bluuebunny/crossref_metadata_2025_split huggingface dataset:
P-1829. Genomic Characterization of Clinically Significant Isolates and Its Effects on Clinical Outcomes, 2022 to 2024
Authors: Contreras Deisy , Grein Jonathan , Morgan Margie A 
Published: January 2025

Abstract

Background
Antimicrobial resistance has evolved into a complex global issue involving many clinically relevant organisms. Among these pathogens, carbapenem-resistant organisms (CROs) are of particular concern due to their limited treatment options and high mortality rates. In collaboration with Solu, whole-genome sequencing (WGS) was performed on clinical isolates recovered from our patient population to gain a better insight into resistance mechanisms present and their direct effect on clinical outcomes.

Methods
For genomic characterization (WGS), a total of 109 carbapenem resistant isolates across three clinically relevant bacterial groups (Enterobacterales, Pseudomonas aeruginosa and Acinetobacter baumannii complex) were sequenced. Solu utilized a hybrid assembly approach utilizing both long reads generated with Oxford Nanopore Technologies (ONT) complemented by Illumina short reads for the reconstruction of bacterial genomes.

Results
Multilocus sequence typing (MLST) revealed genetic diversity among all three groups of bacterial isolates. Among members of the family Enterobacterales, there were eight distinct sequence types: ST-131, ST-1431, ST-167, ST-2155, ST-361, ST-410, ST-685 and ST-405. A. baumannii complex strains mostly comprised of ST-2 and ST-1022. The presence of numerous sequence types was observed with the P. aeruginosa isolates, highlighting the biocomplexity within our patient population. Furthermore, genomic analysis of these isolates disclosed a broad range of antimicrobial resistance genes that span across several classes of antibiotics. Isolates across all genera harbored plasmid-mediated carbapenemase genes bla-NDM-5, bla-NDM1, bla-OXA-48 and bla-OXA23. Interestingly, cefiderocol resistance was primarily associated with the Escherichia coli ST-405 strain containing AMR gene bla-NDM5. Patients associated with a carbapenemase-producing strain were observed to have higher mortality rates (12.8%) and longer length of hospital stay (25.6%).

Conclusion
By having a comprehensive insight into the genomic composition of isolates that make up our patient population, we can provide a more targeted medical treatment approach and investigate and better prevent transmission events.

Disclosures
All Authors: No reported disclosures
P-1866. Polymorphonuclear Myeloid-Derived Suppressor Cells regulates immune reconstitution during HIV infection through PD-L1 and TGF-β signaling
Authors: Xia Huan 
Published: January 2025

Abstract

Background
Although myeloid-derived suppressor cells (MDSCs) are widely recognized for their immunoinhibitory effect in a variety of pathological conditions, their function during human immunodeficiency virus (HIV) infection and the onset of inadequate immune reconstitution remains elusive.
PMN-MDSCs inhibit autologous CD4+ T-cell proliferation and cytokines (IL-2, TNF-α, and IFN-γ) production in HIV INRs.

Methods
We conducted a cross-sectional study in which 30 healthy controls (HC) and 62 HIV-1-infected subjects [31 immunological non-responders (INRs) and 31 immunological responders (IRs)] were selected. After two years of antiretroviral therapy, INRs and IRs were designated as patients with CD4+ T-cell counts &lt; 350 cells/μL and &gt;500 cells/μL, respectively. The proportion of MDSCs was measured and their relationship with HIV disease progression was studied. Specifically, using flow cytometry and real-time PCR, immune regulatory molecules (including programmed death-ligand 1 [PD-L1], arginase 1, inducible nitric oxide synthase, interleukin 10, transforming growth factor beta [TGF-β], and indoleamine 2,3-dioxygenase) that are relevant for MDSCs activity were quantified. Furthermore, we investigated the impact of the blockade of PD-L1 and/or TGF-β signaling on MDSCs and their effects on CD4+ T cells using in vitro functional experiments.
PD-L1 and TGF-β mediate the suppressive effect of PMN-MDSCs on CD4+ T-cells response.

Results
We found that polymorphonuclear MDSCs (PMN-MDSCs) are more abundant and negatively correlated with CD4+ T-cell counts in HIV-infected individuals. PMN-MDSCs suppress CD4+ T-cell proliferation and interferon-γ (IFN-γ) production in INRs. Furthermore, correlations were found between PD-L1 expression on PMN-MDSCs and PD-1+ CD4+ T-cells. TGF-β expression on PMN-MDSCs was likewise enhanced in INRs. Importantly, inhibiting both PD-L1 and TGF-β signaling had a synergistic impact on restoring CD4+ T-cell activity in vitro.

Conclusion
Our findings reveal that the expansion of PMN-MDSCs decreased CD4+ T-cell proliferation and IFN-γ secretion in HIV infection through PD-L1 and TGF-β mediated pathways. Interventions that target both PD-L1 and TGF-β pathways may be novel strategies for enhancing immune reconstitution in INRs.

Disclosures
All Authors: No reported disclosures
638. Using NHSN Annual Self-Reported Dialysis Data to Understand Infection Prevention and Control Practices and their Association with Bloodstream Infections in Dialysis Facilities
Authors: Syed Rabia R , Pavlovsky Lacey , Tyner Kate , German Dan K , Cashatt Christina , Brailita Daniel M , Salman Ashraf Muhammad , Teran Plasencia Juan M 
Published: January 2025

Abstract

Background
Hemodialysis (HD) patients are at increased risk of bloodstream infection (BSI). Although BSI events are surveilled by the National Healthcare Safety Network (NHSN), studies correlating dialysis facilities’ self-reported infection control (IC) practices with BSI events are lacking.Figure 1.Seven Areas of Least Compliance by Facilities
A total of 34 facilities were included. Best practices were selected based on adherence by less than 2/3 of dialysis centers.

Methods
We used 2022 NHSN Annual Outpatient Dialysis Center Practices Survey data for Nebraska facilities to identify 44 questions pertaining to IC practices. These questions were included into a scoring system and dichotomized to adherent (1) or non-adherent (0), leading up to a “best practice (BP) score” for each facility. Questions related to attending IC training initiatives were coded as yes (1) or no (0). Self-reported adherence to CDC Dialysis Safety Core Interventions (DSCI) were coded as following all (1) or some/none (0). We extracted BSI standardized infection ratios (SIR) from NHSN Dialysis Events Surveillance data. Descriptive statistics was used to evaluate facility characteristics and scores. Multivariate regression, using a Poisson model, generated rate ratios (RR) to understand association of trainings/guidelines with BP scores and BSI SIR. Pearson correlation was used to assess association between BSI SIR and BP scores.Figure 2.BSI SIR and Overall Facility Performance Score Distributions

Results
A total of 34 facilities yielded a mean BP score of 36/44 (82%). The top 3 least reported BP strategies included: ointment application to HD catheter during dressing change (adhered by 2 of 34), medications drawn into syringes outside the patient room (adhered by 12 of 34), and patient education on showering with HD catheters (adhered by 15 of 34). Overall, facilities following all DSCI were associated with higher BP scores (RR: 1.11, 95% CI: 1.06, 1.16) and lower BSI SIR (RR: 0.33, 95% CI: 0.13, 0.83) compared to those who followed some or none. Similarly, facilities participating in infection prevention initiatives were associated with lower BSI SIR (RR: 0.39, 95% CI: 0.16, 0.96) compared to those who did not. An inverse association was found between BSI SIR and BP score (p=0.001).

Conclusion
Adherence to DSCI and participation in IC initiatives likely help HD facilities in preventing BSI events and need to be further explored. NHSN annual outpatient dialysis data provides important information about areas where further improvement is needed.

Disclosures
Muhammad Salman Ashraf, MBBS, Merck & Co. Inc: Grant/Research Support
P-1887. Outpatient vancomycin therapy: Rates of acute kidney injury in patients receiving area-under-the-curve-guided dosing as an inpatient followed by transition to trough-guided dosing after discharge
Authors: Honan Benjamin , Lim Lindsay , Hall Nicole M , Kim Janet , De Lima Daniela F 
Published: January 2025

Abstract

Background
Vancomycin is one of the most prescribed antibiotics for hospitalized patients. Targeting an area under the curve to a minimum inhibitory concentration (AUC/MIC) ratio of 400-600 mg*hour/L has been associated with a reduction in vancomycin-induced acute kidney injury (AKI) compared to trough-guided dosing. Data evaluating AUC-guided vancomycin dosing in outpatient parenteral antimicrobial therapy (OPAT) are limited, and resources required for AUC-guided dosing are often unavailable. However, trough-guided dosing has been associated with vancomycin overexposure and in the outpatient setting, rates of AKI as high as 28.5% have been reported. We aim to evaluate outcomes of patients discharged on at least one week of vancomycin on a dose established through AUC-guided dosing during hospitalization followed by trough-guided dosing in the outpatient setting.

Methods
In this retrospective single-center cohort study, we identified 120 patients admitted to the University of Alabama (UAB) Hospital or UAB Hospital-Highlands between October 1, 2021, and March 31, 2022, who met criteria for inclusion. Though we collected additional demographics and clinical information, our primary outcome was the development of AKI, as defined by the 2012 KDIGO guidelines, while receiving vancomycin via OPAT.

Results
Approximately 17% of patients developed an AKI using this hybrid model. The most treated infection was prosthetic joint or hardware-associated infections (40.8%), and the most targeted organism was MRSA (41.7%). Vancomycin monotherapy comprised almost half of the antibiotic regimens on discharge (48.3%); the second agent, if prescribed, was typically a beta-lactam other than piperacillin-tazobactam (36.7%).

Conclusion
Future directions include identifying predictors for the development of AKI while receiving vancomycin via OPAT and comparing outcomes of this hybrid model with a historical cohort of patients at our institution who received trough-guided dosing in both the inpatient and outpatient settings. Given the paucity of data on vancomycin dosing in the outpatient setting, investigating optimal and sustainable OPAT vancomycin dosing and monitoring is of the utmost importance to minimize adverse events and maximize patient safety.

Disclosures
All Authors: No reported disclosures
P-1888. Quantifying the Potential Impact of Dalbavancin on Health Care Metrics Associated with Outpatient Parenteral Antibiotic Therapy Management of Streptococcus and Staphylococcus Infections
Authors: Li Lucy X , Anderson Sean , Judson Seth , Visek Caitlin , Brenon Jessa , Wright William F , Keller Sara C 
Published: January 2025

Abstract

Background
Socially vulnerable patients often complete parenteral antibiotic courses in healthcare facilities due to injection drug use (IDU) history or unstable housing situations, which leads to significant personal and health system costs and prolonged hospitalization risks. Our aim was to assess the potential impact of dalbavancin (DBV) utilization on length of stay (LOS) and adverse outcomes in this patient population.

Methods
Retrospective study of patients ≥ 18 years old who were followed in the Johns Hopkins Health System Outpatient Parenteral Antibiotic Therapy (OPAT) program from 1/1/2021 to 6/30/2023 for Streptococcus and Staphylococcus bone/joint and endovascular infections (n = 900). Descriptive statistics were used to evaluate demographic, microbiologic, and clinical characteristics. Potential demand for DBV was quantified by estimating the impact of transitioning patients to DBV in terms of possible hospital days saved and OPAT-related complications avoided. Subanalyses were completed for patients with IDU history.

Results
Median patient age was 58 years (IQR 44-68 years) and 501/900 (56%) were male. Most patients received vancomycin (30%) followed by cefazolin (24.4%) or anti-staphylococcal penicillin (24.0%), which required central venous catheter placement in 86.6% of patients. The most common indication for OPAT was osteomyelitis (54.8%) followed by endovascular infection. The median LOS after finalization of antibiotic recommendations was 5 days (IQR 3-10 days) with 44.3% requiring skilled nursing facility (SNF) placement. 43.7% of patients experienced an OPAT-related adverse event, almost half of which involved a return to the hospital. Among OPAT patients, 16.4% had an IDU history and 75.8% of them injected within the last 6 months. These patients had longer LOS (8 vs 5 days) after finalization of antibiotic recommendations and more OPAT-related adverse events compared to patients without IDU history (48.0% vs 43.7%).

Conclusion
Patients, especially those with recent IDU, could benefit from DBV in lieu of parenteral antibiotics to complete prolonged treatment courses. Completion of deep-seeded gram-positive infection therapy with DBV vs OPAT has the potential to shorten hospital LOS and reduce the incidence of OPAT-associated adverse events.

Disclosures
All Authors: No reported disclosures
P-1892. Dabbling with Dalbavancin: Implementation and Cost-savings of an Inpatient-to-Outpatient Dalbavancin Pathway
Authors: O’Neal Melissa , Piccicacco Nicholas , Zeitler Kristen , Weber Jaimie , McConnell Douglas , Conn Chris , Carrieri Kari , Hall Susannah , Montero Jose 
Published: January 2025

Abstract

Background
Dalbavancin is a lipoglycopeptide antibiotic with in vitro activity against gram-positive organisms and a terminal half-life of 14.4 days. One dose provides 7 days of therapy whereas a novel 2-dose regimen provides up to 4-6 weeks. These strategies are attractive alternatives to standard of care for patients in whom daily IV antibiotics are not feasible. There also may be a financial benefit as the dosing schedule allows for completion of therapy in the outpatient setting and can reduce hospitalization costs.

Methods
This study is a retrospective chart review of all patients who received dalbavancin at Tampa General Hospital. Our institution approved the use of dalbavancin at no cost to patients for vancomycin-susceptible gram-positive infections who remain hospitalized only to receive IV antibiotics. All patients received at least one 1500mg dose inpatient to save 7 days of hospitalization; some patients planned to follow up a week later in an outpatient clinic for a second 1500mg dose to save at least 4 weeks of hospitalization. Cost estimates are based on the patient’s hospitalization cost prior to receiving dalbavancin and do not include avoided implicit costs.

Results
From 12/13/22 to 3/31/24, 28 patients received dalbavancin; 14 (50%) planned to receive a second dose and 11 (78.6%) successfully received their dose in clinic. The majority of patients (60.7%) reported a history of injection drug use. Most infections were monomicrobial (85.7%) with S. aureus being the most common pathogen. An estimated 527 days of hospitalization were avoided, representing a cost savings of $684,712.44. The institutional drug cost for dalbavancin was $104,772, leading to an estimated net hospital cost savings of $579,940.44. The all-cause 30-day readmission or revisit rate was 28.6%, similar to reported readmission rates in this population, however the 30-day infection-related readmission or revisit rate was favorable (10.7%).

Conclusion
The use of dalbavancin to facilitate discharge resulted in significant cost savings without increasing infection-related readmissions. Further cost-benefit analysis on true economic impact including the reduction in nosocomial infections and avoidance of toxicities is warranted.

Disclosures
All Authors: No reported disclosures
P-1893. Evaluation of Infectious Disease Consultation on Outpatient Antimicrobial Therapy (OPAT) Referral Volume and Outcomes
Authors: Slain Nicole , Mynatt Ryan P , Ruf Kathryn , Cari Evelyn Villacorta , Mansoor Armaghan-E Rehman , Burgess Donna R , Clemons Alisha , Logan Ashley 
Published: January 2025

Abstract

Background
Institutional experience with OPAT is increasingly reported. However, little is known about the referral process across the continuum of care and its impact on OPAT volume and patient outcomes. The purpose of this study is to characterize OPAT referral trends from a multi-service line infectious diseases (ID) group and its impact on end of therapy patient outcomes.

Methods
This retrospective analysis included adult patients referred to the OPAT program from either of the two system hospitals and seen by any of the five inpatient consult teams or the ambulatory ID clinic between June 2021 and July 2022. Patients were identified via a data extraction from the electronic health record by the institution’s Healthcare Analytics Team or Center for Clinical and Translational Sciences. OPAT patients were identified via the OPAT Electronic Data Capture (REDCap) database.

Results
A total of 3738 ID consult orders were placed on 2708 patients, dispersed between four consult teams at hospital 1 (Table 1). The OPAT program received 1504 referrals, 1475 (98.1%) inpatient referrals and 29 (1.9%) outpatient. A total of 914 patients were discharged to receive IV antimicrobials, 723 (78.2%) and 191 (32.9%) (p &lt; 0.00001), for standard OPAT (S-OPAT) and modified OPAT (M-OPAT), respectively (Figure 1). End of therapy outcomes were recorded on 798 (87.3%) patients. The Transplant service had the highest percentage of referrals eligible for S-OPAT (90%); however, it also saw the highest 60-day readmission rate (36.2%) (Table 1). There was no statistically significant difference (p = 0.281) in proportion of referrals with end of treatment failure within the ID services at hospital 1. However, therapy extension was more frequent in the Bone and Joint and General ID teams (p &lt; 0.001). Hospital 2 had more patients that were unable to complete their antimicrobial therapy (14.6%) (Table 3).

Conclusion
Our analysis of patients seen by ID consult services demonstrated a significant portion were ultimately referred for OPAT. Differences in referral rates were noted between service lines, along with differences in 30 and 60-day readmission rates. Overall, end of therapy and clinical outcomes were fairly similar throughout the groups.

Disclosures
Alisha Clemons, APRN, Gilead Sciences: Honoraria
P-1907. Comparing Multisystem Inflammatory Syndrome in Children (MIS-C) Case Characteristics Across Periods of SARS-CoV-2 (SC2) Variant Predominance in Los Angeles County (LAC): 2020-2023
Authors: Collins Christina , de St Maurice Annabelle , Traub Elizabeth , Khanqadri Israa , Finn Lauren E 
Published: January 2025

Abstract

Background
MIS-C is a rare condition in children associated with prior SC2 infection. Limited data show the impact of SC2 variants on the presentation of MIS-C. This study analyzes differences in the presentation of MIS-C cases in LAC when different variants were circulating.
Characteristics of Multisystem Inflammatory Syndrome in Children (MIS-C) Cases, -- Los Angeles County*, California March 1, 2020- December 31, 2023

Methods
This analysis includes MIS-C cases in people &lt; 21 years of age reported to LAC with onset from 3/1/2020-12/31/2023. We defined confirmed SC2 infection as having a documented positive SC2 test with specimen collection date &lt; 60 days prior to MIS-C symptom onset. Where SC2 positive results were not available, we imputed SC2 infection as occurring 30 days prior to MIS-C onset. Infection dates were used to classify cases by variant predominant periods, defined as weeks where &gt; 50% of sequenced specimens reported to LAC were a particular variant as defined by the WHO as a variant of concern. Case demographics and clinical characteristics were compared across variant periods. Analyses were conducted for all reported MIS-C cases and for cases with confirmed SC2 infection. Statistical significance was tested with the Kruskal-Wallis test and chi-squared test [α=0.05].

Results
349 MIS-C cases were reported between 2020-2023 (Table 1). Of these, 102 (29.2%) had a documented SC2 infection. Median age at onset was 7.8 years. 168 (48.1%) had ≥ 1 comorbidity, 124 (35.5%) were admitted to the ICU, and median hospital length of stay (LOS) was 5 days. 18 cases were vaccinated prior to MIS-C onset. The most SC2 infections occurred during the Pre-Delta period (230, 65.9%), while the fewest occurred during the Delta period (57, 16.3%) (Table 2). Median age and proportion of children with ≥ 1 comorbidity decreased across variant periods (p &lt; 0.0001, p=0.0102; respectively). The median LOS was lowest when SC2 infection occurred during the Omicron period (p=0.0370). ICU admission was not statistically different across variant periods.

Conclusion
The LOS, median age, and proportion of cases with comorbidities decreased when SC2 infection occurred during the Omicron period. This may be due to differences in variant pathogenicity, natural immunity decreasing the MIS-C susceptible pool, and younger children being the last group to be eligible for vaccination during later variant periods.

Disclosures
All Authors: No reported disclosures
P-1909. Social Connectedness in the COVID-19 Pandemic’s Aftermath: The Influence of Disease Status
Authors: Kricorian Christopher 
Published: January 2025

Abstract

Background
During the COVID-19 pandemic, maintaining social connectedness became difficult.As the pandemic receded, these challenges eased and allowed people to re-develop their social relationships. However, those with Long COVID (LC) may experience ongoing difficulties given the effects of their illness, but limited research has examined the association of LC with social connectedness.

Methods
The US Census Bureau Household Pulse Survey data was used in this analysis. Data was collected online between January 9 - February 5, 2024, in English and Spanish. Sample size was N=68,544. Social connectedness metrics were compared between those reporting LC, COVID-19 infection that had resolved (Short COVID, or SC), and those who had not experienced COVID (No COVID, or NC). Data were analyzed using χ2 and between group contrast analysis.

Results
When asked how often they feel lonely, those with LC were significantly more likely to say always, usually, or sometimes as compared to SC and NC respondents and less likely to say rarely or never (all comparisons to LC p&lt; .05). In terms of receiving necessary social and emotional support, only 21.6% of those with LC said they always get necessary support, vs. 30.9% for SC and 30.0% for NC (both LC comparisons p&lt; .05). LC respondents were most likely to say they got together with friends or relatives less than once per week (47.1%, vs. 35.3% SC and 43.1% NC, all comparisons p&lt; .05). Those experiencing SC were most likely to say they texted with friends, family or neighbors 5+ times per week (70.1%), followed by LC (65.1%), then NC (59.9%, all comparisons p&lt; .05).

Conclusion
People suffering from LC generally exhibited lower levels of social connectedness and had lower likelihood of obtaining necessary social and emotional support than those who experienced SC or NC. Additional research should be conducted to better understand the causal connections: are people with poorer social connections more likely to experience LC, does LC damage the ability to become or remain socially connected, or both? More research is needed to examine these questions and develop programs to help rebuild and retain social connections in the aftermath of the COVID-19 pandemic.

Disclosures
All Authors: No reported disclosures