Risk factors in wound infection following urologic operations: a prospective study

A total of 134 urologic operations were studied prospectively for postoperative wound infection, the methodology involving direct intraoperative swab taking. Patients' variables were (mean +/- SD): age 32.4 +/- 20.7 years, Quetelet index 27.4 +/- 8, duration of operation 98 +/- 34 minutes, and male:female ratio 9.3:1. Of the 131 intraoperative swabs 28 (21%) were positive, 97% of the organisms being aerobic; 16% of the patients were nasal carriers of S. aureus. The overall wound infection rate was 9%, and it prolonged hospital stay by six days average. Significant risk factors (and their magnitude) were: age over 60 years (x 2.2), prolonged preoperative hospital stay (x 15), and wound contamination (x 4.3 and x 14.3 for classes 3 and 4 wounds respectively). Neither diabetes mellitus, obesity, nor surgeon's rank was contributory. We conclude that, although the 9% rate of postoperative wound infection was acceptable, appropriate prophylactic antibiotics may reduce it further, and, from our data, we would recommend an aminoglycoside (e.g. Amikacin) and Ampicillin combined.