Project description:APEC most often infect chickens, turkeys, ducks, and other avian species, and therefore pose a significant economic burden on the poultry industry worldwide. Few studies have analyzed the genome-wide transcriptional profile of APEC during infection in vivo. In this study, we examined the genome-wide transcriptional response of APEC O2 strain E058 in an in vivo chicken infection model to better understand the factors necessary for APEC colonization, growth, and survival in vivo. An Affymetrix multigenome DNA microarray, which contains most of the genomic open reading frames of E. coli K-12 strain MG1655, uropathogenic E. coli strain CFT073, and E. coli O157:H7 strain EDL 933, was used to profile the gene expression in APEC E058.The genes highly expressed during infection were involved in metabolism, iron acquisition or transport, virulence, response to stress, and biological regulation. Many genes encoding putative or hypothetical proteins were also strongly upregulated, implying that some undiscovered mechanism may underlie APEC pathogenesis.
Project description:Many reports show an association between the Pst system, the Pho regulon related genes and bacterial virulence. Our previous results showed that a functional Pst system is required for full virulence, resistance to serum, polymyxin B and acid shock. However, the interplay between the Pst system and virulence has an unknown molecular basis. To understand global APEC virulent strain responses to Pho regulon activation, we conducted transcriptome profiling experiments comparing the APEC chi7122 strain and its isogenic Pst mutant grown in rich phosphate medium using the Affymetrix GeneChip® E. coli Genome 2.0 Array. The Affymetrix GeneChip® E. coli Genome 2.0 Array contains the genome of the E. coli MG1655 and three pathogenic E. coli strain (EDL933, Sakai and CFT073) representing 20,366 genes. While comparing genes expression between Pst mutant and the wild type chi7122 strain, 471 genes are either up- (254) or down-regulated (217) of at least 1.5-fold, with a p-value inferior or equal to 0.05 and a false discovery rate of 2.71%. Keywords: Escherichia coli, phosphate starvation response, Pho regulon, Pst system, Affymetrix, transcriptional analysis
Project description:APEC most often infect chickens, turkeys, ducks, and other avian species, and therefore pose a significant economic burden on the poultry industry worldwide. Few studies have analyzed the genome-wide transcriptional profile of APEC during infection in vivo. In this study, we examined the genome-wide transcriptional response of APEC O2 strain E058 in an in vivo chicken infection model to better understand the factors necessary for APEC colonization, growth, and survival in vivo. An Affymetrix multigenome DNA microarray, which contains most of the genomic open reading frames of E. coli K-12 strain MG1655, uropathogenic E. coli strain CFT073, and E. coli O157:H7 strain EDL 933, was used to profile the gene expression in APEC E058.The genes highly expressed during infection were involved in metabolism, iron acquisition or transport, virulence, response to stress, and biological regulation. Many genes encoding putative or hypothetical proteins were also strongly upregulated, implying that some undiscovered mechanism may underlie APEC pathogenesis. We identified the in vivo transcriptional response of APEC E058 bacteria collected directly from the blood of infected chickens. Significant differences in expression levels were detected between the in vivo expression profile and the in vitro expression profile in LB medium.
Project description:DNA microarray-mediated transcriptional profiling of avian pathogenic Escherichia coli O2 strain E058 during its infection of chicken
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) 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.