bluuebunny/crossref_metadata_2025_split huggingface dataset:
P-1464. Clinical Outcomes of patients with Infection Secondary to VancomycinResistant Enterococci (VRE)
Authors: Alqura’an Anood , Al khouri Zaid , VanNatta Mollie , Munshi Ruhul , Malek Alexandre 
Published: January 2025

Abstract

Background
Daptomycin dose dependent VRE infection is a growing clinical challenge to patients and healthcare providers. In this study, we sought to describe patients with infections secondary to Daptomycin-susceptible and dose-dependent VRE.

Methods
We conducted a retrospective cohort study of adult patients admitted at Ochsner LSU Health Shreveport- Academic Medical Center who were diagnosed with VRE infections between 2019 and 2024. We evaluated risk factors, comorbidities, treatment regimens and clinical outcomes of VRE infections with daptomycin MIC 4 mcg/ml (group 1) vs those with VRE daptomycin MIC &lt; 4 mcg/ml (group 2).

Results
Out of 85 patients with different VRE infections, 42 (49.41%) had a daptomycin MIC = 4, while 41 (48.23%) had a daptomycin MIC &lt; 4. Different sources of VRE infections were identified among the two groups. Polymicrobial infection rates were 54.76% in group 1 and 60.97% in group 2. History of previous infection with vancomycin-sensitive Enterococcus was observed in 12% of group 1 and 17% of group 2. The majority of Enterococcus isolates were E. faecium: 97.6% in group 1 and 58.5% in group 2. Comparable factors between the two groups included the presence of external lines, coexisting chronic kidney disease (CKD), and previous beta-lactam use. The targeted antibiotics included daptomycin only, linezolid only, or a combination of either one with ceftaroline or a beta-lactam. The duration of daptomycin treatment was 23.86 days in group 1 and 21.8 days in group 2. In group 1, 80.95% received a daptomycin dose higher than the standard dose of 6 mg/kg, compared to 46.34% in group 2. A dose of 10 mg/kg was significantly observed in 33.3% of group 1 and 9.8% of group 2. The 30-day mortality rate in group 1 (MIC = 4) was 11.90%, whereas in group 2 (MIC &lt; 4), it was 14.63%.

Conclusion
Our data revealed a higher incidence of VRE infections with a MIC = 4 mcg/ml among Enterococcus faecium species. Additionally, VRE infections with a higher MIC = 4 were associated with comorbidities such as chronic kidney disease and the presence of external devices and central venous catheters. Understanding these risk factors can aid in identifying high-risk patient populations and implementing targeted preventive measures.

Disclosures
All Authors: No reported disclosures
P-1469. Clinical Impact of Adherence to an Institutional Guideline for Multi-Drug Resistant Gram-Negative Infections
Authors: Cox Alyssa , Minor Sarah , Carr Amy L 
Published: January 2025

Abstract

Background
After publication of the IDSA Guidance on the Treatment of Antimicrobial Resistance Gram-Negative Infections, AdventHealth Central Florida implemented institutional pathways for treating MDR Gram Negative Infections. This study aimed to assess patient outcomes based on adherence or nonadherence to institutional pathways for MDR gram-negative infections.

Methods
This single center retrospective study reviewed hospitalized patients from August 2022 to April 2023. Patients were included if they were at least 18 years of age, hospitalized for at least 72 hours, and had an infection included in the institutional pathways for MDR Gram Negative Infections. Patients were excluded if they had multiple MDR gram-negative organisms or an extended-spectrum beta-lactamase-producing Enterobacterales. Data was collected by manual chart review. Cases which received antimicrobial therapy (drug and dose) aligned with the institutional pathway were classified as adherent. Statistical analysis were performed using StataSE.

Results
Of 1510 patients identified, 52 cases were eligible for inclusion (adherent: n = 22, non-adherent: n = 30). Patient characteristics were similar between groups (Table 1). The most common source of infection was abdominal or respiratory. Difficult-to-treat Pseudomonas was the most common pathogen. The primary outcome, clinical cure, was achieved in 22 (73%) patients in the adherent group and 30 (70%) patients in the non-adherent group (p = 0.830). Outcomes were similar for microbiologic cure, 30-day readmission, length of stay, and incidence of C. difficile infection (Table 2).
Mortality was higher in the adherent group (45% vs 20% p = 0.049) and there were fewer recurrent infections in the adherent group (5% vs 30% p = 0.021). These findings may be attributable to differences in infection source, source control, or severity of illness which were not evaluated in this study. Results support future investigation of pathway-guided care in larger scale study with a comprehensive review of factors influencing antimicrobial selection and clinical outcome.

Conclusion
This review of hospitalized patients with MDR gram-negative infections supports the need for larger scale studies to determine if adherence to pathway-guided care can impact clinical outcomes.

Disclosures
Amy L. Carr, PharmD, BCIDP, Entasis: Advisor/Consultant|Ferring: Advisor/Consultant|Gilead: Advisor/Consultant|InflaRx: Advisor/Consultant|LaJolla: Advisor/Consultant|Melinta: Advisor/Consultant|MicroGenDx: Advisor/Consultant|Shionogi: Grant/Research Support
P-1474. Antimicrobial Therapy of Enterococcus faecium Bacteremia: A Retrospective Comparison of Outcomes with IV or Oral Antimicrobial Therapy
Authors: Contag Caitlin A , Kalaycıoğlu Müge , Shen Sa , Salinas Jorge , Ha David R , Holubar Marisa , Bonilla Hector F 
Published: January 2025

Abstract

Background
Enterococci are one of the most common causes of hospital-associated infections. Enterococcus faecium has particularly been associated with prolonged hospitalizations, frequent comorbid conditions, and high rates of mortality.

Methods
This is a single-center, retrospective study of antibiotic use and outcomes in adult patients with Enterococcus faecium bacteremia from 2018-2022.

Results
111 patients had monomicrobial E. faecium bacteremia. The median age was 58 years (IQR 46.5, 68.5 years) and 63/111 (57%) of patients were male. Of isolates that underwent susceptibility testing, 15/109 (14%) were susceptible to ampicillin and 33/109 (30%) were susceptible to vancomycin. The median length of hospitalization for E. faecium bacteremia was significantly longer than for E. faecalis bacteremia (26 days versus 12 days, p&lt; 0.01). Nearly a third of patients with E. faecium bacteremia died or were discharged to hospice during their index hospitalization (34/111, 31%) compared with 24/136 (18%) of patients with E. faecalis bacteremia (p=0.017). The 30-, 60-, and 90-day mortality was 25%, 32%, and 36% for E. faecium bacteremia and 15%, 18%, and 25% for E. faecalis bacteremia.
Most patients with E. faecium bacteremia were treated with only intravenous (IV) antibiotics. Of the patients who received E. faecium directed antimicrobial therapy, 35/106 (33%) received a combination of IV and oral antimicrobials. Patients treated with IV therapy alone had a higher rate of mortality at 30, 60, and 90 days than those treated with a combination of oral and IV therapy (IV versus oral: 34% versus 3% 30-day mortality, 39% versus 15% 60-day mortality, and 44% versus 18% 90-day mortality). E. faecium bacteremia recurrence within 5 to 90 days occurred in 15/111 (14%) patients. Of these patients, 10/15 received only IV antimicrobials, whereas 5/15 received some oral therapy.

Conclusion
E. faecium bacteremia was associated with prolonged hospitalizations and high rates of mortality when compared with
E. faecalis bacteremia. Patients treated with a combination of oral and IV therapy did not have an increased risk of mortality or bacteremia recurrence. The difference in outcomes is likely related to severity of disease and comorbid factors affecting clinicians’ antimicrobial choice.

Disclosures
All Authors: No reported disclosures
P-1476. Cefiderocol Treatment Outcomes and Risk Factors for Gram-negative Bacterial Infection Treatment Failure
Authors: Rashidi Keemia , Kubin Christine J , Wu Gary , Nelson Brian , Uhlemann Anne-Catrin 
Published: January 2025

Abstract

Background
The IDSA 2023 guidance lacks strong evidence about cefiderocol (FDC) efficacy and real-world data are limited. The aim of this study was to evaluate effectiveness, safety, and risk factors for clinical failure (ClinF) associated with FDC use in hospitalized patients.

Methods
This was a retrospective, observational study. Adults treated with an initial course of FDC for ≥ 48 hours from Feb 2020 - Aug 2023 were included. Primary outcome was clinical success (ClinS) defined as a composite of survival, resolution of signs and symptoms, and absence of both recurrent infection or microbiological failure. Factors associated with success and failure were compared on univariable analysis and those with a p-value &lt; 0.2 and FDC monotherapy were considered for inclusion in a multivariable model for ClinF.

Results
87 patients were included. Most common pathogens: Pseudomonas spp (49%), Acinetobacter spp (29%), and Klebsiella spp 16%. Carbapenem-resistance was reported for 93% of isolates and majority of cases were from a respiratory source (72%). At FDC initiation, 39 patients (45%) were admitted to the ICU and the median PITT bacteremia score was 3 (IQR, 1.5-4). ClinS was achieved in 32 patients (37%). Within this composite, 70% survived, 59% resolved their signs/symptoms, 62% had absence of microbiologic failure, and 63% did not recur within 30 days. 16 patients (18%) developed FDC non-susceptibility (NS) within 90 days. ClinS was associated with urine and intra-abdominal sources, while ClinF was associated with COPD, mechanical ventilation, respiratory sources, and higher PITT bacteremia scores. No significant differences found between age, Charlson comorbidity index score, or monotherapy and combination therapy. COPD was found to be an independent factor associated with ClinF [OR 11.5 (95% CI 1.63-82.28, p=0.014)]. Comparing patients who developed FDC NS to those that did not, solid organ transplant [7(44) vs 14(20); p=0.088], longer antibiotic days prior to FDC [14.5 d vs 7 d; p=0.079], and longer FDC duration [14 d vs 10 d; p=0.023] were more common in those that developed NS.

Conclusion
In this single center experience with mostly respiratory infections, FDC was successfully used with ClinF being associated with underlying illness. The potential development of NS should be further explored.

Disclosures
All Authors: No reported disclosures
P-1516. Addition of Single-Dose Aminoglycosides to Empiric Beta-Lactam Therapy in Septic Shock in a Setting with High Antimicrobial Resistance Rates
Authors: Johnson Allison M , Scipione Marco R , Zhao Jing , Olson Shannon , Huang Alex 
Published: January 2025

Abstract

Background
At the Detroit Medical Center (DMC), the addition of an aminoglycoside (AMG) to β-lactam therapy is recommended in patients with septic shock due to high resistance rates; however, studies assessing the benefit of such combinations have yielded conflicting results. The objective of this study is to compare the outcomes of patients with septic shock who receive empiric β-lactam therapy with and without an AMG.Figure 1.Mortality Outcomes

Methods
This is a retrospective cohort study from 5/2021 to 7/2023. Patients were included if they met the following: 2 of 4 SIRS criteria, received vasopressors, serum lactate &gt; 2 mmol/L, and appropriate empiric antimicrobial therapy within 24 hrs of admission . Patients who received an AMG within 24 hrs of admission were included in the AMG cohort, and those who did not were included in the control group. Key exclusion criteria were COVID-19, burn injury, and transfer to hospice care within 4 days of admission. The primary outcome was all-cause mortality at 7 days ; secondary outcomes included 30-day mortality, vasopressor-free days by day 7, ventilator-free days by day 28, and nephrotoxicity by day 7.Table 1.Patient and treatment characteristics

Results
Seventy-six patients were included (AMG=38; Control=38). The most common source of infection in AMG and control groups was pulmonary (44% vs. 31%, p=0.18). More AMG patients had a presumed SSTI source (17% vs. 0.0%, p=0.0049) patients, positive blood culture (79% vs. 26%, p&lt; 0.0001), prior history of MDRO pathogen (22% vs. 0.0%, p=0.003), and received meropenem as initial empiric therapy (40% vs. 3%, p&lt; 0.0001). APACHE II scores were similar (30 vs. 28, p=0.09). Time to appropriate antibiotic therapy was 4.8 hrs in the AMG group vs. 6.4 hrs in the control group, p=0.81. There were no differences in 7-day mortality (47% vs. 40%, p=0.49), 30-day mortality (63% vs. 53%, p=0.3527), vasopressor-free days by day 7 (2 vs. 2, p=0.08), or ventilator-free days by day 28 (2.5 vs. 8.5, p=0.31). There were also no differences in nephrotoxicity by day 7 (50% vs. 67%, p=0.23).Table 1.Patient and treatment characteristics, continued

Conclusion
Further evaluations should be conducted to determine whether an AMG in combination with β-lactams should be used in patients with septic shock.Table 2.Other clinical outcomes

Disclosures
All Authors: No reported disclosures
P-1533. Assessing the Impact of Antimicrobial Stewardship on Antibiotic De-escalation, Escalation, Discontinuation, and Continuation: A Prospective Observational Study
Authors: Dorairajan Suresh Kumar , Sanjai R , Shibi S , Shobana S 
Published: January 2025

Abstract

Background
This study focuses on the involvement of infectious disease (ID) specialists in patient care regarding the de-escalation, escalation, discontinuation, and continuation of antibiotics, aimed at reducing unnecessary antibiotic usage, in alignment with the World Health Organization (WHO) AWaRe classification

Methods
This prospective observational study was conducted over the month of March 2024 at a 240-bed tertiary hospital in South India. Infectious disease (ID) consultants were actively involved in patient assessment to evaluate the appropriateness of antibiotic prescriptions. Following their assessment, ID consultants made decisions regarding antibiotic management, including de-escalation, escalation, discontinuation, and continuation, based on the patient's clinical condition. Data on antibiotic usage and outcomes, including appropriateness and clinical response, were collected using a simple audit tool. These data were subsequently entered into an Excel spreadsheet and analysed using descriptive statistics.

Results
Out of [1141] patients admitted to the tertiary care hospital, [597] patients received antibiotics, in that [80] were seen by infectious disease (ID) consultants. Among these, [30] patients underwent de-escalation, [10] experienced escalation, [28] had discontinuation, and [12] underwent continuation of antibiotic therapy CategoryFrequencypercentageTotal patients admitted1141100%Patients received antibiotics59752%Infectious disease consultant seen807%De- escalation303%Escalation100.87%Discontinuation283%Continuation121%

Conclusion
The study highlights the critical role of infectious disease specialists in guiding antibiotic therapy decisions, which can lead to more personalized and effective patient care. By reducing unnecessary antibiotic usage and promoting antimicrobial stewardship, this research contributes to improving patient outcomes and combating antimicrobial resistance.

Disclosures
All Authors: No reported disclosures
P-1538. Analyzing Trends and Outcomes of Clindamycin Resistant Invasive Group A Streptococci Infections
Authors: Jordan Tamara , Jagannathan Megha , Kinsey Daniel , Kenney Rachel M , Veve Michael , Suleyman Geehan , Shallal Anita 
Published: January 2025

Abstract

Background
Streptococcus pyogenes (Group A Streptococci; GAS) is a gram-positive bacterium that is a leading cause of life-threatening infections. For invasive infections, IDSA recommends high-dose penicillin and clindamycin (DA). However, increasing resistance to DA has been reported. The aim of this study was to determine the prevalence of DA-resistant GAS and evaluate if DA resistance was associated with worse outcomes.
Table
Comparison of clindamycin susceptible and clindamycin resistant strains of invasive GAS infections

Methods
This was a retrospective cohort study from June 2013 to December 2023 across a five-hospital health system in Southeast Michigan of patients with positive blood cultures for GAS who received DA for anti-toxin therapy identified through Microsoft SQL. Children, polymicrobial bacteremia, incomplete data, receiving linezolid empirically, or those who died within 48 hours of admission were excluded. Patients with DA susceptible (DA-S) GAS isolates were compared to patients with DA resistant (DA-R) GAS isolates. Variables included demographics, infection characteristics, microbiologic data, therapy, and clinical outcomes.
Figure
Cases of GAS bacteremia and percent of clindamycin resistant strains

Results
390 cases were reviewed, and 215 were included in the cohort study [Table]. There was no difference in age, sex, or race among the groups. People who use injection drugs (51.7% vs 48.3%, p=0.07), people experiencing homelessness (PEH; 63.2% vs 36.8%, p=0.001), and chronic hepatitis C infection (HCV; 54.2% vs 45.8%, p=0.007) were more prevalent in the DA-R group; chronic kidney disease was more frequent in the DA-S group (57.1% vs 42.9%, p=0.029). Uncomplicated SSTI was more common in the DA-S group (64.2% vs 35.8%, p=0.022). There was no significant difference in the severity of illness, duration of bacteremia, surgical management, treatment duration, length of stay, readmission or mortality between the two groups. There was an increased incidence of invasive GAS infections beginning in 2022, and 50% of isolates were DA-R in 2023 [Figure].

Conclusion
Although there is an increase in DA-R in invasive GAS infections, there was no significant difference in outcomes among patients with DA-R and DA-S who received standard of care treatment in addition to DA antitoxin therapy. Further research is needed to determine the clinical significance of these findings to inform optimal therapy for these groups.

Disclosures
Rachel M. Kenney, PharmD, BCIDP, Medtronic Inc: Spouse is an employee, stockholder
P-1556. A Retrospective Evaluation of Methenamine Safety and Efficacy in An Older Population at an Academic Medical Center
Authors: Hou Jysheng , Burgos Rodrigo M , Danziger Larry H 
Published: January 2025

Abstract

Background
Urinary tract infections represent a significant cause of morbidity and mortality in older adults. Limited methods exist to prevent recurrent UTI (rUTI) in this high-risk population. Prophylactic low-dose antibiotics are often considered for this purpose, but can be associated with increased adverse effects and development of resistant pathogens. The urinary antiseptic agent methenamine has re-emerged as an antibiotic-sparing alternative for prevention of rUTI, however its role in therapy for older adults is not well characterized.

Methods
Retrospective chart review identified patients prescribed methenamine from 2017 to 2023. Excluded were patients on prophylaxis aged &lt; 60 years at the time of initiation, and those with &lt; 3 months duration. Patients who received antibiotics for breakthrough UTI while on methenamine were included. Patient histories were reviewed 1 year prior to methenamine initiation through the end of prophylaxis. Collected were patient demographics, UTI history prior to methenamine, time to recurrence, laboratory values and adverse effects.

Results
247 patients were prescribed methenamine during the study period. 55 patients met inclusion criteria. On average, methenamine duration was 8.75 months. 27 patients had creatinine clearance (CLcr) values &lt; 60 mL/min. 29 patients received a concurrent recommendation for ascorbic acid. Use of methenamine provided ≥ 3 months without UTI recurrence in 43 patients (78%) with a wide range of Charlson comorbidity index scores and CLcr values, and 29 patients did not have documented UTI for the duration of methenamine therapy. Seven reports of adverse effects were documented, 3 of which led to discontinuation of therapy.

Conclusion
In a population ≥60 years of age, methenamine appears to be safe and effective at preventing recurrent UTIs. The number of patients without UTI decreased with time on methenamine, however 55% of patients who remained on prophylaxis at one year had no documented recurrence. Concurrent ascorbic acid therapy was not consistently recommended in this study population, and was not associated with increased methenamine efficacy. Lower CLcr did not appear correlated with lower efficacy or increased adverse effects of methenamine.

Disclosures
All Authors: No reported disclosures
P-1558. Short vs. Long Durations of Antibiotic Therapy for Pyelonephritis in Kidney Transplant Recipients
Authors: Crew Jordan , Veve Michael , Fitzmaurice Mary Grace , Alangaden George J , Kenney Rachel M 
Published: January 2025

Abstract

Background
Emerging data suggests shorter durations of antibiotic therapy are as effective and safe as longer durations in general populations. The objective of this study is to compare outcomes of short (7-9 days) vs long (10-15 days) durations of antibiotic therapy for acute graft pyelonephritis in kidney transplant recipients (KTRs).
Summary of patient, infection and treatment characteristics.

Methods
IRB-approved retrospective cohort comparing short (7-9 days) to long courses (10-15 days) of antibiotics. Inclusion: Adult patients, hospitalized from 1/1/14 - 12/31/23, history of kidney transplant, acute pyelonephritis, and receipt of at least 7 days of in vitro active antibiotic therapy. Exclusion: renal or perinephric abscess, prostatitis, ≤ 2 months post-transplant. Primary outcome: clinical success, defined as resolution of infection signs and symptoms and confirmed or presumed microbiologic success at end of therapy (EOT). Secondary outcomes: length of stay from pyelonephritis onset, continued resolution of signs and symptoms at 30 days, C. difficile infection within 30 days of EOT, acute rejection, and adverse effects.
Summary of primary and secondary outcomes.

Results
107 patients were included: 19 (17.8%) short-course and 88 (82.2%) long-course. Table 1 describes patient, infection, transplant, and treatment characteristics. There was 1 (5.3%) failure in the short-course group compared to8 (9.1%) failures in the long-course group at EOT (p=0.456). At 30 days, there were 4 (21.1%) failures in the short-course group and 15 (17.0%) in the long-course group (p=0.742). 30-day retreatment was required in 0 short-course and 8 (9.1%) long-course patients, p=0.346. No significant differences were detected for adverse effects: 0 vs. 3 (3.4%); C. diff: 0 vs. 1 (1.1%); or treated rejection: 1 (5.3%) vs. 0 in the short-course vs long-course groups, respectively.

Conclusion
We did not detect differences in outcomes for pyelonephritis treatment in KTRs between those who received short compared to longer courses of antibiotic therapy. Further research is needed to solidify the place of short courses of antibiotic therapy in transplant recipients.

Disclosures
Rachel M. Kenney, PharmD, BCIDP, Medtronic Inc: Spouse is an employee, stockholder