Concept
Efflux pump
Membrane transporter that expels drugs
EFF-luks pump
High-yield clue
Efflux pumps actively export drugs out of the cell and are a classic cause of low-level multidrug resistance.
Overview
A membrane transport protein that actively pumps antibiotics and other toxic compounds out of the bacterial cell, lowering the intracellular drug concentration. It is a major mechanism of multidrug resistance.
Classification
- Membrane transport protein
- Energy-dependent export
- RND family in Gram-negatives
- Broad or narrow substrate range
Lab & identification clues
- Multidrug-efflux vocabulary
- Tetracycline efflux (tet) concept
- RND tripartite-pump vocabulary
Associations
- Tetracycline and fluoroquinolone resistance
- Prominent in Pseudomonas
- Combines with reduced permeability
Commonly confused with
- Porin loss
- Beta-lactamase enzymatic resistance
Your notes
Original microbiology concept summary. Sources checked: OpenStax Microbiology 2e, NCBI Bookshelf Medical Microbiology, and CDC/WHO topic pages where applicable; reviewed 2026-06. Educational only; no diagnosis, treatment selection, infection-control instructions, or specimen-handling guidance.