In Vitro Action of Combinations of Antimicrobial Agents and EDTA-tromethamine on Pseudomonas Aeruginosa

Am J Vet Res. 1983 Aug;44(8):1521-4.


Combinations of EDTA-tromethamine and 7 antimicrobial agents (chloramphenicol, nalidixic acid, oxytetracycline, penicillin, polymyxin-B, streptomycin, and triple sulfa) were tested for synergistic activities against Pseudomonas aeruginosa. Three in vitro tests were used, including minimal inhibitory concentrations of the drugs, a 2-dimensional Microtiter checkerboard technique, and bacterial inhibition studies. A synergistic inhibitory action was observed with combinations of EDTA-tromethamine plus penicillin and EDTA-tromethamine plus oxytetracycline. When chloramphenicol, streptomycin, nalidixic acid, polymyxin-B, or triple sulfa was mixed with EDTA-tromethamine, synergistic action did not occur.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anti-Bacterial Agents / pharmacology*
  • Anti-Bacterial Agents / therapeutic use
  • Dog Diseases / drug therapy
  • Dogs
  • Drug Combinations
  • Drug Synergism
  • Drug Therapy, Combination
  • Edetic Acid / pharmacology*
  • Edetic Acid / therapeutic use
  • Otitis Externa / drug therapy
  • Otitis Externa / veterinary
  • Oxytetracycline / pharmacology
  • Penicillin Resistance
  • Penicillins / pharmacology
  • Pseudomonas Infections / drug therapy
  • Pseudomonas Infections / veterinary
  • Pseudomonas aeruginosa / drug effects*
  • Tromethamine / pharmacology*
  • Tromethamine / therapeutic use


  • Anti-Bacterial Agents
  • Drug Combinations
  • Penicillins
  • Tromethamine
  • Edetic Acid
  • Oxytetracycline