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How do polymyxin antibiotics damage bacterial cell membranes?
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Polymyxin antibiotics, such as polymyxin B and polymyxin E (colistin), damage bacterial cell membranes by binding to phospholipids within the membrane structure.1
By binding to these phospholipids, the antibiotics interfere with the membrane's function as a selective osmotic barrier. This disruption compromises the integrity of the membrane, causing essential macromolecules to leak out of the cell, which ultimately results in the death of the bacterium. Because human cells contain similar or identical phospholipids, these antibiotics can also react with human cell membranes, leading to potential toxicity in patients.21