Ceftriaxone/Metronidazole versus Cefoxitin for Operative Abdominal Trauma: Increased Compliance and A Trend Towards Decreased Infection Rate

Authors:
Jennifer Beavers, Marianna Frazee, Robel Beyene, Jill Streams, Elizabeth Krebs

Body of Abstract:
Background

The preferred perioperative antibiotic regimen for operative abdominal trauma is not well described. In response to an increase in surgical site infection (SSI) rate, our trauma center changed our standard perioperative regimen for abdominal operations from cefoxitin to ceftriaxone and metronidazole. In this study, we aimed to compare the SSI rate in patients receiving each antibiotic regimen, hypothesizing that the transition to ceftriaxone/metronidazole would result in decreased infection rates and improved antibiotic compliance (due to the single required dose of ceftriaxone.)

Methods

This retrospective review evaluated all patients undergoing laparotomy or laparoscopy for trauma from January 2023-July 2025. Patients who received perioperative cefoxitin were compared to those who received ceftriaxone and metronidazole. Those who received a separate, ‘non-standard’ antibiotic regimen or who died within 5 days of operation were excluded. The primary outcome was SSI (either incisional SSI or organ/space infection) within 30 days of operation. Secondary outcomes were measures of antibiotic dosing compliance. Demographics and outcomes were compared using univariate statistics, including chi-square and Wilcoxon rank sum tests. The primary outcome was evaluated using logistic regression, controlling for diabetes, injury severity score (ISS) and hollow viscous injury (HVI.)

Results

A total of 434 patients underwent exploratory laparotomy during the study period, of which 53 were excluded due to death within 5 days and 107 were excluded due to non-standard antibiotic regimens. A total of 283 patients were thus included in the analysis: 173 in the cefoxitin group and 110 in the ceftriaxone/metronidazole group. The groups had similar ages (median 37 vs. 36, p=0.74), rates of comorbidities including diabetes (6% vs. 7%, p=0.76), and median ISS (21 vs. 19, p=0.82). There was an increased rate of HVI in the cefoxitin group (73% vs. 63%, p=0.07). There was a decrease in total infection rate in the ceftriaxone/metronidazole group (21% vs. 12%, p=0.04, Table) as well as decreased organ/space infection rate (19% vs. 9%, p=0.02, Table.) There was a significantly improved rate of patients receiving too few doses of antibiotics (Table), though an increased rate of patients receiving too many doses of antibiotics (Table.) However, on risk-adjusted analysis, the impact of ceftriaxone/metronidazole was not statistically significant (OR 0.52, 95% CI 0.26-1.06, p=0.07.)

Conclusion

A change in the abdominal trauma perioperative antibiotic regimen from cefoxitin to ceftriaxone and metronidazole was associated with improved antibiotic compliance and a trend towards decreased infection rate (with a sizeable reduction in SSI rate however p=0.07 on multivariable analysis.) As centers develop antibiotic protocols, medications with simpler dosing regimens should be considered due to their potential or improved compliance and infection outcomes.