RESEARCH ARTICLE
Microbial Efflux Systems and Inhibitors: Approaches to Drug Discovery and the Challenge of Clinical Implementation
Christina Kourtesi 1, 2, Anthony R Ball 3, Ying-Ying Huang 4, 5, Sanjay M Jachak 6, D Mariano A Vera 7, Proma Khondkar 8, Simon Gibbons 8, Michael R Hamblin 4, 5, 9, George P Tegos*, 1, 4, 5, 10
Article Information
Identifiers and Pagination:
Year: 2013Volume: 7
Issue: Suppl 1
First Page: 34
Last Page: 52
Publisher ID: TOMICROJ-7-34
DOI: 10.2174/1874285801307010034
Article History:
Received Date: 14/11/2012Revision Received Date: 22/1/2013
Acceptance Date: 23/1/2013
Electronic publication date: 22/3/2013
Collection year: 2013

open-access license: This is an open access article licensed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted, non-commercial use, distribution and reproduction in any medium, provided the work is properly cited.
Abstract
Conventional antimicrobials are increasingly ineffective due to the emergence of multidrug-resistance among pathogenic microorganisms. The need to overcome these deficiencies has triggered exploration for novel and unconventional approaches to controlling microbial infections. Multidrug efflux systems (MES) have been a profound obstacle in the successful deployment of antimicrobials. The discovery of small molecule efflux system blockers has been an active and rapidly expanding research discipline. A major theme in this platform involves efflux pump inhibitors (EPIs) from natural sources. The discovery methodologies and the available number of natural EPI-chemotypes are increasing. Advances in our understanding of microbial physiology have shed light on a series of pathways and phenotypes where the role of efflux systems is pivotal. Complementing existing antimicrobial discovery platforms such as photodynamic therapy (PDT) with efflux inhibition is a subject under investigation. This core information is a stepping stone in the challenge of highlighting an effective drug development path for EPIs since the puzzle of clinical implementation remains unsolved. This review summarizes advances in the path of EPI discovery, discusses potential avenues of EPI implementation and development, and underlines the need for highly informative and comprehensive translational approaches.