PHARMACODYNAMIC PARAMETERS OF OFLOXACIN, TOBRAMYCIN AND CEFTRIAXONE AND THEIR EFFECT ON THE BIOLOGICAL PROPERTIES OF SALMONELLAE

The postantibiotic effect and postantibiotic sub-MIG effect of ofloxac in (GAS 82419-36-1), tobramycin (GAS 32986-56-4) and ceftriaxone (GAS 73384-59-5) on two salmonella serotypes(S. typhimurium and S. enteriti dis) were studied. The influence of postantibiotic effect and postanti biotic sub-MIC effect of the antibiotics on prophage induction of the lysogenic S. typhimurium strain and on Congo red binding by both serov ars as indicator of their invasive ability was examined. The postantib iotic effect was induced by exposure of the bacteria to the 2x and 4x MIC concentrations of antibiotics studied for 0.5 h. The postantibioti c effects were different: ceftriaxone induced the longest postantibiot ic effect against S. enteritidis, and the 4x MIC of tobramycin induced the longest postantibiotic effect against S. typhimurium. The postant ibiotic sub-MIC effects lasted longer and in the case of subinhibitory concentrations of tobramycin on S. typhimurium and ceftriaxone on S. enteritidis did not allow any regrowth. The results showed that the po stantibiotic effect and postantibiotic sub-MIC effect of ofloxacin ind uced a prophage of a lysogenic S. typhimurium strain, and the postanti biotic sub-MIC effects of tobramycin influenced Congo red binding by S . enteritidis cells.