bluuebunny/crossref_metadata_2025_split huggingface dataset:
P-838. The effect of transesophageal echocardiogram on clinical decision making for patients with Staphylococcus aureus blood stream infection
Authors: Shaikhli Hiba Al , Wingler Mary Joyce B , Stover Kayla R , Cretella David A , Barber Katie , Wagner Jamie 
Published: January 2025

Abstract

Background
Staphylococcus aureus can lead to severe infections, including bloodstream infections, which are associated with high mortality. Infective endocarditis (IE) is a concerning complication of S. aureus bloodstream infections (SABSIs), which is ruled out by transesophageal echocardiogram (TEE). The COVID-19 pandemic led to a decrease in TEEs at the University of Mississippi Medical Center (UMMC) for patients with SABSIs. This study explores the impact of reduced TEE rates on clinical decisions for SABSI patients.

Methods
This retrospective observational study assessed adult SABSI patients at UMMC, categorizing them into pre-COVID (admitted between 3/1/2018-3/11/2020) and COVID (admitted between 3/12/2020-3/1/2022) groups. A VIRSTA score, indicating IE risk and advocating TEE for high-risk patients (score ≥3), was calculated for patients. Primary outcomes included the rate of confirmed IE and antibiotic duration in pre-COVID and COVID groups. Secondary outcomes included hospital stay, correlation between VIRSTA score and TEE, 90-day mortality, and 60-day re-admission.

Results
Among 214 patients, baseline characteristics were comparable between groups. The rate of confirmed IE (9.4% pre-COVID vs. 12.1% COVID; p = 0.66) and median antibiotic duration (28 days in both groups) showed no significant differences. However, mortality was more likely in the COVID group (22.2% vs 10.4%; p=0.019). Notably, high VIRSTA score patients were less likely to undergo TEE COVID (3.8% vs 18.5%; p = 0.008). There were no differences in other secondary outcomes.

Conclusion
This retrospective study highlights the impact of reduced transesophageal TEE utilization during the COVID-19 pandemic on clinical decision-making for patients with SABSIs, including challenges in risk stratification based on VIRSTA score. Despite a decrease in TEE, there were no differences in confirmed IE diagnosis or duration of antibiotics, but mortality was higher in the COVID-19 group. Based on this study there is an opportunity to provide education related to VIRSTA score utility for risk stratification, which may preserve healthcare resources in select patients.

Disclosures
All Authors: No reported disclosures
P-843. Enhancing Bacteremia Mortality Predictions: A Comparative Study of Machine Learning Models Across Databases
Authors: Kurian James , Adelman Max W , Arias Cesar A , Casarin Stefano , Connor Ashton , Contreras German , Nigo Masayuki 
Published: January 2025

Abstract

Background
Bacteremia is a major cause of morbidity and mortality in hospitals, and multiple scoring mechanisms have been developed to help with risk assessment. In the setting of bacteremia, the Pitt bacteremia score (PBS) has been used. This study develops ML models to predict mortality in bacteremic patients, comparing their performance against the PBS.
Characteristics of Patients
ECI: Elixhauser Comorbidity Index

Methods
We retrospectively identified patients aged over 18 years who developed bacteremia in the Houston Methodist Hospital System (HMH) from June 2016 to June 2023. True bacteremia was defined based on CDC definitions. MIMIC-IV data, a comprehensive, de-identified electronic health record (EHR) database of critical care patients from Boston, USA, served as an external validation dataset. We recorded maximally perturbed values of 34 clinical and laboratory variables within 48 hours before the first bacteremia. Missing values were imputed using multiple imputation chain equation (MICE) method after preprocessing datasets. Each dataset was split into 70:30 training and test datasets. Models including PBS, Logistic Regression (LR), Random Forest (RF), LightGBM (LGBM), and XGBoost (XGB), along with hyperparameter tuning via Optuna, were used in classification tasks to predict 30-day all-cause mortality. AUROCs (Area Under the Receiver Operating Characteristics) for each model on test dataset were created, and they were statistically compared with DeLong’s tests. Probability cutoffs for each model were decided to maintain a specificity close to 95%.
Model Performance of ML Models and Pitts Score against Mortality

Results
Across HMH and MIMIC-IV, 21,972 and 2,439 patients experienced BSIs, respectively. Table 1 summarizes characteristics of the patients. E. coli and Enterococcus spp. were the most common pathogens in HMH and MIMIC-IV, respectively. S. aureus made up 17% of bacteremia. All the ML models exhibited higher AUROCs than that of the PBS. LGBM and XGB achieved the highest AUROCs of 0.878 and 0.824, respectively, surpassing PBS (p &lt; 0.05).

Conclusion
ML models demonstrated higher AUROC and superior performance than that of PBS. ML allows for vast quantities of input data. This ability to process and integrate diverse features may contribute to personalized medicine in infectious diseases.

Disclosures
All Authors: No reported disclosures
P-847. Duration of Daptomycin and Ceftaroline Dual Therapy in Salvage Methicillin Resistant Staphylococcus aureus (MRSA) Bacteremia Prior to Monotherapy De-escalation
Authors: Lechner Josh , Kinn Patrick M , Ince Dilek , Percival Kelly M 
Published: January 2025

Abstract

Background
Methicillin resistant Staphylococcus aureus (MRSA) bacteremia is a serious medical condition known to cause mortality. Earlier escalation to daptomycin and ceftaroline is associated with improved outcomes compared to monotherapy; however, the optimal duration of dual therapy after bloodstream clearance remains unclear.

Methods
This was a single center retrospective cohort study comparing a composite outcome of clinical failure (90-day mortality, 90-day readmission, and bacteremia recurrence) in adult patients with MRSA bacteremia between June 2018 and June 2023 who received dual therapy. Patients who were treated with combination daptomycin and ceftaroline were divided into two groups: patients treated with dual therapy for less than or equal to ten days (short) and patients treated with dual therapy for greater than ten days (long).

Results
The study population included 14 patients in the short group and 13 patients in the long group with 48% female (n=13), 96% white (n=26), median age of 62 years (IQR 54-70), with additional demographics shown in Table 1. There was no statistically significant difference in the primary composite clinical failure outcome (50% vs 38%, p=0.70) which included 90-day infection-related mortality (36% short vs 23% long, p=0.67), 90-day readmission (29% short vs 23% long, p=1), and bacteremia recurrence (7% short vs 0% long). Culture data and antimicrobial usage is shown in Table 2, with patients in the long group receiving a mean of 15 days more of dual therapy than the short group. Patients in the long dual therapy group had longer duration of positive blood cultures after escalation to daptomycin and ceftaroline when compared to the short group (4 days long vs 2 days short) and had longer median hospital length of stays (22 days short vs 25 day long).

Conclusion
Among patients with persistent MRSA bacteremia, short durations of dual therapy with ceftaroline and daptomycin may be adequate once bloodstream clearance is achieved. This study found no difference in 90-day mortality, recurrence, or readmission among patients who received short vs long durations of dual therapy. Further research is needed to identify the optimal duration of dual therapy.

Disclosures
All Authors: No reported disclosures
P-869. Comparison of β-lactams Antibiotics Resistance of Viridans Streptococci in Bacteremic Children and Adults with Malignancy
Authors: Habuka Rie , Aizawa Yuta , Imamura Masaru , Takizawa Jun , Saitoh Akihiko 
Published: January 2025

Abstract

Background
Viridans streptococcus bacteremia (VSB) is an important complication after receiving chemotherapy in patients with malignancy. The increase in antibiotic resistance treating patients with VSB has been a major concern especially in children.

Methods
This is a retrospective study to evaluate patients with malignancy diagnosed with VSB at Niigata University Hospital in Japan between January 2009 and May 2023. Clinical characteristics of the patients, and antibiotic susceptibility of viridans streptococci were evaluated. We used the Mann-Whitney test for numerical variables and the χ2 test, or Fisher’s exact test for categorical variables.

Results
A total of 85 episodes (29 in children, 56 in adults) of VSB were identified during the study period. Acute myeloid leukemia was the most common diagnosis in both children (41%) and adults (61%). The susceptibility rate was significantly lower in children than adults; penicillin (45% vs. 79%, p =. 001), cefepime (52% vs. 91%, p &lt; .001), and meropenem (55% vs. 89%, p &lt; .001). Vancomycin was 100% susceptible in both groups. Based on the susceptibility results, the rate of appropriate initial antimicrobial coverage by empiric therapy was lower in children (59%) than in adults (91%) (p &lt; .001). Severe complications included 2 meningitis cases in children, and a septic shock case in adults, 2 pediatric cases were treated with non-susceptible antibiotics at the onset of fever. No mortality was observed. The median number of previous febrile neutropenia episodes was higher in children (2, IQR 1-4) than adults (1, IQR 0-2) (p &lt; .001). Additionally, the median duration of neutropenia at the onset was longer in children (6.5 days, IQR 4-11days) than adults (5 days, IQR 3-7days) (p = .03). No difference in β-lactam antibiotics use at the onset (7% vs. 0%, p = .11), or β-lactam exposure within 30 days of onset (41% vs. 41%, p = .98) was observed between child and adults.

Conclusion
We demonstrated a high rate of β-lactam antibiotics resistance to viridans streptococci in patients with malignancy, especially in children. The frequent antimicrobial exposure in children might be related to such high resistance. Vancomycin may need to be included in an empiric therapy in the setting where β-lactam antibiotics resistance of viridans streptococci is high.

Disclosures
All Authors: No reported disclosures
P-870. Daptomycin-Susceptible vs. Daptomycin-Non-susceptible Enterococcus Bloodstream Infections: Rates and Predictors of Treatment Failure and Predictors of Daptomycin Resistance
Authors: Olion Kelsey , Moenster Ryan P , Wallace-Lacey Ashleigh , Remensnyder Blake , Linneman Travis W 
Published: January 2025

Abstract

Background
Daptomycin is a well-tolerated option to treat resistant enterococci; however, updated breakpoints from the Clinical Laboratory and Standards Institute (CLSI) have led to increasing numbers of ‘susceptible, dose-dependent’ (SDD) or daptomycin non-susceptible (DNS) isolates.

Methods
This study was to determine if isolation of daptomycin-sensitive enterococcal (DSE) or daptomycin-non-susceptible enterococcal (DNSE) isolates from the blood impacts patient outcomes. A retrospective, observational, cohort of patients within the Veteran’s Affairs (VA) Healthcare System from 1 January 2017 to 31 December 2021 with at least 1 blood culture positive for Enterococcus faecalis or E. faecium was identified. Patients were analyzed in 3 cohorts: 1) all included patients, 2) only patients with minimum inhibitory concentration (MIC) data available, and 3) E. faecium isolates and DSE isolates only. The primary outcome of treatment failure was a composite of 30-day mortality and microbiological failure. Two multivariate regressions were conducted - one to establish predictors of treatment failure and one to establish predictors for daptomycin non-susceptibility.

Results
Two hundred four patients were included (90 DSE, 114 DNSE). In cohort 1, 63.3% (57) DSE patients experienced failure vs. 58.8% (67) in the DNSE group (p = 0.56). Sixty-nine percent (40/58) of DSE patients failed in cohort 2 vs. 56.4% (35/62) of DNSE patients (p = 0.157), and 69% (40/58) of DSE and 64.4% (56/87) of DNSE failed in cohort 3 (p = 0.56). Multivariate regression revealed infectious diseases (ID) consultation (OR 0.402; 95% CI, 0.176-0.918; p = 0.030) was associated with reduced risk of failure, while infection with vancomycin-resistant enterococcus (OR 2.04; 95% CI 1.028-4.049; p = 0.04) and endocarditis/endovascular source of infection (OR 4.33; 95% CI 1.34 – 13.99; p = 0.01) were associated with increased risk of failure. Previous beta-lactam and vancomycin exposure were associated with increased risk of DNSE.

Conclusion
No significant difference in failure between patients with DSE and DNSE bacteremias was observed; however, ID consultation was found to be protective, and previous antibiotic exposure was associated with increased DNSE risk.

Disclosures
All Authors: No reported disclosures
P-887. Evaluation of ceftriaxone and cefotaxime as surrogate markers for oral second and third generation cephalosporins in Escherichia coli strains from blood
Authors: Pham Tho H , Molina Kyle , Huang Vanthida 
Published: January 2025

Abstract

Background
Oral second- and third-generation cephalosporins are increasingly being utilized as oral transitional therapy for Escherichia coli bloodstream infections due to resistance or intolerance to other classes. However, most automated susceptibility systems only include cefazolin (CFZ), ceftriaxone (CRO), or cefotaxime (CTX). We aimed to evaluate the susceptibility correlation of CFZ, CRO, or CTX compared to oral second- and third-generation cephalosporins to determine a potential surrogate breakpoints.
Antimicrobial susceptibility and categorical agreements of intravenous and oral cephalosporins against 100 E. coli strains

Methods
We obtained 100 E. coli blood isolates from HonorHealth and Abrazo Health Systems in Phoenix, AZ from September 2021 to 2023. Broth microdilution was performed according to CLSI using commercially purchased CFZ, CRO, CTX, cefuroxime (CXM), cefaclor (CEC), cefprozil (CPR), cefdinir (CDR), and cefixime (CFM). E. coli ATCC 25922 was utilized as quality control. Categorical agreement and error rates were calculated for drug-drug combinations using CFZ, CRO, or CTX as the surrogate antibiotic for oral cephalosporins.

Results
MIC50/90 values were reported in Table 1. With the recommended CFZ surrogate breakpoint of ≤ 16 µg/mL for oral cephalosporins, the categorical agreement rates were 86% for CEC and 93% for CPR. When applying CRO and CDR breakpoint of ≤ 1 µg/mL, highest categorical agreement rates of 99% were seen with CDR, followed by those of 86% with CPR. Compared to CFZ, CRO, and CXM resulted in higher false susceptible rates with CEC and CPR. However, if CRO and CTX MIC ≤0.06 µg/mL had been used, the categorical rates would have been above 95% with CEC and CPR. CFM susceptibility could not be predicted with CFZ, CRO, or CTX due to high major error rates.

Conclusion
This study suggests potential utility of parenteral first- and third-generation cephalosporins as surrogates for oral counterparts within their respective second- and third- generations. Use of a lower breakpoint for third generation cephalosporins strengthens their role as surrogates. Future investigation is warranted to clinically corroborate these findings.

Disclosures
Kyle Molina, PharmD, Innoviva Speciality Therapeutics: Advisor/Consultant|Melinta: Advisor/Consultant|Melinta: Grant/Research Support|Merck: Grant/Research Support|Shionogi: Advisor/Consultant
367. Enhancing antimicrobial stewardship capacity building and communication across multidisciplinary departments in Chinese hospitals: a national qualitative study
Authors: Wang Xiaomin , Zhou Xudong 
Published: January 2025

Abstract

Background
Antimicrobial stewardship (AMS) programs have been widely adopted and proven to be effective to optimize antibiotic use. After a decade of efforts in mandatory AMS implementation, inappropriate prescribing and antimicrobial resistance are still disproportionately prevalent in China. We aim to investigated the underlying barriers to the mandatory AMS programs from a multidisciplinary health system perspective in the Chinese context.
Example of quotes from interview transcripts that illustrate and validate the themes

Methods
Face-to-face, in-depth qualitative interviews were conducted in 16 public hospitals in eastern, central, and western China. Hospitals were purposely selected with full consideration to represent both economically developing and developed areas and both secondary and tertiary care hospitals. A total of 111 respondents were interviewed, including 38 doctors, 28 clinical pharmacists, 15 microbiologists, 14 infection prevention and control (IPC) specialists, 10 experts from medical service departments, and 6 quality improvement experts. A thematic framework analysis was conducted aided by NVIVO 11 software.
Example of quotes from interview transcripts that illustrate and validate the themes (continue)

Results
Our research identified two key barriers to AMS implementation. 1) Inadequate AMS-related capacities among doctors and nurses. Doctors, especially surgeons, had inadequate knowledge and poor practices on appropriate antibiotic use and had insufficient knowledge and skills in antimicrobial susceptibility testing (AST) and its interpretation. The continuing education in a few hospitals was reported to be crammed with large class sizes and showed little effect on capacity improvement. 2) Poor communication and cooperation between the AMS team and doctors. Compared with AMS team members, doctors had a dominant and powerful position in hospitals. Clinical pharmacists admitted that they were subjected to high pressure and not well respected while conducting routine prescription audit and feedback works. Most (87%) of the interviewed microbiologists were not able to access the electronic health records.

Conclusion
We propose a multi-disciplinary training program covering microbiology, clinical pharmacy, and IPC for newly-recruited health workers (i.e., doctors and nurses), and a communication mechanism among clinical departments and AMS members to facilitate AMS implementation.

Disclosures
All Authors: No reported disclosures
P-894. MRSA bacteremia with high MIC to Vancomycin: A comparison study of Daptomycin, Ceftaroline, and Both
Authors: Al khouri Zaid , Al Qura'an Anood , VanNatta Mollie , Alam Mohammad , Munshi Ruhul , Malek Alexandre 
Published: January 2025

Abstract

Background
Daptomycin (DAP) and/or ceftaroline (CPT) have been used in pts with MRSA bacteremia (MRSAB) with minimum inhibitory concentration (MIC) 2 ug/ml to vancomycin (Vanc). However, head-to-head studies comparing DAP versus CPT or DAP-CPT combination are lacking. In this study, we sought to describe the outcomes and characteristics of pts with MRSAB who received DAP, CPT, or both.

Methods
We performed a retrospective cohort study of adult pts admitted to Ochsner LSU Health Shreveport– Academic Medical Center who were diagnosed with MRSAB MIC 2 ug/ml to Vanc and received DAP, CPT, or both for at least &gt;=72 hours. Pts’ demographics, comorbidities, source of infection, and mortality data were all collected.

Results
We identified 82 pts with MRSAB MIC 2 ug/ml to Vanc. We divided them into 3 groups: DAP (n = 39, 47.6%), CPT (n = 12, 14.6%), and DAP-CPT (n = 31, 37.8%). The mean age was 53 vs 55 vs 63 y, respectively (p-value=0.013). Males were more prevalent than females in the 3 groups. Pts’ demographics at baseline were comparable between the three groups, and there were no statistically significant differences between the three groups in terms of comorbidities. Prior MRSA bacteremia was reported in 5 pts in the DAP-CPT group and DAP group (p-value=0.34). IV drug use was only reported in 5 pts who received DAP(p-value=0.05). SSTI (33.3%) was the leading cause of bacteremia in DAP group followed by osteoarticular and CVC-related infections in 25.6% each. The lung was the most source of infection in 58.3% of Pts in CPT group. In the DAP-CPT arm, IE was the main source of infection (48.4%), followed by endovascular and lung in 38.7% each. IE was statistically significant in DAP-CPT group (p-value=0.002). The mean of MRSA bacteremia was 4 vs 5 vs 9 days in DAP, CPT, and DAP-CPT, respectively while the clearance of MRSA bacteremia after the initiation of each regimen was faster and in favor of Pts who received DAP-CPT (2.3 d), p-value&lt; 0.009. However, the 30-day mortality was higher in patients of the DAP-CPT group (25.8%), p-value=0.02.

Conclusion
Our data demonstrated that pts who received DAP-CPT combination therapy cleared MRSA bacteremia faster than those who received DAP or CPT as monotherapy. Further studies are needed to elucidate if early initiation of the DAP-CPT combination could reduce the mortality rate.

Disclosures
All Authors: No reported disclosures
P-896. Artificial Intelligence Performs Well in Assessing the Clarity of Definitions of Variables in Periprosthetic Joint Infection Studies
Authors: Tenorio Bettina Gabrielle V , Yu Melody Hope Lee , Deslate Angelica Bernadette , Tai Don Bambino Geno 
Published: January 2025

Abstract

Background
Artificial intelligence (AI) has the potential to improve healthcare research methodologies, particularly in addressing the need for consistency and clarity in defining variables in observational studies. However, concerns exist regarding the accuracy and reliability of AI in this context.
Performance of Artificial Intelligence in Assessing Clarity of Definition of Variables

Methods
We reviewed observational studies on prosthetic joint infection studies from 2017-2023, focusing on 13 categories of variables. We used ClaudeAI 2 (Anthropic, San Francisco, CA), a large language model, in analyzing definitions from full texts, instructing it to classify them as objective, subjective, or undefined. Some examples of a highly objective definition are the presence of time element, severity, staging, frequencies, laboratory cut-off, and medication dependence. A simple chart review was deemed subjective.

Results
We included 75 studies with a total of 369 variables in the analysis. AI detected 88% of variables (n=324). Of those detected, 74% (241/324) were correctly classified. It accurately identified antibiotic use and infection type as the variables that are most frequently defined objectively (94%). For the 9/13 categories, it appropriately assessed that most studies lacked definitions. Smoking (20%) and alcohol use (33%) were least frequently defined. Notably, 5 detected variables did not exist in the manuscripts.

Conclusion
The model demonstrated high performance in detecting variables from study text and evaluating the clarity of variable definitions. The false positive detections serve as an important reminder that human oversight remains crucial to ensuring accuracy when integrating AI into the research process. Looking ahead, AI may assist researchers in objectively defining study variables from the outset and verifying the correct application of definitions. More studies are needed on how to optimally integrate its capabilities into the research process.

Disclosures
All Authors: No reported disclosures