A SIMPLE IN-VITRO MODEL TO TEST THE EFFICACY OF ANTIMICROBIAL AGENTS RELEASED FROM DRESSINGS

A new model for in vitro evaluation of an activity of antibacterial ag ents released from delivery systems containing antibiotics or antisept ics was developed. The model was composed of two layers of agar gel of two different concentrations in PBS. In the upper gel, the wells were cut and filled with polyurethane sponges saturated with bacterial bro th culture. The sponges were then covered with tested dressings contai ning antibacterial agent. The model was tested by using two bacterial strains, Pseudomonas aeruginosa or Staphylococcus aureus and experimen tal collagen dressings with doxycyclin, amikacin, or with silver sulfa diazine. The number of colony-forming units (CFU) in the polyurethane sponges was significantly lower under the dressings with antibacterial agents as compared to the control (the same dressing without antimicr obials) during 3 days of observation. The new in vitro model can be re commended for examination of different antibacterial delivery systems instead of experimentally infected wounds in laboratory animals or ins tead of the other in vitro models. (C) 1996 Elsevier Science Inc.