Effect of cell lipid composition on the formation of nonspecific antibiotic resistance in alkanotrophic rhodococci

The antibiotic resistance and lipid composition of rhodococci grown in rich organic media with gaseous or liquid n-alkanes were studied. Hydrocarbon-g rown rhodococci exhibited an increased resistance to a wide range of antibi otics (aminoglycosides, linkosamides, macrolides, beta-lactams, and aromati c compounds). The enhanced antibiotic resistance of rhodococci grown on n-a lkanes correlated with an increased content of total cell lipids (up to 14- 28%) and saturated straight-chain fatty acids (C-16:0, C-18:0, C-21:0) and was accompanied by the appearance of cardiolipin and phosphatidylglycerol i n cells. These lipid compounds are supposed to promote the formation of non specific antibiotic resistance in rhodococci by decreasing the permeability of their cell envelope to antibiotics.