Releasing the inhibition….

Microbial quorum sensing (QS) is a cell density dependent gene expression response triggered by autoinducer chemicals.  QS signals are functionally diverse and include: aggregation, motility and secretion of virulence factors.  Quorum sensing inhibitors (QSI) are substances produced by other bacteria, archaea and protists to regulate QS by: inhibiting autoinducer production, blocking receptors or by degrading it.  QSIs can provide a way to render infections less aggressive, in turn allowing host immune defences and/or antibiotic drugs to be more effective. This review catalogues some 116 QSI molecules isolated so far from marine bacteria, actinomycetes and fungi.

With increasing microbial drug resistance QSIs offer a new means to fight problematic infection.  Crucially, QSIs attenuate virulence without driving strong selective pressure on bacterial survival which would risk perpetuating the evolution of drug resistance.  As we discover how microbes compete and coexist in nature many more molecules with therapeutic applications will be discovered, along with an understanding of multilateral interactions and opening up possibilities to use other tools like bacteriophages in combination.  There is also a need to develop trial protocols to measure the effectiveness of adjuvants such as QSIs and understand how to manage target resistance to QSI.

CHEN, J. W., WANG, B. X., LU, Y. J., GUO, Y. Q., SUN, J. D., WEI, B., ZHANG, H. W. & WANG, H. 2019. Quorum Sensing Inhibitors from Marine Microorganisms and Their Synthetic Derivatives. Marine Drugs, 17, 80.