bluuebunny/crossref_metadata_2025_split huggingface dataset:
173. Evaluating Respiratory Tract Culturing in Mechanically Ventilated Patients: Opportunity for Diagnostic Stewardship
Authors: Tripathi Ravi , Kenaa Blaine , Claeys Kimberly C , Patel Meghana , Maldarelli Mary , Newman Michelle , Leekha Surbhi 
Published: December 2022

Abstract

Background
Overdiagnosis of ventilator associated pneumonia (VAP) is common and may be due, in part, to excessive culturing of the respiratory tract in ventilated patients. We sought to evaluate the appropriateness of these cultures based on clinical characteristics leading to culture acquisition, and the relationship with antibiotic use.

Methods
We included mechanically ventilated adult patients in the Neuroscience and Cardiac Surgery Intensive Care Units at an academic medical center in Baltimore, MD, who had respiratory tract cultures obtained from March 1 to June 30, 2021. The appropriateness of respiratory cultures was evaluated by chart review in a standardized manner using a published algorithm (Figure 1). Clinical characteristics of patients with appropriate vs. inappropriate cultures were compared using Fisher’s exact test.

Results
98 respiratory tract cultures (58 endotracheal aspirates, 25 mini bronchoalveolar lavages (BAL), 13 BALs, and 2 bronchial washings) were evaluated. Of these, 19 (19%) were deemed appropriate and 79 (81%) were inappropriate. Compared to patients with inappropriate cultures, those with appropriate cultures were more likely to demonstrate worsening oxygenation, new or increasing infiltrate on chest x-ray, or hemodynamic instability. The groups did not significantly differ with respect to fever or changes in WBC count (Figure 2). Of 79 inappropriate cultures, 31 (39%) received a clinical diagnosis of VAP from their provider. In 23 (29%) instances, antibiotics were started or changed based on culture results, and 9 (11%) were on empiric therapy for VAP that was continued unchanged. An additional 24 (30%) continued antibiotics not directed toward VAP. Excluding those on antibiotics not directed towards index respiratory culture results, patients received a median of 6 (IQR 2.5, 7) days of therapy.

Conclusion
A large majority of lower respiratory tract cultures in mechanically ventilated patients are potentially inappropriate and associated with overdiagnosis of VAP and unnecessary antibiotic exposure. Incorporating respiratory tract specific attributes into clinical decision making rather than “pan-culturing” for fever or leukocytosis may be an opportunity for diagnostic stewardship in this setting.

Disclosures
Kimberly C. Claeys, PharmD, BioFire Diagnostics: Honoraria.
177. Follow-up Respiratory Cultures in Suspected Ventilator-associated Pneumonia: An Opportunity for Diagnostic Stewardship
Authors: Gomez Cyndi Gonzalez , Albin Owen 
Published: December 2022

Abstract

Background
Ventilator-associated pneumonia (VAP) is overdiagnosed in intensive care units (ICUs) and contributes to antibiotic overuse. Follow-up/test-of-cure culturing practices have garnered stewardship attention in urinary tract infections and gram-negative bacteremia but remain unexplored in suspected VAP. We aimed to ascertain the stewardship implications of repeat respiratory culturing practices in ICU patients.

Methods
Retrospective descriptive cohort study of adult patients in Michigan Medicine ICUs requiring invasive mechanical ventilation in 2019 who had repeat respiratory cultures (RCx) performed within 72 hours after an index respiratory culture. Relevant patient demographics, comorbidities, culture indications and consequent antimicrobial modifications based on RCx were captured.

Results
Of 2340 total respiratory cultures performed, 286 (12%) were RCx. Patient characteristics and indications for culture collection are shown in Figures 1 and 2, respectively. Only 12 patients (4%) had antimicrobial agents modified based on growth of a pathogenic organism from a RCx not covered by the prior antimicrobial regimen. In cases where RCx grew an identical organism with an identical susceptibility profile to the initial respiratory culture, existing antibiotic treatment durations were extended for microbiologic positivity in 12% of cases. Notably, 94 patients (33%) had RCx performed for persistent fevers or leukocytosis, without corresponding changes in ventilator requirements, changes in endotracheal secretions or worsening appearance on chest imaging.

Conclusion
RCx performed within 72 hours of an initial respiratory culture in mechanically-ventilated patients was both common and low-yield. RCx not uncommonly precipitated unnecessary prolongation in antimicrobial treatment durations, and nearly one-third of patients had RCx obtained for persistent fevers or leukocytosis without other signs of VAP treatment failure, a suspect indication for culture collection given that the median time to clinical improvement in VAP clinical trials in 4-5 days. Limiting repeat respiratory cultures in ICU patients represents a potentially valuable opportunity for diagnostic stewardship.

Disclosures
Owen Albin, MD, Charles River Laboratory: Advisor/Consultant|Cipla Pharmaceuticals: Advisor/Consultant|Shionogi Inc: Advisor/Consultant.
178. Impact of a microbiology comment nudge on the diagnostic evaluation of Staphylococcus aureus bacteriuria
Authors: Patel Dimple , Bandali Aiman , Giordano Pamela , Kessler Jason , Roland Robert 
Published: December 2022

Abstract

Background
Staphylococcus aureus is a relatively uncommon cause of urinary tract infections. S. aureus bacteriuria is thought to result most commonly from urinary tract instrumentation (ascending infection) or via hematogenous seeding of the genitourinary tract (descending infection). Given the devastating impact of invasive S. aureus infection and awareness that S. aureus bacteriuria is often a marker for S. aureus bacteremia, growth of S. aureus from urine cultures should prompt urgent clinical assessment, including blood culture collection. In April 2021, a comment nudge was added to the microbiology culture and susceptibility report for all S. aureus isolated from urine cultures performed at the Atlantic Consolidated Laboratory (ACL) at Atlantic Health System. The purpose of this study is to assess the impact of a comment nudge on the diagnostic evaluation of S. aureus bacteriuria.
S. aureus bacteriuria comment nudge

Methods
All patients with S. aureus bacteriuria were retrospectively identified from the ACL microbiology database. The primary endpoint was collection of blood cultures within 96 hours of positive urine culture during the 6-month period pre-comment (October 2020 – April 2021) compared to 6-month period post comment (May 2021 – November 2021). In addition, incidence of S. aureus bacteremia among the patients with collected blood cultures was also evaluated.

Results
S. aureus bacteriuria was identified in 122 patients during the Pre-Comment period and 188 patients in the Post-Comment period. Blood cultures were collected more frequently in the Post-Comment period compared to the Pre-Comment period (64% vs. 51%, p=0.018). Among patients for whom blood cultures were collected, 29% had concomitant S. aureus bacteremia in the Pre-Comment period compared to 16% in the Post-Comment period (p=0.03).

Conclusion
The addition of a comment nudge to the microbiology report of urine cultures growing S. aureus significantly improved follow-up blood culture collection. Health systems may consider implementation of similar interventions, particularly in resource-limited settings, to avoid delayed recognition of S. aureus bacteremia.

Disclosures
All Authors: No reported disclosures.
179. Impact of a Nurse-Pharmacist Driven Antimicrobial Stewardship: Redefining the Team
Authors: Brooks Aislinn , Elarabi Salwa 
Published: December 2022

Abstract

Background
The Centers for Disease Control and Prevention have recognized the worldwide emergence of antimicrobial resistance. The Joint Commission mandated acute care hospitals to implement antimicrobial stewardship (AMS) programs. Core elements were developed to help hospitals achieve this goal. Core elements were updated incorporating nursing-based actions such as optimizing microbiology cultures.

Methods
The aim is ≥20% of ICU C. difficile, respiratory, and urine culture interventions made by the Nurse-Infectious Diseases (ID) Pharmacist AMS team will be accepted by March 4th, 2022. The ID Pharmacist engaged front line nurses in the AMS program by creating algorithms to guide nursing to appropriate culturing practices. Nurses utilized the algorithms to assess appropriateness of the cultures ordered. If deemed inappropriate, nurses contacted the ID Pharmacist and/or ordering physician to intervene. The outcome measure assessed was the percentage of interventions accepted for inappropriate C. difficile, respiratory, and/or urine cultures weekly. Process measures included time (in hours) to discontinue inappropriate cultures and the type of culture addressed. The balancing measure was the average time the Nurse/ID Pharmacist spent to assess appropriateness of ordered cultures.

Results
A total of 69 interventions were made by the Nurse/ID Pharmacist AMS team. Due to a high intervention acceptance rate, the target was changed from 20% to 60% at week 8. Out of the 69 interventions, 91% (n=63) were accepted and resulted in the discontinuation of the culture. The majority of accepted interventions were among urine cultures. The average time to discontinue inappropriate cultures was 2 hours and the average time the Nurse/ID Pharmacist spent to assess appropriateness of cultures was 15 minutes.
Percentage of Interventions Accepted
Data shown reflects the weekly percentage of accepted interventions recommended by the nurse/ID Pharmacist AMS team. Due to the high intervention acceptance rate, target was changed from 20% to 60% in week eight.
Intervention Type
This data reflects the number of accepted interventions for each culture type made by Nurse/ID Pharmacist AMS team resulting in the discontinuation of the inappropriate culture.

Conclusion
The implementation of a Nurse/ID Pharmacist AMS collaboration resulted in a high acceptance of culture interventions leading to discontinuation of inappropriate cultures. AMS nurse champions expanded SEMC’s AMS team and led to improved microbial culture practices in the ICU.

Disclosures
All Authors: No reported disclosures.
182. Impact of Rapid Identification and Phenotypic Results on Clinical, Economic, Antimicrobial Stewardship Outcomes in Patients with Gram-Negative Bacteremia
Authors: Shoop Harold , Fabian Amy , Doyen Shaina 
Published: December 2022

Abstract

Background
Timely and effective antibiotic therapy is a critical determinant of clinical outcome in Gram-negative bacilli (GNB) bloodstream infections (BSI). Conventional antimicrobial susceptibility testing (AST) remains a rate-limiting step in determining targeted therapy. Accelerate Pheno™ (AP) is a novel system providing both identification (ID) and AST results within 8 hours. The primary objective of this study was to determine the impact of rapid ID and AST with AP on time to achieving targeted therapy (TTT).

Methods
This single center, quasi-experimental study compared outcomes with AP (POST; November 2020 to July 2021) versus a historical standard (PRE; November 2019 to July 2020) of rapid diagnostic testing (BioFire® FilmArray®BCID) and conventional AST (VITEK®2) with pharmacist-driven antimicrobial stewardship (AMS) intervention. PRE and POST BSI were retrospectively identified by positive blood culture (BCx) with an on-panel GNB. Inpatients were excluded if less than 18 years of age, pregnant, polymicrobial BCx, BCx with the same organism and source within 7 days, or if died or transitioned to palliative or hospice care before final AST results. Secondary outcomes included inpatient all-cause mortality, hospital and ICU length of stay, hospital-acquired Clostridioides difficile infection, antibiotic and microbiologic costs, days of anti-pseudomonal therapy, antibiotic intensity score, and time to first intervention following Gram stain, ID, and AST results.

Results
Overall, 373 BSI were screened and 294 were included [161 PRE vs 133 POST]. Baseline demographics and characteristics were similar between groups. Median TTT was shorter POST [50 hours (IQR 44–92) vs 28 hours (IQR 14–55), p &lt; 0.05]. Median microbiology testing costs per episode were higher POST [Δ$40.33 (32%), p &lt; 0.05]. Other secondary outcomes did not differ significantly between groups. Pharmacists intervened more POST [69 (43%) vs 77 (58%), p &lt; 0.05]. AP completed ID and AST in 155 of 205 (76%) BSI. Off-panel GNB occurred in 26 (13%) BSI POST.

Conclusion
Implementing the AP system together with an established AMS program resulted in a shorter TTT and a higher cost to test. Clinical, AMS, and other economic outcomes were not impacted by the addition of AP.

Disclosures
All Authors: No reported disclosures.
183. Impact of Revised Piperacillin/Tazobactam Clinical Breakpoints on Enterobacterales Isolates Identified in Blood Cultures
Authors: Moore Nicholas M , Houlihan Joyce H , Varughese Christy A , Hodgson Hayley A , Shankaran Shivanjali , Won Sarah Y , Hayden Mary K 
Published: December 2022

Abstract

Background
Enterobacterales are a significant cause of bloodstream infections (BSI) in hospitalized patients. Prior evidence suggests that treatment with piperacillin/tazobactam may not be ideal for BSI. Piperacillin/tazobactam clinical breakpoints were recently updated by the Clinical and Laboratory Standards Institute (CLSI).

Methods
We retrospectively evaluated Enterobacterales blood isolates identified by MALDI-TOF (Vitek MS, bioMérieux) between January 1, 2017 through December 31, 2021 at Rush University Medical Center in Chicago, Illinois. Antimicrobial susceptibility testing was performed using NM43 or NM56 panels on the MicroScan WalkAway 96 (Beckman Coulter). The range of dilutions of piperacillin/tazobactam included on both panels was 8/4 to 64/4 μg/mL. Minimal inhibitory concentrations (MIC) were interpreted using current CLSI breakpoints.

Results
We evaluated 1597 Enterobacterales isolates. Most isolates identified were Escherichia coli [n=806 (50%)] and Klebsiella pneumoniae [n=358 (22%)]. The majority of isolates (90.4%) were susceptible; 28 (1.8%) isolates were susceptible-dose dependent and 125 (7.8%) were resistant to piperacillin/tazobactam using the new CLSI breakpoints (Table). 236 isolates had a multidrug-resistant phenotype, of which 216 (92%) were confirmed as an ESBL. Among ESBL-producing isolates, the majority (81%) were susceptible [MIC ≤ 8 µg/mL) to piperacillin/tazobactam. Isolates with confirmed carbapenemase production had off-scale MICs ( &gt; 64 µg/mL) (Figure).
Piperacillin/Tazobactam Breakpoint Revision Table
Overall changes in piperacillin/tazobactam interpretations using revised breakpoints.
MDR-Enterobacterales piperacillin/tazobactam MIC distributions
Piperacillin/tazobactam minimal inhibitory concentration distributions among multidrug-resistant Enterobacterales isolates.

Conclusion
While there was an increase in resistance, our results indicate that most Enterobacterales isolates tested susceptible to piperacillin/tazobactam using the revised CLSI breakpoints.

Disclosures
Nicholas M. Moore, PhD, D(ABMM), Abbott Molecular: Grant/Research Support|Cepheid: Grant/Research Support.
187. Nasopharyngeal Testing to Individualize Management of Acute Otitis Media
Authors: Sebastian Thresia , Toseef Mohammad , Kurtz Melanie , Frost Holly M 
Published: December 2022

Abstract

Background
There are &gt; 10 million antibiotics prescribed yearly for acute otitis media (AOM). The associated organism can influence the likelihood of antibiotic benefit and optimal treatment. A rapid diagnostic test (RDT) for AOM could prevent unnecessary antibiotic use, while assuring those likely to benefit from antibiotics receive the appropriate agent. Nasopharyngeal (NP) polymerase chain reaction can effectively exclude the presence of organisms in middle ear fluid and may be useful to individualize care.
Objective: To explore the potential cost-effectiveness and reduction in antibiotics with NP RDTs to direct AOM management.

Methods
We developed two algorithms for AOM management based on NP bacterial otopathogens (Figure1). The algorithms provide recommendations on prescribing strategy (immediate, delayed, or observation) and antimicrobial agent. We utilized a tiering system based on expected pathogen-associated severity and resistance. The primary outcome was the incremental cost-effectiveness ratio (ICER) expressed as cost per quality adjusted life day gained (QALD). We used a decision-analytic model to evaluate the cost-effectiveness of the RDT algorithms compared to usual care from a societal perspective over a 30-day time horizon. Secondary outcomes included the (1) cost at which a RDT would be cost-effective and (2) potential reduction in annual antibiotics used.
Flow diagram Figure 1:Flow diagram for management of AOM including RDT-DP and RDT-OBS algorithms

Results
An RDT algorithm that used immediate, delayed prescribing, and observation based on pathogen (RDT-DP) had an ICER of $1336.15/QALD compared with usual care and strongly dominated the RDT that used only immediate prescribing and observation (RDT-OBS). At an RDT cost of $278.56, the ICER for RDT-DP exceeded the willingness to pay threshold ($274 per QALD gained); however, if the cost of the RDT was &lt; $212.10, the ICER was below the threshold. Both algorithms reduced annual antibiotic use, including broad-spectrum use, compared to usual care (RDT-DP 4.7 million (56% reduction), RDT-OBS 5.4 million (49% reduction), usual care 10.5 million).

Conclusion
The use of a NP RDT for AOM is likely to be cost-effective and substantially reduce unnecessary antibiotic use. These iterative algorithms could be modified to guide AOM management as scientific knowledge evolves.

Disclosures
All Authors: No reported disclosures.
191. Predictive Value of Procalcitonin across Disease States within an Inpatient Veteran Population
Authors: Bowden Jarred , Davis Kelly W , Bennett Jessica G , Eason Jane V , Callicott William , Dash Anwesh , Minrath Rachel , Stearns Evan , Thomas-Gosain Neena , Thomas-Gosain Neena 
Published: December 2022

Abstract

Background
Procalcitonin (PCT) can be elevated with certain bacterial infections. Debate continues as to how to best use this biomarker to guide antibiotic use. The primary objective of this study was to evaluate the correlation of PCT levels and the presence of bacterial infection on admission in the total population and in different disease states.

Methods
This was a multicenter retrospective cross-sectional study of patients admitted with specified infectious diagnoses to two VA Medical Centers from 4/1/2019 to 7/1/2021. Patients were stratified into 4 cohorts for analysis; those with COVID-19, sepsis from respiratory source_(S-R), sepsis from non-respiratory source (S-NR), and respiratory source without sepsis (R). Electronic medical records were reviewed to collect the following: initial procalcitonin, cultures, SIRS criteria, comorbidities (CKD, ESRD, HF, immunosuppressed, surgery within the 7 days), and c-reactive protein. PCT elevation was defined as ≥0.25 ng/mL. The frequency of positive cultures within 72 hours was evaluated for patients with elevated and normal PCT levels to determine the diagnostic performance of PCT overall and for each cohort.

Results
632 of 664 patients were evaluated in this study. PCT is elevated twice as often in the septic groups as compared to the non-septic groups (figure 1). Positive predictive value (PPV) varies from 27% to 63% as compared to negative predictive value (NPV) 53%-79% among the disease state groups (figure 2). Although small numbers, the NPV of PCT improves to 83% in patients with elevated temperature and white blood cells (WBC) (figure 3). Figure 1Figure 2Figure 3

Conclusion
The findings that NPV of PCT appears to be better than PPV, support current recommendations against using this as a diagnostic tool, but rather as a tool to assist with antibiotic de-escalation. Further studies are necessary to confirm whether there are specific markers such as temperature or WBC which may improve the NPV. Our data suggests PCT is less helpful in identifying the presence or absence of bacterial infection in septic versus non-septic patients.

Disclosures
All Authors: No reported disclosures.
193. Rapid Diagnostic Testing and Vancomycin Utilization for Contaminated Blood Cultures
Authors: Lockridge Connor , Paciullo Kristen , Trible Ronald 
Published: December 2022

Abstract

Background
Bacteremia is a prevalent hospital acquired infection that affects nearly one in ten hospitalized patients. Rates of contaminated blood cultures have ranged from 0.6% to 6% in the literature. Vancomycin is often chosen as empiric coverage for gram positive organisms while awaiting bacterial identification. The purpose of this study was to evaluate the impact of GenMark ePlex Blood Culture Identification Panel (BCID) implementation on the duration of vancomycin therapy for blood cultures contaminated with coagulase negative staphylococci (CoNS).

Methods
A retrospective chart review was conducted on patients meeting inclusion criteria during a six month period prior to BCID implementation and post BCID implementation, from 03/01/2019 to 08/31/2019 and 03/01/2021 to 08/31/2021. The primary outcome analyzed was the duration of vancomycin therapy, in hours, in patients with a contaminated blood culture. Contaminated blood cultures was defined as a single blood culture growing CoNS. Secondary outcomes included hospital length of stay, readmission for treatment of contaminated blood cultures, and nephrotoxicity.

Results
This IRB-approved study included 190 patients, 75 in the pre-BCID group and 115 in the post-BCID group. The average duration of vancomycin therapy was 53.7 hours in the pre-BCID group and 20.5 hours in the post-BCID group (p = 0.04). Time to organism identification was reduced from 22.8 hours in the pre-BCID group to 12 hours in the post-BCID group (p = 0.5). Additionally, our study did not find a difference in nephrotoxicity, hospital length of stay, or readmissions between the two groups.

Conclusion
Following implementation of the GenMark ePlex Blood Culture Identification Panel (BCID), there was a reduction in both duration of vancomycin therapy and time to culture identification for blood cultures contaminated with CoNS. Rapid diagnostic testing is helpful in clinical decision-making and can lead to earlier discontinuation of empiric antibiotics, such as vancomycin.

Disclosures
All Authors: No reported disclosures.