bluuebunny/crossref_metadata_2025_split huggingface dataset:
P-1837. Development and Validation of a Novel Multiplex Immunoassay for the Measurement of the Antibodies against Pneumococcal Vaccine Serotypes
Authors: Hayashi Yumiko , Kato Kentaro , Morimoto Konosuke , Ariyoshi Koya , Dhoubhadel Bhim G 
Published: January 2025

Abstract

Background
Enzyme-linked immunosorbent assay (ELISA) is a traditional WHO recommended method to measure antibody levels against pneumococcal vaccines. However, ELISA is limited in its capacity to assess all 24 pneumococcal vaccine serotypes simultaneously, which is time-consuming, labor-intensive, and it requires a large amount of serum samples. Therefore, we require a high-throughput assay to assess all vaccine serotypes simultaneously and efficiently to assess pneumococcal vaccine impact at a population level.

Methods
Twenty-four pneumococcal polysaccharide antigens were coupled with 24 distinct colored microspheres by employing the carboxyl method. These conjugated microspheres were exposed to the WHO reference serum in a well of a 96-well plate. The WHO reference serum contained 24 serotype-specific pneumococcal antibodies whose concentrations were known. After washing, a mouse anti-human IgG monoclonal antibody (a secondary antibody tagged with phycoerythrin) interacted with the antigen-antibody complex, and then the final reaction was read on the Bio-Plex 200 System (BioRad). We performed assay validation parameters, such as sensitivity, specificity, linearity, and reproducibility according to the WHO recommendation.

Results
A 4.0 log10 of dynamic range was observed in all standard curves specific for 24 serotypes. Depending on specific serotypes, a lower limit of quantitation (sensitivity) varied from 0.40 ng/mL to 10.05 ng/mL. The assays were highly specific for individual serotypes, except for 6A and 6B, and 19F and 19A (some cross-reactivity was observed, which was known and expected among these serotypes). Specificity was &gt;90% in all serotypes, except serotypes 8 (87%) and 14 (59%). Reproducibility trials showed that the coefficient of variation for all serotypes was &lt; 20% (desired limit), except serotype 19A (29.7%) and 23F (25.4%).

Conclusion
We have developed and validated the novel microsphere-based assay. As this assay enables the simultaneous measurement of 24 vaccine serotype-specific antibodies in a single well, it will reduce workload, the need for the amount of serum, and the overall cost. We expect to use this assay in pneumococcal vaccine immunogenicity studies among an elderly population in Japan and among young children in Nepal.

Disclosures
Konosuke Morimoto, MD, PhD, Pfizer: Grant/Research Support Koya Ariyoshi, MD, PhD, Pfizer: Grant/Research Support
P-1838. The human Herpesvirus dUTPases of EBV and HSV-1 may contribute to neurological disorders by altering the integrity of the blood brain barrier and promoting a pro-inflammatory microenvironment
Authors: Mena-Palomo Irene , Martinez Victor , Perdersen Irene Munk , Ariza Maria 
Published: January 2025

Abstract

Background
The global prevalence of Herpes Simplex Virus 1 (HSV-1) and Epstein-Barr Virus (EBV) ranges from 60% to &gt;90%. Some herpesviruses have been linked to neurological diseases including Alzheimer’s disease (AD) and one common feature to these pathologies is disruption of the blood-brain barrier (BBB). The BBB is a key structure responsible for protecting the brain from toxic substances due to its high impermeability and providing energy which is critical for proper brain function. While disruption of the BBB is a hallmark of numerous neurological disorders, the mechanisms underlying herpesvirus-induced BBB dysfunction remain elusive.
Herpesvirus dUTPases encoded by EBV and HSV-1 alter blood brain barrier integrity
Stress, aging as well as other environmental and genetic factors can reactivate human herpesviruses to undergo lytic or abortive-lytic replication, which results in the release of viral dUTPases as a free protein or in exosomes. dUTPase-containing exosomes can travel to the brain via the bloodstream and target cells at the blood brain barrier, triggering the release of pro-inflammatory cytokines and disturbing the structural and functional properties of cell-cell contact molecules. Altogether, the herpesviruses dUTPases can contribute to neurological disorders by increasing blood brain barrier permeability and promoting neuroinflammation.

Methods
In this study we investigated whether a viral protein of EBV and HSV-1 called dUTPase can alter BBB integrity using AD clinical samples, in vitro and 3D perfused hiPSC-derived BBB/NVU models, in combination with a multi-system analysis approach that included, trans-endothelial electrical resistance (TEER), confocal imaging, ELISA, proteome array and qRT-PCR/RNAseq.

Results
Exposure of 3D BBB to HSV-1 or EBV dUTPases resulted in significant BBB permeability, reduced TEER, and loss of functional tight junction protein (TJP; ZO-1 and Claudin-5) structural and functional properties. Both dUTPases significantly increased the expression and/or secretion of IL-1β, IL-6 and TNF-α in immortalized human cerebral microvascular endothelial cells, astrocytes and pericytes. A modest but significant increase in IL-1β and IL-6 mRNA was also observed in dUTPase-treated astrocytes. These cytokines are elevated in patients with AD and are known to disrupt BBB integrity and induce neuroinflammation.

Conclusion
In conclusion, this study provides compelling evidence that EBV/HSV-1 dUTPases have the potential to disrupt the BBB and foster a pro-inflammatory environment in the brain. Thus, it highlights a novel mechanism linking common herpesviruses to brain pathologies.

Disclosures
All Authors: No reported disclosures
P-1845. Evaluation of the immunogenicity and protective efficacy of a fusion vaccine based on the class 5a fimbrial tip of Enterotoxigenic Escherichia coli (ETEC) in an Aotus nancymaae CS14+ and CFA/I+ challenge model
Authors: Gaspar Juan Carlos , Moeller Tyler , Prouty Michael , Nunez Rosa , Espinoza Nereyda , Nieto Monica 
Published: January 2025

Abstract

Background
Enterotoxigenic Escherichia coli (ETEC) colonizes intestinal epithelial cells via colonization factors (CFs), fimbrial, non-fimbrial, and helical adhesins. Once attached, ETEC can release enterotoxins including heat-stable toxin (ST) and/or heat-labile toxin (LT) which cause hypersecretion of fluid in the intestinal lumen resulting in watery diarrhea. Currently, there are no effective countermeasures against ETEC, and antibiotic treatments are losing effectiveness due to increasing antimicrobial resistance. Passive or active immunization against CFs are alluring targets to prevent adhesion, colonization, and ultimately, diarrhea. However, ETEC which infects humans exhibits remarkable heterogeneity and expresses at least 29 immunologically different CFs, making it difficult to create a broadly targeting vaccine that is effective in preventing diarrhea caused by multiple ETEC strains. One third of the CFs that have been described belong to one of three phylogenetic families: CFA/I-like family, which is defined as Class 5 fimbriae divided into three subclasses, 5a, 5b and 5c that are highly related in structure and function.

Methods
In this work, we evaluated the efficacy of a vaccine based on the CFA/I adhesin-pilin fusion (CfaEB) fused to the pilins of colonization factor CS14 (CsuA2) and CS4 (CsfA) to generate broad cross-protection against members of subclass 5a. We previously established a non-human primate challenge model for CS14+ ETEC (strain WS3294A) and found that a 5x1012 CFU dose was needed to achieve a sufficiently high (70%) attack rate. Therefore, the same challenge dose was used to evaluate the effectiveness of the vaccine candidate CfaEp3 (CfaEB-CsuA2-CsfA) against ETEC H10407 (CFA/I; n=10) and WS3294A (CS14; n=10).

Results
Animals that received four vaccine doses with dmLT adjuvant, administered intradermally, were protected from challenge with WS3294A (91% efficacy; p=0.05). However, only 20% protection against ETEC H10407 was achieved.

Conclusion
Although the vaccine candidate did not present cross-protection against members of subclass 5a, the model opens the possibility of future testing of combined vaccines to combat infection with the main pathogenic strains of ETEC encountered by travelers, the military, and civilian populations.

Disclosures
All Authors: No reported disclosures
P-1846. Differences in Type 6 Secretion System Composition among Serogroups of Neonatal Meningitis Escherichia coli
Authors: Ienes-Lima Julia , Álvarez-Narváez Sonsiray , Barbieri Nicolle , Nolan Lisa , Logue Catherine 
Published: January 2025

Abstract

Background
Neonatal meningitis is a public health challenge for pediatricians. Neonatal meningitis Escherichia coli (NMEC) is the most common Gram-negative bacterial cause of sepsis and meningitis in newborns in the United States. NMEC strains can replicate in macrophages, survive in the bloodstream and traverse the blood-brain barrier, resulting in meningitis. Most NMEC cases are associated with serogroups O18, O83, O7, O12, O1, and O45 (Logue et al., 2012). Two clusters of the Type 6 Secretion System (T6SS-I and T6SS-II) were identified in an NMEC O18:K1 strain, and studies have demonstrated that T6SS plays an essential role in the pathogenesis of several bacterial species. However, there is still a lack of knowledge regarding the function of some T6SS genes. Here, we investigated the role of T6SS in different NMEC serogroups to identify specific genes that may be used as a potential target for an efficacious prevention strategy.
Characteristics of NMEC strainsFigure 1.Characteristics of NMEC strains used in this study. A) Percentage of serogroups; B) Prevalence of T6SS among the NMEC isolates.

Methods
A total of 120 NMEC genomes were used in this study (n=78 from the Logue Lab collection; n=42 publicly databases). The T6SS clusters were identified through BLAST analysis using NMEC RS218 and O18 as reference genomes. To establish the presence of a specific cluster, a query cover and percentage identity threshold of 60% and 70% were set. The sequence comparisons were performed using the Artemis Comparison Tool (ACT).

Results
The serogroup O18 was the most abundant (23%; n=28), followed by O1 (22%; n=26), and O83 (12%; n=14). Analysis examined the prevalence of both T6SS clusters in the NMEC genomes and identified that they were present in 69% (n=83) of the genomes, while 12% (n=14) have only one of the clusters, and 19% (n=23) have no clusters. The presence of both T6SS clusters was observed in the serogroups O18, O14, and O2/O50. In contrast, no gene of any cluster was identified in serogroup O7. To understand the role of variation among the serogroups, in vitro analyses were performed. The results indicate differences in survival within THP-1 macrophages-like among distinct serogroups.

Conclusion
Our results support the hypothesis that T6SS components differ among the NMEC serogroups, potentially impacting their pathogenicity and ability to cause meningitis. These findings have significant implications for development of a prevention strategy for neonatal meningitis.

Disclosures
All Authors: No reported disclosures
P-1847. Exploring the correlation between time to positivity and positive culture bottle count in Staphylococcus aureus bacteremia: implications for metastatic lesion development
Authors: Ishikawa Kazuhiro , Sekiya Satoru , Mori Nobuyoshi 
Published: January 2025

Abstract

Background
While numerous studies have investigated the correlations among time to positivity (TTP) in blood cultures, the number of positive bottles, and mortality rates, the association with metastatic lesion formation in Staphylococcus aureus (S. aureus) bacteremia remains poorly understood. This investigation aims to assess the impact on the severity of the, mortality, and the frequency of metastatic lesions.
Study Population Flowchart
Flowchart illustrating categorization of S. aureus-positive blood culture cases for assessing TTP, bottle count, severity, mortality, and metastatic lesions.

Methods
A retrospective analysis was conducted on patients over 15 years old, admitted to St. Luke's International Hospital between 2015 and 2023, who tested positive for S. aureus in blood cultures. Patients with polymicrobial patterns or transferred within a week were excluded. Metastatic lesions were identified through chart reviews and imaging.
Baseline Characteristics of Study Participants

Results
From 398 initial cases, 317 patients were included after exclusions (Figure 1). The patient cohort had an average age of 70.3 years (Standard deviation, SD: 17.0), with 62.5% being male, and 22.4% with MRSA infections. The average TTP was 19.9 hours (SD: 11.9) (Table 1). No significant differences were observed in TTP or bottle count in relation to mortality or severity. Further investigation into the relationship with metastatic lesions shown in Table 2 revealed that TTP for patients with intravascular infections was significantly shorter, averaging 16.81 hours (SD: 5.68), compared to 23.45 hours (SD: 13.84) in bacteremia without metastatic lesions. TTP for bone and joint infections was significantly shorter, averaging 17.88 hours (SD: 8.26), compared to bacteremia without metastatic lesions. SSTI did not show a significant difference in TTP. A weak correlation was found between TTP and metastatic lesion counts (r=0.203) (Figure 2). Additionally, TTP and positive set count showed a weak correlation (r=0.544). When TTP cannot be determined, bottle counts may offer an alternative indicator.
number of complications due to S. aureus

Conclusion
While TTP and bottle count were weakly correlated, they failed to predict severity or mortality in S. aureus bacteremia. Positivity within 24 hours warrants further examination for metastatic conditions like intravascular and bone infections. Yet, TTP and bottle counts' predictive value for metastatic lesion quantity is minimal, highlighting the need for thorough physical exams and imaging.
Correlation between number of disseminated lesions and positive time

Disclosures
All Authors: No reported disclosures
P-1860. Staphylococcus aureus nasal colonization and transmission is enhanced by concurrent influenza A virus upper respiratory infection in an infant mouse model
Authors: Ulrich Robert J , Bartlett Stacey , Morales Sabrina M , Rocha Hedy , Ortigoza Mila B 
Published: January 2025

Abstract

Background
Staphylococcus aureus asymptomatically colonizes the anterior nares of 20-30% of the population, and nasal carriage is a major risk factor for invasive S. aureus disease. Furthermore, rates of S. aureus nasal colonization are higher (40-50%) during the first eight weeks of life and colonizing strains can be transmitted among household contacts. Affecting the same niche, influenza A virus (IAV) is a common cause of viral upper respiratory infection (URI), and IAV predisposes the host to post-URI secondary S. aureus pneumonia. Despite the frequency of S. aureus and IAV in a shared anatomic site, the effects of IAV on S. aureus nasal colonization and transmission are understudied, and infant animal models that may better represent the younger high-colonization age group are not reported.
Infant mouse model
Two index pups from each litter were inoculated with S. aureus, and on day three the entire litter was either infected with IAV or mock (PBS) solution. S. aureus shedding is monitored daily and nasal lavage was performed.

Methods
We established nasal colonization in infant B6 mice by inoculating 106 colony forming units (CFU) of S. aureus MRSA strain JE2 and quantified nasal shedding for seven days on S. aureus chromogenic agar plates. For transmission experiments, we colonized two index pups per cage with S. aureus and infected the groups of pups with Influenza A virus (IAV) or mock (PBS) control on day three after S. aureus colonization. Nasal shedding of S. aureus was quantified daily and nasal lavage was performed at day seven.

Results
Infant mice maintain S. aureus nasal colonization at seven days post-inoculation and they can transmit the colonizing strain to naive co-housed pups. IAV infection increases the S. aureus colonization burden 1000-fold by day 5 and the transmission to co-housed naïve pups by 63%.

Conclusion
Influenza A virus infection increases nasal colonization burden of S. aureus and transmission to S. aureus-naive close contacts in an infant mouse model. We anticipate the model to be a starting point for the study of bacteria-virus interactions that contribute to S. aureus colonization in a high-risk population. Moreover, our work will allow for the study of both S. aureus and IAV mechanisms that contribute to S. aureus transmission amongst close contacts.

Disclosures
All Authors: No reported disclosures
P-1863. Maternal Mycobacterial-Specific T-cell Signatures and Infant Risk of Mycobacterium tuberculosis Infection
Authors: Himmelfarb Talia , Warr Alex , Kinuthia John , Matemo Daniel , Mecha Jerphason O , LaCourse Sylvia M , John-Stewart Grace , Harrington Whitney , Hawn Thomas 
Published: January 2025

Abstract

Background
Tuberculosis disease (TB) caused 214,000 pediatric deaths in 2022. A growing body of evidence suggests that HIV exposed uninfected infants (iHEU) are at increased risk for Mycobacterium tuberculosis (Mtb) infection. Harnessing the power of the maternal immune system to protect infants has shown promise in other infections. Yet no well powered study has evaluated the association between maternal mycobacterial-specific T cell memory and infant protection from Mtb infection. To address this knowledge gap, we examined the hypothesis that previously undescribed maternal factors modulate infant immunity to bacillus Calmette-Guèrin (BCG) and Mtb.Fig 1.Mothers of infants negative for Mtb infection had higher proportions of CD8 T cells expressing IL2 in response to mycobacterial antigens.ESAT-6/CFP-10 negative median 0.004710 (95% CI 0.00096000-0.01103), positive median 0.0 (95% CI 0-0.009410). TBWCL negative median 0.01172 (95% CI 0.005340-0.01860), positive median 0.003710 (95% CI 0-0.008467).

Methods
This study was nested within a randomized controlled trial of isoniazid to prevent Mtb infection in 300 iHEU (iTIPS) who were vaccinated with BCG at birth, randomized to isoniazid or placebo at 6-10 weeks, and had Quantiferon-Plus (with IFNγ, IL2, IP10, TNF measured in supernatant) (QFT-4) at 14 months, and/or tuberculin skin testing (TST) at 14 and 24 months. Paired maternal peripheral blood mononuclear cells were collected at the 6-10 week visit. The majority (73%) of mothers started antiretroviral therapy before pregnancy, 26.3% during pregnancy, and 0.7% after pregnancy. Frequency of self-reported history of TB disease was 10.7%. We assessed the response of maternal T cells to Mtb whole cell lysate (TBWCL), a proxy for BCG, and ESAT-6/CFP-10 (E6C10), an Mtb specific peptide pool, by flow cytometry with a T cell panel including surface, memory, and activation markers and IL2, IL17A, IFNγ, and TNF.

Results
Our preliminary analysis of 166 of 235 maternal samples with flow cytometry revealed that mothers of infants with positive TST or QFT-4 had significantly fewer CD8+IL2+ cells in response to TBWCL (median 0.0037% vs 0.0117%, p=0.032) (Fig 1). Conversely mothers of these infants had significantly higher CD4+TNFa+ responses to E6C10 (median 0.0458% vs 0%, p=0.0014) and CD4+IFNγ+ responses to TBWCL (median 0.0533% vs 0.0302%, p=0.0395).

Conclusion
These results establish that maternal mycobacterial-specific immune signatures are associated with infant outcomes, which we plan to further investigate by comparing these maternal signatures with infant T cell response to TBWCL and determining the role of maternal microchimeric cells.

Disclosures
Sylvia M. LaCourse, MD, MPH, Merck: Grant/Research Support|UpToDate: Royalties
P-1880. An Innovative Infectious Diseases Hospitalist Model - Supporting Lean ID Teams
Authors: Ue Frances V , Banerji Debjani , Bruno-Murtha Lou Ann 
Published: January 2025

Abstract

Background
Two-thirds of the US population live in counties with no or below-average ID physician (ID/P) coverage. This workforce shortage is exacerbated by emerging ID threats and an inadequate fellowship match. In response to these demands, we developed an innovative ID hospitalist (ID/H) model. Subspecialty hospitalists have been increasing since the early 2000s, and ID/Hs may provide support to a stretched ID workforce and mitigate burnout.

Methods
Setting: Cambridge Health Alliance (CHA) is an academic, community, safety-net healthcare system in Massachusetts with two hospitals and multiple outpatient clinics. It serves &gt;140,000 patients in Boston’s metro-north region.
Intervention: CHA’s ID Division is composed of 4 attending physicians (2 FTE total in ID), 1 physician’s assistant (PA), and 1 ID pharmacist. Inpatient consultations are usually performed by 2 ID/Ps (1 at each hospital campus) with partial PA support. During high volume and low staffing weeks from 7/2021 to 4/2023 with only 1 ID/P available, a new staffing model was created. An ID/H provided in-person consultations at one campus (with over-the-phone discussion with the ID/P), while the ID/P provided in-person consultations at the other campus. Outcomes were evaluated via surveys to the ID/Ps, chart review analyzing recommendations, and financial modeling of compensation rates at CHA and locum agencies.

Results
An ID/H completed 59 clinical encounters during 21 shifts over 9 weeks in the study period. All ID/Ps had high/highest satisfaction working with an ID/H when ranked on a Likert scale. ID/Ps characterized the impact of the ID/H in Table 1. Qualitative themes included an increase in staffing flexibility and timely patient care.
There was a high adoption rate of consult recommendations (58/59= 98.3%). The majority of consults were sought by the Medicine service (49/59= 83.1%). ID Consults are characterized in Table 2.
This model was cost-effective for department finances compared to utilization of ID moonlighters or locums. Locums are compensated at a much higher hourly rate and due to delays with insurance processing, the institution may not receive reimbursement for their work.

Conclusion
An ID/H model is a novel way to support lean ID teams. Future research is needed to explore if this will attract more physicians to ID.

Disclosures
All Authors: No reported disclosures