2345. Reduction in Testing and Change in Testing Algorithm Associated with Decrease in Number of Nosocomial Clostridium difficile Infections

Abstract Background Previous data at our facility indicated 37% of patients with Clostridium difficile infection (CDI) were receiving at least one laxative at the time of testing, suggesting the possibility of false-positive results. Nucleic acid amplification testing (NAAT) does not distinguish between colonization and infection with C. difficile. We implemented two interventions to address these issues and evaluated our rates of nosocomial CDI before and after these changes. Methods This was a retrospective study of all positive test results for adult patients with nosocomial C. difficile from October 1, 2017 through March 31, 2019 at Vidant Medical Center, a 911-bed hospital. In June, 2018, we implemented a best practice advisory (BPA) in our electronic health record to recommend against testing for CDI in patients receiving laxatives. We reviewed the number of C. difficile tests ordered before and after initiating the BPA. In December, 2018, we removed NAAT and replaced it with a cell cytotoxicity assay (CCA) for specimens that were enzyme immunoassay (EIA) negative and glutamate dehydrogenase (GDH) positive. Antimicrobial use was measured in days of therapy (DOT) per 10,000 patient-days (PD). Mann–Whitney U test was used for continuous variables. Linear regression was used to monitor antimicrobial use. Results The number of C. difficile tests ordered per month decreased 19.5% after implementing the BPA (P < 0.0001). There was a 44% reduction in the number of EIA+/GDH+ specimens per month after the BPA intervention (P = 0.003). Following substitution of CCA for NAAT for EIA-/GDH+ specimens, there was a 61% reduction in the rate of nosocomial CDI (8.6 cases/10,000 PD to 3.3 cases/10,000 PD; P = 0.005). Total antimicrobial use was unchanged over the course of the study (673 to 677 DOT/10,000 PD). Carbapenem use decreased 56% (P = 0.009); cefepime use increased 85%(p = 0.002); quinolone and clindamycin use were unchanged. Conclusion Laxative use in hospitalized patients is common and likely contributes to a false elevation in the CDI rate by identifying carriers in addition to those who have true infection. Implementing a BPA to reduce inappropriate testing and changing our testing algorithm for Clostridium difficile by substituting CCA for NAAT has resulted in a lower rate of nosocomial CDI. Disclosures All authors: No reported disclosures.

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2362. Back to the Future: The Impact of Multi-Step Algorithm C. difficile Testing at a Large Tertiary Medical Center

Open Forum Infectious Diseases ◽

10.1093/ofid/ofz360.2040 ◽

2019 ◽

Vol 6 (Supplement_2) ◽

pp. S813-S814

Author(s):

Jacqueline Bork ◽

Kimberly C Claeys ◽

J Kristie Johnson ◽

Jennifer Jones ◽

Uzoamaka Obiekwe ◽

...

Keyword(s):

Best Practice ◽

Medical Center ◽

Hospital Setting ◽

Nucleic Acid Amplification ◽

Oral Vancomycin ◽

Post Intervention ◽

Days Of Therapy ◽

Step Algorithm ◽

Best Practice Alert ◽

The Impact

Abstract Background Antibiotic stewardship and infection control programs rely on C. difficile infection (CDI) test results to measure CDI incidence in the hospital setting. C. difficile carriage is common and distinguishing infection from colonization is difficult with the highly sensitive nucleic acid amplification testing (NAAT) commonly used. Current guidelines recommend a multi-step algorithm for testing. The impact on patient outcomes and CDI metrics are largely unknown. Methods This was a pre-post study at the University of Maryland Medical Center, evaluating the impact of a CDI testing strategy (introduced October 2018) that simultaneously reported NAAT and confirmatory enzyme immunoassay (EIA) when used with existing best practice alerts for appropriate testing. Pre-intervention (November 2017–September 2018) and post intervention (October 2018–March 2019) periods were compared for mean CDI incidence (CDI per 10,000 admissions) defined by: (1) positive NAAT, (2) reported CDI (last positive test), and (3) treated CDI (receiving oral vancomycin). Both community and hospital-onset cases were included. The NAAT CDI incidence was used as the pre-intervention comparison for all 3 measures. In addition, oral vancomycin days of therapy (DOT) per 1,000 patient-days (PD) was compared. Pre–post comparisons of mean CDI incidence and mean DOT rates were done using Student t-test. Results There were 3,237 samples tested (2,269 pre and 968 post-intervention) with 376 NAAT positive (262 pre and 114 post-intervention). Of the 99 tests with reflex EIA, there were 74 discordant tests (NAAT +/EIA -) with 35 (47%) treated for CDI. Mean NAAT CDI incidence pre-intervention was 54 per 10,000 admissions. Post-intervention mean CDI incidence decreased as follows: 45 NAAT CDI per 10,000 admissions (P = 0.13), 15 reported CDI per 1000 admissions (P < 0.0001), and 28 treated CDI per 10,000 admissions (P = 0.0007). Oral vancomycin DOT per 1,000 PD decreased from 16 to 9 (P = 0.0002). Conclusion C. difficile NAAT testing with confirmatory EIA, in combination with best practice alert, decreased reported and treated cases of CDI, which may distinguish infection vs. colonization and avoid unnecessary treatment, beyond that achieved with alerts that improve appropriate patient selection for testing. Disclosures All authors: No reported disclosures.

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2363. Implementation of a Multi-Step Diagnostic Algorithm for C. difficile Infection

Open Forum Infectious Diseases ◽

10.1093/ofid/ofz360.2041 ◽

2019 ◽

Vol 6 (Supplement_2) ◽

pp. S814-S814

Author(s):

Morgan Walker ◽

Miranda Mitchell ◽

Britney Mellor ◽

Suzanne Buras ◽

Monica Young ◽

...

Keyword(s):

Medical Center ◽

Diagnostic Algorithm ◽

Nucleic Acid Amplification ◽

Test Results ◽

Before And After ◽

Regional Medical ◽

Regional Medical Center ◽

Step Algorithm ◽

Testing Algorithm ◽

Test Result

Abstract Background The diagnosis of C. difficile infection (CDI) in the hospital is challenging asymptomatic colonization rates vary between 3% and 26%. Guidelines recommend multistep testing for CDI diagnosis. On July 1, 2018 a two-step testing algorithm was implemented at our institution. Positive nucleic acid amplification test (NAAT) results reflexed to a toxin enzyme immunoassay (EIA) test. The EIA test result was then used for NHSN reporting; however, both test results were visible to the clinician. Updated guidance on the interpretation of the test and treatment of CDI was released to the medical staff in July. We compared the incidence of CDI lab ID events per 1000 patient-days and the rate of C. difficile antibiotic starts before and after the implementation of the testing algorithm. Methods A retrospective observational study was performed at an 800 bed regional medical center. CDI lab ID events between January 1 and December 31, 2018 were reviewed. Antibiotic initiation of intravenous (IV) and oral (PO) metronidazole and PO vancomycin was collected for all hospitalized patients diagnosed with C. difficile. The incidence of hospital onset (HO) and community-onset (CO) lab ID events as well as the rate of antibiotic starts were compared before and after implementation of the algorithm using a two-sided z test for proportions with an alpha of 0.05. Results The incidence of HO and CO lab ID events per 1000 patient-days decreased significantly from 0.56 to 0.16 (P < 0.0001) and 1.18 to 0.3 (P < 0.0001) after implementation of the testing algorithm (Figure 1). The CDI SIR decreased from 0.729 to 0.322, (P = 0.0048). The rate of antibiotic starts per 1,000 patient-days for IV and PO Metronidazole decreased significantly from 1.1 to 0.45 (P < 0.0001) and 0.86 to 0.35 (P < 0.0001), respectively. PO Vancomycinstarts decreased from 1.51 to 1.23 (P = 0.11) (Table 1). Conclusion A two-step algorithm for diagnosing CDI decreases the overall number of HO and CO C. difficile lab ID events and decreases overall antimicrobial use for CDI. Disclosures All authors: No reported disclosures.

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Clostridioides difficile Testing Stewardship for Laxative Use Is Effective and Safe When Combined With Expert Clinical Input

Infection Control and Hospital Epidemiology ◽

10.1017/ice.2020.696 ◽

2020 ◽

Vol 41 (S1) ◽

pp. s169-s170

Author(s):

Francesca Torriani ◽

Frank Myers Robert El-Kareh ◽

Minji Kang ◽

Randy Taplitz ◽

Shira Abeles

Keyword(s):

Best Practice ◽

Medical Center ◽

Academic Medical Center ◽

Adverse Outcomes ◽

Nucleic Acid Amplification ◽

The Past ◽

Laxative Use ◽

Clostridioides Difficile ◽

Practice Advisory ◽

Expert Input

Background: In January 2019, our large academic medical center implemented hard stops for ordering Clostridiodes difficile nucleic acid amplification testing (NAAT), and required a discussion with an infectious diseases physician if the order was placed in a clinical scenario not consistent with the 2017 IDSA/SHEA C. difficile infection (CDI) testing guidelines. Recently, some groups have expressed concerns that requiring the discontinuation of laxatives may delay the diagnosis of CDI and result in serious adverse outcomes. Methods:C. difficile testing stewardship interventions were performed at 2 hospitals within the same university health system to reduce inappropriate testing. In January 2019, a best practice advisory (BPA) was implemented to alert providers ordering C. difficile NAAT if patients had received laxatives within 24 hours, requiring a discussion with the ID physician to override the hard stop. We reviewed clinical outcomes of patients who had a BPA alert due to laxative use within the past 24 hours April 23 to October 23, 2019. Results: During the study period, there were 235 patients with a BPA because of laxative use within the past 24 hours. Moreover, 55 (23.4%) continued to experience diarrhea after the discontinuation of laxatives and were retested for CDI within 7 days. Only 8 tests returned positive, suggesting that, at most, 3.4% of cases had delayed diagnoses because of the hard stop. This finding is supported by the increase in the percentage of tests positive from 11.6% observed overall to 14.6% (8 of 55) after this intervention. There were no severe CDI cases (ICU admission, colectomy, or death) among patients who had delayed testing due to laxative use. Conclusions: In the setting of laxative use, C. difficile testing stewardship interventions with C. difficile NAAT using a hard-stop BPA are effective in reducing unnecessary testing and safe if they are used in combination with a real-time expert input of the risk of clinical disease.Funding: NoneDisclosures: None

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Nucleic Acid Amplification Test Quantitation as Predictor of Toxin Presence in Clostridium difficile Infection

Journal of Clinical Microbiology ◽

10.1128/jcm.01316-17 ◽

2017 ◽

Vol 56 (3) ◽

Cited By ~ 13

Author(s):

M. J. T. Crobach ◽

N. Duszenko ◽

E. M. Terveer ◽

C. M. Verduin ◽

E. J. Kuijper

Keyword(s):

Nucleic Acid ◽

Clostridium Difficile ◽

Characteristic Curve ◽

Nucleic Acid Amplification Test ◽

Nucleic Acid Amplification ◽

Toxin A ◽

Toxin B ◽

Content Type ◽

Quantitative Results ◽

Testing Algorithm

ABSTRACT Multistep algorithmic testing in which a sensitive nucleic acid amplification test (NAAT) is followed by a specific toxin A and toxin B enzyme immunoassay (EIA) is among the most accurate methods for Clostridium difficile infection (CDI) diagnosis. The obvious shortcoming of this approach is that multiple tests must be performed to establish a CDI diagnosis, which may delay treatment. Therefore, we sought to determine whether a preliminary diagnosis could be made on the basis of the quantitative results of the first test in algorithmic testing, which provide a measure of organism burden. To do so, we retrospectively analyzed two large collections of samples ( n = 2,669 and n = 1,718) that were submitted to the laboratories of two Dutch hospitals for CDI testing. Both hospitals apply a two-step testing algorithm in which a NAAT is followed by a toxin A/B EIA. Of all samples, 208 and 113 samples, respectively, tested positive by NAAT. Among these NAAT-positive samples, significantly lower mean quantification cycle ( C q ) values were found for patients whose stool eventually tested positive for toxin, compared with patients who tested negative for toxin (mean C q values of 24.4 versus 30.4 and 26.8 versus 32.2; P < 0.001 for both cohorts). Receiver operating characteristic curve analysis was performed to investigate the ability of C q values to predict toxin status and yielded areas under the curve of 0.826 and 0.854. Using the optimal C q cutoff values, prediction of the eventual toxin A/B EIA results was accurate for 78.9% and 80.5% of samples, respectively. In conclusion, C q values can serve as predictors of toxin status but, due to the suboptimal correlation between the two tests, additional toxin testing is still needed.

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Clostridium difficile Laboratory Identification Event Reporting – A Need for Diagnostic Stewardship

Open Forum Infectious Diseases ◽

10.1093/ofid/ofx163.994 ◽

2017 ◽

Vol 4 (suppl_1) ◽

pp. S398-S399

Author(s):

Clare Rock ◽

Zoi Pana ◽

Surbhi Leekha ◽

Polly Trexler ◽

Jennifer Andonian ◽

...

Keyword(s):

Clostridium Difficile ◽

Medical Records ◽

Chart Review ◽

Nucleic Acid Amplification ◽

Event Reporting ◽

Laxative Use ◽

Academic Center ◽

The Us ◽

Clinically Significant ◽

Present On Admission

Abstract Background Clostridium difficile LabID event reporting uses electronic laboratory results without chart review. Nucleic acid amplification testing is common in the US. A positive result may represent colonization or C. diff infection (CDI). We review C.difflabID events to ascertain if Hospital-Onest CDI (HO CDI). For non-HO CDI, we identify reason and use a matrix to prioritize clinical areas for intervention efforts. Methods Each C. difflab ID event from Jan 2015 to June 2016 at academic center had chart review for HO CDI; defined significant diarrhea, not present on admission, with no laxatives in prior 48 hours. For non HO-CDI events, reason and receipt of antibiotic treatment within 14 days of the positive test were retrospectively noted. A prioritization matrix, where clinical services were ranked according to number of lab ID events (service’s contribution to the facility C. diffLabID), was multiplied by a rank based on percent of inappropriate tests giving an overall prioritization score for where intervention resources could potentially best be used. Results There were 490 C difficile LabID events; 284 (58%) were HO-CDI; 206 (42%) were inappropriate or delayed testing. Of the 190 with available medical records at time of retrospective review, reasons for not meeting the HO-CDI included laxative use within the previous 48 hours (41%), no clinically significant diarrhea (49.5%); delayed testing (9.5%). See figure. Of 172 patients with inappropriate testing, 159 (92%) were treated for CDI. Medicine and psychiatry ranked first and second on prioritization matrix. See table. Conclusion Nearly half of C. diff LabID events were not true HO CDI, but inappropriate or delayed tests. Prioritization matrix identified medicine and psychiatry as areas where diagnostic stewardship interventions could affect most on facility C. diff LabID. Disclosures K. C. Carroll, GenePOC, Inc.: Grant Investigator, Grant recipient

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Effects of a Remote Antimicrobial Stewardship Program on Antimicrobial Use in a Regional Hospital System

Pharmacy ◽

10.3390/pharmacy8010041 ◽

2020 ◽

Vol 8 (1) ◽

pp. 41 ◽

Cited By ~ 1

Author(s):

Joshua Knight ◽

Jessica Michal ◽

Stephanie Milliken ◽

Jenna Swindler

Keyword(s):

Antimicrobial Stewardship ◽

Antimicrobial Use ◽

Hospital System ◽

Physician Review ◽

Stewardship Program ◽

Time Period ◽

Days Of Therapy ◽

Before And After ◽

Implementation Time ◽

Acceptance Rates

While antimicrobial stewardship programs (ASPs) are well established at most large medical centers, small or rural facilities often do not have the same resources; therefore, different methods must be developed to start or expand ASPs for these hospitals. The purpose of this quality improvement study was to describe the implementation of a pharmacist-led remote ASP and assess the effect on antimicrobial use. Antimicrobial use in days of therapy per 1000 patient days (DOT/1000 PD) was compared between the six months before and after remote ASP implementation. Changes in system-wide, facility-specific, and target antimicrobial use were evaluated. Pharmacist interventions, acceptance rates, and number of times infectious disease (ID) physician assistance was sought were also tracked. System-wide antimicrobial use was 4.6% less in the post-implementation time period than in the pre-implementation time period, with vancomycin, piperacillin/tazobactam, and fluoroquinolones having the greatest reductions in use. Ninety-one percent of interventions made during the post-implementation period were accepted. ID physician review was requested 38 times, and direct ID physician intervention was required six times. Remote ASPs delivered from a central facility to serve a larger system may reduce antimicrobial use, especially against targeted agents, with minimal increase in ID physician workload.

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754. A Two-step Testing Algorithm for Hospital-onset Clostridioides difficile Infection (CDI) Reduces Prescribing of C. difficile (CD) Therapy but Its Ability to Guide Treatment Decisions Remains Unclear

Open Forum Infectious Diseases ◽

10.1093/ofid/ofab466.951 ◽

2021 ◽

Vol 8 (Supplement_1) ◽

pp. S474-S474

Author(s):

Mackenzie Dolan ◽

Heather Cox ◽

Cirle A Warren ◽

Costi Sifri ◽

Melinda Poulter ◽

...

Keyword(s):

Decision Support Tool ◽

Treatment Decisions ◽

Adverse Outcomes ◽

Nucleic Acid Amplification ◽

Test Results ◽

Patient Death ◽

Support Tool ◽

Clostridioides Difficile ◽

Days Of Therapy ◽

Testing Algorithm

Abstract Background Determining true CDI versus CD colonization through CD testing is a continuing challenge. A previously introduced decision support tool at UVA Health significantly reduced inappropriate testing without adverse outcomes. More recently, our methodology changed from nucleic acid amplification test (NAAT) alone to an initial NAAT followed by ELISA for toxin to improve specificity. The purpose of this analysis was to assess provider interpretation of test results, using targeted CD therapy as a surrogate. Methods This single-center, retrospective study evaluated all patients with a positive NAAT (Cepheid Xpert® C. difficile) on day 4 or later of hospitalization following 2-step algorithm implementation from Feb 2020 through Feb 2021. Toxin negative (TOX-) test results (C. DIFF QUIK CHEK COMPLETE®) were accompanied by a comment that discordance may represent colonization or CDI and to consider ID consult. The proportion of toxin positive (TOX+) versus TOX- patients receiving ≥ 1 dose of CD therapy served as the primary outcome with partial courses considered < 10 days. Clinical outcomes were also compared. Results Ninety patients with NAAT+ results were included, of whom 58 (64%) were TOX-. Thirty-two (100%) TOX+ (median days of therapy [IQR] = 14 [11-17]) versus 51 (88%) TOX- patients (median days of therapy [IQR] = 11 [7-14]) received CD therapy (p=0.04). Treatment decisions were guided by ID physicians for 32 (63%) TOX- patients; ID recommendations to discontinue CD therapy were followed in 2 out of 9 (22%) cases. TOX- patients received partial therapy due to patient death (n=5), presumptive colonization (n=3), and provider error (n=1). Of TOX- patients receiving partial or no treatment, there were no CDI-related adverse outcomes during the admission. CDI-related colectomy occurred in 2 (6%) and 1 (2%) TOX+ and TOX- patients, respectively. Five in-hospital deaths with CDI as a contributing factor occurred in the TOX+ group. Conclusion Adoption of a 2-step NAAT plus toxin testing algorithm for hospital-onset CDI reduced the frequency with which TOX- patients received CD therapy but the vast majority were still treated. Most providers considered a positive NAAT indicative of CDI, regardless of TOX status. Disclosures All Authors: No reported disclosures

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2341. Effectiveness of Interventions Targeting Stewardship of Clostridium difficile Testing

Open Forum Infectious Diseases ◽

10.1093/ofid/ofz360.2019 ◽

2019 ◽

Vol 6 (Supplement_2) ◽

pp. S805-S805

Author(s):

Stephanie Sterling ◽

Hochman Sarah ◽

Natalie Kappus ◽

Alexis Reed ◽

Preston Kramer

Keyword(s):

Clostridium Difficile ◽

Best Practice ◽

Cost Savings ◽

Oral Contrast ◽

Healthcare Associated Infection ◽

Post Intervention ◽

Symptomatic Disease ◽

Face To Face ◽

Guideline Compliance ◽

Laxative Use

Abstract Background Clostridium difficile infection (CDI) is the most common healthcare-associated infection. C. difficile PCR assays do not differentiate between colonization (seen in up to 21% of inpatients) and symptomatic disease, highlighting the importance of testing only symptomatic patients. Methods Interventions included system-wide implementation of C. difficile testing guidelines, face-to-face education of licensed providers, and Best Practice Alerts (BPAs) embedded in the electronic health record (EHR) C. difficile PCR order. The guidelines recommend testing only when ≥ 3 liquid bowel movements within a 24-hour period, without laxatives, oral contrast or new enteral feeds in the preceding 24 hours, and without recent C. difficile PCR test (negative ≤ 7 days or positive < 30 days). We reviewed 100 consecutive C. difficile PCR orders across two hospitals pre- and post-intervention to assess compliance with guidelines; performed weekly review of all C. difficile PCRs, all BPA responses and all hospital-onset CDI. Cost savings were calculated based on published estimates of CDI attributable costs. Results Hospital-onset CDI rates fell from 0.75 to 0.48 cases per 1000 patient-days, with an estimated costs savings of $259,555 per quarter and $1.04 million per year. There were no deaths due to CDI and no morbidity due to delayed CDI diagnosis. C. difficile PCR guideline compliance increased from 39% to 53%; orders decreased by 50% post-intervention. Receipt of laxatives and < 3 episodes of diarrhea were the most common reasons for guideline noncompliance. BPAs fired an average of 150 times/month. The most common trigger for BPA was laxative use. Providers canceled PCR orders in 40% of BPA events. Conclusion Interventions incorporating testing guidelines, face-to-face education, and EHR-embedded decision support resulted in fewer C. difficile PCRs orders, increased guideline compliance, lower rates of hospital-onset CDI and cost savings of $1 million per year without an increase in CDI-attributable death or morbidity. Disclosures All authors: No reported disclosures.

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Unnecessary Antimicrobial Use in Patients with Current or Recent Clostridium difficile Infection

Infection Control and Hospital Epidemiology ◽

10.1086/669089 ◽

2013 ◽

Vol 34 (2) ◽

pp. 109-116 ◽

Cited By ~ 37

Author(s):

Megan K. Shaughnessy ◽

William H. Amundson ◽

Michael A. Kuskowski ◽

Douglas D. DeCarolis ◽

James R. Johnson ◽

...

Keyword(s):

Clostridium Difficile ◽

Medical Records ◽

Medical Center ◽

Multivariable Analysis ◽

Patient Characteristics ◽

Veterans Affairs ◽

Antimicrobial Use ◽

Factors Associated ◽

Drug Classes ◽

New Onset

Objective.To determine the fraction of unnecessary antimicrobial use among patients with current and/or recent Clostridium difficile infection (CDI).Design.Retrospective review from January 2004 through December 2006.Setting.Minneapolis Veterans Affairs Medical Center (MVAMC).Participants.Patients with new-onset CDI diagnosed at the MVAMC without another CDI diagnosis in the prior 30 days.Methods.Pharmacy and medical records were reviewed to identify incident CDI cases, non-CDI antimicrobial use during and up to 30 days after completion of CDI treatment, and patient characteristics. Two infectious disease physicians independently assessed non-CDI antimicrobial use, which was classified as unnecessary if not fully indicated. Factors associated with only unnecessary use were identified through univariable and multivariable analysis.Results.Of 246 patients with new-onset CDI, 141 (57%) received non-CDI antimicrobials during and/or after their CDI treatment, totaling 2,147 antimicrobial days and 445 antimicrobial courses. The two reviewers agreed regarding the necessity of antimicrobials in more than 99% of antimicrobial courses (85% initially, 14% after discussion). Seventy-seven percent of patients received at least 1 unnecessary antimicrobial dose, 26% of patients received only unnecessary antimicrobials, and 45% of total non-CDI antimicrobial days included unnecessary antimicrobials. The leading indications for unnecessary antimicrobial use were putative urinary tract infection and pneumonia. Drug classes frequently used unnecessarily were fluoroquinolones and β-lactams.Conclusions.Twenty-six percent of patients with recent CDI received only unnecessary (and therefore potentially avoidable) antimicrobials. Heightened awareness and caution are needed when antimicrobial therapy is contemplated for patients with recent CDI.

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Implementation of Two-Step Clostridioides difficile Testing Algorithm and Management of Possible Carriers

Infection Control and Hospital Epidemiology ◽

10.1017/ice.2020.839 ◽

2020 ◽

Vol 41 (S1) ◽

pp. s269-s270

Author(s):

J. Daniel Markley ◽

Daniel Tassone ◽

Melanie Christian ◽

Leroy Vaughan ◽

Michael P. Stevens ◽

...

Keyword(s):

Medical Center ◽

Tertiary Care ◽

Significant Proportion ◽

Previous History ◽

Retrospective Chart Review ◽

Healthcare Facility ◽

Nucleic Acid Amplification ◽

Considerable Proportion ◽

Testing Algorithm ◽

The Impact

Background: Updated IDSA-SHEA guidelines recommend different diagnostic approaches to C. difficile depending on whether There are pre-agreed institutional criteria for patient stool submission. If stool submission criteria are in place, nucleic acid amplification testing (NAAT) alone may be used. If not, a multistep algorithm is suggested, incorporating various combinations of toxin enzyme immunoassay (EIA), glutamate dehydrogenase (GDH), and NAAT, with discordant results adjudicated by NAAT. At our institution, we developed a multistep algorithm leading with NAAT with reflex to EIA for toxin testing if NAAT is positive. This algorithm resulted in a significant proportion of patients with discordant results (NAAT positive and toxin EIA negative) that some experts have categorized as possible carriers or C. difficile colonized. In this study, we describe the impact of a multistep algorithm on hospital-onset, community-onset, and healthcare-facility–associated C. difficile infection (HO-CDI, CO-CDI, and HFA-CDI, respectively) rates and the management of possible carriers. Methods: The study setting was a 399-bed, tertiary-care VA Medical Center in Richmond, Virginia. A retrospective chart review was conducted. The multistep C. difficile testing algorithm was implemented June 4, 2019 (Fig. 1). C. difficile testing results and possible carriers were reviewed for the 5 months before and 4 months after implementation (January 2019 to September 2019). Results: In total, 587 NAATs were performed in the inpatient and outpatient setting (mean, 58.7 per month). Overall, 123 NAATs (21%) were positive: 59 in the preintervention period and 63 in the postintervention period. In the postintervention period, 23 positive NAATs (26%) had a positive toxin EIA. Based on LabID events, the mean rate of HO+CO+HCFA CDI cases per 10,000 bed days of care (BDOC) decreased significantly from 9.49 in the preintervention period to 1.15 in the postintervention period (P = .019) (Fig. 2). Also, 9 of the possible carriers (22%) were treated for CDI based on high clinical suspicion, and 6 of the possible carriers (14%) had a previous history of CDI. Of these, 5 (83%) were treated for CDI. In addition, 1 patient (2%) converted from possible carrier to positive toxin EIA within 14 days. The infectious diseases team was consulted for 11 possible carriers (27%). Conclusions: Implementation of a 2-step C difficile algorithm leading with NAAT was associated with a lower rate of HO+CO+HCFA CDI per 10,000 BDOC. A considerable proportion (22%) of possible carriers were treated for CDI but did not count as LabID events. Only 2% of the possible carriers in our study converted to a positive toxin EIA.Funding: NoneDisclosures: None

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