Experimental infection with enteropathogenic Escherichia coli identified by PCR using enteric-coated capsules in boxer pups

Abstract

Purpose:To verify the possibility of an experimental infection with enteropathogenic Escherichia coli and to confirm by PCR that the symptoms manifested after infection were due to the virulence factors of the studied bacteria. Methods: Experimental units were 14 healthy pups of Boxer breed, aged 60 days. The animals were divided into three groups. One animal from each litter was included in a control group and the remaining animals were divided into two groups: one inoculated with strain 4083, and another one inoculated with strain SPA14. Gelatinous capsules coated with enteric-coating solution were used for the inoculation of strains. E. coli isolation from feces was performed for all tested animals, and the extracted DNA was subjected to Polymerase Chain Reaction (PCR). Results: All infected animals presented diarrhea and had the gene eae amplified by PCR. Conclusion: The efficiency of PCR for the studied strains indicates that this technique can be recommended for the diagnosis of enteropathogenic Escherichia coli as a differential from other pathogens causing diarrhea. It may also be used in the future to verify whether other virulence factors (bfpA gene and EAF plasmid) persist after infection and to assess the pathogenicity of these bacteria. Key words: Enteropathogenic Escherichia coli. Virulence Factors. Polymerase Chain Reaction. Dogs. RESUMOObjetivo: Verificar a possibilidade de uma infecção experimental com Escherichia coli enteropatogênicas e confirmar por PCR que os sintomas manifestados após a infecção foram decorrentes dos fatores de virulência da bactéria estudada. Métodos: As unidades experimentais foram 14 filhotes saudáveis com idade de 60 dias da raça Boxer. Os animais foram divididos em três grupos, sendo um controle de cada ninhada e o restante dividido em dois grupos, um de animais inoculados com a cepa 4083 e o outro de animais inoculados com a cepa SPA14. Para inoculação das cepas, utilizaram-se cápsulas gelatinosas revestidas com solução de revestimento entérico. O isolamento de E. coli das fezes foi realizado em todos os animais testados, e o DNA extraído foi submetido à técnica de PCR. Resultados: Todos os animais infectados apresentaram diarréia e tiveram a gene eae amplificado por meio de PCR. Conclusão: Através da eficiência da PCR das amostras, a técnica seria recomendada para diagnóstico da Escherichia coli enteropatogênicas como diferencial de outros patógenos que causam diarréia, e, no futuro, verificar se outros fatores de virulência (gene bfpA e plasmídeo EAF) permaneceriam após a infecção, podendo avaliar a patogenicidade das EPEC. Descritores: Escherichia coli Enteropatogênica. Fatores de Virulência. Reação em Cadeia da Polimerase. Cães.

Action of phosphorylated mannanoligosaccharides on immune and hematological responses and fecal consistency of dogs experimentally infected with enteropathogenic Escherichia coli strains

“…Feces were collected by using a sterile swab and inoculated into GN broth incubated at 37 °C overnight for 24 h, which was then sown on McConkey agar (Sigma) incubated at 37 °C for 24 h; one sample per animal was used. One colony from each growth was selected, inoculated into Brain Heart 1nfusion (BHI – Oxoid) broth and incubated at 37 °C overnight for genomic DNA extraction, as described by Gouveia et al (2011) .…”