Perioperative Antibiotic Selection and Surgical Site Infection in Elective Colon Surgery

The highest rates of surgical site infections (SSIs) are associated with colorectal operations (up to 30%). A sentinel paper showed that the use of intravenous (IV) cefazolin and metronidazole was associated with decreased rates of SSI compared with cefoxitin (6% vs 13%). We reviewed the association of SSI with prophylactic antibiotic choice. We specifically investigated the regimens of ceftriaxone and metronidazole IV, cefoxitin IV, or ertapenem.

We conducted a retrospective review of 532 colon surgeries between 2016 and 2018. Inclusion criteria were patients 18-89 years of age undergoing elective colon surgery who received ceftriaxone/metronidazole, cefoxitin, or ertapenem for prophylaxis. All emergent cases were excluded. This resulted in 241 elective colon cases for review. The primary endpoint was to determine if the use of ceftriaxone/metronidazole decreased the rate of SSI.

In total, there were 241 elective colon cases with 21 SSI. We compared SSI rates in the ceftriaxone/metronidazole group to those patients receiving either cefoxitin or ertapenem (4.5% vs 12.2%; P = .035). We then compared SSI in ceftriaxone/metronidazole to SSI in cefoxitin (4.5% vs 10%; P = .13). Finally, we compared SSI in the ceftriaxone/metronidazole group to SSI in the ertapenem group (4.5% vs 14%; P = .03). Comorbidities and underlying factors were similar across all antibiotic groups.

In our experience, the use of ceftriaxone/metronidazole is associated with a decreased SSI rate. Furthermore, ceftriaxone/metronidazole use is superior to the use of ertapenem, with a trend toward superiority over cefoxitin. Based on this study, we recommend ceftriaxone/metronidazole as antibiotic prophylaxis for elective colon surgery.