Antimicrobial prophylaxis in elective colorectal surgery and appendicitis.

The purpose of this presentation is to evaluate the role of anaerobic and aerobic microorganisms in postoperative infections after colorectal surgery and appendicitis, and to evaluate when antimicrobial agents should be administered prophylactically in conjunction with these operations. In one multicenter study, prophylactic regimens against anaerobic and aerobic microorganisms were compared for durations of one and three days after colorectal surgery. In another multicenter study, the effect of a regimen against anaerobes used alone or in combination with an agent against aerobes in one preoperative dose were compared. The different types of operations had different potential for postoperative infections. An antimicrobial agent against anaerobic microorganisms given as one preoperative dose may suffice in surgery on the upper part of the colon, but a combination with an agent against aerobic bacteria is recommended in rectal surgery. The effectiveness of agents against anaerobic and aerobic bacteria in preventing postoperative infections after appendectomy in cases of gangrenous or perforated appendicitis without general peritonitis were compared in another study. This concluded that an agent against anaerobes is recommended when the appendix is gangrenous or perforated.