Indole or Indon’t: Does Indole impact Salmonella biology: motility?

Salmonella are important foodborne pathogens which cause a spectrum of disease in humans ranging from gastroenteritis to Typhoid fever. Motility is essential in physiology and contributes to competitive advantage enabling Salmonella to find a hospitable niche within the gut through chemotaxis. One of the vital roles provided by the intestinal microbiota is to repel invading pathogens from establishing a niche and causing disease, a phenomenon termed colonisation resistance. The small molecule indole, which is produced by members of the intestinal microbiota, has been shown to regulate basic physiology, virulence and biofilm formation in a number of pathogenic bacteria. The objective of this study was to determine whether indole can effect the motility of Salmonella and if so, elucidate how indole is sensed and the subsequent signalling cascade.