P-192. Evaluating the Association of Unnecessary Antibiotic Use with Hospital-Onset <i>Clostridioides difficile</i> Infection at a New York City Hospital

Abstract Background Hospital Onset-Clostridioides difficile infection (HO-CDI) is defined as collection of a positive C. difficile lab result on or after day 4 of a patient’s hospital admission. Reduction of HO-CDI remains a multidisciplinary effort. Prior studies have demonstrated frequent inappropriate antibiotic use among patients with CDI. The objective of this study is to evaluate unnecessary antibiotic use in patients with cases of National Healthcare Safety Network (NHSN)-defined HO-CDI compared to non-CDI controls. Methods This case-control study included inpatient adult patients, from 1/1/23 – 2/28/24. HO-CDI cases were selected from standard institutional review. Non-CDI controls were selected based on hospital admission and negative CDI test sent on or later than day 4 of their admission. Cases and controls were matched 2:1 using patient location and index tests within the same month. Antibiotic use (AU) rate of cefepime, ciprofloxacin, levofloxacin, ceftriaxone, and piperacillin-tazobactam 30 days prior to index test was calculated using NHSN definitions. Primary exposure of interest was inappropriate antibiotic use. Outcomes including hospital length of stay (LOS), all-cause mortality, and subsequent recurrent CDI were recorded. A secondary analysis assessed the relationship between race/ethnicity, inappropriate antibiotic use and HO-CDI. Results Two hundred ninety-six patients were included. AU rate was greater in controls compared to HO-CDI cases (p = 0.01) (Table 1). Inappropriate AU was observed in 24% of cases and 28% of controls (p = 0.48). The most common category of inappropriate AU was inappropriate spectrum, 55% in cases and 81% in controls (Fig 1). There were no statistically significant differences in outcomes. Conclusion HO-CDI cases did not have greater exposure to antibiotic therapy and did not have a higher proportion of inappropriate antibiotic use compared to patients who tested negative for C. difficile. This demonstrates an opportunity to improve antibiotic use, but does not show an association between inappropriate antibiotic use and C. difficile infection. Disclosures All Authors: No reported disclosures