and each group was subcutaneously inoculated in the abdominal region with 0.1 mL of the standard inoculum solution containing each of the strains. A control group [...]

Classification of avian pathogenic Escherichia coli by a novel pathogenicity index based on an animal model

Background: Avian Pathogenic Escherichia coli is the main agent of colibacillosis, a systemic disease that causes considerable economic losses to the poultry industry. In vivo experiments are used to measure the ability of E. coli to be pathogenic. Generally, these experiments have proposed different criteria for results interpretation and did not take into account the death time. The aim of this study was to propose a new methodology for the classification of E. coli pathogenicity by the establishment of a pathogenicity index based in the lethality, death time and the ability of the strain to cause colibacillosis lesions in challenged animals. Materials, Methods & Results: A total of 293 isolates of E. coli were randomly selected to this study. The strains were isolated from cellulitis lesions, broiler bedding material or respiratory diseases and were previously confirmed through biochemical profile. The bacterial isolates were kept frozen at -20C. The strains were retrieved from stocks and cultured in brain-heart infusion broth overnight at 37C to obtain a final concentration of 109 UFC/mL. A total of 2940 one-dayold chicks from commercial breeding hens were randomly assigned to groups containing 10 animals and each group was subcutaneously inoculated in the abdominal region with 0.1 mL of the standard inoculum solution containing each of the strains. A control group [...](AU)

Utilização de inteligência artificial (redes neurais artificiais) para a classificação do comportamento bioquímico de amostras de Escherichia coli isoladas de frangos de corte / The use of artificial intelligence (artificial neural networks) to classify the biochemical reactions of Escherichia coli isolates from broilers

A Escherichia coli é comumente encontrada na avicultura e muitas vezes sua presença no organismo dos animais e/ou contaminando as camas de aviários não causa estranheza. Por outro lado, a utilização de inteligência artificial, especificamente redes neurais artificiais, está sendo crescentemente empregada como ferramenta para medir relações não lineares entre variáveis. Neste trabalho foram usados os dados disponíveis referentes a 261 amostras da bactéria oriundas de camas de aviários, lesões de celulite e quadros respiratórios de frangos de corte. O diagnóstico laboratorial envolveu o isolamento do agente, a caracterização dos genes associados à virulência, as lesões provocadas pela inoculação em pintos, o Índice de Patogenicidade das amostras e a resistência antimicrobiana a 14 antibióticos que foram as entradas das redes neurais e sete provas bioquímicas as saídas. A principal conclusão deste artigo foi de que as redes neurais foram capazes de realizar a classificação correta do comportamento das amostras com amplitude de 87,80% a 98,37%. A sensibilidade e a especificidade das classificações obtidas variaram de 59,32% a 99,47% e de 80,00% a 98,54%, respectivamente.(AU)

The Escherichia coli is often found in the poultry industry and, many times, its presence in the organism of the animals and/or contaminating the litter of poultry houses dont cause surprise. On the other hand, the use of artificial intelligence, specifically, artificial neural network, is being increasingly used as tool to measure not linear relations between variables. In this work we used available data from 261 samples of the bacterium isolated of poultry litter, lesions of cellulitis and respiratory problems of broilers. The laboratory diagnosis involved the isolation of the agent, the characterization of the genes associates with the virulence, the lesions provoked by the inoculation in day-old-chicks, the Pathogenicity Index of the samples and the antimicrobial resistance against 14 antibiotics. Those variables were the inputs of the neural network and the outputs were seven biochemical tests. The main conclusion of this paper was that the neural network were capable to make correct classification of the biochemical reactions of all the samples with amplitude from 87.80% to 98.37%. The sensitivity and the specificity of the classifications varied from 59.32% to 99.47% and from 80.00% to 98.54%, respectively.(AU)

Utilização de inteligência artificial (redes neurais artificiais) para a classificação do comportamento bioquímico de amostras de Escherichia coli isoladas de frangos de corte / The use of artificial intelligence (artificial neural networks) to classify the biochemical reactions of Escherichia coli isolates from broilers

A Escherichia coli é comumente encontrada na avicultura e muitas vezes sua presença no organismo dos animais e/ou contaminando as camas de aviários não causa estranheza. Por outro lado, a utilização de inteligência artificial, especificamente redes neurais artificiais, está sendo crescentemente empregada como ferramenta para medir relações não lineares entre variáveis. Neste trabalho foram usados os dados disponíveis referentes a 261 amostras da bactéria oriundas de camas de aviários, lesões de celulite e quadros respiratórios de frangos de corte. O diagnóstico laboratorial envolveu o isolamento do agente, a caracterização dos genes associados à virulência, as lesões provocadas pela inoculação em pintos, o Índice de Patogenicidade das amostras e a resistência antimicrobiana a 14 antibióticos que foram as entradas das redes neurais e sete provas bioquímicas as saídas. A principal conclusão deste artigo foi de que as redes neurais foram capazes de realizar a classificação correta do comportamento das amostras com amplitude de 87,80% a 98,37%. A sensibilidade e a especificidade das classificações obtidas variaram de 59,32% a 99,47% e de 80,00% a 98,54%, respectivamente.

The Escherichia coli is often found in the poultry industry and, many times, its presence in the organism of the animals and/or contaminating the litter of poultry houses don’t cause surprise. On the other hand, the use of artificial intelligence, specifically, artificial neural network, is being increasingly used as tool to measure not linear relations between variables. In this work we used available data from 261 samples of the bacterium isolated of poultry litter, lesions of cellulitis and respiratory problems of broilers. The laboratory diagnosis involved the isolation of the agent, the characterization of the genes associates with the virulence, the lesions provoked by the inoculation in day-old-chicks, the Pathogenicity Index of the samples and the antimicrobial resistance against 14 antibiotics. Those variables were the inputs of the neural network and the outputs were seven biochemical tests. The main conclusion of this paper was that the neural network were capable to make correct classification of the biochemical reactions of all the samples with amplitude from 87.80% to 98.37%. The sensitivity and the specificity of the classifications varied from 59.32% to 99.47% and from 80.00% to 98.54%, respectively.

Laryngotracheitis: reproducibility of the disease and comparison of diagnostic methods

O vírus da laringotraqueíte (VLT) causa de leve a severa doença respiratório em galinhas, o propósito do nosso estudo foi usar um isolado brasileiro de VLT para reproduzir a doença em frangos através da infecção experimental e comparar três métodos de diagnóstico (nested PCR, isolamento viral e histopatologia) para detectar o VLT. Quarenta e oito frangos inoculados intratraquealmente com VLT e outros 48 com PBS, apresentaram sinais respiratórios leves 48 horas após a infecção (PI), mas nenhum sinal após o dia 10 PI. A cada dois dias, seis aves foram selecionados arbitrariamente do controle e do grupo infectado, sacrificados e as traquéias coletadas. Ambos nested PCR e isolamento viral detectaram o vírus do dia 2 até o dia 12 PI. No entanto, no dia 12 PI, a PCR detectou o DNA viral em 100% das amostras enquanto o isolamento viral detectou em somente 33% das amostras. Histopatologia da traquéia revelou corpúsculos de inclusão intranuclear nos dias 8 e 10 PI. Os resultados indicam que o VLT isolado de campo estudado é de baixa patogenicidade e que o protocolo de Nested PCR foi capaz de detectar amostras positivas por um período mais longo da infecção do que muitos testes de diagnósticos descritos.

Laryngotracheitis: reproducibility of the disease and comparison of diagnostic methods

Infectious laryngotracheitis virus (ILTV) cause mild to severe respiratory disease in chickens, the purpose of our study being to use Brazilian isolate of ILTV to reproduce ILTV disease in chickens by experimental infection and to compare three diagnostic methods (nested polymerase chain reaction (PCR), virus isolation, histopathology) for detection of ILTV. Forty-eight chickens intratracheally inoculated with ILTV and a further 48 with PBS, showing mild respiratory signs 48 hours post infection (PI) but no signs of infection after day 10 PI. Every 2 days PI, six birds were arbitrarily selected from the control and infected groups, sacrificed and the trachea collected. Both the nested PCR and virus isolation detected the virus from day 2 until day 12 PI. However, at day 12 PI, PCR detected ILTV DNA in 100% of the samples while the virus isolation method detected ILTV in only 33% of the samples. Tracheal histopathology showed intranuclear inclusion bodies on days 8 and 10 PI. The results indicate that the field-isolate of ILTV studied by us is of low pathogenicity and that our nested PCR protocol was able to detect positive samples over a longer infection period than many ILTV diagnostic test already described.

O vírus da laringotraqueíte (VLT) causa de leve a severa doença respiratório em galinhas, o propósito do nosso estudo foi usar um isolado brasileiro de VLT para reproduzir a doença em frangos através da infecção experimental e comparar três métodos de diagnóstico (nested PCR, isolamento viral e histopatologia) para detectar o VLT. Quarenta e oito frangos inoculados intratraquealmente com VLT e outros 48 com PBS, apresentaram sinais respiratórios leves 48 horas após a infecção (PI), mas nenhum sinal após o dia 10 PI. A cada dois dias, seis aves foram selecionados arbitrariamente do controle e do grupo infectado, sacrificados e as traquéias coletadas. Ambos nested PCR e isolamento viral detectaram o vírus do dia 2 até o dia 12 PI. No entanto, no dia 12 PI, a PCR detectou o DNA viral em 100% das amostras enquanto o isolamento viral detectou em somente 33% das amostras. Histopatologia da traquéia revelou corpúsculos de inclusão intranuclear nos dias 8 e 10 PI. Os resultados indicam que o VLT isolado de campo estudado é de baixa patogenicidade e que o protocolo de Nested PCR foi capaz de detectar amostras positivas por um período mais longo da infecção do que muitos testes de diagnósticos descritos.