bluuebunny/crossref_metadata_2025_split huggingface dataset:
P-1587. The Utility of Using FilmArray Meningitis-Encephalitis PCR Panel (MEP) in Children Admitted with Meningitis and Encephalitis at LUMC. Is it a Useful Diagnostic Stewardship Tool?
Authors: AL-Sayyed Ban H , Covington Kelli , Nicoski Pamela , Feffer Marina , Heyn Madeleine , Hunter-McElroy Gabriella , Pal Shibangi , Lie Louise , Mannaa Jenin 
Published: January 2025

Abstract

Background
MEP allows for rapid detection or exclusion of pathogens causing meningitis and encephalitis (ME) in neonates and children. Studies showed its high sensitivity and specificity as a tool in diagnosing ME and reducing duration of antibiotics. We conducted a retrospective study in our institution to evaluate MEP usage in our pediatric population suspected to have ME, assess the agreement between MEP and CSF culture and cell count results, and measure the impact of MEP results on discontinuing empiric antimicrobials.

Methods
We reviewed electronic records of patients aged 0–18 years admitted with possible ME from January 1, 2019 to April 30, 2023. We excluded patients with VP shunt infections and malfunctions, immunocompromised hosts, patients who did not receive antibiotics, and cases who had CSF culture done without MEP on admission.

Results
We included 136 patients admitted with possible ME and treated with antibiotics. Of all patients, 6.5% had viral PCR detected (n=9), 3.7% had bacterial PCR detected (n=5), 89% had negative PCR (n=122). Antibiotics were started before lumbar puncture in 77% of cases (n= 105). Only 23% were tapped before initiation of antibiotics (n = 31). There was 99.2% positive agreement between MEP and CSF culture results after viral isolates were removed (n=126/127). CSF pleocytosis was present in 19.4% of cases (n=25/129), and results were discordant with MEP in 17.1% of cases (n=22/129). Empiric vancomycin was started in 37% of patients who had no additional focus of infection on admission (n=41/111), and was discontinued within 12 hours of MEP results in 51% of cases (n=21/41). Empiric antibiotics were discontinued within 36 hours of negative MEP results in 31.5% of cases (n=35/111). Acyclovir was combined with antibiotics empirically in 13.5% of cases only (n=15/111).

Conclusion
MEP is an important diagnostic stewardship tool. It is highly sensitive and specific in diagnosing ME in children. However, agreement with CSF cultures might be limited by antibiotic treatment prior to lumbar puncture. MEP helps in quick de-escalation of empiric antibiotics and reduces unnecessary prolonged therapy in children treated with antibiotics before obtaining CSF. Using CSF pleocytosis as an indication for MEP testing has a low yield.

Disclosures
All Authors: No reported disclosures
P-1611. Clinical Evaluation of the Selux Rapid Next Generation Phenotypic Antimicrobial Susceptibility System for both Direct-from-Colony and Positive Blood Cultures
Authors: Morgan Margie A , Smith Stuart G , Contreras Deisy 
Published: January 2025

Abstract

Background
The Selux next-generation phenotyping (NGP) system (SeluxDx) utilizes a proprietary 384-well panel for Gram-positive and Gram-negative antibiotic susceptibility testing available direct-from-colony and Gram-negative from positive blood culture.

Methods
Previously tested bacteria on the Phoenix M50 were used for direct-from-colony assessment. Gram-negative (n=100) and Gram-positive (n=30), were grown on 5% sheep’s blood agar plates and incubated overnight at 35oC. Testing dilution was prepared in saline in the range of 0.4-0.6 McFarland and then inoculated into either the Gram-positive or Gram-negative panel utilizing the system’s automated inoculator platform. Positive blood cultures were concentrated using the Selux Separator automated platform and a pre-prepared McFarland sample was generated to inoculate the Gram-negative panel, and a viable bacterial pellet produced for identification testing. All panels were processed using the Selux Analyzer platform and categorical and essential agreement was calculated for FDA approved bug-drug combinations.

Results
The overall essential agreement for the Gram-negative panel was 97% (97/100) and categorical agreement was 94% (94/100). Two very major errors included Ertapenem in an Escherichia coli and an Enterobacter cloacae complex isolate where the Selux system failed to detect resistance. For the Gram-positive panel, categorical agreement was found to be 96.7% (29/30) with one very major error in Staphylococcus aureus for Clindamycin. Selux generated an AST result for 98% (40/41) of the concentrated blood culture samples. The overall categorical agreement between Selux and the Accelerate Pheno® system was 93%. Major discrepancies (2.4%) and very major discrepancies (4.8%) detected involved the testing of Piperacillin/Tazobactam. The pellet generated an identification to species on 45/48 (94%) of samples using the Bruker MALDI Biotyper®.

Conclusion
The Selux NPG system proved to be a reliable rapid automated platform for both Gram-negative and Gram-positive isolates from direct-from-culture and for rapid AST from positive blood culture Gram-negative isolates. The 384-well panel allows for future adaption of novel antimicrobial agents to meet the demand of an ever-changing resistance landscape.

Disclosures
All Authors: No reported disclosures
P-1616. Treatment Rates of Patients with Toxin Negative, PCR Positive C.difficile After a Change in Reflex Testing Order
Authors: Berke Marten , Miller Molly M , Ringsdorf Brook A , Hankins Richard , Van Schooneveld Trevor C , Bergman Scott J 
Published: January 2025

Abstract

Background
On 12/11/23, our academic medical center changed from primarily GDH antigen/toxin A/B combination testing with reflex to C. difficile PCR in discordant samples (Figure 1) to PCR (either direct or from a multiplex gastrointestinal pathogen panel (GIPP)) as initial screening with positive specimens reflexed to antigen/toxin testing (Figure 2). After the algorithm change, we evaluated treatment rates for patients with positive PCR results who tested negative for C. difficile toxin.

Methods
New guidance for C. difficile infection (CDI) was posted on the Antimicrobial Stewardship website and education was provided to clinicians on the algorithm. Data was collected for inpatients ≥ 19 years old who were toxin negative, but antigen and PCR test positive for C. difficile from 10/1/22-3/31/24. GIPP could be ordered first during the entire period, but only in the first 3 hospital days. Treatment and recurrence rates for patients having a PCR test first were analyzed compared to rates for those with initial antigen/toxin tests. Treatment was counted if initiated within 2 days of test and continued ≥ 5 days, according to proposed NHSN definitions, and included oral vancomycin, fidaxomicin, or metronidazole if vancomycin was contraindicated. Based on estimated treatment rates, a sample size of 177 patients was targeted to detect a change from 80% to 60% treatment.

Results
Out of 179 discordant CDI results prior to the testing change, treatment occurred in 151 (85.4%) cases. After the change, treatment was prescribed 26 out of 46 (56.5%) times, a 34% reduction (p&lt; 0.01). Baseline characteristics were similar in each group, and 56.9% of tests were ordered in the first 3 days of hospital stay. Overall, when an antigen test was performed first and a positive PCR reported last, treatment occurred in 84 of 91 (92.3%) cases. When a PCR test was performed first and a negative toxin resulted last, treatment was prescribed in 93 of 134 (69.4%) cases (p&lt; 0.01). Treatment was the same in each group (99% vancomycin). Recurrence rates were similar regardless of testing order, 5.4% with antigen first vs. 4.4% with PCR test first.

Conclusion
Treatment rates for patients with discordant CDI results were significantly lower after the order of testing changed and when a negative toxin result was presented last.

Disclosures
Trevor C. Van Schooneveld, MD, FSHEA, FIDSA, AN2 Therapeutics: Grant/Research Support|BioMerieux: Grant/Research Support|BioMerieux: Honoraria|Thermo-Fisher: Honoraria
P-1619. Diagnostic Stewardship: Over-testing for Herpes Simplex Virus in Bronchoalveolar Lavage Specimens
Authors: Lin Oliver , Burnette Bailey , Reece Becky 
Published: January 2025

Abstract

Background
HSV-1 is estimated to affect 3.7 billion worldwide (67% prevalence), primarily manifesting as oropharyngeal lesions. Although HSV can be commonly detected by polymerase chain reaction (PCR) in bronchoalveolar lavage (BAL) specimens, true HSV pneumonitis is rare and most positive specimens reflect colonization or asymptomatic reactivation, not active respiratory infection. This study evaluates the appropriateness and frequency that diagnostic HSV-1/2 qualitative DNA PCRs are ordered on BAL specimens at a tertiary medical center and its impact on treatment and patient outcomes.
Immune Status of Patients Tested for Opportunistic Infections

Methods
Patients at a single tertiary medical center who had HSV-1/2 qualitative DNA PCR performed on any specimen in 2022 were identified by lab order. Testing performed on non-BAL specimens were excluded from data collection. De-identified clinical history, risk factors, immune status, concomitant testing, treatment, and outcomes were recorded to secure database for analysis.
Immune Status Guiding Treatment in HSV Positive Patients

Results
HSV-1/2 qualitative DNA PCR testing was performed on BAL specimens from 131 unique patients. Of the 131 patients, 50 (38.2%) were immunosuppressed as defined by active malignancy, pharmacologic immunosuppression, neutropenia, HIV positive thus most testing was performed on immunocompetent patients without risk factors. 16 patients had a positive qualitative PCR (12.2%) of which 6 patients were treated with antiviral therapy (4.6%). 12 patients (9.2%) were tested more than once on different occasions, 4 of which were positive. 1 patient had a documented final diagnosis of HSV pneumonitis treated with acyclovir.

Conclusion
HSV pneumonitis is a rare manifestation of a common infection that is associated with critical illness, poor outcomes. Many patients will have positive PCR testing of BAL specimens due to inoculation from the upper respiratory tract but this typically does not reflect true infection. Only in the context of significant immunosuppression, compatible clinical presentation can HSV pneumonitis be diagnosed. Excessive ordering of HSV testing leads to unnecessary healthcare expenditure and confounds the clinical picture and decision making. We suggest limiting HSV testing to immunosuppressed patients with the appropriate clinical presentation and use of cytopathology to help confirm diagnosis.

Disclosures
All Authors: No reported disclosures
P-1620. Use of Multiplex PCR and Antimicrobial Stewardship Intervention to Optimize Antimicrobial Therapy in Pneumonia Patients at a Community Teaching Hospital
Authors: Politis Paula A , England Matthew , File Thomas M 
Published: January 2025

Abstract

Background
Patients admitted to the hospital with community-acquired pneumonia (CAP) or those who develop hospital-acquired pneumonia (HAP) are usually treated with broad spectrum antimicrobials for several days while awaiting the results of gold standard respiratory culture. Recently, our health system instituted a rapid Pneumonia PCR Panel (PN) that has increased the yield of pathogen-specific, actionable results in significantly less time than culture allowing for faster optimization of antimicrobial therapy. Our Antimicrobial Stewardship Program (ASP) routinely follows and provides recommendations based on the results of the PNs. The purpose of our quality improvement project was to assess the optimization of antimicrobial therapy associated with use of the PNs and ASP intervention.
Table 1

Methods
We performed a retrospective review of patients admitted to our institution on whom ASP intervened with a PN performed for the timeframe of January 2023-March 2023. We assessed ASP intervention type, respiratory culture and PN results, and patient location.

Results
There was a total of 91 patients with PNs/respiratory cultures evaluated. 52 (57%) patients were in the ICU. 38% of cultures were positive with &gt; 1 bacterial organism isolated whereas 82% of PNs were positive with &gt; 1 organism identified. 34/35 of positive cultures had the same organism identified on PN. Of negative cultures (no growth, flora, or C. albicans), 42/56 had a positive PN for a potential pathogen, including viruses and/or bacteria. Microorganisms identified by PN in culture negative cases are listed in Table 1. In 73% of patients, the PN lead to recommendations by the ASP for more appropriate antimicrobials. Interventions included: de-escalation (50), change antibiotic for better coverage (21), duration of therapy (32), discontinue antibiotic (3), other (5), and recommend initial PN (9). In cases where ASP recommended the PN, 6 patients were appropriately covered or de-escalated by the medical team, 2 had ASP intervention, and 1 patient expired.

Conclusion
The use of the PN increased the yield of potential etiologic pathogens in patients with CAP and HAP, and when paired with ASP recommendations led to overall optimized antibiotic use and enhanced antimicrobial stewardship.

Disclosures
Thomas M. File, Jr., MD, MSc, MACP, FIDSA, Eagle Pharmaceuticals: Member of DSMB for clinical trial|MicroGenDx: Advisor/Consultant|Nabriva: Advisor/Consultant|Paratek Pharmaceuticals: Advisor/Consultant|Pfizeer: Grant/Research Support|shionogi: Advisor/Consultant|thermoFisher Scientific: Advisor/Consultant
P-1621. Utilization of Repeated Procalcitonin Assays at A Tertiary Care Center
Authors: Andrade Reema , Norman Sarah J , Ramdeen Sheena 
Published: January 2025

Abstract

Background
Procalcitonin (PCT) is a biomarker which has been shown to be safe and effective for reducing antibiotic exposure in patients with respiratory infections and sepsis. In current clinical practice, PCT has become a promising new biomarker for the early detection of systemic bacterial infections. In 2017, the US Federal Drug Administration (FDA) approved its use to guide antibiotic stewardship efforts in people with these conditions. Prior studies have also found value in repeated PCT measurements to inform antibiotic use in the first few days of empiric treatment. Although the use of PCT has steadily increased, failure to use the results in clinical decision-making limits its utility in antibiotic stewardship. The purpose of this study was to describe how repeated PCT tests are utilized at a large tertiary care center to guide antibiotic stewardship.

Methods
There were 1,002 patients between April 2023 and October 2023 who had a PCT test ordered, including 116 with two or more tests. Fifty of those with at least two PCT tests were selected randomly for a retrospective chart review and analysis.

Results
The median age of the cohort was 57 years, with 26 (52%) males and 24 (48%) females. Twenty-six patients received antibiotics before the PCT was tested, and 24 did not. Among the patients with at least two PCT tests, antibiotics were discontinued in 11 (22%), continued in 13 (26%), escalated in 14 (28%), and de-escalated in 6 (12%). Nine (53%) of the patients whose antibiotics were discontinued or de-escalated had PCT values that improved on repeat tests, and eight (43%) had PCT values that increased. The most common infectious diseases diagnosis was pneumonia, and three patients had more than three concurrent infections. Twenty patients had more than two PCT tests ordered. The median length of stay was 33 days, and ten patients died during their hospitalization.

Conclusion
Having more than one PCT test may be helpful in clinical decision-making and guiding antibiotic stewardship efforts, but it did not appear to have a major impact in reducing antibiotic use in this cohort. The study findings support the need for further optimization of PCT testing to aid in antibiotic stewardship at this center.

Disclosures
All Authors: No reported disclosures
P-1622. Decreasing Cellulitis Length of Stay with Implementation of Rapid Diagnostic Test
Authors: Shah Rishita , Grohmann Stephen , Hart Catherine 
Published: January 2025

Abstract

Background
Skin and soft tissue infections (SSTIs) have been an increasing burden in the recent years. Rapid diagnostic tests can be useful to rule out Staphylococcus aureus as a pathogen. Northwestern Lake Forest Hospital (NLFH) did not have MRSA purulent wound PCR onsite and was sent out to another hospital. It was noticed that patients had longer length of stay (LOS) in our system compared to cohorts with patients diagnosed with cellulitis. We evaluated patients with cellulitis without major complications (DRG 603) and found an average LOS of 0.86. The goal was to reduce LOS of patients with cellulitis without major complications with the addition of a rapid diagnostic tool in our lab.
Length of Stay Run Chart
Shows LOS prior to project and after interventions

Methods
NLFH was under-utilizing rapid diagnostic testing to quickly identify if Staphylococcus aureus was an organism for SSTI. We also analyzed turnaround times (TAT) of send out testing compared to on-site testing with regards to observed to expected LOS. We used a multi-modal and phased approach with education, upgrades to our electronic health record (EHR), creation of an updated SSTI Clinical Pathway, and implementation of onsite MRSA purulent wound PCR (Table 1). Our primary goal was to reduce LOS. Another goal was to reduce TAT of testing.
Interventions were applied January to June of 2022 and post intervention data was collected May – July 2023. Education was done to emphasize ordering in the ED. Providers were informed on EHR updates in Epic and best practice alerts were implemented as a reminder to place a picture in the EHR and order correct tests.
Summary of Interventions

Results
Baseline data was collected and observed over expected length of stay was 0.89. Among other NM hospitals across our system, we were in the 79th percentile for cellulitis without major complications. TAT for testing results was also elevated in the pre-intervention timeframe to an average of 21 hours. We found a reduction in LOS with implementation of MRSA purulent wound PCR and education to 0.65. NLFH ranked in the 90th percentile across our system during the post analysis period. When we evaluated TAT during our post intervention period, the time decreased to an average of 6 hours.
MRSA purulent wound PCT Turn Around Times
Shows pre and post interventions TAT for testing

Conclusion
Implementation of a MRSA purulent wound PCR at NLFH helped improve TAT to identification of Staphylococcus aureus. Next steps would be to evaluate the impact on vancomycin utilization.

Disclosures
All Authors: No reported disclosures
P-1623. Implementation of MRSA Nasal PCR Pharmacy Protocol on Vancomycin Use for SSTI
Authors: Withers Sarah , Lipe Abigale , Jozefczyk Caroline , Faulkner-Fennell Carmen M , Eskens Danielle 
Published: January 2025

Abstract

Background
Recent published literature has shown that methicillin-resistant Staphylococcus aureus (MRSA) polymerase chain reaction (PCR) nasal swabs have similar utility for skin and soft tissue infections (SSTI) to well-established pneumonia data with a specificity ranging from 92.2-94% and negative predictive value ranging from 92-94%. The purpose of this study was to evaluate the effect of implementing a pilot pharmacy-led protocol for ordering MRSA PCR nasal swabs in vancomycin-treated SSTI.

Methods
A single-center, pre- and post-implementation observational study was conducted on adult floor patients admitted to a single institution between March 2023 to January 2024 who were on vancomycin for only the indication of SSTI. Exclusion criteria included Gram positive organism in blood culture, admission to any ICU, or if the suspected infection was a deep surgical site infection, necrotizing fasciitis, osteomyelitis, or a vascular graft infection. The primary outcome of duration of vancomycin therapy was compared between pre- and post-implementation groups. Secondary outcomes included length of hospitalization, acceptance rate of de-escalation, total duration of antibiotic therapy, SSTI-related readmissions within 30 days, and MRSA PCR statistics.

Results
A total of 229 patients were included in the study with 160 patients in the pre-protocol group and 70 patients in the post-protocol group. 52.4% of patients were male and 78.2% of patients were white with majority of SSTI being lower extremity cellulitis. There was an increase in MRSA PCR collection from 14.4% to 48.6% in the post-protocol group and in MRSA PCR pharmacy interventions from 0.6% to 28.6%. Duration of vancomycin therapy was similar between both groups and the average total duration of antibiotic therapy was longer than current guideline recommendations for SSTI.

Conclusion
While there was an increase in MRSA PCR nasal swab usage after piloting a new MRSA PCR protocol, the PCR results did not have a significant change on antibiotic utilization for skin and soft tissue infections. As a result of this study, alternative stewardship efforts have been identified for skin and soft tissue infection management.

Disclosures
All Authors: No reported disclosures
P-1626. Impact of Repeat Blood Cultures Among Adult Cancer Patients with Gram-Negative Bacilli Bacteremia on Patient-Oriented Outcomes
Authors: Tang Wesley , Vuong Nancy N , Jiang Ying , Dailey Garnes Natalie J 
Published: January 2025

Abstract

Background
Gram-negative bacilli (GNB) bacteremia is a common and often fatal infection with mortality rates estimated to be 14-34%. Follow-up blood cultures (FUBCs) are blood cultures that are repeated after an initial positive culture. FUBCs are used to assess the appropriateness and duration of antimicrobial therapy. Currently, no guidelines exist regarding the use of FUBC for GNB bacteremia, and the utility is not well-studied in adults living with cancer. We aimed to characterize the impact of FUBC in GNB bacteremia on patient-centered outcomes in patients with cancer.

Methods
We conducted a single-center, retrospective study in patients ≥18 years, hospitalized during 2022, living with cancer, and with laboratory-confirmed GNB bacteremia. FUBC was defined as a blood culture performed within 7 days of initial positive blood culture. We gathered information on the source of bacteremia, identified organisms, presence of antimicrobial resistance, and comorbidities. Categorical variables were compared using Chi-square or Fisher’s exact test. Independent predictors of length of hospital stay were obtained via generalized linear model analysis. Logistic regression analysis was used to identify predictors of unplanned hospital readmission and mortality.

Results
Overall 94% (590/626) of patients with GNB bacteremia had a FUBC at our institution. Among those with FUBC, the majority were without growth (73%). 116/590 (20%) of patients had persistent GNB bacteremia. Patients with persistent or alternative growth on FUBC had higher mortality compared to those with negative FUBC (41% and 53% vs 17%, p&lt; 0.001). Patients with a new organism on FUBC had longer length of stay compared to those with no growth on FUBC (aOR 1.55, 95% CI [1.09-2.20]). Patients with a single organism on repeat culture had a higher rate of mortality.

Conclusion
The majority of patients with FUBC did not show growth. We observed that patients who underwent FUBC had lower mortality than those without FUBC. Patients with new organisms identified on FUBC were associated with longer length of stay. Patients with positive FUBC may be characterized as high risk for mortality. Despite the majority of FUBC without growth, there may be a mortality benefit in identifying those patients with positive FUBC in patients living with cancer.

Disclosures
Natalie J Dailey Garnes, MD, MPH, MS, AlloVir: Grant/Research Support