Background: Clostridioides difficile PCR is extremely sensitive but cannot differentiate colonization versus active disease. Over diagnosis of C. difficile infection (CDI) has negative consequences including overuse of antibiotics targeting C. difficile, increased hospital-acquired (HA)-CDI rates, and increased healthcare costs. We describe the implementation of a Clinical Decision Support tool embedded in the C. difficile order and the result on testing, HA-CDI rates and healthcare costs. Methods: The C. difficile order was updated in June 2023 with 4 dynamic questions that reflex if specific criteria are identified in the electronic medical record in the prior 24 hours: less than 3 loose stools documented, receipt of laxative, opioid antagonist, oral contrast, or tube feed initiation. If any criteria are identified, an embedded alert triggers and the provider must choose “yes, high clinical suspicion” or “no (exit and cancel order)” in addition to providing an order indication. All inpatient C. difficile tests were reviewed from July 1 to Sept 30, 2022 (pre-update) and July 1 to Sept 30, 2023 (post-update). An order rate was calculated per 10,000 patient days as well as HA-CDI rate. Cost analysis was completed using direct lab costs and published costs of $35,000 per HA-CDI. Results of the order questions were reviewed post-update. Incident rate comparison was completed using medcalc. Results: Pre-update, 1147 tests were conducted, with an order rate of 104.3. Post-update, 919 tests were performed, with an order rate of 86.6. The positivity rate was 16.1% pre-update and 14.7% post-update. The incidence rate difference was 0.00177 (P 15 (145, 16%). 166 (18%) patients who received laxatives (18 positive, positivity rate 11%) were still tested. Conclusion: Implementation of a dynamic order led to a significant reduction in the total number of C. difficile PCR tests performed with associated reduction in HA-CDI and cost savings. Despite this, patients receiving laxatives were still being tested for C. difficile, highlighting the need for ongoing education and feedback. These results support the use of dynamic ordering for diagnostic stewardship, which can benefit both patients and hospitals.

A clinical decision support menu requiring selection of urine culture (UC) indication within outpatient and inpatient settings of a large integrated health care system significantly reduced UC sample collection. Clear documentation of selected UC indication in most post-intervention cases affirms its potential as an effective diagnostic stewardship strategy.

Penicillin (PCN) allergy delabeling is an important component of antimicrobial stewardship; however, widespread implementation has lagged. We found that most patients had low-risk PCN allergy histories eligible for delabeling without skin testing. Pharmacist-led risk stratification and drug challenge expanded access to delabeling independently from an Allergy/Immunology service.

Background: Clostridioides difficile infections (CDI) are a crucial public health threat becoming a worldwide problem. In 2017, there were 223,900 incident cases and 12,800 deaths in the United States. Underlying conditions, such as diabetes mellitus (DM), put individuals at a greater risk for developing an infection. Whereas CDI was once believed to be mostly healthcare-associated, increasing evidence points to transmission in community settings (CA). We investigated characteristics of CA CDI and associations between pre-existing conditions and CA incident CDI cases using data from Tennessee’s CDI surveillance program, an active population- and laboratory-based surveillance system conducted through CDC’s Emerging Infections Program. CA incident CDI case data were downloaded from the Incident Case Management System from 2017 to 2021. Count and percentages were determined for each underlying condition, number of underlying conditions, and biological sex. Chi-square analyses determined associations between underlying conditions and sex. Statistical analyses were conducted using SAS v9.4. 2,326 CA incident CDI cases were identified from the catchment area. The case rates per 100,000 population between 2017 and 2021 were 79.7, 81.9, 73.7, 50.7, and 49.6. A total of 39% of the cases were 65 years or older. Most cases were women (64.8%). The overall prevalence for any underlying condition among CA CDI cases was 67.4%. A total of 29.4% of incident cases had one condition, 18.5% had two conditions, and 19.4% had three or more conditions. The most frequently reported pre-existing conditions was DM (22.9%) and gastrointestinal disease (21.7%). We looked at the prevalence of underlying conditions separated in men and women. Men with CA CDI were more likely to have chronic kidney disease (CKD) (19.1% vs 12.7%), DM (26.0% vs 21.2%), immunocompromised conditions (6.4% vs 3.6%), liver diseases (6.5% vs 2.8%), and plegias (1.0% vs 0.2%) than women with CA CDI. Women with CA CDI were more likely to have chronic lung diseases (17.4% vs 12.6%) and connective tissue diseases (4.9% vs 2.2%) than men with CA CDI. Although the incident CA CDI case rate in Davidson County decreased from 2018 to 2021, it remains a significant threat. In this analysis, underlying conditions in persons with CA CDI were highly prevalent. Men were more likely to have underlying conditions in general, and specifically CKD and DM, than women. Improving understanding of the prevalence of these conditions with CA CDI cases, along with their antibiotic use and community exposures, can help drive prevention strategies to mitigate CA CDI transmission.

Candida auris is an emerging pathogen responsible for healthcare-associated infections and outbreaks. This organism has a high tolerance to both high temperatures and high salinity. We describe our experience with a C. auris outbreak in an 8-bed inpatient burn unit at an academic medical center.

Background: Prior research has implicated contaminated surfaces in the transmission of Clostridioides difficile within the hospital. To reduce the risk of transmission, enhanced environmental hygiene is performed in rooms of patients with known C.difficile infection (CDI). We wished to evaluate the residual impact of environmental surfaces on hospital-onset CDI (HO-CDI) by comparing HO-CDI rates before and after the opening of a new 504-bed hospital building, HUP Pavilion (PAV). We hypothesized that we would observe a reduction in HO-CDI after opening of PAV due to a reduced burden of C.difficile spores in the environment. Methods: We included NHSN reported HO-CDI rates for 28 months prior and 24 months after opening of PAV. Upon opening, patients were divided between the old building (HUP) and PAV. We included all patient units before and after opening. We created hierarchical models of HO-CDI rates using Stan Hamiltonian Monte Carlo (HMC) version 2.30.1, via the “cmdstanr” and “brms” packages with a GAM smooth function by month and intervention period with default, weakly-informative priors. Results: At baseline, there was an average of approximately 20,100 patient days per month, subsequently divided between HUP and PAV (mean 10,100 and 12,100 patient days per month). After opening of PAV, we observed a reduced HO-CDI rate (mean 0.21 vs 0.31 per 1000 patient days, P=0.01). When comparing the two specific buildings after opening of PAV, there was a greater reduction noticed in the old building (HUP) as compared to the new building (PAV) (0.12 vs 0.29 per 1000 patient days) (Figure 1). The predicted contrast in HO-CDI rate (Figure 2), shows no immediate change in HO-CDI after opening, however a sustained reduction estimated at 0.1 HO-CDI events per 1000 patient days for the duration of follow-up. Conclusions: We observed a reduction in HO-CDI rates after the opening of a new hospital building. The difference in HO-CDI rates between hospital buildings after the move is likely due to the concentration of high-risk patient cohorts within this building. Our findings suggests that there remains an opportunity to reduce HO-CDI through environmental hygiene. However, it is possible that other factors beyond surface environment contributed to an observed reduction in HO-CDI, including other concurrent infection control interventions that focused on smaller populations within the hospital. In future work we will investigate the durability of this observed effect with additional analyses including patient-level risk for HO-CDI.

Background: Nucleic acid amplification tests (NAAT) do not distinguish between colonization and Clostridioides difficile (C.diff) associated diarrhea. On April 5th 2023 our laboratory introduced a new C. diff testing methodology. Previously, if a C. diff screen result was negative for toxin and positive for glutamate dehydrogenase (GDH), a second confirmatory test was conducted with NAAT. This confirmatory test was removed from our testing algorithm. NAAT testing may be ordered ad hoc when clinically relevant diarrhea persists, and alternative etiologies have been excluded. We wanted to evaluate the impact of change with testing methods. Method: Retrospective review of all inpatient hospital-acquired C.diff infections reported to NHSN database from Ascension Michigan Market which comprises 14 acute care hospitals from June 2019 to August 2023. Data for C diff was analyzed every quarter. The risk adjustments used to calculate the Standardized Infection Ratios (SIRs) for C. diff infections was set at 0.48 based on CDC mean SIR established for acute care hospitals in 2022. Results: A total of 14 acute care hospitals were included from which 866 C.diff cases were reported during this period. Overall, the SIR dropped from 0.59 from June-August 2019 to 0.32 reported from March-May 2023; 45.7 % decrease. The maximum reduction in SIR was seen post intervention at 0.21 from June-August 2023 which was 78.3% below the benchmark of 0.48. (Figure) Conclusions: Strategies to optimize current laboratory tests are critical to differentiate C. diff infection from colonization. The current strategy by changing the testing method led to substantial reduction in C-diff. Diagnostic stewardship studies should ideally include outcome measures targeted to post-intervention patients to determine clinical relevance and patient safety. Optimizing test utilization remains a critical component of quality healthcare delivery. Future NHSN updated surveillance definition will require incorporating clinical decision-making into the metric; that is including a combination of any positive C-diff test plus initiation of antibiotic therapy for C-diff.

Disclosure: Reese Cosimi: Advisory Board - Abbvie

Our qualitative analysis of interviews with remote Australian healthcare professionals found that they require reliable, local antimicrobial resistance (AMR) data reflecting the geographical diversity of the population they serve. The optimal use of AMR data must consider challenges within this setting, including high staff turnover, limited diagnostic capacity, and antibiotic shortages.

Background: Patients colonized with Clostridioides difficile are at risk of transmitting C. difficile to other patients, and of developing C. difficile infection (CDI). Known risk factors for carriage include previous hospitalization, gastric acid suppression and previous CDI. Data regarding duration of carriage and its predictors are lacking but could be useful to better understand the natural evolution of carriage and better estimate the likelihood of transmission or progression to CDI. Methods: We performed a retrospective cohort study of C. difficile colonized patients with > = 1 admission to a tertiary academic institution between November 2013 and January 2017. Colonization status was determined upon hospital admission by detection of TcdB gene by polymerase chain reaction on a rectal screening swab, as part of a systematic screening program. Overall duration of carriage and predictors of prolonged carriage were explored using Kaplan-Meier methods and Cox regression. Results: There were 134 patients, who after having a positive initial screening test (and therefore identified as colonized with C. difficile), had subsequent testing. The median age was 77 years (IQR, 66 to 85), and 53.6% of the patients were female. After hospital discharge, 26 (19.4%) colonized patients progressed to CDI. Mean duration of follow up was 269 days, with a median of 179 days. Median duration of carriage was 211 days, (95% confidence interval (CI) [157, 264]). Predictors associated with decreased duration of C. difficile colonization included younger age (HR per unit decrease (year), 1.013; 95% CI, 1.025 to 1.001; p=0.03), and receipt of antibiotics in the 3 months prior to first admission (mean days to clearance of patients with and without recent antibiotic use, 252 days vs 372 days, respectively; HR, 1.55; 95% CI, 1.01 to 2.36; p < 0 .04). By contrast, the presence of comorbidities (e.g. heart failure, diabetes, cancer, and chronic kidney disease), the use of proton-pump inhibitors (PPIs), the receipt of antibiotics during the first admission, and the duration of first hospitalization were not associated with significant differences in duration of carriage. Conclusion: This study is the largest cohort of C. difficile carriers with longitudinal follow up of their colonization status. It highlights the extended duration of carrier status especially in older patients and identifies predictors of prolonged carriage. Further studies are needed to understand the underlying relationship with the predictors identified in this study.

Background: The diagnosis of Clostridioides difficile infection (CDI) is challenging. Despite guideline-directed, multistep testing algorithms and diagnostic stewardship, the treatment of C. difficile colonization persists. The testing algorithm at our system utilizes an initial real-time PCR test (PCR) for Toxin B gene, which if positive, reflexes to an enzyme immunoassay (EIA) for detecting Toxins A and B. Discordant results (PCR +/EIA -) are suggestive of colonization, but the majority of patients with discordant results are treated for CDI. Correlation of C. difficile EIA B polymerase chain reaction (PCR) cycle thresholds (Ct) with the presence of free EIA and disease severity has been observed, but the ability to use Ct in the decision to treat patients with discordant results is unclear. Our study assesses if Ct values and other clinical characteristics favor treatment in select patients with discordant Methods: A retrospective chart review was performed of adult patients (≥ 18-year-old) with positive C. difficile PCR results that were admitted to our health system between June 01 and August 31, 2023. C. difficile PCR and Ct results were obtained by Cepheid GeneXpert and Toxin A and B EIA results were obtained by Meridian Bioscience Immunocard. Patients with discordant (PCR+/EIA) and true positive (PCR+/EIA+) results were compared. We assessed demographics, past medical history, clinical characteristics, severity of illness, PCR Ct values, treatment, and clinical outcomes including: 30-day all-cause mortality and re-admission, and 60-day CDI repeat testing and treatment. Results Of the 122 patients identified, 89 patients had discordant results and 43 had true positive Results: Severity of illness and other clinical and laboratory characteristics were similar between both groups. Mean Ct values were significantly lower for true positive results compared to discordant results, 24.28 vs 29.27, respectively (p26 (p=.08). Of the patients with discordant results, 73 completed treatment for CDI and no difference in clinical outcomes was observed compared to patients with discordant results that were not treated. Conclusion Ct values were lower among patients with true positive results compared to patients with discordant Conclusion: There were no statistically significant different rates of severe or fulminant CDI among patients with discordant results and Ct values < 26, although this finding may be limited by sample size and Ct may be helpful in deciding which discordant patients to treat.

Background: Our institution utilizes a two-step algorithm consisting of an initial polymerase chain reaction (PCR) test with positive results reflexed to an enzyme immunoassay (EIA) for toxin. Institutional guidelines implemented during the COVID-19 pandemic recommended applying clinical judgment to patients with PCR+/Toxin- (discordant) results when determining if treatment is indicated. Pre-pandemic, we found that clinicians continued CDI-directed therapy in 56% of patients following the Toxin- result. Our study aims to identify how clinicians interpret PCR+/Toxin- results and reasons for management decisions post-pandemic. Methods: At an academic medical center, we conducted a retrospective cohort study of the first 50 inpatient charts with PCR+/Toxin- results from August to October 2022. Data was abstracted from clinical, pharmacy, and microbiology databases. The primary outcome was the proportion of patients continued on CDI-directed therapy for ≥24 hours after the Toxin- result became available. Secondary outcomes included the proportion of patients prescribed a full treatment course for CDI and the reasons for continuing treatment. Results: There were 37 patients (74%) who started CDI-directed treatment after initial PCR+ Results: Of these patients, 59% (22/37) were continued on treatment for ≥24 hours after the Toxin- result (primary outcome). 77% (17/22) of these patients who met the primary outcome completed full treatment courses. Three patients were transitioned to prophylaxis dosing after the Toxin- result. The most common reason for continuing treatment after discordant results was high clinical suspicion for CDI (Figure). There were no CDI-related complications in this 50-patient cohort. In immunocompromised patients, 70% (16/23) started treatment after initial PCR+ results and 81% (13/16) met the primary outcome. In patients admitted specifically to immunocompromised inpatient services, 90% (9/10) started treatment after initial PCR+ results and 100% (9/9) met the primary outcome. Conclusion: The majority of patients started on treatment after the PCR+ result were continued on treatment following the Toxin- result, though several of these patients did not complete full treatment courses. Treatment rates were similar to our pre-pandemic baseline. When patients were continued on treatment after discordant results, clinicians cited appropriate high clinical suspicion. Notably, every patient admitted to an immunocompromised service was continued on treatment after Toxin- Results: Overall, clinicians are following institutional guidelines by applying clinical judgement when interpreting discordant Results: Further research will help identify what variables affect clinician interpretation and management practices for discordant results, which will help shape institutional guideline updates, clinician education, and additional stewardship interventions.

Introduction: Hospital-onset Clostridioides difficile infection (HO-CDI), reported as laboratory-identified (LabID) event, is common in patients with chronic kidney disease (CKD), especially those with end-stage renal disease (ESRD), and is associated with prolonged length of hospitalization and more severe disease. CKD patients are at increased of developing CDI due to frequent antimicrobial and healthcare exposures. The objective of this study was to assess recent trends of HO-CDI in patients on a nephrology unit at our academic, tertiary care institution. Methods: Retrospective cross-sectional study of patients with HO-CDI who were hospitalized on a nephrology unit between January 2021 to December 2023. Collected variables included: demographic data, characterization of HO-CDI risk factors, infection and diagnosis (including prior history of CDI, toxin versus nucleic acid amplification test [NAAT] positivity, number of loose stools), CDI rate (defined as CDI count/patient days x1000), standardized antimicrobial administration ratio (SAAR) for high-risk for CDI antimicrobials (defined by the National Healthcare Safety Network), and infection prevention and control (IPC) practices, including hand hygiene audit rates. Results: A total of 30 HO-CDI infections were reported on the nephrology unit [Table], with 8 occurring in 2021, 5 in 2022, and 17 in 2023. The median age of patients was 70.8 (range: 37-96) years, and most patients (57%) were female. The majority of patients were admitted from home (73%), and two patients (7%) had a history of CDI in the last 6 months. Among the CDI cases, 60% were NAAT positive and toxin negative, and only 50% had >3 bowel movements (BM) within 24 hours prior to the positive test. Ten percent received promotility agents prior to testing. Most cases (77%) occurred when other CDI patients were on the unit. Hand hygiene compliance rates averaged 81% over the three-year period [Figure 1A]. Eight-four per cent of patients received antibiotics within 30 days of CDI diagnosis; SAAR was >1 for quarters 2 and 4 in 2022, and quarter 1 in 2023 [Figure 1B]. Conclusion: On our nephrology unit, patients often had < 3 BM within 24 hours of CDI diagnosis, and 60% of cases were toxin-negative, NAAT-positive, suggesting possible C. difficile colonization, rather than true infection. In addition, an elevated SAAR correlated with high CDI rates. Multicomponent interventions may be required to reduce the rates of HO-CDI in CKD patients. Opportunities include emphasis on diagnostic and antimicrobial stewardship, environmental cleaning and adherence to IPC practices, including hand hygiene.

Background: Catheter-associated urinary tract infection (CAUTI) is among the most prevalent healthcare-associated infections. Clinical diagnosis of CAUTI and National Healthcare Safety Network (NHSN) definitions do not always align. Most patients with indwelling urinary catheters ultimately develop asymptomatic bacteriuria (ASB) due to bacterial colonization and may be misattributed as CAUTI. Urine cultures ordered on patients with ASB may lead to reporting of non-clinically significant CAUTI to NHSN. We sought to examine factors associated with ordering inappropriate urine cultures in patients with urinary catheters. Methods: All CAUTIs that were reported to the NHSN at a large academic medical center in Eastern North Carolina were evaluated from October 2021-July 2023. A logistic regression model was fit for patients treated for urinary tract infection (UTI) with the following covariates: age, sex, time of urine culture order, provider type, and days that the urinary catheter was in place. All data analysis was performed in SAS (SAS Institute Inc., SAS 9.4, Cary, NC: SAS Institute Inc., 2002-2023). Results: Table 1 demonstrates patient characteristics stratified by treatment for UTI. The analysis suggests that abnormalresults from urine cultures ordered overnight were less likely to be treated with antibiotics,and this result was statistically significant in both the adjusted and unadjusted analyses – see table 2 and 3. The model also suggests abnormal results from urine cultures ordered by housestaff and older patients were more likely to be treated for UTI, but these results were not statistically significant – see table 3. Finally, the longer a catheter was in place the less likely an abnormalurine culture was to be treated and this finding was statistically significant – see table 3. Conclusion: Cultures that did not prompt antimicrobial treatment did not impact patient care decisions and could be considered as inappropriate orders. This can result in CAUTIs reported to NHSN that were not clinically significant. Abnormal results from cultures that were ordered by the overnight team were less likely to be treated for clinical UTI and this may represent an important target for diagnostic stewardship interventions.

Background: Indwelling urinary catheters (UCs) generate biofilm that grows over time, raising concern that after several days any culture from a UC may generate a false positive result. Whether and when to replace a UC prior to culture is controversial, with prior studies recommending anywhere from 3 to 14 days as appropriate, but with no conclusive data. We evaluated urine culture results across a large healthcare system where, beginning in 2019, some facilities adopted the practice of changing UC before collection if indwelling for 3 days or more. Method: Analysis was from nursing electronic health record documentation of UC changes and urine cultures collected on patients with indwelling UC in 2022. UC changes were defined as a stop followed by a start within 12 hours. Patient exclusion criteria included a UC other than “temporary/indwelling” and surgical procedure during the admission. Statistics applied Pearson’s Chi-squared test with Yates continuity correction using R Core Team (2023) R: A Language and Environment for Statistical Computing. Result: Total UC episodes meeting criteria was 88,347 across 152 acute care hospitals. Episodes in days was 0-3 for 65%, 4-9 for 29% and >9 for 6%. Most urine cultures were taken at 3 days (p UC Changed? Culture Negative Culture Positive No 4916 (98.8%) 61 (1.2%) Yes 588 (98.7%) 8 (1.3%) Cultures were positive at the same rate whether a UC change occurred or not at >3 days (p=0.96). No difference was found in NHSN reported CAUTI prevalence among the UC change vs. no change in the >3 day groups. Conclusion: Urine culture results do not appear to be impacted by UC change as early as 3 days. UC change without benefit may generate unnecessary costs and complications.