Microbiology & Immunology

Peptidase-containing ABC transporters (PCATs) are a widely distributed family of transporters which export peptide substrates containing a double-glycine motif (GG peptides). In gram-positive bacteria, PCATs secrete pheromones used for cell-to-cell signaling and antimicrobial peptides called bacteriocins used for interbacterial killing and competition. PCATs recognize GG peptides through their N-terminal signal sequences, but little is known about how PCATs distinguish between different GG peptides.

Our group has previously demonstrated that in critically ill patients, the lungs and other end-organs are enriched with gut-associated bacteria. This observation has re-ignited the "gut translocation hypothesis" of multi-organ failure: that in patients with shock, increased intestinal permeability results in dissemination of gut bacteria and bacterial products, contributing to the pathogenesis of multi-organ failure. In this talk, I will share recent observations exploring the mechanisms and significance of gut translocation in critical illness.