Orally Administered Trimethoprim-Sulfamethoxazole and Metronidazole as Infection Prophylaxis in Elective Colorectal Surgery.

Background: This randomized clinical trial evaluated orally administered trimethoprim-sulfamethoxazole and metronidazole (TSM) in elective colorectal surgery as prophylactic for post-operative surgical site infections (SSI).

Methods: Patients undergoing elective colorectal resection were evaluated for inclusion. Randomized subjects received either orally administered TSM or intravenously administered cefuroxime and metronidazole (control group, CXM). The primary endpoint was the rate of SSI.

Results: A total of 1073 subjects were randomized to either control (540) or TSM (533). 486 patients in the TSM group and 499 in the control group were followed-up with after 4 weeks. Thirty-seven (3.8%) patients were afflicted by SSI at discharge from hospital and 69 (7.0%) at follow-up four weeks after surgery. After four weeks, the rate of incisional SSI was 7.0% in the TSM group and 3.6% in the control group (p=0.022). For organ/space SSI and the other complications monitored in the study, no differences were observed between the groups.

Conclusion: Orally administered TSM as prophylaxis before elective colorectal surgery results in a low rate of organ/space SSI but an increased rate of incisional SSI compared with intravenously administered cefuroxime and metronidazole. Thus, when considering orally administered TSM, because of environmental concerns or for economic reasons, the slightly increased infection rate has to be kept in mind.