bluuebunny/crossref_metadata_2025_split huggingface dataset:
P-2276. Shifting trends over time in patients admitted with presumed or confirmed Pneumocystis jirovecii pneumonia without underlying human immunodeficiency virus infection from 2006 to 2023 in Singapore
Authors: Koh Matthew C Y , Ngiam Jinghao Nicholas , Tambyah Paul , Lum Lionel H W 
Published: January 2025

Abstract

Background
Pneumocystis jirovecii pneumonia (PJP) is an opportunistic infection associated with significant morbidity and mortality in immunocompromised hosts. PJP has emerged as a significant pathogen affecting non-HIV infected hosts, with wider use of novel immunosuppressive therapies. We sought to describe changing trends in the clinical profile and outcomes of patients without underlying HIV diagnosed with PJP.
Clinical characteristics of patients with pneumocystis pneumonia without underlying HIV
Clinical characteristics of patients with pneumocystis pneumonia without underlying HIV

Methods
A total of 93 consecutive patients without HIV, with presumed or confirmed PJP, admitted to a tertiary hospital in Singapore were studied from 2006-2023. The cohort was divided into the first 44 patients from 2006-2014, and the second 49 patients from 2015-2023. Data on each patient’s clinical background, presenting symptoms, laboratory data as well as clinical outcomes such as need for intensive care, mechanical ventilation or mortality were tabulated.

Results
Over the years, there was no significant differences in the age or sex of patients with PJP. However, there was a decrease in proportion of haematological malignancy as a predisposing condition for PJP (38.6% vs 14.3%), but an increase in the proportion of patients with autoimmune/inflammatory conditions presenting with PJP (13.6% vs 26.5%). A smaller proportion of patients presented without PJP prophylaxis in more recent years (100.0% vs 81.6%, p=0.030), and shortness of breath was a less common symptom (90.9% vs 63.3%, p=0.002). A greater proportion of patients were diagnosed using PJP PCR. Overall mortality (36.4% vs 26.5%), as well as the need for mechanical ventilation (31.8% vs 34.7%) and intensive care (50.0% vs 53.1%) did not differ between the groups.

Conclusion
In this single centre retrospective study, there have been significant changes over almost two decades in the clinical profile of patients without underlying HIV who had PJP infection. A greater proportion of patients had autoimmune and inflammatory conditions, while the proportion of those with haematological malignancy decreased. This may be due to the implementation of standardised protocols for PJP prophylaxis. More cases were detected using PCR, which appears to be a helpful adjunct to microscopic examination. Morbidity and mortality from PJP in such non-HIV immunocompromised hosts however remains high and has not declined over the years.

Disclosures
Paul Tambyah, MBBS (S'pore), Diplomate, American Board of Internal Medicine and Infectious Diseases, Moderna: Grant/Research Support|Sanofi-Pasteur: Grant/Research Support
P-2277. Impacts of Ongoing Quinolone Prophylaxis Following Quinolone-Resistant Bacteremia in Neutropenic Patients
Authors: Acevedo Sarah , Park Stacy 
Published: January 2025

Abstract

Background
Guidelines that suggest fluoroquinolone (FQ) prophylaxis for intermediate to high-risk hematologic malignancy patients are based primarily on evidence of reduction in bloodstream infections (BSIs) in historic studies, despite no demonstrated reduction in other outcomes such as mortality, septic shock, or ICU admissions. In the era of widespread FQ use for prophylaxis and increasing antimicrobial resistance, ongoing re-evaluation of the benefit is needed. Patients with BSI due to FQ-resistant gram-negative organisms may have particularly reduced benefit from ongoing FQ prophylaxis, however data on this topic is limited. We evaluated characteristics of neutropenic patients with BSI in an attempt to better inform the risk/benefit balance in this population.
Figure 1.
Numerical breakdown of bacteremia episodes

Methods
We extracted episodes of gram-negative BSI during a neutropenic episode lasting at least 7 days in adult inpatients with hematologic malignancy and/or stem cell transplant (study period 11/1/2020-11/1/2023). For each BSI episode we collected data on treatment (agent, duration, line removal), FQ susceptibility, underlying disease, neutropenia, and FQ exposure within 90 days. For episodes with an opportunity to resume prophylaxis following treatment of bacteremia (based on persistent neutropenia or recurrent neutropenia with 90 days), we determined rates of recurrent BSI within 90 days, stratified by FQ resistance and decision to resume FQ prophylaxis.

Results
There were 82 BSI episodes (69 first episodes, 13 recurrent) among 62 patients. FQ resistance was common in first episodes (34/69, 49%) and median prior FQ exposure within 90 days was 16 days. 43 episodes had an opportunity to resume FQ prophylaxis and 19/43 (44%) had FQ resistance. FQ prophylaxis was resumed in 16/19 (84%) with FQ resistance and 21/24 (88%) without, with rates of recurrent bacteremia within 90 days of 44% and 29% respectively. There were no episodes of recurrent bacteremia when FQ prophylaxis was not resumed (0/6).Table 1.Characteristics of bacteremia episodes with an opportunity to resume fluoroquinolone prophylaxis following treatment

Conclusion
Among bacteremia episodes with eligibility for FQ prophylaxis following treatment, recurrent bacteremia was common, particularly when FQ resistance was present. FQ prophylaxis may have little or no benefit in this setting, however larger studies and controlled data are needed.

Disclosures
All Authors: No reported disclosures
P-2278. CMV Viremia and Disease in Pediatric Liver Transplant Patients: a Multi-national Systematic Review and Meta-analysis
Authors: Shieb Mohamad , Stern Eric J , Hasanain Rand 
Published: January 2025

Abstract

Background
Cytomegalovirus (CMV) viremia (Defined as a single detectable CMV RNA PCR) and disease (defined as CMV viremia with compatible systemic and/or localized signs and symptoms) remain a leading cause for mortality and morbidity in the pediatric solid organ transplant recipient. This systemic review aims at pooling data from the leading pediatric transplant institutions globally to identify the overall incidence of and risk factors associated with CMV viremia and/or disease in pediatric liver transplant recipients.
PRISMA flow diagram

Methods
A systemic review of Pubmed and OVID databases was conducted since the inception to 01 April 2024. 24 articles were included from the USA, UK, South Africa, India, Japan, Finland, Canada, Turkey, Mexico, Thailand, Greece, Israel and Australia. A total of 1964 liver transplants were included. Median age was 50 months with 47.8% males. Data related to demographics, incidence, donor and recipient CMV serological classification (Donor (D) and Recipient (R)) and risk factors for CMV viremia/disease were extracted from the articles and subsequently analysed. This review was registered in Prospero: CRD42023477476

Results
The Incidence of CMV viremia and disease in pediatric liver transplant patients in this review were 34% and 8.4% respectively, with statistically significant higher risk in the CMV D+/R+ category compared to other D/R serologic groups (P value &lt; 0.05). , Additional risk factors identified for CMV viremia/disease included younger age, biliary atresia, high steroid doses, and rejection attacks.

Conclusion
This meta-analysis highlights that CMV viremia and disease post-liver transplantation are significant health concerns in pediatric populations. Identifying high risk populations for targeted CMV monitoring and potentially preemptive therapy to mitigate CMV-associated morbidity and mortality is a critical cornerstone of pediatric transplant medicine. Further studies are warranted to explore additional risk factors and to refine prevention and treatment strategies for CMV in pediatric transplant recipients.

Disclosures
All Authors: No reported disclosures
P-2299. Febrile neutropenia in cancer: a retrospective analysis in a dominican tertiary hospital
Authors: Reyes Yeison , Chaddy Báez Lia Michelle , Disla-Pineda Karla Marie , Calcano Ruben , Guzman-Ricardo Francisco , Ledesma Jose 
Published: January 2025

Abstract

Background
Febrile neutropenia (FN) poses a significant threat to cancer patients, often leading to severe infections. This study aims to characterize the epidemiology and sources of infection among hospitalized cancer patients experiencing FN at Hospital General de la Plaza De la Salud. By elucidating these factors, we strive to enhance patient care and outcome within our context.
Source: Statistical registry of the authors.

Methods
We conducted a retrospective study at a 289-beds in a tertiary care center in the Dominican Republic from March 2021 to March 2024, assessing 258 hospitalized patients with severe neutropenia. 42 cancer patients met the inclusion criteria (absolute neutrophil count less than 500 cells/µL and fever greater than 38.3°C) and data was collected reviewing the eCharts.
Source: Statistical registry of the authors.

Results
24 patients were male (57.1%), with a median age of 44 (IQR=27). 34 (80.9%) patients had hematologic malignancy, with acute myeloid leukemia being the most common (n=19; 45.2%), followed by non-Hodgkin lymphoma (n=7; 16.7%). Cause of fever was identified for 28 patients, which included bacteremia (13/28; 30.9%), respiratory tract infection (7/28; 16.7%), skin and soft tissue infection (5/28; 11.9%) and others (3/28; 10.7%). An etiological agent was documented in 20 cases, of which the most common was bacterial (15/20;75%); Pseudomonas aeruginosa (6/15; 40%), Escherichia coli (5/15; 33.3%), and Klebsiella pneumoniae (2/15; 20%), 4/20 (20%) were viral; 3/4 due to SARS-COV2 and 1/4 due to dengue, and 1/20 (5%) had Candida albicans. 14 (33.3%) patients had fever of unknown origin. 24/42 patients (68%) had a MASCC score &lt; 21. Mortality rate was 30.9% (n=13), of which 12 (92%) had a MASCC score &lt; 21 (p=0.02).
p=0.33.
Source: Statistical registry of the authors.

Conclusion
This study emphasizes how infectious complications greatly impact cancer patients experiencing febrile neutropenia, especially those with hematologic malignancies. Bacterial infections, notably Pseudomonas aeruginosa and Escherichia coli, are prevalent, highlighting the urgency of precise diagnostic methods for tailored antimicrobial treatment. The link between low MASCC scores and higher mortality rates focuses the importance of this risk assessment tool in guiding clinical decisions. These findings stress the necessity for improved multidisciplinary strategies to enhance the outlook for this vulnerable patient group.
MASCC risk vs outcome
p=0.02
Source: Statistical registry of the authors.

Disclosures
All Authors: No reported disclosures
P-2300. Invasive Pulmonary Aspergillosis-Mimicking Pseudomonas aeruginosa Pneumonia in Immunocompromised Patients
Authors: Yoon Choseok , Chang Euijin , Bae Seongman , Jung Jiwon , Kim Min Jae , Chong Yong Pil , Lee Sang-Oh , Choi Sang-Ho , Kim Yang Soo , Kim Sung-Han 
Published: January 2025

Abstract

Background
Pseudomonas aeruginosa (PA) pneumonia is occasionally misdiagnosed as invasive pulmonary aspergillosis (IPA) in immunocompromised patients, especially transplant recipients or those with hematologic malignancy who have risk factors for IPA. However, there are limited data on this area. We thus investigated the clinical features and CT findings of PA pneumonia in immunocompromised patients.

Methods
All immunocompromised patients who were diagnosed as PA pneumonia was retrospectively reviewed in a tertiary hospital between 2017 and 2023. PA pneumonia was classified as follows; “confirmed”: positive culture from sterile tissues (blood, tissue, etc.) with radiologic compatible findings with pneumonia, “probable”: i) abnormalities on chest X-ray, ii) culture growth from non-sterile sources such as sputum or bronchoalveolar lavage fluid, iii) improvement with the use of anti-pseudomonal antibiotics without the use of antifungal agents, and “possible”: cases that do not meet the above criteria but cannot rule out PA pneumonia.

Results
Of 16 immunocompromised with PA pneumonia, 13 (81%) were male, and 9 (56%) were transplant recipients. Of these 16 patients, 9 (56%) were classified as “confirmed”, 5 (31%) “probable”, and the remaining 2 (13%) “possible”. 7 (44%) patients with PA pneumonia had concurrent IPA, with 1 proven IPA and 6 probable IPA. The remaining 9 patients with PA pneumonia alone revealed macronodules (n=5), mass-like consolidation (n=6), cavitary lesions (n=6), and halo sign (n=4) in initial CT findings. Of the 16 patients with PA pneumonia, 4 (25%) received inappropriate antifungal therapy.

Conclusion
About half of immunocompromised patients with PA pneumonia had concurrent IPA, but about one quarter of immunocompromised patients with PA pneumonia received inappropriate antifungal therapy.

Disclosures
All Authors: No reported disclosures
P-2314. Assessing Hazard Ratio of Recurrent Spontaneous Bacterial Peritonitis: Impact of Antibiotic Prophylaxis in Cirrhotic Patients
Authors: Nguyen Trong-Tuong , Arab Niki , Kim Brian , Jeng Arthur 
Published: January 2025

Abstract

Background
Spontaneous bacterial peritonitis (SBP) is a severe infection of the ascitic fluid in individuals with advanced liver disease and ascites. The American Association for the Study of Liver Diseases recommends antibiotic (abx) prophylaxis (ppx) for patients with a history of SBP, low ascitic fluid protein (&lt; 1.5 g/dL), or advanced cirrhosis with ascites. However, prophylactic antibiotics cause collateral damage and their efficacy in reducing SBP recurrence remains uncertain. This study assesses the recurrence rates between groups receiving prophylaxis and those without.

Methods
Single centered, retrospective cohort study aimed to estimate the hazard ratio (HR) for recurrent SBP in patients with and without SBP ppx. Patients meeting criteria of cirrhosis with documented ascites and polymorphonuclear leukocyte count ≥ 250 cells/µL were randomly selected between 2017 to 2023. The primary outcome was time to recurrent SBP. Cox proportional hazard models were used to estimate the HR and 95% confidence intervals (CIs).

Results
38 patients were included, 4 patients received SBP ppx. The HR for recurrent SBP was not statistically significant [0.765 (95% CI -1.58, 1.04)] between use of SBP ppx and those with no ppx abx. This analysis was controlled for age, gender, alcohol use, cancer, diabetes, chronic kidney disease, chronic lung disease, autoimmune disease, and HIV status. Incidentally we found that, of the 4 patients who received prophylaxis, 2 developed extended spectrum beta lactamase (ESBL) producing gram negative infections in either ascitic or blood cultures.

Conclusion
Our analysis did not demonstrate a statistically significant difference in the hazard of recurrent SBP between patients with versus without ppx. SBP ppx was found to have potential risk of recurrent SBP with more resistant ESBL-producing pathogens for those on SBP ppx. Additional study may be warranted to further elaborate the benefit vs risk of SBP ppx in terms of development of resistance.

Disclosures
All Authors: No reported disclosures
P-2326. The Under-recognized Burden of Lassa Virus Infection in Liberia
Authors: Nimely Catherine , Kerkula Emmanuel , Krajewski Taylor , Colt McKenzie , Flomo Alfred , Fofana Amara , Kerkula Stanley , Remont Thomas , Watts Rosie , Tozay Sam , Mollan Katie R , Zivich Paul , Ricks Minnie , Wohl David A , Fischer William A , Sibley Jefferson 
Published: January 2025

Abstract

Background
Lassa virus (LASV) is a persistent and lethal threat in endemic regions of West Africa. While severe disease due to Lassa fever (LF) is responsible for 5000-10,000 deaths annually, there is evidence of a wide spectrum of clinical manifestation of LASV infection.

Methods
The Coalition for Epidemic Initiative (CEPI) sponsored ENABLE study is a prospective, observational, cohort study of the prevalence and incidence of LASV infection and LF in five West African countries: Nigeria, Liberia, Sierra Leone, Guinea, and Benin. LASV seroprevalence was determined by LASV nucleoprotein (NP) IgG at entry (ReLASV NP IgG ELISA). Participants were assessed every 2 weeks in-person for fever with and without LF symptoms. Febrile events triggered LASV RT-PCR (RealStar Lassa Virus RT-PCR Altona 2.0). To assess for subclinical LASV infection, serum was collected every 6 months for 2 years from a subset (Infection Cohort) for LASV NP IgG.

Results
In Liberia, 5,005 were enrolled between April 2021 and December 2023; 25 withdrew before data collection. Of the remaining 4,980 participants, 1,018 were in the Infection Cohort and 591 of these provided samples at all 5 time points. At entry, 2,259 (45%) were LASV NP IgG positive. Entry LASV NP IgG seropositivity increased with age with the lowest prevalence among those 2-5 years (101 of 510, 20%, CI: 17-24%) rising to a peak among participants 30-39 years (322 of 564, 57%, CI: 53-61%). Of the 591 with serological results at all 5 timepoints, 314 (53%) were LASV NP IgG negative at study entry and 68 (22%) had at least a single change in serostatus from seronegative to seropositive. Over 24-months, 1,176 febrile events in 818 participants were identified and of these 10 (1%) had LASV RNA detected.

Conclusion
In this 24-month longitudinal study of individuals in a LASV hyperendemic area of West Africa, close to half were LASV seropositive at enrollment, and across two years of follow-up, 1 in 5 participants who were LASV seronegative at entry had observed seroconversion. However, only a small number of LF cases (n=14) were identified through symptom-driven testing dependent on fever. These findings indicate that in this region of Liberia LASV infection is common, increases during the first decades of life, but is rarely clinically detected.

Disclosures
Katie R. Mollan, MS, Gilead Sciences: Grant/Research Support|Ridgeback Biotherapeutics: Grant/Research Support
P-43. A Single Composite Peptide Vaccine Comprising Conserved Influenza Epitopes Formulated with ALFQ Adjuvant Induced Broadly Reactive Antibodies to Human, Avian, and Swine Influenza Viruses
Authors: Rikhi Nimisha , Sei Clara J , Rao Mangala , Kroscher Kellie , Matyas Gary , Schuman Richard F , Muema Kevin , Lange Camille , Assiaw-Dufu Aba , Alving Carl R , Fischer Gerald W 
Published: January 2025

Abstract

Background
Reassortant influenza strains containing genes from human, avian, and/or swine origin, have led to major outbreaks, such as the 2009 swine flu pandemic. The ongoing global spread of highly pathogenic avian influenza (HPAI) A/H5N1 virus among poultry highlights the risk of zoonotic transmission leading to pandemics. A universal influenza vaccine that generates broadly neutralizing antibodies against influenza viruses is crucial for preventing future pandemics. Previous studies with our unconjugated composite peptide vaccine (two-peptide combination), which targets multiple highly conserved epitopes on influenza virus, generated broadly reactive antibodies to human and avian strains, including HPAI A/H5N1 viruses. A single peptide vaccine approach offers formulation and scale-up advantages. Here, we demonstrate that a novel, unconjugated, single composite peptide vaccine comprising highly conserved epitopes of hemagglutinin (HA), neuraminidase (NA), and matrix (M1/M2/M2e), and a universal T cell epitope, formulated with the highly potent adjuvant Army Liposomal Formulation with QS21 (ALFQ), induced broadly reactive antibodies to human, avian, and swine influenza strains.

Methods
ICR mice were immunized intramuscularly on days 0, 21, and 35 with 2μg of composite influenza peptide vaccine LHNVD-110, formulated with ALFQ adjuvant. Isotype-specific IgG titers to peptides and influenza A (H1N1pdm09, H3N2, HPAI H5N1) and B (Victoria, Yamagata) viruses were analyzed by ELISA. Neutralizing titers were determined using the microneutralization assay and inhibition of HA using the HAI assay.

Results
Robust serum IgG1 antibodies to human, avian, and swine influenza A and B viruses were induced. Post-immunization serum demonstrated neutralization and HA inhibition of Group 1 and 2 influenza viruses.

Conclusion
An unconjugated single composite peptide vaccine comprising highly conserved HA, NA, and matrix epitopes, formulated with ALFQ adjuvant, generated broadly reactive antibodies to human, avian, and swine influenza strains and neutralized seasonal and pandemic strains. This single composite peptide vaccine provides a cost-effective, and easily scalable strategy towards a universal influenza vaccine to combat future pandemics.

Disclosures
All Authors: No reported disclosures
P-54. High Dose Intramuscular Influenza Vaccine in Solid Organ Transplant Patients. A Systematic Review and Meta-analysis
Authors: Rahimi Shahmirzadi Reza , Abdar Esfahani Meisam , Couban Rachel , Cairns Sarah , Elsayed Sameer , Silverman Michael 
Published: January 2025

Abstract

Background
Seasonal influenza can cause serious illness and even death, especially in immunocompromised people such as solid organ transplant recipients (SOT). Early results from some studies show that high dose (HD) intramuscular (IM) vaccine might help boost the body's immune response in transplant patients. Given the uncertain benefits and harms associated with various IM vaccine doses a synthetized appraisal of the evidence is warranted.Figure 1:Seroconversion rate in Influenza A(H1N1) (SC H1N1) Forest plot

Methods
Randomized controlled trials of adults who underwent SOT and received IM influenza vaccine and compared , IM influenza HD vaccine with standard dose. The outcomes of interests are seroconversion rate (SCR) for H1N1,H3N2, and graft rejection after vaccination. We searched MEDLINE, Embase, and Cochrane CENTRAL until Jan 2024. Screening, data extraction, risk of bias and certainty of evidence assessment were assessed by two reviewers.Figure 2:Seroconversion rate in Influenza A (H3N2) (SC H3N2) Forest plot

Results
Pooling data from the 5 studies (1281 patients) shows moderate quality of evidence in the SCR towards using HD influenza vaccine in H1N1 type and high-quality evidence for H3N2 type . (RR 1.87 (1.25 to 2.79), RR 1.54 [1.31 to 1.80]). Analysis of five studies indicated that HD influenza vaccine results in no difference in graft rejection. (RR 0.73 [0.37 to 1.45]). High quality evidence showed that HD influenza vaccine reduce serious adverse events in SOT patients. (RR 0.71 [0.52 to 0.96]). Data from three studies shows HD influenza vaccine may results in little to no difference in confirmed clinically influenza. (low certainty of evidence) (RR 1.16 [0.58 to 2.29]).Figure 3:Graft rejection (GR) Forest plot

Conclusion
Our systematic review indicates that HD influenza vaccine probably increases SCR in H1N1 and increases SCR in H3N2.HD vaccine, also may not increase graft rejection and reduces serious adverse events in SOT patients.
GRADE Summary of Findings (SoF) Table

Disclosures
Reza Rahimi Shahmirzadi, MD, Pfizer: Grant/Research Support Meisam Abdar Esfahani, MD, Pfizer: Grant/Research Support Michael Silverman, MD, FRCP, FACP, AAHIVMed, Pfizer: Grant/Research Support