Efflux-mediated drug resistance in bacteria: an update

Drugs. 2009 Aug 20;69(12):1555-623. doi: 10.2165/11317030-000000000-00000.


Drug efflux pumps play a key role in drug resistance and also serve other functions in bacteria. There has been a growing list of multidrug and drug-specific efflux pumps characterized from bacteria of human, animal, plant and environmental origins. These pumps are mostly encoded on the chromosome, although they can also be plasmid-encoded. A previous article in this journal provided a comprehensive review regarding efflux-mediated drug resistance in bacteria. In the past 5 years, significant progress has been achieved in further understanding of drug resistance-related efflux transporters and this review focuses on the latest studies in this field since 2003. This has been demonstrated in multiple aspects that include but are not limited to: further molecular and biochemical characterization of the known drug efflux pumps and identification of novel drug efflux pumps; structural elucidation of the transport mechanisms of drug transporters; regulatory mechanisms of drug efflux pumps; determining the role of the drug efflux pumps in other functions such as stress responses, virulence and cell communication; and development of efflux pump inhibitors. Overall, the multifaceted implications of drug efflux transporters warrant novel strategies to combat multidrug resistance in bacteria.

Publication types

  • Research Support, N.I.H., Extramural
  • Review

MeSH terms

  • Animals
  • Anti-Bacterial Agents / metabolism*
  • Anti-Bacterial Agents / pharmacology*
  • Bacteria / drug effects*
  • Biofilms / drug effects
  • Carrier Proteins / biosynthesis
  • Carrier Proteins / metabolism*
  • Drug Resistance, Bacterial / physiology*
  • Gram-Negative Bacteria / drug effects
  • Gram-Negative Bacteria / metabolism
  • Gram-Positive Bacteria / drug effects
  • Gram-Positive Bacteria / metabolism
  • Humans
  • Mycobacterium / drug effects
  • Mycobacterium / metabolism


  • Anti-Bacterial Agents
  • Carrier Proteins