Role of multiple efflux pumps in Escherichia coli in indole expulsion

FEMS Microbiol Lett. 1999 Oct 15;179(2):345-52. doi: 10.1111/j.1574-6968.1999.tb08748.x.


Escherichia coli chromosome encodes several multidrug transporters. Despite their protective function against antibacterial agents, the specific physiological actions of these transporters are not fully understood. E. coli produces indole, a metabolite of tryptophan, under physiological conditions. Defined inactivation of the acrEF gene, the product of which is known as an energy-dependent multiple drug efflux pump, decreased indole excretion while reintroduction of the acrEF gene restored it. A DeltaacrEF mutant accumulated more intracellular indole than the parent. This mutant was more susceptible to the growth-inhibitory effect of indole than the parent. These results indicate that the AcrEF system plays a significant role in indole efflux.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carrier Proteins / genetics
  • Carrier Proteins / physiology*
  • Escherichia coli / drug effects
  • Escherichia coli / metabolism*
  • Indoles / metabolism*
  • Microbial Sensitivity Tests


  • Carrier Proteins
  • Indoles