Decreased binding of polymyxin by polymyxin-resistant mutants of Salmonella typhimurium

Polymyxin-resistant pmrA strains were shown to absorb only about 25% of the amount of polymyxin absorbed by the corresponding polymyxin-sensitive parent strains. The lipopolysaccharide from the pmrA strains bound less polymyxin than the lipopolysaccharide from the parent strains.