THE USE OF BIODEGRADABLE AMIKACIN MICROSPHERES TO PREVENT VASCULAR GRAFT INFECTION

The following study was performed to determine if an antibiotic impreg nated in a biodegradable polymer can prevent infection and eradicate i noculum bacteria from contaminated polytetrafluoroethylene vascular gr afts. Poly(glycolide-co-dl-lactide) amikacin microspheres (PAM) measur ing 50-100 mu m were designed to deliver 100 mg (PAM 100) or 300 mg (P AM 300) amikacin per unit dose. Twenty mongrel dogs had a short segmen t of infrarenal aorta replaced with a graft that had been bathed in a 2 cc solution of Escherichia coli and Staphylococcus aureus (3 X 10(8) CPU/ml). Dogs were divided into three groups: Controls had contaminat ed grafts placed and received no therapy; PAM 100 and PAM 300 were use d, respectively, to cover the grafts in the other two groups. Animals were sacrificed 14 days postoperatively at which time grafts were exam ined and cultured. Among controls, 7/8 had clinical graft infections a nd all had positive cultures for S. aureus (8/8) or E. coli (5/8). Non e of the treated animals had clinical graft infections (P < 0.001). Po sitive cultures were obtained for S. aureus in 2/8 (P less than or equ al to 0.007) and E. coli in 0/8 (P less than or equal to 0.03) PAM 100 dogs and for S. aureus in 0/8 (P less than or equal to 0.0002) and E. coli in 0/8 (P less than or equal to 0.03) PAM 300 dogs. Two PAM 100 and four PAM 300 dogs had rare growth of contaminant bacteria (NS). In conclusion, PAM can prevent clinical graft infection and completely e radicate a standardized bacterial inoculum. (C) 1994 Academic Press, I nc.