Silencing Bacterial Communication Through Enzymatic Quorum-Sensing Inhibition

Abstract

Numerous bacterial functions, such as virulence and biofilm formation, are controlled by a cell density-dependent communication mechanism known as quorum sensing (QS), in which small diffusible molecules are released, allowing bacteria to coordinate their behavior once a minimal effective quorum has been reached. The interference with these signaling systems, also known as quorum-sensing inhibition (QSI), represents a promising strategy to tackle bacterial infections. In the past decade, numerous enzymes capable of inactivating QS signals have been described, an activity also known as quorum quenching (QQ). Most known QSI enzymes degrade or modify the Gram-negative QS signal molecules N-acyl-homoserine lactones (AHLs); nonetheless, the specificity of these enzymes as signal quenchers remains unclear as some enzymes have been related, among others, to metabolism of other molecules and to the use of signaling molecules as energy source. Meanwhile, bacterial enzymatic QSI has been explored as a novel anti-pathogenic therapy to control bacterial infections with positive results in plants, the nematode infection model and in aquaculture field. The advantage of enzymatic QSI is that generally displays a wider spectrum of activity than inhibitors or antagonists that are generally more specific, allowing the interference with a higher number of signaling systems.