Why might colistin affect Gram negative bacteria more severe

Why might colistin affect Gram negative bacteria more severely than gram positive bacteria?

Solution

These cationic regions in colistin work by interaction with bacterial outer membrane, and function by displacing calcium and magnesium bacterial counter ions in the lipopolysaccharide. Hydrophobic/hydrophilic regions hence it interacts with the membrane like a detergent does , it thus solubilizes the cytoplasmic membrane.

Since most gram positive bacteria dont have outer membrane hence solistin has nothing to interact much hence it works mostly for gram negative strains than gram positive strains.

Hope that answers your question .... should u need further clarification regarding this feel free to comment and discuss .... I will be glad to reply

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