bluuebunny/crossref_metadata_2025 huggingface dataset:
204. Clostridioides difficile screening among asymptomatic carriers admitted for bone marrow transplantation: Navigating optimal stewardship strategies
Authors: Hofmann Justin , Habib Alma , Tran Nikki , MacDowell Sarah , Choe Hannah , Liscynesky Christina , El Boghdadly Zeinab
Published: January 2025

Background

Toxigenic Clostridioides difficile (CD) approximately colonizes 11-39% of allogeneic and 13% of autologous hematopoietic stem cell transplantation (HCT) candidates. Colonization increases risk for CD infection (CDI). Thus, in 2018, our institution established universal CD PCR screening on admission to the HCT unit to decrease hospital onset CDI rates. CD colonized patients received primary prophylaxis with twice daily oral vancomycin (OV) if antibiotics were initiated. Here, we share our experience with this process and subsequent diagnostic and therapeutic stewardship interventions.

Methods

We retrospectively analyzed adult HCT patients who had stool CD PCR screening within 72 hours of HCT admission between 12/2018 to 8/2021. Outcomes were stratified by CD screen positive vs negative within 100 days post-HCT. CD PCR was the methodology used for CDI diagnosis during this time frame.

Results

We reviewed 237 patients (autoHCT, n=154; alloHCT, n=83). Patient characteristics are described in Table 1. Thirty alloHCT and 52 autoHCT patients screened positive for CD. Prior antibiotic use was observed more in the CD colonized group. Nine (11%) screen-positive patients developed CDI in 100 days versus 13 (8.4%) screen-negative. No significant differences in other outcomes were noted (Table 2). Diarrhea occurred in 76 (92.7%) of the screen-positive patients and 144 (92.9%) of the screen-negative. A second CD PCR test was ordered in 18 patients from the positive group and 129 from the negative group; 16 of 18 (88.9%) converted to a negative result without any CD-directed treatment and 9 of 129 (7%) became positive. In 9/2023, CD screening policy ceased in lieu of a 2-step CD PCR plus toxin A/B enzyme immunoassay (EIA) for clinical suspicion of CDI. This change reduced CDI rate and antibiotic utilization (Figures 1,2).Figure 1.Decrease in anti-CDI antimicrobial utilization in the bone marrow transplant unit over time following two-step CD testing implementation in 9/2023

Conclusion

Regardless of CD carrier status, diarrhea is an inevitable early post-HCT adverse effect due to commonly used conditioning chemotherapies for autoHCT and alloHCT. Screening for CD carriage on HCT admission may not accurately assess risk of future CDI and may only reflect transient carriage in some patients. Better CDI diagnostic tools such as 2-step test is needed in this population to avoid over diagnosis and treatment of CDI.Figure 2.Decrease in anti-CDI antimicrobial utilization and CDI rate of all patients (including non-transplant patients) admitted to the cancer center over time following two-step CD testing implementation

Disclosures

Hannah Choe, MD, Abbvie: Advisor/Consultant|Actinium: Advisor/Consultant|Incyte: Advisor/Consultant|Ironwood: Advisor/Consultant|Regimmune: Advisor/Consultant|Sanofi: Advisor/Consultant
303. The A-Stop Study: Rapid Tests for Candida Infection in Non-neutropenic Critically-ill Patients - A Multicentre Diagnostic Test Accuracy Study
Authors: McMullan Ronan
Published: January 2025

Background

Among critically-ill patients, antifungal therapy is usually driven by risk rather than a confirmed diagnosis. This leads to overtreatment, due to both low confidence in culture-based diagnostics and the time-critical nature of antifungal treatment. Such overtreatment undermines antimicrobial stewardship which could be improved if rapid, non-culture, tests reliably exclude disease.

Methods

This was a prospective multicentre diagnostic test accuracy study of three rapid tests for Candida infection: beta-D-glucan (BDG), Associates of Cape Cod, and two PCR-based tests (Fungiplex Candida, Bruker Corporation; & T2Candida, T2 Biosystems). In brief, patients were eligible for recruitment within 24hr of being started empirically on antifungal therapy for suspected Candida infection if they were not neutropenic. In the primary analysis, diagnostic accuracy metrics were derived by comparing index test results to the EORTC/MSGERC definition of proven Candida disease for patients in intensive care units (ICU). In a secondary analysis, the tests were compared with a constructed reference standard for proven + probable Candida disease. Since the purpose of these tests was to rule-out disease, sensitivity and negative predictive value (NPV) were the focus.

Results

Of 4005 patients screened for eligibility, 1251 participants were recruited from 57 UK ICUs between 2018-2023. Of these, 1223 were evaluable against the definition of proven disease and 54 met that definition. In total, 1215, 1217, and 507 participants had an evaluable BDG, Fungiplex, and T2Candida test, respectively. For proven disease, the most sensitive test was BDG (69%), followed by T2Candida (44%) and Fungiplex (28%); the NPV of each of these three tests was 97%. The sensitivity was predictably lower for the proven + probable disease group (N=124), ranging from 18%-58%, yet NPV remained above 90% for all three tests.

Conclusion

There is an opportunity to reduce unnecessary antifungal prescribing in this patient group. Each of the tests evaluated had lower sensitivity than previously reported but, because of low disease prevalence, they had high NPV. Modelling the effects of using the tests to stop empiric treatment may further guide how best to apply the tests in practice.

Disclosures

All Authors: No reported disclosures
304. Global Incidence of Viral Lower Respiratory Tract Disease (LRTD) Episodes and Hospitalizations (2010–2021)
Authors: Maslova Ekaterina , Fageras Malin , Gillespie Kate W , White Lisa , Raferty Quinn , Oros Andrei , Sinha Pratik
Published: January 2025

Background

The COVID-19 pandemic highlighted the impact of viruses on lower respiratory tract diseases (LRTD); however, the global burden of viral LRTD is undefined. To bridge this gap, we estimated the global incidence of viral LRTD and hospitalizations in 2010–21.

Figure 1. Global incident count of viral LRTD episodes by viral etiology (2010–2021). Non-viral causes are shown for comparison.

Methods

We used the Global Burden of Diseases, Injuries, and Risk Factors 2021 (GBD) framework and a Bayesian meta-regression tool (DisMod-MR 2.1) to estimate the global incidence of viral LRTD. We defined viral LRTD as clinician-diagnosed pneumonia/bronchiolitis, capturing symptoms such as cough, difficulty breathing, fever, and chest discomfort. Viral LRTD were categorized by pathogen (SARS-Cov2; influenza; respiratory syncytial virus [RSV]; ‘other’). We estimated hospitalizations by applying a country-specific scalar, informed by inpatient admission data and a country-specific healthcare access and quality index from the GBD, on pathogen-specific estimates of LRTD for each country. In data sparse regions, estimates were generated by extrapolation.Figure 2.Global incident count of viral LRTD hospitalizations, by viral etiology (2010–2021). Non-viral causes are shown for comparison.

Results

Average global incidence (per 100,000 person-years [PY]) of viral-associated LRTD episodes was 1,198 in 2010–19 and 25,716 in 2020–21. The number of viral LRTD cases was 880 million in 2010–19 and 4 billion in 2020–21. Average overall global incidence (per 100,000 PY) of viral LRTD hospitalizations was 170 (123 in 2010–19; 388 in 2020–21). The total number of hospitalizations was 90 million in 2010–19 and 61 million in 2020–21. Influenza and ‘other’ viruses accounted for most viral LRTD episodes (Figure 1) and hospitalizations in 2010–19 (Figure 2). Viral LRTD episode rates remained stable until 2019, while hospitalization rates increased. A decrease in influenza- and RSV-related episodes and hospitalizations was noted in 2020–21.

Conclusion

Viral LRTD are common and incur substantial global healthcare burden. Year-on-year increases in severe cases requiring hospitalization, most recently compounded by the COVID-19 pandemic, are alarming. Given the previously underappreciated scale of the problem, increased surveillance and novel therapeutic options may help reduce the burden of viral LRTD.

Disclosures

Ekaterina Maslova, ScD, AstraZeneca: Employee of AstraZeneca|AstraZeneca: Stocks/Bonds (Private Company) Malin Fageras, PhD, AstraZeneca: Full time employee|AstraZeneca: Stocks/Bonds (Private Company) Lisa White, PhD, AstraZeneca: Advisor/Consultant Pratik Sinha, MBChB/PhD, AstraZeneca: Advisor/Consultant|Prenosis Inc: Board Member
P-809. Evaluating the Usage, Safety, and Accuracy of Vancomycin Dosing Practices at VA Eastern Colorado Health Care System (VA ECHCS)
Authors: Hart Caitlin , Christoffersen James , Scott Catherine
Published: January 2025

Background

Vancomycin is a glycopeptide antibiotic used as a mainstay of therapy for gram positive bacterial infections, including MRSA (methicillin-resistant staphylococcus aureus). Vancomycin requires pharmacokinetic calculations to determine dosing and close therapeutic drug monitoring to achieve goal trough between 15-20 mg/L (AUC/MIC goal between 400-600 mg ■h/L) and prevent nephrotoxicity. The purpose of this study is to assess our current vancomycin usage patterns, including empiric dosing accuracy & safety outcomes to help inform a decision whether a change to our current practice is indicated.

Methods

This retrospective, observational cohort study evaluated 117 vancomycin trough levels from 63 patients who received at least two doses of vancomycin between August 1, 2022 and July 31, 2023. Patients were excluded if they received hemodialysis or were dosed by random levels in the setting of severe renal dysfunction. Collected demographics included age, sex, weight, height, BMI, indication for vancomycin, dosing, trough levels, source of infection, MRSA nares, concomitant nephrotoxic medications, spinal cord injury diagnosis, serum creatinine, and cystatin C. Estimated AUC was calculated using VancoPK.com based on the reported trough using patient specific pharmacokinetic parameters. This study is exempt from IRB approval.

Results

A total of 58 trough levels from 49 patients were included. The majority of patients were male (87.7%) with an average age 61±13 years old. Out of the 58 trough levels evaluated, 20 (41%) were at goal. Of the levels not a goal 27 (71%) were subtherapeutic, and 11 (29%) were supratherapeutic. The estimated AUC was at goal for 35 (60%) of the 58 total troughs. Of the 27 patients who had a subtherapeutic trough 21 (77%) had an AUC at goal, and 14 of them increased the dose despite having a therapeutic AUC. Only 1 patient (2%) developed possible vancomycin associated AKI (acute kidney injury).

Conclusion

A higher number of patients were within therapeutic range when evaluating AUC compared to trough. The low incidence of vancomycin associated AKI was likely due to low frequency of supratherapeutic troughs in this study. Further analysis of these results will be used to identify opportunities for education and improvement of our current vancomycin dosing process.

Disclosures

All Authors: No reported disclosures
P-814. Utility of PET-CT Scan in Staphylococcus aureus Bacteremia
Authors: Peterson Christopher , Tokala Mamata Reddy , Ndolo Ruth , Stocki Christopher , Stayrook Sydney , O’Shea John-Paul , Bansal Ekta , Espriella Mariana Gomez de la , Fazili Tasaduq
Published: January 2025

Background

Staphylococcus aureus bacteremia is a common yet serious infection with high morbidity and mortality. The timely identification of the primary source of infection and any associated metastatic foci is crucial for guiding appropriate management strategies and improving patient outcomes. Positron emission tomography-computed tomography (PET-CT) scans offer a non-invasive imaging modality that combines the metabolic information provided by PET with the anatomical detail provided by CT. Our investigation aims to show that PET-CT is a useful modality for improving mortality in patients with S. aureus bacteremia.Table 1:Demographic Variables of Participants

Methods

Patients with S. aureus bacteremia who underwent PET-CT at Roanoke Memorial Hospital between November 2020 and November 2022 were identified through electronic health records. These were matched with a control group comprised of patients with S. aureus bacteremia who did not undergo PET-CT scans. Logistic regression analysis was employed for statistical comparison between groups.Table 2:PET Group Results

Results

A total of 132 patients were included in the study, with 66 in both the PET group and the group without PET (Table 1). Patients undergoing PET-CT had significantly lower odds of mortality compared to those without the scan (OR=0.404, 95% CI: 0.167 - 0.980, p=0.0451). In the PET-CT group, PET-CT detected a new foci of infection in 57.6% of cases and a source control procedure was performed in 25.8% of cases as a result of PET-CT findings (Table 2). Subgroup analysis within the PET group showed positive PET scan uptake in the majority of patients (93.94%), with whole-body PET-CT being the most commonly performed imaging protocol. Antibiotic duration was adjusted in 33% of patients based on PET-CT findings. Patients in the PET-CT group received a longer course of antibiotics (36.8 vs 29.3 days)(Table 3).Table 3:Primary and secondary outcomes

Conclusion

These results underscore the potential clinical utility of PET-CT in guiding therapeutic interventions. Here we observed a lower mortality in patients with S. aureus bacteremia who underwent PET-CT imaging, as well as increased performance of source control procedures and longer antibiotic duration. PET-CT scans offer a comprehensive assessment of infection localization assisting clinicians in identifying occult foci of infection.

Disclosures

All Authors: No reported disclosures
P-818. Unraveling Mortality Drivers in Gram-negative Bloodstream Infections to Guide Antimicrobial Stewardship Efforts
Authors: Burgess David S , Olney Katie B , Burgess Donna R , Cotner Sarah , VanHoose Jeremy , Turner Leah Catherine , Bruning Rebecca
Published: January 2025

Background

Bloodstream infections (BSIs) represent a significant clinical challenge due to their association with substantial morbidity and mortality. This study aimed to identify predictors of mortality in Gram-negative BSIs to guide more effective antimicrobial stewardship strategies.

Methods

Adult inpatients with Gram-negative BSIs from our academic medical institution between July 2022 and August 2023 were included. Data collected included patient demographics, microbiological data, clinical management variables (qPitt, Charlson Comorbidity Index (CCI), ICU admission, length of stay), ID consultation, and clinical outcomes. Logistic regression and CART analysis identified mortality predictors.

Results

In total, 441 predominately Caucasian patients (85.7%), with a mean age 58.5 yrs and 49.4% male, were included. Majority (61.5%) of infections were community-acquired, with 43.1% requiring ICU admission and 43.8% receiving an ID consultation. Overall mortality was 20.0% with the following prevalence and mortality rates: E. coli (39.7%, 14.9%), K. pneumoniae (14.1%, 17.7%), P. aeruginosa (9.1%, 35.0%), S. marcescens (7.5%, 24.2%), and E. cloacae (5.2%, 17.4%). Multivariable regression identified hospital-acquired infection (p < 0.001), qPitt > 2 (p < 0.001), and ICU admission (0.001) as independently associated with increased mortality. Additionally, renal disease (p=0.025), cancer (p = 0.026), and cardiovascular disease (p=0.040) were significant contributors to mortality. CART highlighted ICU admission as the primary driver of mortality, with higher mortality rates compared to non-ICU admissions (32.1% vs 10.8%, p< 0.001). Among ICU patients, a CCI >4 was identified as a secondary driver of mortality, with rates of 14.5% for CCI < 4 and 39.0% for CCI >4, p=0.001. Non-ICU patients with a length of stay < 8 days had lower mortality (3.3% vs 16.6%, p = 0.001). ICU patients received fewer ID consultations compared to non-ICU patients (49.3% vs 36.7%, p =0.007).

Conclusion

This study underscores the impact of Gram-negative BSIs, particularly regarding ICU admission’s role in mortality. Addressing disparities in ID consultations offers opportunities for optimization of patient outcomes through enhanced care coordination.

Disclosures

Sarah Cotner, PharmD, BCPS, Gilead Sciences, Inc: Advisor/Consultant
P-820. Impact on outcomes and detection of Infective Endocarditis in patients with Staphylococcus aureus bacteremia following an Infectious Disease Consultation: A Quasi-experimental study
Authors: Kumar Deepak , Kaur Navneet , Bohra Gopal Krishna , Kumar Midha Naresh , Meena Durga Shankar , Deora Surender , Choudhary Rahul , Tak Vibhor , Neetha T R , kanagiri Tejasvi , Khatod Yash
Published: January 2025

Background

Staphylococcus aureus Bacteremia (SAB) is associated with high morbidity and mortality ranging from 10-40% with an in-hospital mortality of 13-50%. The primary concern is its ability to cause metastatic complications in as many as 53% of cases which contributes to poor prognosis. The positive impact of formal Infectious Disease consultation (IDc) in SAB management is a well-known concept in Western Countries.

The published data from developing countries is limited, with particularly no studies available from India.

The present study was undertaken to know the impact of ID consultation on outcomes and detection of IE in SAB patients

Workflow of ID Consultation in SAB cases

Methods

This was a quasi-experimental study carried at a tertiary care centre of Western India after approval from Institutional Ethical Committee (IEC).

Inclusion criteria: All hospitalised patients with confirmed blood stream infections (BSI) due to Staphylococcus aureus

Exclusion criteria: Patients with Polymicrobial BSI, with documented SAB in previous 12 weeks and patients surviving ≤72 hours after positive index blood culture

The data of SAB with ID consultation was collected prospectively between January 2023-December 2023 and the data without IDc was collected retrospectively from January 2021 – December 2022. Informed consent was taken from every study participant; however, IEC waived the requirement for informed consent for the retrospective two-year data of SAB.

The primary and secondary outcomes were analyzed

The workflow of ID consultation is summarised in Fig. 1

Baseline characteristics of patients with Staphylococcus aureus bacteremia

Results

A total of 55 patients were diagnosed with SAB in IDc group and 45 were included in final analysis.

A total of 180 patients were diagnosed with SAB in retrospective data who had no access to IDc and 148 were included in final analysis.

Table 1 shows the comparison between demographic profile, co-morbidities and risk factors associated with SAB cases in IDc group vs no IDc group. Most of them were comparable except Diabetes mellitus and Steroid use which was higher in IDc group.

Table 2 depicts statistically significant difference between primary and secondary outcomes among IDc group in comparison to no IDc group.

Primary and Secondary outcomes in patients with SAB

Conclusion

Timely ID consultation in cases of SAB is prudent as this can help in streamlining the management and can bring out improved outcomes for patients.

Disclosures

All Authors: No reported disclosures
P-822. Unraveling the Landscape of Staphylococcus aureus Bloodstream Infection: Insights from a Single-Center Study
Authors: Naguthevar Santhanam , Kaur Navneet , Neetha T R , Khatod Yash , kanagiri Tejasvi , Kumar Bhuvanesh , Ravindra Akshatha , Tak Vibhor , Kumar Deepak , Meena Durga Shankar , Kumar Midha Naresh
Published: January 2025

Background

Staphylococcus aureus significantly impacts human health, with global prevalence ranging from 13% to 74% and 37% in India. By delving into the intricacies of this bloodstream infection, we aim to provide valuable insights into its manifestations, risk factors, and antibiotic sensitivities, crucial for guiding tailored treatment strategies and optimizing patient outcomes.

Methods

Between February 2022 and January 2024, a prospective observational study was conducted at AIIMS, Jodhpur, India, encompassing all blood culture-positive Staphylococcus aureus patients, with comprehensive collection of clinical, epidemiological, microbiological, and outcome data.

Results

In our study, we observed a diverse demographic distribution among Staphylococcus aureus bloodstream infection cases. The most common age group affected was 1-20 years, comprising 29.82% of cases, followed closely by individuals aged 21-40 years (24%), 41-60 years (23.27%), and those over 60 years old (22.91%).

Clinical manifestations varied, with Hospital-Acquired Pneumonia (HAP) being the most common syndrome at 31.27%, followed closely by Central Line-Associated Bloodstream Infection (CLABSI) at 27.27%. Other prevalent syndromes included Community-Acquired Pneumonia (CAP; 17.45%), Bone & Joint infections (22.54%), Meningitis (10.18%), Urinary Tract Infection (UTI; 2.54%), Skin and Soft Tissue Infections (SSTI; 4%), and Endocarditis (4%).

Regarding Staphylococcus aureus strain types, Methicillin-Sensitive Staphylococcus aureus (MSSA) constituted the majority of cases at 55.64%, followed by Methicillin-Resistant Staphylococcus aureus (MRSA) at 42.54%, and Vancomycin-Resistant Staphylococcus aureus (VRSA) at 1.82%.

Among the recorded outcomes, the majority of patients (78.54%) showed improvement following treatment, while 16.36% of patients succumbed to the infection. Additionally, 5.09% of patients were lost to follow-up.

Conclusion

Despite progress, many patients succumbed or were lost, highlighting the need for vigilant monitoring and enhanced treatments. Our study underscores the urgency to improve outcomes and curb Staphylococcus aureus infections.

Disclosures

All Authors: No reported disclosures
P-823. Navigating Staphylococcus aureus Bloodstream Infections in Pediatrics: A Comprehensive Analysis
Authors: Naguthevar Santhanam , Tak Vibhor , Abhishek Kumar S , Khera Daisy
Published: January 2025

Background

Staphylococcus aureus bacteraemia poses substantial morbidity and mortality risks in children, with infection rates ranging from 1.5 to 3.5 per 1000 hospitalizations. Diagnosis and management of Staph. aureus is challenging. This study aims to delineate the spectrum of Staph. aureus bloodstream infections (BSI) in paediatric patients, aiding in the development of more effective management strategies.

Methods

Conducted at AIIMS, Jodhpur, India, from February 2022 to January 2024, this prospective observational study gathered clinical and microbiological data from 82 patients with Staphylococcus aureus BSI.

Results

In this study, the most commonly affected age group was children under 5 years, constituting 39.02% of cases, followed by those aged 11 to 15 years (31.71%), 16 to 20 years (17.07%), and 6 to 10 years (12.19%).

In the observed clinical syndromes, the most common was bone and joint infections, affecting 34.15% of patients, followed by healthcare-associated pneumonia (HAP) at 30.49%. Meningitis was observed in 13.41% of cases, while community-acquired pneumonia (CAP) accounted for 17.07%. Central line-associated bloodstream infections (CLABSI) were reported in 7.32% of patients, with skin and soft tissue infections (SSTI) noted in 3.66% of cases. Urinary tract infections (UTI) represented the least common, affecting 1.22% of patients.

Methicillin Resistant Staphylococcus aureus was present in 54.88% of cases, followed by Methicillin Sensitive Staphylococcus aureus at 40.24%, and Vancomycin Resistant Staphylococcus aureus at 4.88%.

In terms of outcomes, the majority of patients, constituting 75.61%, experienced improvement in their condition. Unfortunately, 21.95% of patients succumbed to the infection, while a small proportion, accounting for 2.44%, were lost to follow-up.

Conclusion

MRSA underscores the challenges posed by antimicrobial resistance. Our comprehensive analysis of Staphylococcus aureus bloodstream infection reveals multifaceted challenges in its management..

Disclosures

All Authors: No reported disclosures
P-833. The trends of hospital-onset bacteremia at a tertiary care center and the impact of the establishment of infectious diseases department on its incidence: a 10-year longitudinal study
Authors: Kawamoto Yuya , Doi Yohei , Honda Hitoshi
Published: January 2025

Background

Hospital-onset bacteremia (HOB) is defined as the onset of bacteremia occurring three or more days after hospitalization. The incidence density of HOB has recently been used to assess the quality of overall hospital infection control practice in lieu of the central line-associated bloodstream infection incidence rate since the HOB incidence might better predict the length of stay, hospital costs, and mortality rates. At the study institution, Infectious Diseases (ID) department was established in April 2018. The present study aims to investigate the incidence density of HOB prior to and after the establishment of ID department.

Change and trend of the incidence density of HOB before and after the establishment of ID department as determined by ITSA.

Methods

We investigated the monthly incidence density of HOB per 1,000 patient-days from 2013 through 2023 at Fujita Health University Hospital. The trends of overall incidence of HOB and HOB by causative pathogens group, including Streptococcus species (spp), Staphylococcus aureus, Coagulase-negative staphylococci (CNS), Enterococcus spp., Enterobacterales, and Candida spp. were tracked. Changes in the trend of HOB before (from July 2013 through March 2018) and after (from April 2018 through June 2023) the establishment of ID department were evaluated. Interrupted time series analysis was used for statistical analyses.

Change and trend of the incidence density of HOB before and after the establishment of ID department as determined by ITSA.

Results

In total, 4,422 HOB events were identified during the study period. The overall incidence density of HOB was 0.94 per 1,000 patient-days. Comparison of the incidence of HOB between the period before and after the establishment of ID department revealed an immediate increase in the incidence of overall HOB (+0.3246; P< .001 for change in level) and HOB caused by S. aureus (+0.10; P< 0.001 for change in level), CNS (+0.12; P< 0.001 for change in level), and Candida spp. (+0.05; P=0.03 for change in level). A significant trend increase in the incidence of HOB was also observed in HOB due to S. aureus (+0.002; P< .001 for change in trend) Candida spp. (+0.002; P=0.002 for change in trend), and Enterobacterales (+0.002; P=0.002 for change in trend).

Conclusion

The overall incidence density of HOB has increased significantly in the last decade, and the trend was steeper after the establishment of ID department. Improvement in ID clinical practice may contribute to increasing the detection of HOB.

Disclosures

Yohei Doi, MD, PHD, AbbVie: Honoraria|Entasis: Grant/Research Support|Gilead: Advisor/Consultant|GSK: Advisor/Consultant|Meiji Seika: Advisor/Consultant|Moderna: Advisor/Consultant|Pfizer: Advisor/Consultant|Shionogi: Advisor/Consultant|Shionogi: Honoraria Hitoshi Honda, MD, Moderna Inc: Honoraria|Pfizer: Honoraria|Shionogi: Honoraria
P-834. Epidemiology and Duration of Therapy in Patients with Gram-negative Bloodstream Infections: Retrospective Analysis 2.15.0.02.15.0.0
Authors: Al Lawati Hawra J , Earle Ellen , Lee Matthew S
Published: January 2025

Background

Longer courses of antibiotics can be associated with antimicrobial resistance and adverse effects. Randomized clinical trials support treating uncomplicated gram-negative bloodstream infections (GN-BSI) for a shorter duration with a consensus that a seven-day course of antibiotics is appropriate. Prior to the implementation of a GN-BSI treatment guideline at our institution, we aimed to assess the characteristics of patients with GN-BSI and the duration of antibiotic therapy (DOT).

Methods

We retrospectively reviewed adult inpatients with GN-BSI over a period of 6 months. Patients were excluded if they had a concomitant gram-positive bloodstream infection or if they were transitioned to comfort-focused care within 48 hours of their first positive blood culture. Complicated GN-BSI was defined as having any of the following: bone, joint, endovascular, or foreign body involvement, lack of source control, immunocompromised status, or failure to show clinical improvement or culture clearance within 72 hours. The primary outcome was the mean DOT in patients with GN-BSI.

Results

100 patients met the inclusion criteria. Escherichia coli (54 cases) was most frequent organism. Urine (41) was the predominant source of bacteremia. Cefepime (48) was the most common empiric antibiotic. Of the 91 patients with available ceftriaxone susceptibility results, 84% had a susceptible organism. Of the 51 patients with a complicated GN-BSI, the leading cause was immunosuppression. Table 1 presents a comparative analysis of complicated vs. uncomplicated GN-BSI. Complicated GN-BSI had longer DOT (20 vs. 11 days, P< 0.005) and fewer patients transitioned to oral therapy (33% vs. 67%, P< 0.005).

Conclusion

At our institution, patients with uncomplicated GN-BSI have a shorter DOT and are more likely to transition to oral therapy than those with complicated GN-BSI. However, the mean DOT for uncomplicated infections remained longer than seven days and a large number of uncomplicated GN-BSI patients did not transition to oral therapy, indicating room for improvement in local practice through antimicrobial stewardship initiatives.

Disclosures

All Authors: No reported disclosures
314. Ceftazidime-Avibactam Versus Meropenem-Vaborbactam for the Treatment of Carbapenem-Resistant Enterobacterales Infections
Authors: Karaba Sara M , Hareza Dariusz A , Hawes Armani , Bergman Yehudit , Fiawoo Suiyini , Hyoung Lee Jae , Cosgrove Sara E , Simner Patricia J , Tamma Pranita
Published: January 2025

Background

Infections due to carbapenem-resistant Enterobacterales (CRE) are increasing in the United States, most commonly the result of Klebsiella pneumoniae carbapenemase (KPC) production. Both ceftazidime-avibactam (CZA) and meropenem-vaborbactam (MVB) are preferred treatment options for CRE infections but comparative effectiveness data to assist clinicians with preferentially selecting between these agents are limited.

Baseline characteristics of 118 patients treated with ceftazidime-avibactam or meropenem-vaborbactam for carbapenem-resistant Enterobacterales

Methods

We conducted an observational study of patients with CRE infections between 2018–2023 who received ≥ 3 days of CZA or MVB across five Maryland hospitals. Susceptibility to the administered agent (i.e., CZA or MVB) was required for eligibility. Inverse probability weighting (IPW) using propensity scores was used to assess the primary outcome of 30-day mortality. Development of resistance (i.e., ≥ 4-fold increase in MIC of the agent used to treat the index infection) within 90 days assessed by broth microdilution was a secondary outcome.

Baseline characteristics of 75 patients treated with ceftazidime-avibactam or meropenem-vaborbactam for carbapenem-resistance Enterobacterales that harbored KPC genes

Results

In the entire cohort there were 95 and 23 patients in the CZA and MVB groups, respectively. Balance was achieved across all variables in the IPW cohort (Table 1). 30-day mortality was similar between the antibiotic groups comparing CZA to MVB (aOR 0.997, 95% CI 0.86–1.63, p=0.97) and in the subgroup of 75 patients with isolates with an identified blaKPC gene present who underwent IPW with good balance achieved (Table 2) (aOR 1.02, 95% CI 0.85–1.21, p=0.87).

Conclusion

In a cohort of patients with CRE infections treated with either CZA or MVB, 30-day mortality was similar. The frequency of subsequent emergence of resistance is currently being investigated.

Disclosures

Sara M. Karaba, MD, PhD, MHS, Entasis: Advisor/Consultant Patricia J. Simner, PhD, Affinity Biosensors: Grant/Research Support|BD Diagnostics: Grant/Research Support|bioMérieux: Grant/Research Support|Entasis: Personal fees|GeneCapture: Personal Fees|Merck: Personal fees|OpGen Inc: Grant/Research Support|Qiagen: Grant/Research Support|Shionogi: Personal fees|T2 Biosystems: Grant/Research Support
P-864. Systematic Review and Meta-analysis of the Impact of Infectious Diseases Consultation on Management and Outcomes of Staphylococcus aureus Bacteremia in Children
Authors: Santhanam Haripriya , Muthukumarasamy Nirmal , Hsieh Mariana Kim , Brust Karen , Wellington Melanie , Naito Toshio , Samuelson Riley J , Marra Alexandre , Kobayashi Takaaki
Published: January 2025

Background

Staphylococcus aureus is a common cause of both community-acquired and nosocomial bacteremia in children. Multiple studies evaluating the role of infectious disease consultation (IDC) in adult patients with Staphylococcus aureus bacteremia (SAB) have shown a protective effect of IDC on mortality and recurrence rates. However, there is limited data available regarding the impact of IDC on outcomes of SAB in the pediatric population.

Literature Search on the Impact of Infectious Disease Consultation in Pediatric Patients with Staphylococcus aureus Bacteremia

Methods

This systematic literature review and meta-analysis were performed per the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement and the Meta-Analysis of Observational Studies in Epidemiology (MOOSE) guidelines. A search strategy to identify publications about SAB and IDC in children was developed in collaboration with a health sciences librarian. The primary outcomes were all-cause mortality and SAB recurrence rates. Crude or unadjusted numbers were used for the pooled odds ratios (ORs) as adjusted ORs were not available in all articles.

Meta-analysis of outcomes of Staphylococcus aureus Bacteremia in pediatric patients

Results

Among 972 articles screened, 8 studies were included in the systematic review, of which, 2 were retrospective cohort studies, 2 were prospective cross-sectional studies, and 4 were quasi-experimental studies. The quality of 6 studies was considered good ( >18 of 28 possible points) per the Downs and Black quality tool while two studies were considered fair (15 – 18 points). Five of 8 studies directly evaluated the impact of IDC on outcomes in pediatric SAB and included in the meta-analysis. Pooled results showed IDC was associated with significantly lower mortality in pediatric SAB with low heterogeneity (pooled OR = 0.44, 95% confidence interval [CI]: 0.20−0.97, I2 = 0%). IDC was associated with lower recurrence rates, however this was not statistically significant with moderate heterogeneity (pooled OR = 0.24, 95% CI: 0.04 to 1.34, I2 = 56%).

Funnel Plot of Mortality and Recurrence in Pediatric Patients with Staphylococcus aureus Bacteremia

Conclusion

Our study suggests that IDC significantly improves the mortality of pediatric patients with SAB. Given there have been only five papers evaluating the same topic, with most being retrospective studies at a single center, a multicenter prospective study will be required. Our study provides a strong argument in favor of policies such as “automatic” IDC for children with SAB.

Disclosures

All Authors: No reported disclosures
P-866. Epidemiology and Risk Factors for Mortality in Clostridial Bacteremia: A Retrospective Multicenter Observational Study
Authors: Okazaki Aiko , Okugawa Shu , Kobayashi Tatsuya , Kawada Miki , Kawase Kyotaro , Nakayama Shin , Wakabayashi Yoshitaka , Kitazawa Takatoshi , Takezawa Riko , Tatsuno Keita , Koyano Saho , Higurashi Yoshimi , Ikeda Mahoko , Harada Sohei , Tsutsumi Takeya
Published: January 2025

Background

Clinical studies on clostridial bacteremia are scarce, and the factors associated with mortality have not been well investigated. Furthermore, the distribution of Clostridium species varied among studies. To investigate the epidemiology of clostridial bacteremia and the factors associated with mortality, we conducted a study in Japan.

Methods

This multicenter, retrospective, observational study was conducted in four Japanese hospitals. Patients with bacteremia in whom Clostridium spp. were detected in blood cultures between 2007 and 2021 were included. Only the first episode of infection was included and blood culture contamination was excluded. Clinical data were collected from the electronic medical records of each hospital. Comparisons between survival and death groups were performed to identify risk factors associated with in-hospital mortality.

Results

A total of 278 patients were included in the study. C. perfringens was the most common species (52.9%), followed by C. ramosum (9.7%) (Table 1). The median age of the patients was 77 years, and 61.9% were male. Comorbidities included malignancy (38.1%), diabetes mellitus (29.9%), and gallstones (18.0%). More than 50% of the infections were community-acquired (68.0%). Polymicrobial bacteremia was present in 56.8% of patients. The most common source of infection was the intestinal tract (30.2%) followed by the biliary tract (23.0%). The median Pitt bacteremia score of the patients was two. The in-hospital mortality rate was 25.9%. Of these, 34.7% died within three days of positive blood culture. Mortality rates did not differ significantly between C. perfringens and non-C. perfringens. The independent risk factors for in-hospital mortality were hepato-pancreato-biliary malignancy, chronic heart failure, Pitt bacteremia score, acute renal failure, and pneumonia as the source of infection (Table 2).

Conclusion

C. perfringens was the most common pathogen, but the distribution of other species differed from those reported in other studies. More than one-third of all in-hospital deaths occurred within three days of positive blood culture. To improve prognosis, it is necessary to elucidate the pathogenesis of bacteremia in the early acute phase and develop therapeutic strategies.

Disclosures

Sohei Harada, MD, PhD, MSD: Honoraria|Shionogi: Honoraria
P-867. Carbapenem-resistant gram-negative bacterial infections in South India: A four-year retrospective study
Authors: Dorairajan Suresh Kumar , Rajakumar Ratheesh
Published: January 2025

Background

Carbapenem-resistant Gram-negative bacteria (CRGNB) posed a global healthcare threat due to antibiotic resistance. In India, carbapenem resistance surged, and Ceftazidime–avibactam (CAZ-AVI) and Aztreonam (AZT) saw increased use without efficacy data. Previous international studies comparing polymyxins with CAZ-AVI plus AZT highlighted the need for region-specific evaluation. Here, we report the epidemiological, clinical, and treatment outcomes of patients admitted with CRGNB infections in a South Indian tertiary care referral hospital.

Common CRO'S reported during the study period

Methods

This retrospective study was conducted at a 250-bed tertiary care referral hospital in South India. Over the last four years (2019 to 2023), we identified all blood culture results indicating the growth of carbapenem-resistant Gram-negative bacteria (CRGNB). Subsequently, we systematically reviewed the medical records of these patients, focusing on demographical, clinical, microbiological, and outcome data. Blood cultures utilized the BacT/ALERT (Biomerieux) culture system, and species identification was accomplished with the VITEK GNI card (Biomerieux). Antibiotic susceptibility testing followed the revised Clinical and Laboratory Standards Institute performance standards. Data were entered into an Excel spreadsheet, and descriptive statistics were employed for data interpretation.

Results

The study comprised 122 patients with positive blood cultures for carbapenem-resistant Gram-negative bacteria (CRGNB), with 70.50% males and 29.50% females, averaging 58.3 years. Common CRGNBs were identified, as shown in Figure 1. Minimum Inhibitory Concentrations (MICs) for colistin were available on 34.4% occasions. CRGNBs exhibited a 41% mortality rate. Combinational therapy (n=79) for CR showed lower mortality than monotherapy (n=43), especially Colistin monotherapy (72% mortality) and Polymyxin B (20%) compared to ceftazidime avibactam + aztreonam (14%) mortality.

Conclusion

A 41% mortality rate was noted in patients with CRGNB infections in South India, with significantly higher mortality (72%) associated with colistin monotherapy. Future strategies should focus on the role of combination therapies to enhance patient outcomes in the context of CRGNB infections.

Disclosures

All Authors: No reported disclosures
365. Amoxicillin Direct Oral Challenge in Patients with High-Risk Allergic Reaction
Authors: Le Bryan , Joshi Shyam , Ham YoungYoon
Published: January 2025

Background

Historically, penicillin skin testing (PST) has been the first step in allergy evaluation, followed by an oral challenge (OC). Recently, there have been studies looking at the safety of direct OC in patients without a prior PST, mostly in patients with a history of a mild reaction, such as distant rash or unknown reactions. There is, however, a paucity of data for OC without a PST for patients who report a high-risk reaction to penicillin. Our hospital protocol allows for OC without PST of patients who have had a severe IgE-mediated reaction, as long as the reaction occurred more than 10 years ago.

Methods

Patients over the age of 18 admitted with a high-risk penicillin allergy who were tested with a direct OC were included. High-risk reactions include anaphylaxis, angioedema, hives, as well as shortness of breath. Patients that had a PST prior to an OC or did not have a penicillin allergy were excluded. Data collected were age at the time of challenge, reported allergy and historic reaction, presence of other high-risk allergies, onset to symptoms, time since last reaction, and result of OC. If the challenge resulted in a reaction to penicillin and inability to de-label the allergy, data on reaction and use of rescue medications were also collected.

Results

Of the 288 patients who had received an OC at our institution, 9 were excluded due to prior PST and 2 were excluded due to a non-penicillin allergy. One hundred eight were additionally excluded due to their initial allergic reaction not being high-risk. One hundred sixty-nine patients were included in the analysis. Of the 169 patients with a history of high-risk reactions, 46 patients specifically reported anaphylaxis and 34 patients reported angioedema. One hundred and fifty-nine patients (94.1%) passed the OC and had the allergy de-labeled. Of the 10 patients (5.9%) who reacted during the OC, 3 required diphenhydramine and one required albuterol. The rest did not require the use of rescue medications and were simply observed until the reaction passed. Epinephrine was not used for any patient as a rescue medicine.

Conclusion

Direct OC without a prior PST for patients who report a high-risk allergic reaction to penicillin drugs is reasonable after 10 years have passed from the initial reaction.

Disclosures

YoungYoon Ham, PharmD, Gilead: Honoraria
P-879. Predicting Antimicrobial Resistance and Empiric Treatment Failure in Hospital-Onset Sepsis Using Machine Learning on Electronic Health Records
Authors: Cohen Scott A , Morris John G , Prosperi Mattia
Published: January 2025

Background

Antimicrobial resistance (AMR) is a major cause of treatment failure in hospital-onset sepsis. Approaches to guide empiric antimicrobial therapy are urgently needed. We utilized machine learning to predict empiric treatment failure and AMR patterns within a high-risk hospital-onset sepsis cohort using electronic health records (EHRs).

Methods

We examined hospitalizations with documented bacterial infection from 2010 to 2023 at a tertiary-care academic hospital system. Hospital-onset sepsis was defined using CDC Adult Sepsis Event criteria. Empiric therapy was considered adequate if all pathogens isolated were susceptible to antimicrobials administered. AMR patterns included methicillin (MRSA), extended-spectrum beta-lactamase (ESBL), vancomycin (VRE), ceftriaxone, and carbapenem (CRE). Features for prediction were patient characteristics, hospitalization details, and clinical severity metrics measured within 24 hours prior to sepsis onset. Linear and non-linear machine learning models were evaluated using bootstrap validation and out-of-bag area under the receiver operating characteristic curve (AUC).

Results

Among 49,581 hospitalizations, 2019 (4%) hospital-onset sepsis encounters were identified. Mean (SD) age was 65 (16.4) years and 900 (45%) were female. At 24 hours after sepsis onset, 377 (19%) received inadequate empiric treatment and 911 (45%) infections expressed AMR. Those who received inadequate empiric treatment were 8.2 (95%CI: 6.2-10.9) times more likely to have an AMR infection. Random forest model was best-performing, with AUC (95%CI) for any AMR pattern, VRE, and CRE at 0.64 (0.63-0.64), 0.71 (0.69-0.72), and 0.70 (0.67-0.73), respectively. The AUC (95%CI) for predicting inadequate empiric antimicrobial treatment was 0.65 (0.64-0.66) with a sensitivity of 64% (58-69%) and specificity of 52% (46-68%) at optimal probability thresholds.

Conclusion

In a hospital-onset sepsis cohort with prevalent AMR, machine learning approaches utilizing limited EHR data accessible at initial sepsis recognition had moderate, but clinically insufficient, discriminatory ability in predicting AMR and empiric antimicrobial treatment failure. Future research will evaluate the utilization of large language models using unstructured EHRs.

Disclosures

All Authors: No reported disclosures
P-881. A Retrospective Review of Enterobacter cloacae complex Bacteremia: 2019-2023
Authors: Harder Samuel , Leitch Maison Z , Lee Bonita , Smith Stephanie W , Stokes William
Published: January 2025

Background

Enterobacter cloacae complex is one of the most common Enterobacterales considered at moderate to high risk for clinically significant AmpC production. AMP-C betalactamases confer resistance to broad spectrum cephalosporins and common beta-lactam betalactamases including Amoxicillin-Clavulanate and Piperacillin-Tazobactam. Carbapenems are often used empirically when this organism is isolated but there is a current gap in the literature regarding in which circumstances non-carbapenem antibiotics can be used safely for patients with enterobacter cloacae complex infections. The aim of this study was to examine independent predictors of mortality for patients with enterobacter cloacae complex bacteremia and identify patients which can appropriately receive non-carbapenem based therapy safely and effectively without negative impacts on mortality.

Methods

We conducted a retrospective analysis of 285 episodes of enterobacter cloacae complex bacteremia. The main outcome measure was mortality at 30 days.The χ2 or Fisher's exact test were used to compare categorical variables. To identify the independent risk factors of infection and mortality, a binary logistic regression model was used to control for the effects of confounding variables.

Results

Of 285 patients 17.5% (50) were deceased at 30 days, 110 patients received a beta-lactam betalactamase inhibitor combination initially and 80 patients received an initial broad spectrum cephalosporin. Of 209 patients for whom antibiotic data was available 73 were changed to a carbapenem within 24 hours of the initial blood culture being drawn. In univariate analysis only source was identified as a statistically significant risk factor for mortality at 30 days. In univariate and multivariate binary logistic regression analysis change to carbapenem within 24 hours of blood culture was not an independent risk factor of death at 30 days.

Conclusion

Change to carbapenem within 24 hours of cultures being taken was not an independent risk factor of 30 day mortality. Further studies are needed to determine in what group broad spectrum cephalosporins or beta-lactam betlactamase inhibitors are appropriate therapy for enterobacter cloacae.

Disclosures

All Authors: No reported disclosures