Team:Waterloo/Project

The paradox in developments in the area of antimicrobial agents, although often effective, is that improper use of these antibiotics often causes pathogenic microorganisms to become resistant to treatments and more difficult to combat. One such example is methicillin resistant staphylococcus aureus (MRSA). The bacteria may cause infections through tissue invasion and subsequent toxin production. Such infections are easily transmitted through physical contact and are a growing concern in hospitals. The detection of these pathogens is traditionally done by swabbing and culturing the suspected infection. This process is time inefficient and highly resource intensive. Additionally, in the time it takes to get a clear diagnostic, bacteria may have had the opportunity to colonize tissue and establish drug resistance. There is a distinct need for rapid, on-site detection of these pathogens. Our design presents a novel approach to pathogen detection that involves the engineering of a non-pathogenic organism to detect and produce a signal in the presence of S. Aureus.

Populations of bacteria, including S.Aureus, are able to coordinate behaviours, such as the production of virulence factors for evasion of a host's immune response, through quorum sensing. Small diffusible signalling molecules called auto-inducers are excreted in proportion to population density. The quorum sensing systems of S. aureus involves the Agr two component regulatory system. The signalling molecule involved is AIP (auto-inducer peptide). Our system will detect the presence of S. aureus by using the Agr two-component regulatory system in E.coli with RFP as the indicator. The non-pathogenic organism, E.Coli, will in effect eavesdrop on the signals being sent by S.aureus and react at lower levels than are detected in the natural quorum sensing system. This will allow for the quantitative detection of S.aureus in a quick and efficient manner. The system may also be extended to inhibit the S.aureus infection.