Project description:Avian pathogenic Escherichia coli (APEC) is a subset of extraintestinal pathogenic E. coli that causes detrimental losses to the poultry industry. Vaccines to reduce APEC in chickens have been partially successful, but many lack protection against multiple serotypes of APEC. Recombinant attenuated Salmonella vaccine (RASV) strains have been used to induce immunity against Salmonella in production chickens and can be modified to deliver foreign antigens as well. This study evaluated the transcriptome of chicken spleens and assessed prevention of APEC infection following vaccination with RASV strains, including a RASV carrying an E. coli antigen. Four-day-old White Leghorn chicks were orally vaccinated with RASV c8025(pYA3337) carrying an empty plasmid, c8025(pYA4428) carrying genes for E. coli common pilus (ECP), a combination of RASVs c8025(pYA3337) and c8025(pYA4428), or PBS (unvaccinated). To assess the host response to vaccination, antibody titers were measured by ELISA and spleen samples (n = 5) were collected from combination vaccinated and unvaccinated groups of four-week-old chickens for RNA sequencing. Five-week old chickens were challenged via air sac with APEC strains APEC-O2 and c7122 (O78). Blood was obtained 24 hours post-challenge, heart, liver, lung, and spleen were collected 48 hours post-challenge for enumeration of E. coli, and gross colibacillosis lesions were scored at necropsy. Chickens vaccinated with RASV strains elicited anti-E. coli EcpA, as well as cross reactive anti-E. coli IutA and IroN IgY antibodies. IgA results. In some organs, bacterial loads and lesions scores were numerically reduced, but no significant differences were detected for vaccinated compared to unvaccinated chickens. Transcriptome results. This data indicates that RASVs could be used to stimulate the immune system and is an initial step toward developing improved therapeutics to combat APEC infections in chickens.
Project description:Avian Pathogenic Escherichia coli (APEC) are a group of extra-intestinal E. coli that infect poultry, and are able to cause a variety of diseases, systemic or localized, collectively designated as colibacillosis. Colibacillosis is the most common bacterial illness in poultry production, resulting in significant economic losses world-wide. Despite of its importance, pathogenicity mechanisms of APEC strains remain not completelly elucidated and available vaccines are not fully effectives. In order to better understand which genes could be related to pathogenicity in different APEC isolated, a microarray analyses of two APEC strains representing: Swollen Head Syndrome and Omphalitis was carried out.
Project description:Avian Pathogenic Escherichia coli (APEC) are a group of extra-intestinal E. coli that infect poultry, and are able to cause a variety of diseases, systemic or localized, collectively designated as colibacillosis. Colibacillosis is the most common bacterial illness in poultry production, resulting in significant economic losses world-wide. Despite of its importance, pathogenicity mechanisms of APEC strains remain not completelly elucidated and available vaccines are not fully effectives. In order to better understand which genes could be related to pathogenicity in different APEC isolated, a microarray analyses of two APEC strains representing: Swollen Head Syndrome and Omphalitis was carried out. We used the microarray methodology to evaluate the expression profile of two different APEC strains
Project description:Avian pathogenic Escherichia coli strains frequently cause extra-intestinal infections and are responsible for significant economic losses in the poultry industry worldwide. APEC isolates are closely related to human extraintestinal pathogenic E.coli strains and may also act as pathogens for humans. In this work, three type VI secretion systems were deleted to analyze which pathogenicity characteristics would change in the mutants, compared to wild type strain (SEPT 362). Four Avian Pathogenic Escherichia coli strains (one wild type and three deleted mutants) were grown at 37°C in Dulbecco´s Modified Eagle´s Media (DMEM) media until reach O.D 600 = 0.8, for RNA extraction and hybridization on Affymatrix microarrays.
Project description:Avian pathogenic Escherichia coli strains frequently cause extra-intestinal infections and are responsible for significant economic losses in the poultry industry worldwide. APEC isolates are closely related to human extraintestinal pathogenic E.coli strains and may also act as pathogens for humans. In this work, three type VI secretion systems were deleted to analyze which pathogenicity characteristics would change in the mutants, compared to wild type strain (SEPT 362).
Project description:Colisepticemia caused by avian pathogenic Escherichia coli (APEC) results in annual multimillion dollar losses to the poultry industry. Recent research suggests that APEC may have an important role in public health as well. Generally, colisepticemia follows a respiratory tract infection in which APEC penetrate the respiratory epithelium to enter the bloodstream. From the bloodstream, bacteria may spread to various internal organs resulting in perihepatitis, pericarditis, and other conditions. The aim of this study was to identify molecular mechanisms enabling APEC to survive and grow in the bloodstream. To do so, we compared the transcriptome of APEC O1 during growth in Luria-Bertani broth and chicken serum. Selected genes that were significantly up-regulated in chicken serum were then subjected to mutational analysis to confirm their role in APEC pathogenesis. Several categories of genes, predicted to contribute to adaptation and growth in the avian host, were identified. These included several known virulence genes and genes involved in adaptive metabolism, protein transport, biosynthesis pathways, stress resistance, and virulence regulation. Several genes with unknown function, which were localized to pathogenicity islands or APEC O1’s large virulence plasmid, were also identified, suggesting that they too contribute to survival in chicken serum. This genome-wide analysis provides novel insight into processes that are essential to APEC O1’s survival and growth in chicken serum.
Project description:Colisepticemia caused by avian pathogenic Escherichia coli (APEC) results in annual multimillion dollar losses to the poultry industry. Recent research suggests that APEC may have an important role in public health as well. Generally, colisepticemia follows a respiratory tract infection in which APEC penetrate the respiratory epithelium to enter the bloodstream. From the bloodstream, bacteria may spread to various internal organs resulting in perihepatitis, pericarditis, and other conditions. The aim of this study was to identify molecular mechanisms enabling APEC to survive and grow in the bloodstream. To do so, we compared the transcriptome of APEC O1 during growth in Luria-Bertani broth and chicken serum. Selected genes that were significantly up-regulated in chicken serum were then subjected to mutational analysis to confirm their role in APEC pathogenesis. Several categories of genes, predicted to contribute to adaptation and growth in the avian host, were identified. These included several known virulence genes and genes involved in adaptive metabolism, protein transport, biosynthesis pathways, stress resistance, and virulence regulation. Several genes with unknown function, which were localized to pathogenicity islands or APEC O1’s large virulence plasmid, were also identified, suggesting that they too contribute to survival in chicken serum. This genome-wide analysis provides novel insight into processes that are essential to APEC O1’s survival and growth in chicken serum. Two-condition experiment: LB vs. chicken serm; four biological replicates, independently grown and harvested.