Quorum Sensing and Developing Novel Antibiotics: Part 2 Lecture Notes

Keywords: quorum sensing; Vibrio cholerae; group behavior; pathogen; virulence; biofilms; high-cell-density; low-cell-density; autoinducer; chemical signaling; antibiotics

Vibrio cholerae, like many other bacteria, uses quorum sensing to synchronize gene expression on a population-wide level. Upon infection of its human host, V. cholerae immediately initiates expression of virulence genes and causes an acute infection.

This immediate use of quorum sensing stands in stark contrast to bacterial pathogens that cause persistent infections and only initiate virulence factor expression after reaching high-cell-density in the host. The unique V. cholerae quorum sensing mechanism provides an opportunity to explore strategies in which quorum sensing autoinducer molecules are supplied to treat bacterial infections.

Toward this end, the structure of the V. cholerae-specific autoinducer, CAI-1, was determined and synthetic CAI-1 was produced. Indeed, addition of CAI-1 to cultures of V. cholerae decreased production of virulence factors, and protected a mouse from infection with V. cholerae. The results of these experiments underscore the importance of identifying quorum sensing molecules and characterizing their potential use in novel antibacterial treatments.

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