***Background.*** We observed high rates of *Clostridium difficile* infections (CDI) among 2 surgical units at UCSF despite improvements in hand hygiene, adherence to contact precautions, and environmental cleaning. Our objective was to identify risk factors for CDI among surgical patients at our institution.

***Methods.*** We designed a case-control study that included 46 patients with hospital-onset CDI who were directly admitted to 2 surgical units between July 2012 and September 2013. Each case was matched to 2 controls without CDI selected from the same unit and calendar quarter by incidence density sampling. We used conditional logistical regression for bivariate analysis and included risk factors with a p-value less than 0.2 into a final multivariate model to identify independent risk factors for CDI (p-value \< 0.05).

***Results.*** Cases and controls were similar in demographics, underlying comorbidities, need for emergency surgery, total parenteral nutrition, enteral feeding, use of bowel prep and gastric acid suppressants. Multivariate analysis revealed that receipt of ertapenem (OR = 4.41, p = 0.003; 95% CI 1.7-11.7), cystectomy (OR 5.29, p = .03; 95% CI 1.1-24.5) and Whipple procedure (OR 5.58, p = .048, OR 1.02-30.6) were associated with a significantly increased risk of CDI. The median ertapenem duration among the cases and controls was 1 day of therapy (DOT), interquartile range 0.5 DOT to 1 DOT. We noted that ertapenem prophylaxis was highly associated with CDI risk on bivariate analysis (OR 4.2, p = .003, 95% CI 1.64-10.8) and this also held true when included in multivariate analysis (OR = 3.89, p = .009, 95% CI 1.41-10.8).

***Conclusion.*** Surgical procedures with prolonged operative time such as cystectomies and Whipple procedures may be independent risk factors for CDI, although numbers were small in our study. Ertapenem, particularly its use as prophylaxis, was associated with an increased risk of CDI among surgical patients, which may offer an appropriate target to improve antibiotic stewardship among the surgical patient population.

***Disclosures.*** **All authors:** No reported disclosures.

[^1]: **Session:** 203. *Clostridium difficile* Infection: Epidemiology, Presentation, Treatment

[^2]: Saturday, October 11, 2014: 12:30 PM
