Venue: Edificio Povo 2, via Sommarive nr. 9, Povo (Tn) - Room B101
At 2:00 p.m.
- Sacha Lucchini - Institute of Food Research, Norwich Research Park, Colney Ln, Norwich, Norfolk NR4 7UA, Regno Unito
The lower gastrointestinal tract harbours a large and diverse community of commensal microorganisms, whose presence protects the host from invading organisms. It has been proposed that enteric pathogens can overcome this colonisation resistance by inducing inflammation and thus perturbing the endogenous microbiota. The molecular mechanisms involved in the adaptation of pathogens and resident bacteria during the infectious process are poorly understood. As bacteria rapidly adapt their gene expression to the surrounding environment, analysis of their transcriptional profile can provide information on the changes occurring in the local environment and on the adaptive mechanisms involved. We have successfully set up methods to analyse the in vivo gene expression profile of gut bacteria, which enabled us to investigate the changes induced by the murine pathogen Citrobacter rodentium in mice with different degrees of susceptibility to the infection. The in vivo transcriptional profiles of the resident microbiota and the pathogen suggest that the presence of C. rodentium resulted in minor changes in the expression of the main metabolic pathways in the microbiota of mice with low susceptibility to the pathogen. In contrast, infection in highly susceptible mice induced significant metabolic alterations, possibly providing the pathogen access to a wider range of nutrients and thus an increased competitiveness. The transcriptomics data were further supported by NMR metabonomic analysis of faecal waters. This approach provides an invaluable insight into the adaptive mechanisms of commensal and pathogenic bacteria that are required for persisting in the GI-tract.