Effects of carbon sources on antibiotic resistance in Pseudomonas aeruginosa
Conrad, R.S.; Wulf, R.G.; Clay, D.L.
Antimicrobial Agents and Chemotherapy 15(1): 59-66
1979
ISSN/ISBN: 0066-4804 PMID: 106771 Document Number: 152552
The metabolism of branched-chain amino acids, branched-chain acyl derivatives, D-glucose, L-glutamate and Mueller-Hinton medium was investigated to determine their effects on the growth, lipid composition and antibiotic susceptibility of P. aeruginosa. The unsaturated fatty acid content of the readily extractable lipids was altered by growth on selected branched-chain amino acids and their acyl derivatives. Bacteria grown on branched-chain acyl derivatives became more susceptible to polymyxin B and colistin. The effect acyl derivatives had on increasing susceptibility was also manifest in mixed media which contained an acyl derivative and a C source which did not increase susceptibility. Growth on branched-chain amino acids gave mixed results which were dependent on a number of factors, including unique manifestations of individual amino acids, growth conditions and availability of other C sources. The cultural conditions which altered susceptibility to polymyxin antibiotics did not correlate with similar effects on susceptibility to carbenicillin and gentamicin. An adaptive resistance to polymyxin B was observed when the sole C source was D-glucose or L-glutamate.