bluuebunny/crossref_metadata_2025_split huggingface dataset:
P-877. Effectiveness of Oral Step-down Antibiotic Therapy in Uncomplicated Enterococcus faecalis Bloodstream Infection
Authors: Al Mansi Sarah , Pokalsky Margaret , Turnley Katherine , Freeman Andrew , Brandon Bookstaver P , Kohn Joseph , Winders Hana R , Withers Sarah , Al-Hasan Majdi N 
Published: January 2025

Abstract

Background
The transition from intravenous (IV) to oral antibiotic therapy is a common strategy in the management of uncomplicated bloodstream infection (BSI). However, the role of oral step-down therapy in uncomplicated Enterococcus faecalis BSI has not been defined. This retrospective cohort study examines the effectiveness of oral step-down antibiotics compared to standard IV therapy in uncomplicated E. faecalis BSI.
Risk factors for treatment failure in uncomplicated Enterococcus faecalis bloodstream infection (BSI)
*Early clinical failure criteria include systolic blood pressure &lt;100 mmHg or vasopressor use, heart rate &gt;100 beats/minute, respiratory rate ≥ 22 breaths/minute or mechanical ventilation, altered mental status, white blood cell count &gt;12,000/mm3.

Methods
Adults with uncomplicated E. faecalis BSI admitted to 10 Prisma Health hospitals in South Carolina from January 2021 to June 2023 were evaluated. Clinically insignificant positive blood cultures, polymicrobial, recurrent, persistent, and complicated BSI were excluded. Deaths within 7 days were excluded to mitigate immortal time bias. Multivariate Cox proportional hazards regression examined the risk of treatment failure (all-cause mortality or recurrence) within 90-day. Wilcoxon rank sum test compared hospital length of stay (HLOS) between the two groups.

Results
Of 476 screened patients, 131 with uncomplicated E. faecalis BSI were included in the analysis. The median age was 70 years, 84 (64%) were men, and 46 (35%) had a urinary source of infection. Eighty-seven patients (66%) received standard IV therapy and 44 (34%) were transitioned to oral step-down therapy. Median antibiotic treatment durations were 15 and 14 days, respectively. Patients in the oral step-down group received 6 days of IV antibiotics followed by 8 days of oral therapy, most commonly oral aminopenicillins (33/44; 75%). In the multivariate Cox model, oral step-down therapy was not associated with increased risk of treatment failure compared to standard IV therapy (hazard ratio 0.91, 95% confidence intervals 0.31-2.63; Table). HLOS was 7 days in the oral step-down group and 11 days in the standard IV group (p&lt; 0.001).

Conclusion
Transitioning patients with uncomplicated E. faecalis BSI from IV to oral step-down antibiotic therapy appears to be a promising strategy with shorter HLOS and no significant increase in the risk of treatment failure. These results should be confirmed in larger multicenter studies prior to routine implementation in clinical practice.

Disclosures
All Authors: No reported disclosures
P-880. Risk Factors of In-Hospital Mortality among Adult Patients with Burkholderia cepacia Complex Bacteremia Admitted to the Philippine General Hospital: A Retrospective Cohort Study
Authors: Fernandez Sergie Paul Christoffer C , Salamat Maria Sonia 
Published: January 2025

Abstract

Background
Burkholderia cepacia complex (BCC) has emerged as a significant nosocomial pathogen, particularly in immunocompromised patients, leading to various infections with a high mortality rate. There is limited data on BCC bacteremia in the Philippines. Hence, more study is necessary to enhance patient management and outcomes.
This study aims to identify significant risk factors for in-hospital mortality among adult patients with BCC bacteremia at the Philippine General Hospital. Additionally, it seeks to describe clinical characteristics, common foci of infection, and antimicrobial susceptibility patterns of BCC.

Methods
A retrospective cohort study included adult patients admitted to the Philippine General Hospital with documented BCC bacteremia from January 2020 to December 2023. Demographic and clinical data were extracted from medical records, and BCC identification and resistance patterns were determined using the VITEK 2 system and MALDI-TOF technology. Statistical analyses were performed to identify mortality risk factors.

Results
Out of 172 patient charts reviewed, 171 cases were included in the final analysis. Most patients were male, with a mean age of 52.7 years. Central-line associated bloodstream infections (CLABSI) were the most common source of bacteremia. Approximately 65% of cases received inappropriate empirical therapy. Resistance was highest for Meropenem (13.5%), followed by Co-trimoxazole (11.8%), while Ceftazidime and Minocycline showed lower resistance rates. All-cause mortality was 22.2%, with BCC bacteremia accounting for 57.9% of these deaths. Male gender, septic shock, mechanical ventilation, and prolonged duration of ineffective antimicrobial therapy were the significant risk factors for all-cause mortality.

Conclusion
The study revealed a significant in-hospital mortality rate associated with BCC bacteremia, predominantly caused by CLABSI and compounded by high antimicrobial resistance and inappropriate empirical therapy. These findings underscored the need for accurate microbiological diagnostics, appropriate antibiotic usage, and robust infection control practices to improve patient outcomes.

Disclosures
All Authors: No reported disclosures
P-885. Clinical Characteristics and Molecular Epidemiology of Invasive Nontypeable Haemophilus influenzae Disease at a Tertiary Medical Center in Washington, DC
Authors: Stone Stephen , Spence Matthew , Roberts Afsoon , Ruiz Maria Elena , Siegel Marc O , Collins Lauren F , Lohsen Sarah , Satola Sarah W , Yee Rebecca , Lucar Jose A 
Published: January 2025

Abstract

Background
The incidence of invasive nontypeable H. influenzae (NTHi) is on the rise, and NTHi now causes the majority of invasive H. influenzae infections across all age groups. While these presentations are usually among people at the extremes of age, we observed a recent increase in invasive NTHi cases in adults at our institution compared to previous years. Here, we report their clinical presentation and the subsequent molecular epidemiology investigation.
Characteristics of Patients With Invasive Nontypeable Haemophilus influenzae (NTHi) Infection, GW Hospital, December 2022-August 2023
Abbreviations: HIV, human immunodeficiency virus; MSM, men who have sex with men; MSK, musculoskeletal; LOS, length of hospital stay; N/A, information not available; HBV, hepatitis B virus; C1, clonal cluster 1; C2 clonal cluster 2; NC, non-cluster
* in cells/mm3

Methods
We describe the demographics, clinical characteristics, and outcomes of individuals hospitalized at our institution with invasive NTHi disease between December 2022 and August 2023. Invasive NTHi disease was defined as infections beyond the respiratory tract or skin. Data was obtained from retrospective chart abstraction. Available bacterial isolates were sent to the Georgia Emerging Infections Program laboratory for polymerase chain reaction (PCR) and whole genome sequencing (WGS), and were categorized as belonging to clusters 1 or 2 (C1, C2) or as non-cluster, as described previously.

Results
Nine cases [median age 55 (32-76) years, 100% male, 89% Black] were identified. Five individuals were living with HIV (PWH) on antiretroviral therapy, with median CD4 count 348 (range 32-984) cells/mm3, and all except one were virologically suppressed. Six patients identified as men who have sex with men (MSM). Five patients presented with musculoskeletal manifestations. Seven isolates were available for PCR/WGS: one isolate belonged to C1, three to C2, and three as non-cluster. The mean hospital stay was 11 (range 3-28) days. Three patients required admission to the intensive care unit, all of which died.

Conclusion
This case series identified nine patients within a nine-month span presenting with invasive NTHi disease, an abrupt rise from our local historical data. We noted an overrepresentation of PWH and MSM, with over half of isolates belonging to two previously identified clonal clusters associated with similar demographics. Future research is needed to better understand novel transmission routes, clinical characteristics, genotypic relatedness, and geographic spread of invasive NTHi disease.

Disclosures
Rebecca Yee, Ph.D, Biomerieux: Grant/Research Support
P-888. Variability in Durations of Therapy for Gram-Negative Bloodstream Infections Across U.S. Hospitals
Authors: Sutton Jesse , Lee Jae Hyoung , Engers Drew , Fong Karen , Gupta Alok , Karaba Sara M , Malani Anurag , McCoy Christopher , Pillinger Kelly E , Quartuccio Katelyn , Slish Judianne C , Tamma Pranita , Jenkins Timothy C 
Published: January 2025

Abstract

Background
There is a paucity of data on durations of antibiotic therapy utilized in clinical practice for patients with Gram-negative bloodstream infections (GN-BSI). The objectives of this study were to describe treatment durations for patients with GN-BSI and evaluate variability across U.S. hospitals.
Histogram of antibiotic treatment durations

Methods
This was a retrospective cohort study of patients hospitalized at 24 hospitals (16 academic, 4 community, and 4 Veterans Affairs) with a GN-BSI between January 1, 2019 and December 31, 2019. Episodes of GN-BSI from a urinary, intra-abdominal, hepatobiliary, vascular catheter, skin and soft tissue, or respiratory source were included while those associated with a bone, joint, central nervous system, or endovascular infection or prostatitis were excluded. Subgroups of interest were cases of uncomplicated bacteremia and those with underlying immunosuppression. Uncomplicated bacteremia was defined as: (1) achievement of source control, when applicable; (2) absence of immunosuppression; and (3) resolution of fever and hypotension within 3 days.
Variability in median duration of therapy across hospitals

Results
3,956 episodes of GN-BSI were included, of which 2,007 were uncomplicated bacteremia and 1,202 involved underlying immunosuppression. Urinary tract (55%), intra-abdominal (14%), and hepatobiliary (12%) sources accounted for the majority of the infections, while E. coli (53%), K. pneumoniae (12%), and P. aeruginosa (8%) were the most common pathogens. The median duration of therapy in the overall cohort and uncomplicated and immunocompromised subgroups was 12 (interquartile range [IQR] 9 - 15) days, 11 (IQR 8 - 14) days, and 11 (9 - 14) days, respectively (Figure 1). In the overall cohort, there was marked variation in treatment durations across hospitals, with the median duration as low as 5 (IQR 3 - 7) days and as high as 14 (IQR 10 - 17) days (Figure 2). Similar variability was observed in the uncomplicated bacteremia and immunocompromised subgroups.

Conclusion
There is marked variation in treatment durations for GN-BSI across U.S. hospitals. Dissemination of interventions to promote evidence-based short durations of therapy for uncomplicated bacteremia and elucidating the optimal duration of therapy in immunocompromised patients will be necessary to standardize care and reduce unnecessary antibiotic use.

Disclosures
Sara M. Karaba, MD, PhD, MHS, Entasis: Advisor/Consultant Kelly E. Pillinger, PharmD, AHFS: Contractor Judianne C. Slish, Pharm.D., BCPS, Glaxosmithkline Pharmaceuticals: Honoraria
P-902. Etiology, Clinical Characteristics, Prognosis and Outcomes of Acute Central Nervous System Infections: A Prospective Study
Authors: Pillai Ashwin , Godin Shea-Lee , Edul Nazir 
Published: January 2025

Abstract

Background
Various pathogens can cause central nervous system (CNS) infections. Early recognition and treatment significantly improves outcomes. Clinical features and outcomes vary by etiology and clinical phenotype, making diagnosis challenging. We report a single-center experience emphasizing the clinical profile and prognostic factors of this entity.

Methods
We conducted a two-year prospective, observational study at a tertiary care center in Western India. Patients suspected to have CNS infections underwent a standardized workup that included neuroimaging and CSF polymerase chain reaction panel testing. Patients were followed throughout the admission. The outcomes recorded were duration of intensive care unit (ICU) stay, hospital stay, modified Rankin Scale (mRS) at discharge and mortality.

Results
We included 75 patients (53 male, 22 female). The mean age was 43±19 years. Most infections were viral (69%) – 40% encephalitis, 17% meningitis and 12% meningoencephalitis. Viral infections surged in the monsoon and post-monsoon period (Fig. 1). Tuberculous meningitis accounted for 16% cases, pyogenic meningitis for 7%, and cryptococcal meningitis for 5%. Mucor cerebritis and brain abscesses accounted for 3%. Presenting symptoms, CSF, and neuroimaging findings are listed in Fig. 2-4.
Mortality was highest for cryptococcal meningitis (25%); followed by pyogenic meningitis (20%); and viral encephalitis and tuberculous meningitis (16.7% each). Increased risk of mortality was observed with: new-onset seizures (relative risk [RR] 3.58, 95% confidence intervals [CI] 1.03-12.45, p&lt; 0.001); a Glasgow Coma Scale (GCS) &lt; 8 (RR: 6.85, 95% CI 2.00-23.40, p=0.002); and the presence of dilated ventricles on imaging (RR: 5.25, 95% CI 1.99-13.82, p&lt; 0.001).
Increasing age correlated with a longer ICU stay (r=0.37, p&lt; 0.001), hospital stay (r=0.33, p=0.002), and worse functional status at discharge reflected by a higher mRS (p=0.04). GCS at presentation correlated inversely with functional recovery reflected by the mRS at discharge (p&lt; 0.001).
CSF findings varying by etiology
CSF findings varying by etiology

Conclusion
The etiology and prognosis of acute CNS infectious varies by region and season. A detailed history, thorough
physical examination, neuroimaging and CSF analysis are vital as each provides diagnostic and prognostic information.

Disclosures
All Authors: No reported disclosures
370. Swimming Against the Current: Outcomes of Standard versus Modified Outpatient Parenteral Antimicrobial Therapy (OPAT) Services
Authors: Villacorta Cari Evelyn , Mansoor Armaghan-E Rehman , Thornton Alice C , Clemons Alisha , Mynatt Ryan P , Logan Ashley , Burgess Donna R , Soria Jaime 
Published: January 2025

Abstract

Background
OPAT programs enable intravenous (IV) antibiotic treatment outside the hospital, either at home or in an outpatient facility. We established institutional OPAT criteria to identify patients who could safely complete OPAT at home (standard, or S-OPAT) and those with potential barriers (modified, or M-OPAT). The study aims to compare outcomes in both groups.

Methods
We conducted a retrospective cohort study analyzing data collected via OPAT program operations from July 2019 to March 2024. These data were collected using the REDCap electronic data capture system. Statistical analyses were performed with Stata 17.

Results
The analysis included 3,344 patients referred to the OPAT program, with 2,746 (82.1%) assigned to the S-OPAT group and 598 (17.9%) to the M-OPAT group. The median age was similar in both cohorts, and Male patients were 1,583 (58.9%) in S-OPAT and 389 (65.1%) in M-OPAT (p = 0.001). The most prevalent infection treated in both groups was Osteomyelitis: 535 (19.5%) patients in S-OPAT and 156 (26.1%) patients in M-OPAT (p&lt; 0.001), followed by bacteremia at 484 (17.6%) patients in S-OPAT and 107 (17.9%) in M-OPAT (p= 0.859).
A history of IV drug use was reported in 108 (4.0%) patients of S-OPAT and 200 (33.4%) patients of M-OPAT. M-OPAT patients reported barriers such as lack of social support (homelessness, inability to administer antibiotics at home, or requiring additional medical care) in 422(70.6%) patients, incarceration in 58 (9.7%) patients, and antibiotics received during dialysis sessions in 58 (9.7%) patients.
Reported outcomes, including clinical improvement, were not significantly different between these groups [S-OPAT: 2367 (86.2%) vs. M-OPAT: 530 (88.8%); (p=0.11)]. Treatment completed as expected, extended, or discontinued were as follows: S-OPAT 2106 (76.7%) vs. M-OPAT 486 (81.3%), (p=0.015); S-OPAT 398 (14.5%) vs. M-OPAT 67 (11.2%), p=0.037; and S-OPAT 237 (8.6%) vs. M-OPAT 43 (7.2%), p=0.289.

Conclusion
Despite the higher prevalence of social and medical challenges in the M-OPAT cohort, treatment outcomes, including clinical improvement and completion rates, were comparable to those in the S-OPAT group; the study highlights the feasibility and effectiveness of outpatient antibiotic treatment, even in patients facing significant barriers to care.

Disclosures
Alisha Clemons, APRN, Gilead Sciences: Honoraria
P-920. Free-living Ameba Infections Diagnosed by Cell-free DNA Blood Testing – United States, 2018-2023
Authors: Haston Julia C , Imada Erin , Roy Shantanu , Davlantes Elizabeth , Freeland Amy , Ali Ibne 
Published: January 2025

Abstract

Background
Free-living amebae (FLA) including Acanthamoeba spp., Balamuthia mandrillaris, and Naegleria fowleri live in soil and water worldwide and cause severe infections in humans. Approximately 15 people in the United States are infected by FLA each year; most do not survive. Early diagnosis and treatment improve outcomes. Targeted testing options for FLA require tissue or cerebrospinal fluid (CSF) and are offered at &lt; 5 laboratories in the U.S., making it challenging to diagnose infections quickly and non-invasively. Detection of FLA infections via cell-free DNA testing of blood (Karius Test®) has increased in recent years.

Methods
The Centers for Disease Control and Prevention (CDC) maintains a database of confirmed FLA cases reported through the CDC FLA Clinical Consultation Service or national surveillance efforts. This database was used to identify and describe cases in which a Karius Test® first detected an FLA infection.

Results
In 2018-2023, 9 U.S. FLA infections were diagnosed with Karius Test® and reported to CDC, including 4 Acanthamoeba, 4 Balamuthia, and 1 Naegleria case. These represent 10% of FLA cases reported to CDC in this timeframe (9/93). Four of these cases were reported in 2023 (22% of FLA cases in 2023), an increase over previous years. FLA had not been suspected in 8/9 cases before receiving results. Eight patients presented with meningitis or encephalitis; 1 had only skin findings. FLA diagnoses were subsequently confirmed by other methods in 7/7 cases for which tissue or CSF was available. Duration from hospitalization or symptom onset to Karius Test® result was 5-14 days. One patient was diagnosed postmortem; the others were initiated on anti-amebic therapy. No patients ultimately survived, though 3 patients were treated for several weeks.

Conclusion
Cell-free DNA testing (Karius Test®) of blood is increasingly being used to diagnose FLA infections. Nearly all patients described were diagnosed by Karius Tests® before FLA infections had been suspected. Early diagnosis can allow early treatment, inform clinical decision-making, and contribute to the further understanding of FLA infections through surveillance. In patients with suspected FLA infections or encephalitis of unknown etiology, Karius Test® may be useful, particularly when tissue or CSF is not available.

Disclosures
All Authors: No reported disclosures
P-923. Characterization of the use of the FilmArray Molecular panel for the diagnosis of central nervous system infection
Authors: zapata Silvana , Roldan Daniel Montoya , Villa franco Pablo , patricia isaza Sandra , Atehortua Santiago , Zapata Carolina , Lopez estrada Carolina , Trompa Iván 
Published: January 2025

Abstract

Background
The Biofire FilmArray® Meningitis/Encephalitis Panel (FAME) has proven to be a valuable tool for etiological diagnosis. Despite this, we know little about its clinical impact.This investigation aims to characterize the clinical, epidemiological, therapeutic variables and outcomes of adults with suspected meningitis and/or encephalitis (ME) who underwent FAME panel, in two 3rd level hospitals in Medellín-Colombia.
Central nervous system infection diagnosis
Definitive diagnosis based on clinical and microbiologic criteria

Methods
Retrospective cohort study in 257 patients over 16 years of age, with suspected central nervous system infection with less than 4 weeks of symptoms who underwent FAME panel. Comparisons were made between those with positive and negative FAME panel results, and a medical record evaluation committee determined whether central nervous system infection was present.
Identification of pathogens by Film Array meningitis encephalitis
Pathogens identified

Results
57.19% (147) of the patients presented central nervous system infection, with 70 patients (26.07%) with a positive FAME panel result; the most frequent involvement being bacterial meningitis 37 (52.9%), and among those with negative FAME panel it was aseptic meningitis 23 (15.64%) followed by meningeal tuberculosis 15 (10.2%). Altered consciousness (74.3%), fever (63.4%) and headache (63.4%) predominated in the FAME-positive group, as did higher cerebrospinal fluid (CSF) leukocyte count, glucose consumption and hyperproteinorrachia (p =0.0001). A positive FAME panel result was associated with greater modification of empirical to definitive antibiotic therapy and discontinuation of unnecessary antibiotics, while negative results were associated with shorter hospital stays, fewer neurological sequelae, and lower antibiotic consumption.
Of the total number of patients with positive FAME, 9 had a CSF leukocytes of less than 5 cells/mm3. Additionally, of the total, eight (8) had pharmacological or disease-related immunosuppression, and only one case had a positive FAME for Varicella zoster without medical or pharmacological immunosuppression with normal CSF.

Conclusion
FAME panel in the appropriate context can provide valuable information for decision-making in patients with suspected central nervous system infection; a rational use and restrictive criteria in prescription could improve the benefits without incurring in excessive costs.

Disclosures
All Authors: No reported disclosures