Pump it up: occurrence and regulation of multi-drug efflux pumps in Bacteroides fragilis.

Bacteroides fragilis is a gram-negative anaerobic commensal that can be a virulent pathogen when it escapes its normal niche in the human gut. Recent increases in reports of multi-drug resistance strains of this organism have lent urgency to understanding its mechanisms of antimicrobial resistance. We have identified and characterized RND-type multi-drug efflux pumps in B. fragilis which can pump out a variety of substrates and whose transcription levels can be elevated by a wide variety of antimicrobials, antiseptic agents, bile and other stressors. Our research is directed toward understanding how the efflux pump genes are controlled and how we may exploit that understanding to develop more effective, targeted therapy that will cure the infection without disrupting the entire gut microbiome that is so important in many aspects of human health.