Colorectal surgery: short-term prophylaxis with clindamycin plus aztreonam or gentamicin

A randomized study was conducted to compare the effectiveness of aztreonam plus clindamycin with that of gentamicin plus clindamycin for prophylaxis of infection following colorectal surgery. A total of 138 patients undergoing elective colorectal surgery were randomized to treatment with clindamycin (600 mg) plus either aztreonam (1 g) or gentamicin (80 mg) 30 minutes before and 8 and 16 hours after surgery. The study included 122 patients (88.4%) with colorectal carcinoma. Samples from the abdominal cavity and from the subcutaneous tissues were taken for bacteriologic study. All samples from the abdominal cavity yielded microorganisms; both aerobic and anaerobic bacteria were isolated. Wound infections occurred in eight patients (12.1%) in the aztreonam group and in 12 patients (16.7%) in the gentamicin group. Escherichia coli, Bacteroides species, enterococci, and staphylococci were isolated most frequently from wounds and were often isolated from bacteriologic samples from the abdominal cavity of the same patients. The incidence of septic complications reflected the extent of nutritional and immunologic impairment. No significant differences were found between groups in the rate of urinary tract or lower respiratory tract infections. Aztreonam/clindamycin appears to be a valid alternative to gentamicin/clindamycin for the prophylaxis of infections following colorectal surgery.