antibioticsbooks

Cyclic Lipopeptides
16
Agent: daptomycin
Daptomycin is the only cyclic lipopeptide that has
made its way onto the market. It has a unique
mechanism of action and target compared with
other antibiotics. Daptomycin binds to the cell membrane
of Gram-positive bacteria, weakening it and
allowing essential ions to leak out of the organism.
This leads to a rapid depolarization of the membrane
potential and cessation of needed cell processes,
leading to cell death. Interestingly, instead
of blowing the bacteria apart as beta-lactams do,
daptomycin leaves the dead bacteria intact.
Mechanism of Action
Daptomycin inserts into the cell membrane of
Gram-positive organisms, leading to the leakage
of intracellular cations that maintain membrane
polarization. The result is rapid depolarization and
cell death.
Spectrum
Good: MSSA, MRSA, streptococci
Moderate to Good: enterococci, including VRE
Poor: anything Gram-negative