Experimental animal model of surgical wound infection applicable to antibiotic prophylaxis

Wound infection, defined as accumulation of pus draining spontaneously or after opening of the wound, developed in 19 out of 22 guinea pigs (86%) after intraincisional contamination with 10(7) Escherichia coli plus 10(8) Bacteroides fragilis before wound closure. Antibiotic prophylaxis with gentamicin plus clindamycin significantly reduced the wound sepsis rate from 86% to 29% (p less than 0,001). Pus for bacteriological studies was available in all cases of wound infection but one, and culture always revealed both Escherichia coli and Bacteroides fragilis. The animal model presented employs widely accepted criteria for wound infection, and avoids culture of tissue homogenates.