How do efflux pumps contribute to increased antibiotic resistance in bacteria?

• A. By increasing the rate of bacterial cell division to dilute the effect of antibiotics
• B. By producing enzymes that degrade antibiotics before they reach their target
• C. By actively transporting antibiotics out of the bacterial cell, reducing intracellular drug concentration
• D. By altering the structure of the bacterial cell wall to prevent antibiotic entry

Answer: (C)

Verified step by step guidance

1. Understand that efflux pumps are protein transporters located in the bacterial cell membrane that actively expel toxic substances, including antibiotics, out of the cell.
2. Recognize that by pumping antibiotics out, efflux pumps reduce the intracellular concentration of the drug, which decreases its effectiveness at reaching its target inside the bacterium.
3. Note that this mechanism does not involve increasing bacterial cell division or producing enzymes to degrade antibiotics, nor does it involve altering the cell wall structure.
4. Realize that the active transport by efflux pumps is an energy-dependent process, often using ATP or proton motive force to move antibiotics against their concentration gradient.
5. Conclude that the primary contribution of efflux pumps to antibiotic resistance is their ability to lower the intracellular antibiotic levels, thereby allowing bacteria to survive and grow despite the presence of the drug.