Diagnostic Stewardship Intervention Research Articles

A Diagnostic Stewardship Intervention to Improve Utilization of 1,3 β-D-Glucan Testing at a Single Academic Center: Five-Year Experience.

(1,3)- β-D-glucan (BDG) testing is one of the noninvasive tests to aid diagnosis of invasive fungal infections (IFIs). The study results have been heterogenous, and diagnostic performance varies depending on the risks for IFI. Thus, it is important to select appropriate patients for BDG testing to prevent false-positive results. An algorithmic diagnostic stewardship intervention was instituted at a single academic medical center to improve BDG test utilization. The BDG test order in the electronic health record was replaced with the BDG test request order, which required approval to process the actual test order. The approval criteria were (1) immunocompromised or intensive care unit patient and (2) on empiric antifungal therapy, or inability to undergo invasive diagnostic procedures. A retrospective observational study was conducted to evaluate the efficacy of the intervention by comparing the number of BDG tests performed between 1 year pre- and post-intervention. Safety was assessed by chart review of the patients for whom BDG test requests were deemed inappropriate and rejected. The number of BDG tests performed per year decreased by 85% from 156 in the pre-intervention period to 24 in the post-intervention period. The average monthly number of BDG tests performed was significantly lower between those periods (P = .002). There was no delay in IFI diagnosis or IFI-related deaths in the patients whose BDG test requests were rejected. The sustained effectiveness of the intervention was observed for 5 years. Institution of the diagnostic stewardship intervention successfully and safely improved BDG test utilization.

Diagnostic stewardship in infectious diseases: a scoping review.

Introduction. The term 'diagnostic stewardship' is relatively new, with a recent surge in its use within the literature. Despite its increasing popularity, a precise definition remains elusive. Various attempts have been made to define it, with some viewing it as an integral part of antimicrobial stewardship. The World Health Organization offers a broad definition, emphasizing the importance of timely, accurate diagnostics. However, inconsistencies in the use of this term still persist, necessitating further clarification.Gap Statement. There are currently inconsistencies in the definition of diagnostic stewardship used within the academic literature.Aim. This scoping review aims to categorize the use of diagnostic stewardship approaches and define this approach by identifying common characteristics and factors of its use within the literature.Methodology. This scoping review undertook a multi-database search from date of inception until October 2022. Any observational or experimental study where the authors define the intervention to be diagnostic stewardship from any clinical area was included. Screening of all papers was undertaken by a single reviewer with 10% verification by a second reviewer. Data extraction was undertaken by a single reviewer using a pre-piloted form. Given the wide variation in study design and intervention outcomes, a narrative synthesis approach was applied. Studies were clustered around common diagnostic stewardship interventions where appropriate.Results. After duplicate removal, a total of 1310 citations were identified, of which, after full-paper screening, 105 studies were included in this scoping review. The classification of an intervention as taking a diagnostic stewardship approach is a relatively recent development, with the first publication in this field dating back to 2017. The majority of research in this area has been conducted within the USA, with very few studies undertaken outside this region. Visual inspection of the citation map reveals that the current evidence base is interconnected, with frequent references to each other's work. The interventions commonly adopt a restrictive approach, utilizing hard and soft stops within the pre-analytical phase to restrict access to testing. Upon closer examination of the outcomes, it becomes evident that there is a predominant focus on reducing the number of tests rather than enhancing the current test protocol. This is further reflected in the limited number of studies that report on test performance (including protocol improvements, specificity and sensitivity).Conclusion. Diagnostic stewardship seems to have deviated from its intended course, morphing into a rather rudimentary instrument wielded not to enhance but to constrict the scope of testing. Despite the World Health Organization's advocacy for an ideology that promotes a more comprehensive approach to quality improvement, it may be more appropriate to consider alternative regional narratives when categorizing these types of quality improvement interventions.

Blood culture algorithm implementation in emergency department patients as a diagnostic stewardship intervention

Blood cultures (BCx) are important for selecting appropriate antibiotic treatment. Ordering BCx for conditions with a low probability of bacteremia has limited utility, thus improved guidance for ordering BCx is needed. Inpatient studies have implemented BCx algorithms, but no studies examine the intervention in an Emergency Department (ED) setting. We performed a quasi-experimental pre-/post-intervention study from 12/1/2020 to 10/31/2023 at a single academic adult ED and implemented a BCx algorithm. The primary outcome was the blood culture event rates (BCE per 100 ED admissions) pre- and post-intervention. Secondary outcomes included adverse event rates (30-day ED and hospital readmission and antibiotic days of therapy). Seven ED physicians/APP reviewed BCx for appropriateness, with monthly feedback provided to ED leadership and physicians. After BCx algorithm implementation, the BCE rate decreased from 12.17 BCE/100 ED admissions to 10.50 BCE/100 ED admissions. Of the 3,478 reviewed BCE, we adjudicated 2153 BCE (62%) as appropriate, 653 (19%) as inappropriate, and 672 (19%) as uncertain. Adverse safety events were not statistically different pre/post-intervention. Implementation of an ED BCx algorithm demonstrated a reduction in BCE, without increased adverse safety events. Future studies should compare outcomes of BCx algorithm implementation in a community hospital ED without intensive chart review.

Changing the culture: impact of a diagnostic stewardship intervention for urine culture testing and CAUTI prevention in an urban safety-net community hospital.

Cultures from urinary catheters are often ordered without indication, leading to possible misdiagnosis of catheter-associated urinary tract infections (CAUTI), increasing antimicrobial use, and C difficile. We implemented a diagnostic stewardship intervention for urine cultures from catheters in a community hospital that led to a reduction in cultures and CAUTIs.

A quasi-experimental study of a bundled diagnostic stewardship intervention for ventilator-associated pneumonia

ObjectivesDiagnostic error in the use of respiratory cultures for ventilator-associated pneumonia (VAP) fuels misdiagnosis and antibiotic overuse within intensive care units. In this prospective quasi-experimental study (NCT05176353), we aimed to evaluate the safety, feasibility, and efficacy of a novel VAP-specific bundled diagnostic stewardship intervention (VAP-DSI) to mitigate VAP over-diagnosis/overtreatment. MethodsWe developed and implemented a VAP-DSI using an interruptive clinical decision support tool and modifications to clinical laboratory workflows. Interventions included gatekeeping access to respiratory culture ordering, preferential use of non-bronchoscopic bronchoalveolar lavage for culture collection, and suppression of culture results for samples with minimal alveolar neutrophilia. Rates of adverse safety outcomes, positive respiratory cultures, and antimicrobial utilization were compared between mechanically ventilated patients (MVPs) in the 1-year post-intervention study cohort (2022–2023) and 5-year pre-intervention MVP controls (2017–2022). ResultsVAP-DSI implementation did not associate with increases in adverse safety outcomes but did associate with a 20% rate reduction in positive respiratory cultures per 1000 MVP days (pre-intervention rate 127 [95% CI: 122–131], post-intervention rate 102 [95% CI: 92–112], p < 0.01). Significant reductions in broad-spectrum antibiotic days of therapy per 1000 MVP days were noted after VAP-DSI implementation (pre-intervention rate 1199 [95% CI: 1177–1205], post-intervention rate 1149 [95% CI: 1116–1184], p 0.03). DiscussionImplementation of a VAP-DSI was safe and associated with significant reductions in rates of positive respiratory cultures and broad-spectrum antimicrobial use. This innovative trial of a VAP-DSI represents a novel avenue for intensive care unit antimicrobial stewardship. Multicentre trials of VAP-DSIs are warranted.

The impact of a blood-culture diagnostic stewardship intervention on utilization rates and antimicrobial stewardship.

Blood-culture overutilization is associated with increased cost and excessive antimicrobial use. We implemented an intervention in the adult intensive care unit (ICU), combining education based on the DISTRIBUTE algorithm and restriction to infectious diseases and ICU providers. Our intervention led to reduced blood-culture utilization without affecting safety metrics.

Implementation of a diagnostic stewardship intervention to improve blood-culture utilization in 2 surgical ICUs: Time for a blood-culture change.

We compared the number of blood-culture events before and after the introduction of a blood-culture algorithm and provider feedback. Secondary objectives were the comparison of blood-culture positivity and negative safety signals before and after the intervention. Prospective cohort design. Two surgical intensive care units (ICUs): general and trauma surgery and cardiothoracic surgery. Patients aged ≥18 years and admitted to the ICU at the time of the blood-culture event. We used an interrupted time series to compare rates of blood-culture events (ie, blood-culture events per 1,000 patient days) before and after the algorithm implementation with weekly provider feedback. The blood-culture event rate decreased from 100 to 55 blood-culture events per 1,000 patient days in the general surgery and trauma ICU (72% reduction; incidence rate ratio [IRR], 0.38; 95% confidence interval [CI], 0.32-0.46; P < .01) and from 102 to 77 blood-culture events per 1,000 patient days in the cardiothoracic surgery ICU (55% reduction; IRR, 0.45; 95% CI, 0.39-0.52; P < .01). We did not observe any differences in average monthly antibiotic days of therapy, mortality, or readmissions between the pre- and postintervention periods. We implemented a blood-culture algorithm with data feedback in 2 surgical ICUs, and we observed significant decreases in the rates of blood-culture events without an increase in negative safety signals, including ICU length of stay, mortality, antibiotic use, or readmissions.

Analysis of health care facility-onset Clostridioides difficile infection (CDI) in a hematopoietic cell transplant (HCT) unit: A call for diagnostic stewardship in a complex patient population

Nearly half the patients identified as having health care facility-onset Clostridioides difficile infections on a hematopoietic cell transplant unit had an alternative clinical explanation for diarrhea, including conditioning regimen toxicity or other medications. Our study supports that targeted diagnostic stewardship interventions should be explored and that additional risk-adjustments considered for facilities with oncology hematopoietic cell transplant wards in the National Healthcare Safety Network LabID Clostridioides difficile infection standardized infection ratio model.

91. Implementation of a blood culture algorithm in emergency department patients as a diagnostic stewardship intervention

Abstract Background Blood cultures (BCx) are commonly ordered for patients at low risk of bacteremia. Liberal ordering can increase false-positive results due to contamination, along with increasing length of stay, excess antibiotics, and unnecessary diagnostic procedures. We implemented an algorithm for appropriate blood culture obtainment (Figure 1) in an academic tertiary care emergency department (ED) and assessed the intervention’s impact on various operational, clinical, and safety metrics.Figure 1:ED Blood culture algorithm Methods We performed a prospective cohort study in the Duke University Hospital ED from 12/2022 to 3/2023 using historical controls from 12/2020-11/2022. The BCx algorithm was disseminated in-person, electronically, and accessible online. Weekly chart review of all eligible patients for algorithm adherence was completed by 7 ED clinicians with monthly feedback provided to all ED providers. We defined a BCx event as 1 or more BCx sets within 24 hours. We excluded patients &amp;lt; 18 years, absolute neutrophil count &amp;lt; 500 109/L, and heart and lung transplant recipients. We measured BCx order volume, indication, algorithm adherence, BCx positivity rate, antibiotic days of therapy (DOT), and 30-day hospital readmission. Results Average monthly BCx volume was 1387 pre-intervention compared to 1226 post-intervention (p= 0.046). An increase in culture positivity was see post-intervention with a rate of 13.9% compared to 11.23% in the pre-intervention group (Figure 2, p&amp;lt; 0.001). The majority of the 2168 BCx adhered to the algorithm. (Figure 3). The most common reasons for non-adherence were isolated fever or leukocytosis (29%), non-severe community-acquired pneumonia or healthcare-associated pneumonia (6.9%) and non-severe cellulitis (4%). No change in DOT (786 vs. 783 days of therapy per 1000 patient days, p-value 0.85) (Figure 4) or monthly 30-day hospital readmission (21.1% vs 19.6%, p-value 0.30) was observed.Figure 2:Blood cultures drawn per month and % appropriate pre/post-intervention (N=2168)Figure 3:Algorithm Adherent vs. Algorithm Non-Adherent blood cultures per month (N=2168)Figure 4:Emergency Department anti-bacterial days of antibiotic therapy per 1000 patient days Conclusion Introduction of a BCx algorithm in an academic tertiary care ED, resulted in a decrease in BCx volume, increase in BCx positivity rate, and no increase in DOT or readmission was observed. (Table 1)Table 1:Blood culture volume, positivity rate, days of antibiotic therapy, and 30-day readmission Disclosures Jessica Seidelman, MD, MPH, Uptodate: content editor for pelvic osteomyelitis page

90. The Diagnosis of Ventilator-associated pneumonia (DIVA) trial: Results of a Clinical Trial of a Bundled VAP Diagnostic Stewardship Intervention

Abstract Background Ventilator-associated pneumonia (VAP) is commonly overdiagnosed &amp; a primary driver of antibiotic overuse within intensive care units (ICUs). Antimicrobial stewardship programs have successfully leveraged diagnostic stewardship interventions (DSIs) to prevent overdiagnosis/overtreatment of diverse clinical syndromes, yet this approach has not been extended to VAP. In this trial, we aimed to evaluate the safety, feasibility &amp; efficacy of a novel DSI care bundle (DSI-CB) targeting VAP. Methods The DIVA trial (NCT05176353) was a pilot/feasibility trial conducted in 2 ICUs at Michigan Medicine from February 2022-February 2023. A DSI-CB targeting the respiratory culture testing pathway was implemented sequentially in study ICUs, using an interruptive electronic health record clinical decision support tool &amp; modifications to microbiology laboratory workflows (Table 1). Providers were counseled on DSI-CB use during bimonthly educational sessions during trial rollout &amp; via monthly email reminders thereafter. Rates of prespecified co-primary safety and secondary efficacy outcomes were compared between the postintervention study cohort &amp; 5-year preintervention historical controls using negative binomial regression. Interrupted time series analysis was used to evaluate ICU antibiotic utilization rates (ICU-AURs) to account for temporal trends. Results 1810 patients were admitted to study ICUs following DSI-CB implementation, 29% of whom were eligible for DSI-CB use. DSI-CB was utilized in 77% of eligible patients. Patient demographics, comorbidities &amp; measures of acute severity of illness were similar pre- &amp; post-intervention. DSI-CB implementation was not associated with increases in primary adverse safety outcomes (Table 2). DSI-CB implementation was associated with significant reductions in rates of total respiratory cultures ordered, rates of positive respiratory cultures &amp; reductions in both total &amp; broad-spectrum ICU-AURs (Table 2, Figure 1). Conclusion Implementation of a novel VAP DSI-CB was safe, feasible &amp; associated with significant reductions in rates of respiratory culture positivity and ICU-AURs. This represents the first trial of a DSI targeting VAP &amp; a novel avenue for ICU antimicrobial stewardship. Large-scale trials are warranted. Disclosures Owen Albin, MD, Biomeriux: Grant/Research Support|Charles River Laboratories: Advisor/Consultant|Shionogi: Advisor/Consultant Weirauch J. Andrew, RRT, Drager Medical: Equipment loaned for research purposes, but no monetary funds were provided.|Jones and Bartlett Learning: Honoraria Krishna Rao, MD, MS, Merck &amp; Co.: Grant/Research Support|Rebiotix: Advisor/Consultant|Seres Therapeutics: Advisor/Consultant|Summit Therapeutics: Advisor/Consultant Keith S. Kaye, MD, MPH, Entasis: Advisor/Consultant|Entasis: Honoraria|GSK: Advisor/Consultant|GSK: Honoraria|Merck: Advisor/Consultant|Merck: Honoraria|Shionogi: Advisor/Consultant|Shionogi: Honoraria|VenatoRx: Advisor/Consultant|VenatoRx: Honoraria

165. Changing the Culture of Obtaining Urine Cultures; Diagnostic Stewardship Intervention Leading to Sustained Reduction in Inpatient CAUTI Rates

Abstract Background Asymptomatic bacteriuria (ASB) is common in patients with urinary catheters and unneeded urine cultures (UC) can lead to misidentification of CAUTI. We evaluated the long-term effectiveness of restricting UC utilization on the incidence of inpatient CAUTI and if the COVID pandemic influenced CAUTI rates. Methods A UTI evaluation panel was implemented at our academic medical center in April 2015 requiring clinician documentation of UTI symptoms or criteria supporting UC in the absence of symptoms or pyuria. UC was performed reflexively if the following were present: documented symptoms, pyuria ( &amp;gt; 10WBC), and no contamination ( &amp;gt; 100 squamous cells) (Figure 1). UC in at risk patients without symptoms or pyuria were performed. CAUTI data was collected using NHSN methodology with 2014 CAUTI rates recalculated using 2015 definitions. Three periods were compared: Pre-implementation (1/2014-3/2015), post-implementation (4/2015-3/2020) and COVID (4/2020-6/2022). NHSN SIR and SUR were compared where available (4/2015-3/2020 vs. 4/2020-6/2022). Poisson regression was used to model rate of infection per month. A generalizing estimating equation was used for interrupting time series model to compare rates of infection.Figure 1:Urinalysis algorithm*At-risk population: neutropenia, kidney/pancreas transplant, pregnancy, impending urologic surgery, age &amp;lt;3 years Results Urine culture rates decreased in both post and COVID periods and catheter days decreased in the post but not COVID period (Table 1). CAUTI rates per 1000 CD decreased 40% between pre- and post-intervention (p=0.0001) and were unchanged during COVID, (p=0.61) although the slope of change did alter from decreasing to increasing (Figure 2). Quarterly SURs decreased during COVID while the institutional SIR increased non-significantly.Table 1:Comparison of Change in Urine Culture CAUTI and Catheter Days Between Periods (Pre=1/2014-3/2015; Post=4/2015-3/2020; COVID=4/2020-6/2022). UC=Urine cultures; PD=Patient days; CAUTI=Catheter-associated UTI; CD=Catheter daysTable 2:Median Quarterly Urinary Catheter SUR and CAUTI SIR Post-Intervention (Q1/2016-Q1/2020) Compared to COVID (Q2/2020-Q2/2022)SUR=Standardized Utilization Ration; SIR=Standardized Infection Ratio Figure 2: Conclusion Our intervention decreased urine cultures and CAUTI. There was a non-statistically significant increase in CAUTI during the COVID pandemic with the direction of rate of change going from negative to positive. This may have been due to diversion of resources from infection prevention programs. Catheter use decreased throughout; this may have impacted the metrics which used CD as a denominator (CAUTI, NHSN SIR) as both showed non-significant increases during COVID. Disclosures Trevor C. Van Schooneveld, MD, FSHEA, FACP, AN2 Therapeutics: Grant/Research Support|Biomeriuex: Advisor/Consultant|Biomeriuex: Grant/Research Support|Insmed: Grant/Research Support|Thermo-Fischer: Honoraria Mark E. Rupp, MD, 3M: Advisor/Consultant|Citius: Advisor/Consultant|contrafect: Grant/Research Support|Teleflex: Advisor/Consultant

Reduction in catheter-associated urinary tract infections following a diagnostic stewardship intervention

Catheter-associated urinary tract infections (CAUTIs) are a frequent hospital-acquired infection and public health concern. In an attempt to reduce the number of CAUTIs, an intervention that emphasized the appropriate laboratory evaluation by ordering providers was implemented. This intervention supplemented ongoing standard bundle protocols. Compared to the 16 months before the intervention, there was a significant decrease in the number of CAUTIs during the 12-month intervention period.

Impact of diagnostic stewardship interventions in the collection process of fungal blood cultures.

We implemented 2 interventions to improve utilization and contamination at our institution: kits to improve appropriate sample collection and an electronic order alert displaying appropriate indications of fungal blood cultures. An electronic order alert when ordering fungal blood cultures was associated with decreased utilization without decrease in positivity rate.

Diagnostic Stewardship - The right test for the right patient with the right consequences

In 2023, the Society for Healthcare Epidemiology of America (SHEA) Task Force issued a practice recommendation on the integration of diagnostic stewardship into antibiotic stewardship (ABS) programs, which focuses on optimizing sample collection, processing, and reporting to ensure a correct test result on the one hand, and on the justifying indication to perform diagnostics on the other.Unnecessary microbiological or serological tests produce results that can then lead to unnecessary further tests for clarification or unnecessary antibiotic administration. A classic example is "routine" urine cultures before non-urological, surgical interventions, which often lead to the treatment of asymptomatic bacteriuria. Every microbiological diagnosis must therefore be preceded by a specific question, whereby screening examinations from epidemiological questions must be clearly distinguished from clinical requirements. A particular problem is the distinction between contamination, colonization and infection, especially when samples are taken from catheters or drains. These materials should always be evaluated with extreme caution and may only be accepted at all if the clinical question is clear and subject to this very reservation. This article summarizes the existing evidence on diagnostic stewardship interventions and recommendations on their implementation, extrapolating the international literature to the specifications of the German health care system.

Impact of mandatory nucleic acid amplification test (NAAT) testing approval on hospital-onset Clostridioides difficile infection (HO-CDI) rates: A diagnostic stewardship intervention.

Misclassification of Clostridioides difficile colonization as hospital-onset C. difficile infection (HO-CDI) can lead to unnecessary treatment of patients and substantial financial penalties for hospitals. We successfully implemented mandatory C. difficile PCR testing approval as a strategy to optimize testing, which was associated with a significant decline in the monthly incidence of HO-CDI rates and lowering of our standardized infection ratio to 0.77 (from 1.03) 18 months after this intervention. Approval request served as an educational opportunity to promote mindful testing and accurate diagnosis of HO-CDI.

Clinical Course of Children 1 to 24 Months Old With Positive Urine Cultures Without Pyuria

ObjectiveTo describe the clinical course of children with positive urine cultures without pyuria who were not given antibiotics initially, identify predictors of subsequent antibiotic treatment, and evaluate the association between subsequent treatment and urinary tract infection (UTI) within 30 days. MethodsWe conducted a multicenter retrospective cohort study of children 1 to 24 months old who had positive urine cultures without pyuria and who were not started on antibiotics upon presentation to 3 health care systems from 2010 to 2021. Outcomes included clinical status at the time urine cultures resulted, escalation of care (emergency department visit or hospitalization) and subsequent antibiotic treatment within 7 days, and subsequent UTI within 30 days of presentation. ResultsOf 202 included children, 61% were female and median age was 9 months. Of 151 patients with clinical status information when cultures resulted, 107 (70.8%, 95% confidence interval [CI] 62.9–77.9%) were improved. Two of 202 children (1.0%, 95% CI 0.2–4.0%) experienced care escalation. Antibiotics were started in 142 (82.2%) children, and treatment was associated with prior UTI (risk ratio [RR] 1.20, 95% CI 1.15–1.26) and lack of improvement (RR 1.22, 95% CI 1.13–1.33). Subsequent UTI was diagnosed in 2 of 164 (1.2%, 95% CI 0.1–4.3%) treated and 0 of 36 (0%, 95% CI 0–9.7%) untreated children. ConclusionsSeventy percent of children with positive urine cultures without pyuria improved before starting antibiotics; however, >80% were ultimately treated. Future research should study the impact of diagnostic stewardship interventions and various urine testing strategies to optimize the management of children evaluated for UTI.retain-->

The impact of a blood-culture diagnostic stewardship intervention on utilization rates and antimicrobial stewardship

Background: Blood cultures are often ordered when an infection is suspected; however, they have a low yield in most cases. The overuse of blood culture is associated with high contamination rates, resulting in excess diagnostics, unnecessary antibiotics, longer hospital stays, and higher hospital costs. We evaluated the safety of a multifaceted intervention, which encompassed education and blood-culture restriction, and its impact on blood-culture utilization and antibiotic use in adult intensive care unit (ICU) patients. Methods: The study was performed between October 2020 and October 2021 in the 12 general medicine and specialty ICUs of a quaternary academic care center. The intervention, implemented in April 2021, included providing education to ICU and infectious disease physicians based on an algorithm adapted from the Johns Hopkins DISTRIBUTE study in addition to restricting blood-culture ordering on these units to these providers. The month of April 2021 was excluded as a washout period. Study outcomes comprised blood-culture utilization, blood-culture positivity, days of therapy (DOT), and length of therapy (LOT), which were compared across the study periods using IRR or the Pearson χ2 test, as appropriate. In addition, 30-day mortality and 30-day ICU readmission were evaluated utilizing multiple COX regression models. Results: In total, 6,303 patients (2,087 MICU, 3,636 SICU, and 580 both) were included in the study, with a median age of 65 years (IQR, 21). Most participants were male (57.5%), with a median length of stay of 175 hours (IQR, 186). After the intervention, blood-culture utilization rates decreased from 15.4% to 12.4% (IRR 0.80, 95% CI, 0.76–0.85) (Fig. 1). There was no difference in blood-culture positivity between the preintervention period (11.05%) and the postintervention period (11.64%; P = .459). Days of therapy decreased from 1,180 to 1,130 per 1,000 patient days (IRR, 0.96; 95% CI, 0.95–0.98), and the length of therapy decreased from 602 to 579 per 1,000 patient days (IRR, 0.96; 95% CI, 0.94–0.99) (Fig. 2). There was no difference in 30-day mortality (P = .241) nor 30-day ICU readmission (P = .888) across the study periods after adjusting for potential confounders (Table 1). Conclusions: Our multifaceted intervention decreased blood-culture and antimicrobial utilization in the ICUs without significantly affecting the positivity rate, mortality, or readmission. This study suggests that educating providers on appropriate blood-culture use along with restriction could safely improve healthcare outcomes. Further studies are warranted to validate our results across various institutions and to evaluate the impact of blood-culture optimization in non-ICU patients.Disclosures: None

Assessment of endotracheal aspirate culture appropriateness among adult ICU patients at an academic medical center

Background: Ventilator-associated pneumonia (VAP) is a significant cause of mortality in intensive care units (ICUs), but minimal research exists regarding the appropriateness of ordering endotracheal aspirate cultures (EACs). We evaluated the diagnostic utility of rationales given for EAC collection in ICUs at an academic medical center to assess potentially inappropriate EAC ordering. Methods: The study population comprised all adult patients admitted to an ICU in 2019 who underwent EAC collection. A random 10% sample from this population, stratified by ICU type, was selected. Clinical and diagnostic characteristics within 24 hours of EAC collection were identified by chart review. Clinical documentation was reviewed to identify ICU provider rationales for ordering EAC. Results: In total, 749 patients underwent EAC collection. Among them, 75 patients comprised the random sample, of whom 7 (9.3%) were excluded due to extubation before culture collection. Figure 1 shows patient distribution by ICU type. From these 68 patients, 105 EACs were collected. Of these, 41 (39%) were positive for potential pathogens, and 59 (56.2%) had explicit rationales for EAC collection, including fever (44.1%), hypoxia (18.6%), leukocytosis (16.9%), secretions (11.9%), shock (10.2%), and radiologic findings (8.5%). Also, 43.8% of EACs had no explicit rationale for collection. Table 1 shows sensitivities, specificities, positive likelihood ratios (LRs), and negative LRs for these rationales and related characteristics. Conclusions: EACs were commonly ordered without clear clinical indications. Of the noted rationales for EAC collections, most performed poorly at predicting positive cultures, which challenged common rationales for ordering EAC. This study could serve as a foundation for diagnostic stewardship interventions for EAC, potentially decreasing unnecessary cultures.Disclosures: None

Clinical factors and diagnoses associated with inappropriate urine-culture ordering in primary care

Background: Inappropriate urine-culture ordering is associated with increased antibiotic prescribing in myriad care environments, including acute and long-term care. In primary care, where urinary tract infections (UTIs) are commonly encountered, the appropriateness of urine-culture ordering has not been well described. We examined the appropriateness of urine-culture ordering and factors associated with inappropriate urine-culture ordering in primary care. Methods: We conducted a secondary analysis of data from a previous prospective study that included patients aged ≥18 years presenting with provider-suspected UTI with an accompanying urine culture at 2 safety-net, primary-care clinics in Houston, Texas, between November 2018 and March 2020. Patients with complicated or uncomplicated UTI were included, but those with a urinary catheter and pregnant females were excluded. Urine cultures were considered appropriate if the patient had an evidence-based symptom of UTI (ie, dysuria, frequency, urgency, hematuria, fever, chills, costovertebral angle tenderness, suprapubic, pelvic, or flank pain, or nephrolithiasis) as a diagnostic code or listed in providers’ free-text documentation. Diagnostic codes for symptoms that were not evidence based were grouped into categories based on body system, visit type (eg, routine visit), or sign or symptom clusters. We evaluated the relationships among demographic and clinical factors, the clinic visited, and non–evidence-based diagnostic codes with inappropriately ordered cultures. Results: We examined 870 cultures from 807 patients. Overall, 61.5% of patients were Hispanic (61.5%) and 23% were African American or Black. Also, 70.6% were women; the mean age was 49.2 years (SD, 14.6); and the mean Elixhauser score was 1.9 (SD, 5.4). Among the 870 cultures, 210 (24%) were ordered inappropriately. Dysuria (n = 289), frequency (n = 129), and UTI or cystitis (n = 117) were the most common, evidence-based codes among appropriate cultures. In the adjusted model, the nonteaching clinic (aOR, 6.33) and diagnostic codes comprising the following categories were associated with inappropriate culturing: acute lower back pain (aOR, 5.42), cardiac-related visits (aOR, 2.41), urinary incontinence (aOR, 4.46), routine health visits (aOR, 3.66), urine characteristics (aOR, 14.32), voiding difficulties (aOR, 3.88), and well-woman visits with a gynecological exam or family planning aspect (aOR, 12.27) (all P &lt; .05). Conclusions: This research highlights potential gaps or miscues in provider behavior related to urine culture ordering, and unveiled problematic culturing related to urine characteristics and to routine visits, especially of a gynecological nature. This information can be incorporated into diagnostic stewardship interventions to address misconceptions, and to further explore the reasoning or processes wherein urine cultures are ordered for routine visits.Financial support: NIAID UM1AI104681Disclosure: None

Predictors of antimicrobial use in intensive care unit patients

Background: Identification of predictors of antibiotic use can inform targeted antimicrobial stewardship initiatives and can account for sources of bias in before-and-after interventional stewardship studies. To date, no study has identified clinical predictors of antimicrobial use within intensive care units (ICUs), where antimicrobial resistance is most prevalent and problematic. Methods: As part of an ongoing prospective, single-arm, pilot feasibility trial of an ICU diagnostic stewardship intervention, we performed a nested retrospective cohort study to explore associations between patient clinical variables and ICUs antimicrobial use and resistance rates (AURs). We included all patients hospitalized in 3 ICUs (surgical, medical, and cardiac) from 2017 to 2021 at Michigan Medicine, a large, tertiary-care, academic medical center. Data were extracted from the electronic medical record using a structured query. Admission-level data were captured, including patient demographics, medical comorbidities, International Classification of Disease, Tenth Revision (ICD-10) admission diagnoses, as well as calendar day-level data including vital signs, clinical and microbiologic laboratory data, measures of acute severity of illness, ventilator–supplemental oxygen metrics, and procedural interventions using current procedural terminology (CPT) codes. ICU AURs were defined as total antibiotic days of therapy per patient per 100 ICU days. Associations between clinical variables and ICU AURs were calculated as rate ratios (RRs). Multiple imputation using fully conditional specification was performed to create 25 imputation data sets. Negative binomial regression models were constructed for each data set using backward selection. Variables retained in &gt;50% of models were included in a final multivariate model. Results: In total, 15,177 ICU patient admissions were captured. Age, sex assigned at birth, and race did not independently associate with ICU AURs. Comorbidities, medical interventions, admission diagnoses, and laboratory data that independently associated with ICU-AURs are shown in Table 1. The clinical variables most strongly associated with increased ICU-AURs were pneumonia (RR, 1.55; 95% CI, 1.451.64), bacteremia (RR, 1.35; 95% CI, 1.25– 1.46), intraabdominal infection (RR, 1.35; 95% CI, 1.18–1.55), SOFA score (RR, 1.27; 95% CI, 1.14–1.42), abnormal WBC (RR, 1.26; 95% CI, 1.20–1.32), and immunocompromised status (RR, 1.20; 95% CI, 1.10–1.31). Clinical variables most strongly associated with decreased ICU-AURs were cardiac ICU (RR, 0.56; 95% CI, 0.52–0.60), COVID-19 (RR, 0.62; 95% CI, 0.56–0.70), and receipt of an invasive nonsurgical procedure (RR, 0.90; 95% CI, 0.82–0.98). Conclusions: In this single-center retrospective cohort study, several clinical variables were independently associated with ICU-AURs. These results may be used to identify patient subgroups for potentially high-yield ICU-based stewardship interventions and to account for sources of bias in before-and-after studies of ICU-based stewardship interventions.Disclosures: None