bluuebunny/crossref_metadata_2025 huggingface dataset:
P-1423. Barriers to Care: Improving Outpatient Follow-Up for Patients on Long-Term Oral Antimicrobial Therapies
Authors: Cummins Heather , Benefield Russell J , Certain Laura
Published: January 2025

Background

Best practice for patients on COpAT (Complex Outpatient Antimicrobial Therapy) includes close follow-up once discharged from the hospital. However, some patients discharged with COpAT do not receive monitoring for complications, increasing their risk for re-admission. There is limited analysis regarding patient-specific social determinants of health (SDOH) that may contribute to a reduced follow-up rate. We aimed to determine the percentage of patients discharged on long-term oral antibiotics who received recommended outpatient Infectious Disease (ID) support and potential barriers to follow-up for quality improvement.Table 1:Outcomes associated with social determinants of healthSelected social determinants of health associated with specified monitoring and outcomes. Bolded values are considered statistically significant.

Methods

In this single-center cohort, patients discharged between 1/1/2021 and 12/31/2022, on ≥ 2 weeks of oral antibiotics, age > 18 years, with inpatient ID consult, and with recommendations for follow-up in the University of Utah ID Clinic were examined. SDOH included distance from the medical center, age, race/ethnicity, employment status, substance use, homelessness, and history of bipolar disorder/psychoses. We assessed patient outcomes of treatment failure or lost to follow-up within 90 days post-discharge. We also evaluated the time to appointment, lab monitoring, and number of adverse drug events (ADEs) after discharge.

Results

One hundred ninety-seven patients met the inclusion criteria for the cohort. Median times to suggested lab monitoring and ID appointment were 13 and 21 days post-discharge respectively. 71% completed lab monitoring within 90 days of discharge. After 90 days, 19% of patients were lost to follow up and 20% had experienced treatment failure. Those younger than 55, unemployed, or experiencing substance use were more often lost to follow-up. Individuals with substance use or age < 55 had a longer time to lab monitoring. Patients with a history of substance use had fewer ADEs (Table 1).

Conclusion

SDOH that contribute to patient outcomes include a history of substance use and unemployment, suggesting an area of clinical quality improvement. Additionally, those younger than 55 were more often lost to follow-up. Further examination of follow-up protocol for these patients is important to improve patient outcomes.

Disclosures

Russell J. Benefield, PharmD, BCPS-AQ ID, Paratek Pharmaceuticals: Grant/Research Support Laura Certain, MD, PhD, Zimmer Biomet: Advisor/Consultant
P-1425. Paxlovid Utilization and Social Vulnerability: Trends in Connecticut from 2022-2023
Authors: Hohenstein Laura , Maloney Meghan , Banach David
Published: January 2025

Background

The COVID-19 burden disproportionately affects communities with lower socioeconomic status and high social vulnerability, as well as minority racial groups. Disparities have also been described in nirmatrelvir/ritonavir (Paxlovid) prescription rates across socioeconomic strata.

Differences in nirmatrelvir-ritonavir dispensing rates between SVI quartile groups from March 2022 – February 2023

Methods

We performed an ecological analysis of associations between CDC social vulnerability index (SVI) and nirmatrelvir-ritonavir dispensing rates in Connecticut census tracts. SVI was categorized in four quartiles (low, low-medium, medium-high, and high). Nirmatrelvir/ritonavir dispensing locations were geocoded and dispensing rates per 1,000 population were calculated as the sum of courses dispensed per census tract during March 2022–February 2023. Independent-T tests were used to compare SVI in census tracts with and without medication dispensing sites. ANOVA with Tukey’s test was used to identify differences in dispensing rates by SVI quartile with paired t-test to identify significant differences before and after availability of the bivalent COVID-19 booster vaccine (March–August 2022 vs. September 2022–February 2023).

Demographic and COVID-19 characteristics of census tracts with and without a nirmatrelvir/ritonavir dispensing site

Results

Mean SVI was higher in 367 census tracts with a dispensing site (mean 0.56) compared to 506 census tracts without a dispensing site (mean 0.45) (p < 0.01). Nirmatrelvir/ritonavir dispensing rates were lower in census tracts with high SVI (55.9 courses per 1000 people) compared to census tracts with low-medium SVI (93.1; difference -37.2 95% confidence interval (CI) [-68.5, -5.9]) and census tracts with medium-high SVI (96.6; difference -40.7, 95% CI [-69.9, -11.5]). Dispensing rates were higher after availability of the bivalent COVID-19 booster vaccine compared to before (p < 0.05), except in census tracts with high SVI where there was no statistically significant difference.

Nirmatrelvir/ritonavir dispensing rates per 1,000 population by census tract SVI quartile before and after availability of the bivalent COVID-19 booster vaccine

Conclusion

Census tracts with high social vulnerability were less likely to have a dispensing site and had lower nirmatrelvir/ritonavir dispensing rates per 1,000 population. Observed differences in dispensing might signify inequities in healthcare access or medication prescribing. Findings highlight the importance of understanding and addressing barriers to accessing therapeutics in high vulnerability areas during public health emergencies.

Disclosures

Meghan Maloney, MPH, Pfizer Global R&D: Former employee, separated in 2009. I do have a retirement entitlement which I do not actively manage/no stock options. PGRD offers periodic buy outs
P-1451. Missed Opportunities for HIV Diagnosis in Mexico City: Unveiling the Gender Gap
Authors: Sierra-Barajas Nancy , Caro-Vega Yanink , Sierra-Madero Juan G , Benavides Rodrigo Ville , López-Iñiguez Alvaro , Mejia-Castrejon Jessica , Juarez-Campos Karen , Silva-Casarrubias Angelina , Crabtree-Ramírez Brenda
Published: January 2025

Background

Women in Mexico are not considered a key population for acquiring HIV, consequently, neither the patients nor their physicians are aware of this risk. This lack of recognition may contribute to late diagnoses and unfavorable clinical outcomes. This study aims to determine the frequency of missed opportunities for HIV diagnosis (MOHD) in a tertiary care center in Mexico City.

Methods

A questionnaire for newly enrolled healthcare patients was routinely applied since 2013 to look for MOHD, at the HIV Clinic of a tertiary care center in Mexico City. MOHD was defined as a healthcare encounter in which a) HIV diagnosis was not made, b) was prompted by a clinical manifestation related to HIV, and c) occurred at least 30 days before the HIV diagnosis was confirmed. Frequency and proportion of MOHD by sex were reported, we described demographics, presence of AIDS at enrollment and compared the proportion of MOHD and AIDS defining events by gender.

Results

A total of 1,143 questionaries were applied from January 1st 2013, to December 31st 2023; 107 (9.4%) respondents were female and 1036 (90.6%) were male. A total of 486 (42.5%) patients reported experiencing symptoms related to HIV before their diagnosis, with 36 (7.4%) being women. 466 of 486 sought medical attention for their symptoms: 403 patients had data to establish MOHD, 27 were women and 376 men. MOHD was considered in 18/27 (66%) women and in 155/376 (41%) men (p=0.03). Among the patients with MOHD, 10/18 (56%) of the women and 52/155 (34%) of men had AIDS at enrollment in HIV care (p=0.02).

In the MOHD group, women's mean age was 43 years (SD=12.2) vs 35 in men (SD=12.2, p=0.01), 39% were married (7/18) vs. 11% of the men (17/155) (p< 0.01), and years of education were similar: 12.2 (SD= 4.6) vs. 13.2 (SD=4.2), respectively (p=0.51).

Conclusion

This study reveals a higher proportion of missed opportunities for HIV diagnosis and AIDS in women compared to men. Women with MOHD were older and married in a higher proportion than men. Our results underscore the urgent need of strategies for increasing awareness of HIV risk in Mexican women.

Disclosures

All Authors: No reported disclosures
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

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 < 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 < 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 < 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

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

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< 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

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 < 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

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 > 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< 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< 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

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

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

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 < 60 years at the time of initiation, and those with < 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 < 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

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
P-1570. D-mannose for Prevention of Recurrent Urinary Tract Infection in Adult Women: An Updated Systematic Review and Meta-analysis
Authors: Krishna Mrinal Murali , Joseph Meghna , Ezenna Chidubem , Sreemathy Lal Sadasivan
Published: January 2025

Background

Urinary tract infections (UTIs) are prevalent, especially among women as approximately 50% of all healthy women will encounter at least one episode of UTI during their lifetime. An estimated 25%-35% of them will experience a recurrence within the following year. Prolonged antibiotic therapy for prophylaxis of UTI poses the risk of antimicrobial resistance, alteration of normal flora, and high costs to the patient. D-mannose, a polysaccharide may reduce UTI by preventing the adherence of bacteria to uroepithelium by binding to the type1 pili and saturating the adhesin FimH. D-mannose is commonly marketed for urinary tract health and is touted to contribute to better antimicrobial management within primary care settings. We performed an updated meta-analysis comparing prophylaxis with D-mannose versus placebo or no treatment for prevention of recurrent UTI in adult women.

Methods

We systematically searched PubMed, Scopus, and Cochrane Central databases for trials comparing D-mannose versus placebo or no treatment for UTI prophylaxis in adult women. Outcomes of interest included one or more episodes of UTI within 6 months of randomization and adverse events. Statistical analysis was performed using R software. Heterogeneity was assessed using I2 statistics. The analysis was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guideline (Figure 1).

Risk estimation for recurrent UTI

Results

The systematic review identified three randomized controlled trials including 846 participants. Prophylaxis with D-mannose was given to 428 (50.59%) participants. The risk of recurrent UTI within 6 months of randomization (RR 0.75; 95%CI 0.46-1.23; p=0.259; I2=52%) showed no significant difference between the groups (Figure 2). Adverse events (RR 0.81; 95%CI 0.09-6.91; p=0.847; I2=94%) were also similar between the groups (Figure 3).

Risk estimation for adverse events

Conclusion

In contrast to a previous meta-analysis, our study found that prophylaxis with D-mannose did not reduce the risk of recurrent UTIs in adult women. Adverse events were also comparable between the groups.

Disclosures

All Authors: No reported disclosures
P-1576. An Exploration of the Utility of Urinalysis Criteria in Predicting Urine Culture Positivity
Authors: Patel Shivum , Njeri Wainaina J
Published: January 2025

Background

Urinalysis (UA) testing with reflex to culture is commonly ordered and is considered a tool for both diagnostic and antibiotic stewardship. Criteria for culture delineate normal from abnormal values leading to use for diagnosis of urinary tract infections (UTI). However, urinalysis criteria which predict urine culture growth that correlate with UTI are not well elucidated. The objective of this study is to evaluate the utility of several different indicators in urinalysis as reflex criteria to urine culture.

The area under the curves are: 0.618 for WBCs, 0.607 for nitrites, 0.570 for LE by semi-quantitative testing, and 0.479 for LE by numeric testing.

Methods

Retrospective review of 14,212 unique de-identified samples of paired urinalysis and urine culture collected in the Froedtert Health System in Milwaukee, Wisconsin from 9/22/22 to 8/23/23. All urine specimens were included regardless of collection method. Cultures were deemed to be positive if growing at least 100,000 colony-forming units (CFU) of a likely urinary pathogen and were evaluated for white blood cells (WBC), leukocyte esterase (LE), and nitrite positivity in the corresponding urinalysis.

Results

For each criterion, sensitivity and negative predictive values (NPV) were calculated at varying thresholds. A threshold of 5 WBCs provided the greatest NPV at 88.60%, and the greatest sensitivity at 89.76%. Next, receiver operating characteristic (ROC) curves were generated and the area under the curves were: 0.618 for WBCs, 0.607 for nitrites, 0.570 for LE by semi-quantitative testing, and 0.479 for LE by numeric testing.

Conclusion

Of the three urinalysis criteria, WBC had the best sensitivity and NPV but the ROC curves suggest that none of the tests predict significant urine culture growth well, emphasizing the importance of clinical context in both determining when to test and how to interpret. As diagnosis of a UTI does not simply rest on certain CFU growth or uropathogen on urine culture, but requires incorporation of history and physical findings, the next stage will be to correlate urine testing results with symptoms.

Disclosures

All Authors: No reported disclosures
P-1591. Harnessing Artificial Intelligence for Rapid Interpretation of BCID2 Results: A Pre-Validation Study of a Generative Pre-trained Transformer (GPT)
Authors: Tassone Daniel , Ian Langford , Markley John D , Ye Julia , Hitchcock Matthew M
Published: January 2025

Background

Artificial intelligence (AI) has great potential to enhance patient care, but significant questions remain about implementation and safety. Antimicrobial stewardship programs (ASP) could leverage AI to assist with prospective audit and feedback (PAF) interventions such as interpretation of blood culture results and rapid optimization of antimicrobials. At our institution, PAF interventions are performed by the ASP as soon as possible when BioFire® Blood Culture Identification 2 Panel (BCID2) results are available. However, these interventions are time consuming and often delayed due to limited resources. To address this gap, we developed a Generative Pre-trained Transformer (GPT) tool to assist non-infectious disease (ID) providers with interpretation of BCID2 results. Herein, we aim to describe the process of training the GPT and report pilot study results of the tool’s accuracy compared with ASP recommendations.

Methods

Using OpenAI’s GPT-4.0, our GPT was trained to synthesize patient-specific treatment advice by analyzing BCID2 results and anonymized patient data. Training focused on applying local as well as national evidence-based recommendations for the management of bacteremia, and providing feedback to the GPT when errors were recognized. A scoring rubric was designed to compare GPT treatment recommendations to gold standard ASP recommendations for the management of bacteremia (Figure 1). An independent infectious disease expert reviewer applied the rubric to determine the accuracy of the GPTs recommendations.

Results

Five cases of bacteremia were retrospectively reviewed. The GPT recommendations were 67% concordant with best practices, compared to 93% for the ASP (Table 1).

Conclusion

In this pilot study, a GPT was trained to interpret and manage bacteremia and achieved 67% concordance with best practices. Although inferior to ASP recommendations, GPT is a promising AI tool that warrants further investigation to aid in ASP interventions. Our GPT has been retrained based on our findings, and a larger prospective validation study is underway.

Disclosures

Daniel Tassone, PharmD, BCIDP, Merck: Honoraria
P-1592. Diagnostic Stewardship Cutoffs for Urinalysis Results Prior to Performing a Urine Culture: Analysis of Data from a Healthcare System
Authors: Kupferwasser Deborah , Kang Amy Y , Chen Liz , Huse Holly K , Miller Loren G
Published: January 2025

Background

Urinary Tract Infections (UTIs) are commonly overdiagnosed. Some labs conduct urinalysis (UA) as a preliminary screening before proceeding to urine culture to reduce processing unnecessary samples. However, the optimal UA cutoffs for this diagnostic stewardship intervention are not well defined.

UA squamous epithelial cells were not graphed b/c the value crossed the diagonal at multiple points.

Methods

We performed a retrospective, cross-sectional analysis of urine studies performed from 2/1/21-1/31/23 at the Los Angeles County Department of Health Services (4 medical centers & 20 clinics). We examined patient encounters in which a UA was ordered synchronously with a urine culture. We excluded patients who were pregnant, undergoing a urologic procedure, < 3 months of age, or neutropenic. We examined the diagnostic accuracy, receiver operating characteristic (ROC) curves, and area under the curve (AUC) for pre-screening urinalysis parameters prior to urine culture performance. From the macroscopic test, we examined leukocytes and nitrite. From the microscopic exam, we examined bacteria, white blood cells (WBC), and squamous epithelial cells. We investigated each test’s correlation with a uropathogen isolated from culture.

Sensitivity and specificity of urinalysis WBC cutpoints for identifying uropathogens

Results

We examined 81,907 paired urinalysis and urine cultures (17,842 inpatient and 64,065 outpatient). Among the urine cultures, organisms isolated included 24,683 (30%) uropathogens, 4,373 (5%) organisms sometimes considered uropathogens, 3,000 (4%) organisms rarely considered a uropathogen, 30,511 (37%) multiple organisms, and 293 (0.7%) a non-uropathogen of clinical significance; 19,047 (23%) cultures were negative. When predicting a urine culture positive for a uropathogen, the UA parameter with the best diagnostic accuracy was WBCs (AUC: 0.758), followed by leukocytes, bacteria, nitrite, and squamous epithelial cells. (AUC: 0.723, 0.707, 0.652, and < 0.500, respectively) (Figure). The sensitivity and specificity of WBC cutoffs are outlined in the Table.

Conclusion

In a large dataset of paired urinalysis and urine cultures, WBC on microscopic urinalysis showed highest diagnostic accuracy at predicting isolation of a uropathogen on urine culture. Stewardship programs should consider this parameter as the screening test for urine culture performance.

Disclosures

Amy Y. Kang, Pharm.D., BCIDP, Paratek Pharmaceutical: Grant/Research Support Loren G. Miller, MD MPH, Armata: Grant/Research Support|Contrafect: Grant/Research Support|GSK: Grant/Research Support|Merck: Grant/Research Support|Paratek: Grant/Research Support
582. Feeling the Vibes: An Investigation Into Resident Physician Antibiotic Prescribing Practices
Authors: Dickson David , Jordan Jaime , Vijayan Tara
Published: January 2025

Background

Efforts to improve inpatient antibiotic prescribing are limited by a lack of insight into the heuristics and thought processes that influence the complicated decisions around antimicrobial use. We aimed to explore antimicrobial therapeutic decision making among resident physicians at a large academic health system.

Figure 1. Thematic map of resident trainee antibiotic decision making process

Methods

We performed a qualitative study with a constructivist paradigm employing semi-structured, in-person focus groups of Internal Medicine interns and residents at the UCLA Ronald Reagan and Santa Monica Medical Centers from December 2023 through January 2024. Sessions were recorded, auto-transcribed, and edited for accuracy. Two researchers independently performed a thematic analysis of three distinct focus group transcripts.

Results

25 residents participated in a total of three focus groups. Residents consistently identified a clear general approach to prescribing antibiotics, including triaging critical illness and identifying the following: the presence of infection; the source of infection; the antibiotic that covers the likely pathogens; and co-morbid conditions and risk factors. Two broad themes regarding initial acquisition of an approach to antibiotics emerged: institutional culture or “oral tradition,” and internal and external clinical resources. A major challenge in therapeutic decision-making centered around navigating uncertainty (Figure 1). Comments on the inconsistency of clinical reasoning and “vibes-based” prescribing were common. Residents identified certain safety net strategies to mitigate the anxieties associated with this uncertainty (Figure 1). Resident confidence improved over time via habit formation and trial and error, particularly when working independently as the Night Admitting Resident. ID physicians and pharmacists provided a model approach for therapeutic reasoning and supported residents to take risks they were otherwise reluctant to take (such as de-escalation).

Conclusion

Despite articulating a systematic approach to antimicrobial prescribing, resident therapeutic decision-making remains subject to many vulnerabilities, including emotional prescribing. A reliance on the ID consult as a safety net may account for increases in consult volume and requires further investigation.

Disclosures

All Authors: No reported disclosures
P-1604. Utilization of MRSA Nasal PCR to De-escalate Vancomycin Therapy in Inpatients with Suspected Pneumonia
Authors: Hedvat Jason , Patel Mudita , Ajit Anjali Anne , Rosen Elisabeth L , Perlman David C , Koshy Sanjana
Published: January 2025

Background

MRSA nasal screening has been proposed as a tool to facilitate de-escalation of vancomycin in patients with pneumonia. The objective of this study was to evaluate the impact of MRSA nasal PCR testing in patients with pneumonia in terms of length of anti-MRSA therapy and clinical outcomes.

Methods

This was a retrospective single center pilot study conducted at Mount Sinai Beth Israel during January 1, 2022 – March 31, 2022 (pre-availability of MRSA nasal PCR) and August 1, 2023 – October 31, 2023 (post-availability of MRSA nasal PCR). The primary outcome was the duration of vancomycin therapy in days in the pre-PCR compared to the post-PCR group. Secondary outcomes included the number of vancomycin levels drawn, 30- and 90- day mortality, hospital length of stay, and incidence of new acute kidney injury (AKI) during treatment. Comparisons were performed using Chi-squared or Fischer’s exact test for categorical variables and Student’s t test or the Mann-Whitney U test for continuous variables, as appropriate. P < .05 was considered statistically significant.

Results

One-hundred and eighty-five patients were included, 91 in the pre-PCR group and 94 in the post-PCR group. The most common pneumonia indication was community acquired pneumonia (CAP) in 78% of patients. Among patients that received vancomycin therapy for CAP, only 30% (21/70) and 17.3% (13/75) had risk factors warranting anti-MRSA therapy in the pre-PCR and post-PCR groups respectively. The median duration of vancomycin therapy was significantly shorter in the post-PCR group than the pre-PCR group (0.9 days vs. 1.8 days; p < .05). Fewer patients required 2 or more vancomycin levels drawn in the post-PCR versus the pre-PCR group (20.2% vs 41.8%; p < .05). 30-day mortality was lower in the post-PCR group (12.8% vs 25.3%), but not significantly (p=0.08). No differences were found in other clinical outcomes including 90- day mortality, hospital length of stay, and incidence of new AKI during treatment.

Conclusion

MRSA nasal PCR testing resulted in shorter duration of vancomycin therapy and reduced drug level monitoring without compromising clinical outcomes in patients with suspected pneumonia. Additional education is needed to ensure appropriate utilization of empiric anti-MRSA therapy in CAP patients with risk factors.

Disclosures

All Authors: No reported disclosures