title: PTFE graft treated with silver norfloxacin (AgNF): drug retention and resistance to bacterial challenge.
abstract: Norfloxacin (NF) and silver norfloxacin (AgNF) were used to coat polytetrafluoroethylene (PTFE) vascular prostheses by using triododecylmethylammonium chloride as a cationic surfactant. The relative retention of the drug on the graft after subjecting it to the biological environment for 3 weeks and antibacterial activity against coagulase-positive Staphylococcus aureus and Escherichia coli were determined. In addition, the ability of AgNF-coated PTFE grafts to sterilize perigraft tissue after mixed bacterial contamination was studied and compared with control PTFE grafts in 10 dogs. At the end of 21 days, 15 and 18% of AgNF were retained on the grafts tested in in vitro and in vivo experiments, respectively. During the same time AgNF-coated grafts from in vitro experiments exhibited significant antibacterial activity (25 mm zone of inhibition (z.i.)), but antibacterial activity was negligible (10 mm z.i.) in the grafts from in vivo experiments. NF retention on the grafts could not be determined because of spectral interference by blood. The antibacterial activity of NF-coated grafts significantly declined after 24 hr in in vivo experiments, hence further evaluation of NF-coated grafts was not done. Seven perigraft sites surrounding AgNF-coated grafts were sterile, but only one perigraft site surrounding control grafts was sterile (P less than 0.05). Cultures from six of nine perigraft infections surrounding control grafts yielded heavy bacterial growth. There was only one wound infection at the site of AgNF graft while there were seven severe wound infections at control graft sites. AgNF-coated grafts exhibited prolonged antibacterial activity compared to NF-coated grafts and offered significant protection against infection from local bacterial contamination.
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents; D001807:Blood Vessel Prosthesis; D004285:Dogs; D004927:Escherichia coli Infections / Q000517:prevention & control; D024841:Fluoroquinolones; D066298:In Vitro Techniques; D009643:Norfloxacin / Q000031:analogs & derivatives* / Q000378:metabolism / Q000627:therapeutic use; D011138:Polytetrafluoroethylene; D011292:Premedication; D013203:Staphylococcal Infections / Q000517:prevention & control; D013530:Surgical Wound Infection / Q000517:prevention & control*
chemical_list: D000890:Anti-Infective Agents; D024841:Fluoroquinolones; C045339:silver norfloxacin; D011138:Polytetrafluoroethylene; D009643:Norfloxacin