759. Impact of Clostridium difficile (CD) Nucleic Acid Amplification Test (NAAT) Approval on Hospital-Onset C. difficile Infection (HO-CDI): A Diagnostic Stewardship Intervention

Abstract Background NAAT is highly sensitive in detecting toxigenic CD but if used inappropriately can lead to overdiagnosis and financial penalties. Despite diligent infection control (IC) measures, HO-CDI rates at our hospital remained above target benchmarks. We implemented mandatory CD testing approval to decrease HO-CDI rates. Methods On 7/1/2019, we implemented CD testing approval for stool samples collected after admission day 3 in our 129-bed community hospital. An algorithm instructed providers about approval granted by IC 7 days-a-week. The micro-lab would not process samples unless pre-approved. We prospectively collected data on demographics, ICU, laxative, antibiotic use, CDI signs/symptoms, prior CDI and outcomes (length of stay, in-hospital death) and estimated unadjusted relative risk ratios comparing those whose test was approved vs not approved. We also performed an interrupted time series analysis to assess the trend change of CD testing and HO-CDI per 1000 patient days (x 1000-PD) in the 18 months following the intervention (7/2019 - 12/2020) compared to the pre-intervention period (01/2018 - 6/2019). Lastly, using the National Healthcare Safety Network criteria, we calculated pre and post-intervention Standard Infection Ratios (SIR). Results A total of 72 samples required CD testing authorization; 65 (90%) were approved. Baseline demographics, in-hospital death and length of stay were similar in both groups, but approved patients were 4 times as likely to have ≥ 3 loose stools in 24h compared to not approved. The number of CD tests was 13 at baseline with a decrease of 6 tests in the 1st month of intervention (95% CI: -10.0, - 1.35), followed by an insignificant decline in the monthly trend (-0.14; 95%CI: -0.49, 0.20). There were 22 HO-CDI pre-intervention and 10 post-intervention. Pre-intervention, incidence of HO-CDI was 0.51 cases x 1000-PD and increased every month by 0.11 (95% CI: 0.07,0.16). In July 2019, there was a significant decline of 1.16 case x 1000-PD (95% CI: -1.99, -0.33), followed by monthly decline (-0.16; 95% CI: -0.23, -0.09). Our calculated SIR after the intervention decreased to 0.77 from 1.03. Trends of CD testing and HO-CDI in the pre-intervention and post-intervention period Conclusion CD testing approval is a successful strategy to optimize testing and lower HO-CDI rates, without resulting in worst outcomes even when CD test was not approved. Disclosures All Authors: No reported disclosures


Impact of Clostridium difficile (CD) Nucleic Acid Amplification Test (NAAT) Approval on Hospital-Onset C. difficile Infection (HO-CDI): A Diagnostic Stewardship Intervention.
Francine Touzard-Romo, MD 1 ; Gail Jackson, BSN, RN, CIC 2 ; Sarah Andrea, PhD 3 ; Whitehead Valerie, MLS 3 ; Tiffany Chargualaf, MLS 3 ; John Lonks, MD 4 ; 1 Newport Hospital, Alpert Medical School of Brown University, East Greenwich, Rhode Island; 2 Newport Hospital, Newport, Rhode Island; 3 Lifespan, Providence, Rhode Island; 4 The Miriam Hospital / Alpert Medical School of Brown University, Providence, Rhode Island Session: P-36. HAI: C. difficile Background. NAAT is highly sensitive in detecting toxigenic CD but if used inappropriately can lead to overdiagnosis and financial penalties. Despite diligent infection control (IC) measures, HO-CDI rates at our hospital remained above target benchmarks. We implemented mandatory CD testing approval to decrease HO-CDI rates.
Methods. On 7/1/2019, we implemented CD testing approval for stool samples collected after admission day 3 in our 129-bed community hospital. An algorithm instructed providers about approval granted by IC 7 days-a-week. The micro-lab would not process samples unless pre-approved. We prospectively collected data on demographics, ICU, laxative, antibiotic use, CDI signs/symptoms, prior CDI and outcomes (length of stay, in-hospital death) and estimated unadjusted relative risk ratios comparing those whose test was approved vs not approved. We also performed an interrupted time series analysis to assess the trend change of CD testing and HO-CDI per 1000 patient days (x 1000-PD) in the 18 months following the intervention (7/2019 -12/2020) compared to the pre-intervention period (01/2018 -6/2019). Lastly, using the National Healthcare Safety Network criteria, we calculated pre and post-intervention Standard Infection Ratios (SIR).
Results. A total of 72 samples required CD testing authorization; 65 (90%) were approved. Baseline demographics, in-hospital death and length of stay were similar in both groups, but approved patients were 4 times as likely to have ≥ 3 loose stools in 24h compared to not approved. The number of CD tests was 13 at baseline with a decrease of 6 tests in the 1st month of intervention (95% CI: -10.0, -1.35), followed by an insignificant decline in the monthly trend (-0.14; 95%CI: -0.49, 0.20). There were 22 HO-CDI pre-intervention and 10 post-intervention. Pre-intervention, incidence of HO-CDI was 0.51 cases x 1000-PD and increased every month by 0.11 (95% CI: 0.07,0.16). In July 2019, there was a significant decline of 1.16 case x 1000-PD (95% CI: -1.99, -0.33), followed by monthly decline (-0.16; 95% CI: -0.23, -0.09). Our calculated SIR after the intervention decreased to 0.77 from 1.03.

S478 • OFID 2021:8 (Suppl 1) • Abstracts
Conclusion. CD testing approval is a successful strategy to optimize testing and lower HO-CDI rates, without resulting in worst outcomes even when CD test was not approved.
Disclosures. All Authors: No reported disclosures

Incidence, Predictors and 30-Day Outcomes of Clostridoides difficile Infection in Patients Undergoing Cystectomy: A Nationwide Analysis Using the ACS-NSQIP Database
Armaghan-e-Rehman Background. Clostridoides difficile infection is the second most common healthcare acquired infection (HAI) and the most common gastrointestinal HAI, with an estimated 365,200 cases reported by the CDC in 2017. CDI continues to remain a major cause of inpatient admission and utilization of healthcare resources. The exact incidence of peri-procedural CDI with cystectomy is unknown, and reported incidence of CDI in literature vary widely Methods. We conducted an analysis of patients undergoing cystectomy between 2015 and 2017 using the ACS National Surgical Quality Improvement Program (NSQIP) to study the incidence, risk factors and 30-day post-surgical outcomes associated with CDI following cystectomy. Developed by the American College of Surgery, this is a nationally validated, risk-adjusted, outcomes-based program designed to determine and improve the quality of surgical and post-surgical care.
Results. The incidence of CDI following cystectomy was 3.6% in our patient cohort. 18.8% of patients developed CDI following hospital discharge. Non-elective surgeries, and complete cystectomy procedures had higher rate of CDI. 48.4% of patients with CDI had a preceding post-operative infection. Post-operative organ space infections (OR 1.95), post-operative renal failure (OR 2.38), post-operative sepsis (OR 2.49) and septic shock (OR 2.33) were independently associated with development of CDI, (all p values < 0.05). Patients who developed post-operative CDI during hospitalization had lengthier hospital admissions than those who did not develop a CDI (OR 2.29) and had a higher risk of DVT formation (2.48), and were also more likely to have unplanned readmissions (OR 7.8) Conclusion. This is the first nationwide study looking at inpatient and 30-day post-operative CDI after cystectomy in the US. A sizable number of patients experience CDIs after cystectomy procedures, and CDI development is associated with an increase in length of stay and unplanned readmissions. This study lends further evidence to the need for continued interventions and initiatives to reduce this burden of post-operative CDI. Background. Clostridioides difficile infection (CDI) is a common complication in patients undergoing cancer treatment with cytotoxic chemotherapy. Exposure to antibiotics or chemotherapy disrupts the microbiome by killing protective intestinal flora which consequently promotes C. difficile spore germination and disease. The host defense against CDI includes colonization resistance conferred by the healthy microbiome and innate defenses provided by intestinal epithelial cells. One protective factor secreted by Paneth cells of the intestinal epithelium is lysozyme, an enzyme that degrades the cell walls of Gram-positive bacteria such as C. difficile. We hypothesized that chemotherapy-induced mucosal barrier injury and the resultant death of Paneth cells leads to decreased production of lysozyme. We thus sought to examine changes in lysozyme concentration in stools of chemotherapy patients.

Host Intestinal Defenses Against Clostridioides difficile Infection in Chemotherapy Patients
Methods. We collected stool samples from six patients undergoing cancer treatment at four different time points. The first stool sample corresponded to the day prior to the start of chemotherapy (day zero). We then performed ELISA assays to determine the lysozyme concentration for each stool sample.
Results. On day zero, the lysozyme levels (n=6) averaged 268.1 ± 131.7 ng/mL. Over the course of chemotherapy, the lysozyme levels decreased 78.70 ± 24.19% from the starting value. The lowest values were observed around days 5 through 11 for most patients, coinciding with when they were most neutropenic around day 11. One of the patients developed CDI on day 5 and experienced more fluctuating lysozyme levels thereafter. On the day that the patient developed CDI, lysozyme was measured as 6.63 ng/mL. Throughout treatment, 3/6 patients showed recovery of lysozyme production with white blood cell recovery.
Conclusion. Our data indicate that chemotherapy causes decreased concentrations of lysozyme in stool. Low lysozyme levels could in part account for the increased susceptibility to CDI during chemotherapy. Future experiments will include bioinformatics analyses to determine how the microbiome changes in response to chemotherapy. Together, these experiments will inform our approach to determining patient susceptibility to chemotherapy-associated CDI.
Disclosures. Background. IDSA recommends use of fidaxomicin or oral vancomycin for treatment of initial episode or first recurrence of Clostridioides difficile infection (CDI). This study aimed to evaluate impact of a clinical decision support order set driving appropriate use of fidaxomicin on utilization of CDI drug treatments and associated clinical outcomes.
Methods. This was a retrospective, quasi-experimental study evaluating CDI therapies pre-(8/2016-11/2017) and post-(5/2018-1/2020) CDI order set implementation at a level-one trauma center located in Virginia. Admitted adult patients were included if CDI testing was positive for a 1 st or 2 nd episode and received active CDI treatment. Exclusions included fulminant CDI and CDI diagnosis by PCR with < 3 bowel movements or laxative use within 24 hours. The primary outcome was CDI recurrence within 30 days of completing therapy in patients who achieved clinical cure. Secondary outcomes were evaluated at 30 and 90 days and included sustained response and CDI-related readmissions.
Results. After screening, 186 patients in the pre-group and 187 in the post-group were included. Median age was 68 [59-77], most patients had an initial CDI episode (88.2%) and were diagnosed with severe CDI (50.7%). Baseline characteristics were similar between each group on Charlson comorbidity index, ICU admission, CDI risk factors, and concomitant antibiotic use. Primary treatment options in the pre-group were most commonly metronidazole 47.9% and oral vancomycin 50.5%, and in the post-group were fidaxomicin 56.7% and oral vancomycin 41.7% (Figure 1). CDI recurrence rates at 30 days post-index medication (17.2% vs. 6.3%, p=0.004) were lower in the post-group (Table 1). Clinical cure (84.4% vs. 94.1%, p=0.002) and sustained response at 90 days (55.9% vs. 73.3%, p< 0.001) were higher in the post-group. CDI recurrence rates at 90 days and CDI-related readmissions at 30 and 90 days were also lower in the post group.  Conclusion. Implementation of the CDI order set increased fidaxomicin use and was associated with a decrease in CDI recurrences and CDI-related readmissions and increase in clinical cure and sustained response. Findings suggest increased first-line use of fidaxomicin results in better clinical outcomes.