What is the action of daptomycin, and what type of bacteria does it target?

Daptomycin is an antibiotic that disrupts cell membrane function in bacteria, leading to depolarization and ultimately cell death. This mechanism of action makes it particularly effective against Gram-positive bacteria, including strains resistant to other treatments such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE).

The antibiotic interacts with the membrane of these bacteria to form complexes that cause leakage of cellular ions and affect the integrity of the bacterial cell membrane. This is distinct from many other antibiotic classes that target cell wall synthesis, protein synthesis, or DNA synthesis, each of which has a different mechanism of action and bacterial target spectrum. The focus on Gram-positive organisms is crucial—Daptomycin is not effective against Gram-negative bacteria due to their outer membrane structure, which provides an added barrier against such larger molecules and disruptors.