Indole as a regulator of bacterial physiology

Abstract

During the last years, indole has been the subject of study, this is chemically defined as an aromatic bicyclic heterocycle, from the synthesis of tryptophan after its degradation by tryptophanase (TnaA); in turn has been implicated as a signalling molecule used by several bacteria to establish multiple behaviours. Most studies have focused mainly on Escherichia coli (E. coli), which produces a small amount of indole during the transition from exponential to stationary phase. According to the literature review, indole plays a fundamental role in many bacterial processes, mainly: biofilm formation, virulence, acid resistance, antibiotic resistance and persistent cell formation; the concentrations of this molecule play an important role in regulating these mechanisms; on this basis, indole could control undesired bacterial physiological processes, offering us a new therapeutic alternative to different behaviours of microorganisms. The objective of this bibliographic review is to expand the area of knowledge about indole as a regulator of diverse bacterial mechanisms, and thus motivate further research on this molecule and its therapeutic use.