bluuebunny/crossref_metadata_2025_split huggingface dataset:
P-63. Real-World Effectiveness of Influenza Vaccine Over a Decade During the 2011–2021 Seasons: Implications of Vaccine Mismatch
Authors: Jung Choi Yu , Young Song Joon , Wie Seong-Heon , Suk Choi Won , Lee Jacob , Lee Jin-Soo , Keun Kim Young , kim Shin-Woo , Hee Lee Sun , Park Kyung-Hwa , Won Jeong Hye , Gu Yoon Jin , Seong Hye , Nham Eliel , Yun Noh Ji , Jin Cheong Hee , Joo Kim Woo 
Published: January 2025

Abstract

Background
Influenza imposes a significant healthcare burden in Korea, leading the government to initiate a national immunization program. Previous studies on vaccine effectiveness (VE) were limited to single-season estimation in Korea.
Matching status of epidemic influenza virus strains and vaccine strains in each season from the 2011/2012 to 2020/2021 seasons

Methods
This multicenter prospective cohort study enrolled patients with influenza-like illnesses at 10 medical centers in Korea from 2011–2021. The demographic and clinical data were collected from questionnaire surveys and electronic medical records. Using a test-negative design, we aimed to investigate the effectiveness of a seasonal influenza vaccine for antigenic matching of the vaccine and circulating viral strains over 10 seasons.
Vaccine effectiveness against laboratory-confirmed influenza

Results
Overall, 5,322 adults aged ≥65 years were enrolled. Only three (33.3%) of nine seasons showed &gt;70% antigenic match between vaccine and circulating strains. Influenza VE was significantly variable by season, ranging from -46.9% (95%confidence interval [CI]: -127.6–5.2) in the 2011/12 season to 47.7% (95%CI: 22.6–64.7) in the 2016/17 season. A significant difference was observed in the VE depending on whether the vaccine strains matched with epidemic strains: 28.8% (95%CI: 8.8–44.8) in matched seasons versus -12.0% (95%CI: -30.0–3.7) in mismatched seasons. Across the study period, influenza-related hospitalizations were reduced by 13.6% (95%CI: 0.7–24.8) with vaccination. In a subgroup analysis, the VE against influenza-related hospitalization was 48.4% (95%CI 29.6–62.2) in A/H3N2 dominant seasons and 53.8% (95%CI: -73.4–87.7) in A/H1N1 dominant seasons, respectively.
Vaccine effectiveness against laboratory-confirmed influenza by the matching status of vaccine and epidemic strains

Conclusion
Influenza vaccine mismatch was frequent over the study period, leading to negligibly low VE in mismatched seasons. Influenza vaccination reduces the risk of influenza-related hospitalizations.
Estimates of vaccine effectiveness for influenza-related hospitalizations

Disclosures
All Authors: No reported disclosures
P-65. Results from A Phase 2 Clinical Trial for Treatment of Bone And Joint Infections with Afabicin, A First-in-Class Selective Anti-Staphylococcal Antibiotic
Authors: Shamaei Tousi Alireza , Marquardt Moritz , Menetrey Annick , Nowakowska Justyna , Dao Justine , Cameron David , Catala-Goldschmidt Charlotte , Chaves Ricardo 
Published: January 2025

Abstract

Background
Staphylococci are the most common causative pathogens in bone and joint infections (BJI). Treatment for BJI is a major clinical challenge, with recurrent and persistent infections occurring in 40% of patients. Afabicin is the most advanced FabI inhibitor in clinical development and has the potential to be the first microbiome-sparing anti-staphylococcal antibiotic. Currently, a Phase 2 trial in BJI (NCT03723551) is enrolling patients to be treated for 3-6 weeks with afabicin or standard of care (SoC). Results of the first cohort in this study (2-3 weeks treatment) are presented here

Methods
In an ongoing multicenter, open-label, Phase 2 study, the safety, tolerability, and efficacy of afabicin was compared to those of SoC, in the treatment of patients with BJI. Patients with osteomyelitis, septic arthritis, or prosthetic joint infections were randomized (5 afabicin: 1 SoC) to receive IV and oral treatment for 14 to 21 days. Afabicin treatment (55 mg IV/ 80 mg PO BID) was compared to a pre-defined SoC treatment.

Results
Twenty patients were included in microbiological intent-to-treat (mITT) population and were treated for up to 21 days with afabicin or SoC (17 afabicin and 3 SoC). The mean treatment duration was 20.1 days for afabicin and 19.7 days for SoC. Overall, osteomyelitis was the most common diagnosis (85%). The most frequent baseline pathogen was Staphylococcus aureus (19 patients), and 18 patients had methicillin-sensitive S. aureus. All 20 patients were treatment responders at End of Treatment (EoT) visit. The clinical response at 4 weeks post EoT was 13 of 15 patients in the afabicin arm, consistent with patient exposure being above PK/PD targets derived from non-clinical modeling. All 3 patients in the SOC arm achieved clinical response at 4 weeks post EoT. At 12 weeks post EoT, the clinical response rate was 13 of 15 patients in the afabicin arm and 2 of 3 patients in the SoC arm. A similar safety profile was observed in the afabicin arm versus SoC arm.

Conclusion
The clinical response rate and safety profile of 2-3 weeks treatment of staphylococcal BJI with afabicin was comparable to SoC. These data support exploring longer durations of treatment in the study. Additionally, the impact of Afabicin on BJI patient’s gut microbiota will be explored.

Disclosures
Alireza Shamaei Tousi, PhD, Debiopharm International: Salary Moritz Marquardt, n/a, Debiopharm International: Salary Annick Menetrey, n/a, Debiopharm International: Salary Justyna Nowakowska, n/a, Debiopharm International: Salary Justine Dao, n/a, Debiopharm International: Salary David Cameron, PhD, Debiopharm International S.A.: Salary Charlotte Catala-Goldschmidt, n/a, Debiopharm International: Salary Ricardo Chaves, n/a, Debiopharm International S.A.: Salary
P-68. Comparison of vancomycin vs daptomycin for prosthetic joint infections
Authors: Maria Tedeschi Carissa , Slain Douglas , Mehta Meera , Johnson Jessica , Lastinger Allison 
Published: January 2025

Abstract

Background
A combination of surgery and extended durations of antimicrobials are the mainstays of therapy for patients with prosthetic joint infections (PJI). In the Infectious Diseases Society of America Clinical Practice Guidelines for Diagnosis and Management of PJI, daptomycin is an ‘alternative regimen’ for patients with methicillin-resistant Staphylococcus aureus (MRSA) and other methicillin-resistant coagulase-negative Staphylococcus (CoNS) species. The side effect profile of daptomycin may also be more tolerable than that of vancomycin, the preferred agent. This study aims to investigate the tolerability and efficacy of vancomycin versus that of daptomycin for patients with PJI. This topic has not been widely compared in literature for patients with monomicrobial PJIs.

Methods
This was a retrospective, observational assessment of patients who received vancomycin or daptomycin after surgery for prosthetic knee or hip infections. Patients were followed in our University Hospital’s Orthopedic Infectious Diseases Clinic between 1/1/2019 and 4/30/2023. Medical records were reviewed including demographics, type of surgery, adverse effects (AEs), and relapse rates at 6 weeks, 6 months, and one year.

Results
Seventy-nine patients were included: 56 initiated therapy with vancomycin and 23 with daptomycin. The primary outcome was the incidence of therapy-altering AEs. Twenty-two patients in the vancomycin group and 4 patients in the daptomycin group experienced AEs that led to therapy changes (39.3% vs 26.1%, p=0.07). The secondary outcome was the incidence of recurrent infection and was tracked in a subset of 39 vancomycin and 23 daptomycin patients. At 1 year, 10 vancomycin patients required additional unplanned surgery, while only 1 daptomycin patient experienced this (17.9% vs 4.3%, p=0.04). The only statistically significant difference found in baseline characteristics was that more antibiotic spacers were placed in the long-term follow-up daptomycin patients (15 vs 16, p=0.034).

Conclusion
There was no statistically significant difference in tolerating vancomycin vs daptomycin, however, daptomycin may lead to fewer relapses long-term in patients with MRSA and CoNS infections.

Disclosures
All Authors: No reported disclosures
P-93. Contezolid in Patients with Spinal Infections
Authors: Wei Bo , Zhang Xiucui , Wang Jianrong 
Published: January 2025

Abstract

Background
Methicillin-resistant Staphylococcus aureus (MRSA) is a common cause of spinal infections (SI) requiring long-term use of antibiotic therapy. Linezolid (LZD) is effective in treating MRSA in different clinical scenarios, but its long-term use is limited due to risk of significant thrombocytopenia. Contezolid (CZD) is a new generation of oral oxazolidinone with potentially less myelosuppressive effect. However, data on the use of CZD in patient with SI is currently lacking. This study aims to evaluate the use of oral CZD in patients with spinal infections due to MRSA.

Methods
Single-center, retrospective study in 7 patients with SI caused by MRSA. All patients experienced platelet count decreased during treatment with LZD and were rapidly switched to CZD (800 mg, po, bid) for &gt; 4 weeks. We evaluated the clinical outcomes (within six months after treatment), adverse reactions and the platelet counts.

Results
7 patients met the criteria for this study (median age 58, IQR 56.5-64.5, 14.3% female). With LZD treatment for a median of 14 days ( IQR 12-14 ), platelet count decreased from normal range 125-300 × 109/L to 65–75 × 109/L. After switching to CZD for 2 weeks, the platelet counts recovered to &gt; 100 × 109/L in all subjects. At the time of the switch 5 patients still had increased C-reactive protein. After approximately 2 months of oral CZD treatment(median duration 28 days, IQR 26-31.5 ), all patients improved clinically and CRP levels returned to normal (Table 1). Follow up MRI results also indicated radiologic improvement (Figure 1). Clinical evaluation, CRP and MRI six months after therapy indicated no recurrence in any subjects. During the treatment with CZD, only 2 patients experienced mild nausea, with no serious adverse reported.

Conclusion
In patients with SI due to MRSA experiencing thrombocytopenia with LZD, This limited study of oral CZD, as a rescue therapy for hematogenous osteomyelitis and thrombocytopenia after treatment with LZD, is encouraging and suggests that CZD may with more study be an excellent option for the treatment of SI due to MRSA.

Disclosures
All Authors: No reported disclosures
P-94. Can Fluoroquinolones Be Used for the Treatment of Deep-Seated Streptococcus anginosus group Infections?
Authors: Miller Whitney , Jenkins Timothy C , Parry Joshua , Studnicka Sebastian , Delino Nicole , Young Heather 
Published: January 2025

Abstract

Background
Invasive infections caused by Streptococcus anginosus group are increasingly common. Some experts recommend against treatment with fluoroquinolone (FQs) dues to potential development of fluoroquinolone resistance; however, this is not based on clinical data. The aim of this study is to compare the safety and effectiveness of FQ-based antibiotic regimens with non-FQ regimens for the treatment of deep-seated S. anginosus group infections.

Methods
This was a retrospective cohort study of patients hospitalized at Denver Health Medical center between 4/1/2016 and 10/31/2023 with a deep-seated infection and isolation of S. anginosus group from tissue, bone, synovial or pleural fluid. Cases were categorized as having been treated with a fluoroquinolone as part of their antibiotic regimen or not. The primary outcome was treatment success at 90 days as defined as absence of the following: recurrent infection, need for repeat surgical intervention or hospital readmission related to the primary infection. Secondary outcomes included antibiotic-related adverse events and central venous catheter complications.

Results
144 cases of deep-seated infection involving a S. anginosus group were identified; 69 received a FQ while 75 were treated with other antibiotics. Those in the FQ group were more likely to discharge on oral antibiotics (64 [93%] vs. 40 [53%], p&lt; .001) and had a shorter duration of intravenous therapy (2 days vs. 13 days, p&lt; .001). Treatment success occurred in 62 (90%) patients in the FQ group and 69 (92%) patients in the non-FQ group (p=0.65). Rates of antibiotic-related adverse events and vascular complications were similar between groups. Of patients who received a FQ, no patients had treatment failure or recurrent infection with an isolate resistant to a FQ.

Conclusion
FQs appeared to be a safe and effective treatment option for deep-seated S. anginosus group infections and facilitated early transition to oral therapy, while the development of FQ resistance was not observed.

Disclosures
All Authors: No reported disclosures
P-126. Host Factors Associated with Failure of Fecal Microbiota Transplant for Recurrent Clostridioides difficile Infection: 10- Year Real World Experience in a Dedicated C. difficile Clinic
Authors: Yohannes Kibret , Nguyen Joseph D , Setiady Initha , Hyun Shin Jae , Warren Cirle A , Phillips Emma C , Hays R Ann , Behm Brian 
Published: January 2025

Abstract

Background
Clostridioides difficile infection (CDI) continues to be an antibiotic-associated infection of urgent concern. Fecal microbiota transplantation (FMT) is the most effective treatment of recurrent CDI (rCDI). Despite high success rates, FMT has proven to be ineffective in 5-20% of cases. Factors associated with failure have not been clearly defined. We seek to better understand factors predictive of failure in patients who have undergone FMT.
Failure Rate by Comorbidity

Methods
A retrospective chart review was conducted on adult patients who were screened at the Complicated C. difficile Clinic at the University of Virginia Health System and received FMT for rCDI between 2013 and 2022. Electronic medical records were thoroughly reviewed to collect data on demographics, comorbidities, CDI history, laboratory values prior to FMT, and performance after FMT. Primary outcome was failure of FMT, defined as either rCDI or death within one year.
Failure Rate by Lab Values

Results
240 patients with rCDI were treated with FMT: 70.4% were female, median age was 68 (range: 20 to 96), and median episodes of CDI was 4 (range: 1 to 25). Within one year, 24.6% of patients experienced failure: 18.3% of patients experienced rCDI and 7.1% died. Univariate analysis showed that older age (≥70), male sex, ≥4 episodes of CDI, hypertension, diabetes mellitus, malignancy, elevated TSH, anemia, and low zinc were linked to failure. Older age, ≥4 episodes of CDI, hypertension, and elevated TSH were also associated with recurrence. Male sex, diabetes mellitus, elevated TSH, anemia, and low zinc were associated with death. Multivariate analysis showed that older age, ≥4 episodes of CDI, and diabetes mellitus were linked to failure while older age and ≥4 episodes of CDI were linked to recurrence.
Failure Rate by Number of C. difficile Infections

Conclusion
FMT continues to hold up as an effective treatment for rCDI. At one year follow-up, about 1 in 4 patients who underwent FMT at our institution experienced failure. Older age, ≥4 episodes of CDI, elevated TSH, anemia, and low zinc appear to be associated with failure, but additional research is needed to clearly define causality. Our results underscore the importance of recognizing factors that can predict failure and be targeted to further improve outcomes of FMT.
Failure Rate by Sex

Disclosures
Jae Hyun Shin, MD, Ferring: Grant/Research Support Cirle A. Warren, MD, Ferring Pharmaceuticals: Site PI for ROAR
P-139. Characteristics of Veteran Travelers at the Clement J. Zablocki Veterans Affairs Medical Center
Authors: Mulaikal Bianca , Gundacker Nathan , Sherman Katherine 
Published: January 2025

Abstract

Background
Travel location, demographics, and the type of travel are critical determinants of the pre-travel consultation. Veterans represent a unique subpopulation of the US. They earn higher average salaries than their non-veteran counterpart and have access to free healthcare. This puts them in a position to spend more on personal travel, yet there is a paucity of data on veterans' travel preferences and habits. In this study, we examined veteran travel characteristics to provide information on how best provide pre-travel consultation.

Methods
This is a retrospective chart review of veterans who presented to the Clement J Zablocki Veterans Affairs Medical Center (VAMC) infectious disease clinic for a pre-travel consultation between 7/1/2017 and 4/11/2023.

Results
Of the 181 veterans in this study, 150 were male, 29 were female, and two were unknown. The mean traveler was 55.62 years old. Asia (n=87, 48.1%) was the most frequently traveled continent, followed by Africa (n=47, 26%). Veterans were independently traveling (n=121, 67%) for durations greater than one week (n=164, 91%), with 13.3% traveling for at least 2-3 weeks. Within Asia, 23% (n=20) traveled to the Philippines, 26% (n=23) to Vietnam, and 17% (n=15) traveled to Thailand, of these 67% traveled for 4 weeks or more (n=29, 67%).

Conclusion
According to data collected in 2020 by the United Nations World Tourism Organization (UNWTO), the world's top 10 destinations are all within Europe and North America and account for 40% of all global travel. In addition, most group travel is generally one week long. Comparatively, veterans travel longer, more independently, and to more diverse parts of the world. Veteran travel clinics need to be equipped to discuss risks or longer term travel including international health care, safe sex practices and vaccines such as rabies and Japanese encephalitis.

Disclosures
All Authors: No reported disclosures
P-143. Interpreting Prognostic Factors Associated with In-Hospital COVID-19 Mortality in a Peru Sample using Shapley Additive Explanations on Ensemble Learning
Authors: Dai Na , Briceno Ruben K , Castaneda Alex , Tresierra Miguel , Esteban Maribel , Rosas Moises , Hinojosa Rene 
Published: January 2025

Abstract

Background
COVID-19 has infected over 4.5 million and killed more than 222,000 people in Peru. Research on key factors for in-hospital mortality in these patients is limited. Our study aims to understand prognostic factors linked to the mortality of patients with COVID-19 receiving treatment in Peru. A modified SHapley Additive exPlanations (SHAP) method was proposed.
Table 1

Methods
Clinical and laboratory data were collected prospectively about all patients that were admitted in the inpatient setting at Hospital De Alta Complejidad Virgen De La Puerta and Hospital víctor Lazarte Echegaray Essalud from March 1st to December 31st 2020 with a COVID-19 diagnosis clinically. Ten base predictors were first implemented using the ML algorithms such as Random Forest. Prediction performance on the area under the receiver operating characteristic (AUC) was computed. The SHAP method was then applied to each predictor based on resampled train sets for 30 trials. Factor importance in each trial was estimated by averaging SHAP scores across all predictors, weighted by AUC.
Table 2 (Part 1/3)

Results
After applying inclusion and exclusion criteria (n=) 1,857 patients were selected from a total of 2,000 admitted patients. Several factors out of 281 in total achieved stable importance scores with statistical significance while others were not. Among poor prognostic factors were low PaO2/FiO2 ratio (SV: 4.135, 95% CI: [4.107, 4.163]), shortness of breath (SV: 4.975, 95% CI: [4.864, 5.086]), and productive cough (SV: 2.037, 95% CI: [1.99, 2.080]). Among favorable factors were high PaO2/FiO2 ratio (SV: 3.832, 95% CI: [3.816, 3.848]), low D dimer (SV: 0.875, 95% CI: [0.859, 0.891]) and lymphocyte counts (SV: 1.319, 95% CI: [1.297, 1.340]). For medications, dexamethasone w. air (SV: 2.186, [2.095, 2.277]) was the most effective. For oxygen support, binasal cannula (SV: 0.841, 95% CI: [0.826, 0.857]) and high flow cannula (SV: 0.663, 95% CI: [0.633, 0.693]) are associated with more favorable prognosis than invasive ones.
Table 2 (Part 2/3)

Conclusion
Clinical symptoms and evidence associating acute respiratory distress and sepsis, as well as immune responses less specific to viruses, suggest a likelihood of COVID-19 mortality, consistent with global findings. Our SHAP variant generated reasonable prognostic interpretation about COVID-19 mortality in Peru.
Table 2 (Part 3/3)

Disclosures
All Authors: No reported disclosures
P-153. Malaria in a military hospital in Bogotá, Colombia, 2023 – 2024
Authors: Medina-Lozano Leidy J , Oviedo Naranjo Julián Camilo , espinosa Murcia Mariana , Faccini-Martínez Álvaro A 
Published: January 2025

Abstract

Background
In Colombia malaria is an endemic mosquito-borne disease. Although military personnel are recognized as a high-risk group for malaria, little is known about on features of this parasitic disease in Colombian military members.

Methods
We recorded data on demographic, clinical, laboratory and treatment of patients with confirmed malaria diagnosis (positive thick blood smear or Rapid Diagnostic Test), attended in a reference military hospital, located in Bogotá, Colombia, from February 2023 to April 2024. Cases of severe malaria and recurrence were classified following the last WHO guidelines. Dengue and malaria coinfection were defined as a confirmed malaria case with positive dengue NS1 antigen.

Results
During the study period, 97 patients were attended; all of them males, in active military service, and the median age was 25 years. Most (70%) consulted between November 2023 and April 2024 (Figure 1), and the main Colombian departments where the infections were acquired were Chocó (29%), Córdoba (22%) and Nariño (12%) (Figure 2). Plasmodium vivax was the main etiology (79%), follow by P. falciparum (17%), mixed infections (3%) and Plasmodium sp. (1%); four patients had coinfection with dengue. Most (51%) were attended at the emergency department, 39% at general ward, and 10% required intensive care unit. Recurrences were diagnosed in 36%, and the remaining as new infections. Among clinical features, the main symptoms were fever (88%), headache (75%) and chills (64%); and the main signs were jaundice (25%), abdominal pain (21%) and mild dehydration (12%) (Table 1). The median days of fever at hospital admission was five. Severe malaria was diagnosed in 8 patients. Among laboratory findings, thrombocytopenia was the most frequent (77%), follow by hyperbilirubinemia (71%). Hepatosplenomegaly was the most finding at the abdominal ultrasound (49%) (Table 2). Regarding treatment, 92% of P. vivax cases received chloroquine-primaquine; 69% of P. falciparum cases received artemether-lumefantrine and single dose primaquine; mixed infections cases received artemether-lumefantrine and primaquine; and all severe malaria received intravenous artesunate. No deaths were recorded.

Conclusion
Malaria remains a potential health threat to Colombian military personnel.

Disclosures
All Authors: No reported disclosures