bluuebunny/crossref_metadata_2025_split huggingface dataset:
230. Risk factors for bacteremia in patients receiving extracorporeal membrane oxygenation (ECMO) during the COVID-19 pandemic
Authors: Hendrix Curtis , Radcliffe Christopher , Tantawy Hossam , Roberts Scott C 
Published: November 2023

Abstract

Background
Patients receiving extracorporeal membrane oxygenation (ECMO) are at high risk for bacteremia which can cause substantial morbidity and mortality. We sought to evaluate risk factors for bacteremia in patients receiving ECMO during the COVID-19 pandemic to better characterize those most at risk and areas for prevention.

Methods
A retrospective case control study evaluating patients receiving ECMO support at Yale New Haven Hospital from April 2020 – September 2021 was performed. Cases of patients who developed bacteremia were matched 1:2 to control patients on ECMO who had blood cultures drawn but who did not develop bacteremia. There were no set criteria for drawing the blood cultures; when to draw blood cultures were per provider’s discretion. Only the first set of blood cultures drawn were analyzed.

Results
60 patients received ECMO support and had blood cultures drawn, 20 (33.3%) with bacteremia matched to 40 (66.7%) without bacteremia. Independent risk factors for bacteremia included being diagnosed with COVID-19 (70.0% vs 40.0%, p = 0.028), days on ECMO until culture (13.4 vs 6.2 days, p = 0.005), days on mechanical ventilation until culture (17.5 vs 7.7 days, p = 0.002), corticosteroid use (75.0% vs 40.0%, p = 0.011), ECMO type (80.0% veno-venous [VV] and 20.0% veno-arterial vs 37.5% veno-venous and 62.5% veno-arterial, p = 0.002), proning (60.0% vs 22.5%, p = 0.004), and preceding antibiotic days during the admission (16.1 days vs 9.3 days, p = 0.025). There was no difference in any evaluated infectious metric (white blood cell count, daily maximum temperature, procalcitonin, CRP, d-dimer, ferritin, fibrinogen, LDH) on the day of blood culture in those with compared to those without bacteremia.

Conclusion
Patients receiving ECMO support who developed bacteremia were more likely to be on VV-ECMO, proned, receive corticosteroids, and be on mechanical ventilation for longer periods of time, all factors associated with severe COVID-19. Additional risk factors included more days on ECMO and prior antibiotic use. No laboratory metric was predictive of bacteremia, highlighting the challenges in accurately predicting bacteremia in the ECMO patient population.

Disclosures
All Authors: No reported disclosures
232. Malnutrition is Associated with Poor Outcomes in Patients Hospitalized with Staphylococcus aureus Bacteremia
Authors: Saad Baraa , Saleh Nourhan , Alkhader Aseel , Garg Nikita , Reynoso David 
Published: November 2023

Abstract

Background
Staphylococcus aureus bacteremia (SAB) is one of the most common and clinically significant bacterial infections worldwide. Malnutrition has been linked to poor outcomes in various infectious and non-infectious diseases. The objective of this study is to investigate the impact of malnutrition on the outcomes among adult patients hospitalized with SAB.

Methods
A cohort study was conducted using the Nationwide Inpatient Sample (2016-2019). Adult hospitalizations with Methicillin-Sensitive or -Resistant Staphylococcus aureus bacteremia were identified and stratified by the presence of malnutrition using ICD-10 codes. The primary outcome was in-hospital mortality. Secondary outcomes included ICU admissions, septic shock, mechanical ventilation, length of stay (LOS), and hospital charges. Multivariate regression analysis adjusted for confounding factors.

Results
Of 518,840 SAB patients, 14.10% had malnutrition. Malnourished patients showed higher rates of mortality, septic shock, mechanical ventilation, mean LOS, and hospital charges. Multivariate analysis revealed malnutrition as an independent predictor of worse outcomes. Adjusted odds ratios were 1.60 for mortality (P&lt; 0.001), 1.69 for septic shock (P&lt; 0.001), and 1.75 for mechanical ventilation (P&lt; 0.001). Adjusted mean LOS and total charges increased by 6.14 days and $87,885 for malnourished SAB patients. Outcomes were similar for MSSA and MRSA.

Conclusion
Our study highlights the significant impact of malnutrition on outcome among patients hospitalized with SAB. We found that malnourished individuals with SAB had higher rates of mortality, septic shock, mechanical ventilation, prolonged hospital stays and increased financial burden. These results emphasize the critical need to address and recognize malnutrition as a significant risk factor in the management of SAB. Further research and interventions targeting the issue of malnutrition in SAB patients are needed to enhance outcomes, decrease associated mortality and morbidity, and reduce healthcare cost.

Disclosures
All Authors: No reported disclosures
243. A Laboratory Intervention to Enhance Recognition of Bacteremia in Patients with Staphylococcus aureus Bacteriuria
Authors: Vaillant James J , Chesdachai Supavit , Comba Isin Y , Tabaja Hussam , Yetmar Zachary A , Abu Saleh Omar M 
Published: November 2023

Abstract

Background
Staphylococcus aureus bacteriuria (SABU) represents 0.2–4% of all positive urine cultures. While asymptomatic colonization or infection of the urinary tract is possible, hematogenous seeding from S. aureus bacteremia (SAB) represents a potentially life-threatening condition. The rate of concomitant SAB is estimated to be 6.9–17.2% among those with SABU, and these patients are at higher risk of in-hospital mortality, infective endocarditis, embolic events, and vertebral osteomyelitis. Detection of SABU represents an opportunity for early detection and intervention in SAB.

Methods
We conducted a retrospective analysis of clinical and microbiological characteristics of adult patients with SABU as our pre-intervention baseline. We then implemented a comment with the urine culture result in the electronic medical record (EMR) advising providers about the possibility of concomitant bacteremia. We conducted an interim analysis of early post-intervention data.
Figure 1: Study Workflow
Figure 1: Study workflow depicting case recruitment and blood culture results.
Figure 2: Intervention Flag
Figure 2: Example of intervention comment displayed with the urine culture result in the EMR.

Results
250 adult patients developed SABU from January 1, 2021, to January 31, 2023. Of these, 87 (34.8%) had urinary tract symptoms, and 91 (36.4%) had a chronic indwelling urinary catheter. 74 (29.6%) patients had blood cultures collected within 7 days of positive urine culture. The presence of urinary symptoms or indwelling catheter was not associated with blood culture collection. Only 22 patients (8.8%) had SAB with SABU. One patient was diagnosed with SAB 20 days after detection of SABU with infective endocarditis and disseminated infection, representing a delay in diagnosis.
Following implementation of the intervention, an additional 86 patients with SABU had the result comment displayed in the EMR. Blood cultures were collected in 19 (22.1%) patients, and 2 (2.3%) were positive for S. aureus. There were no significant differences in rates of blood culture collection or SAB after implementation of the EMR result comment.

Conclusion
Our results show a similar rate of SABU associated SAB to that previously reported in the literature. Delayed diagnosis of SAB in SABU is uncommon but does occur rarely with significant morbidity. The addition of a result comment is a simple and cost-effective intervention; however, evaluation of its efficacy is presently limited by a short follow-up duration.

Disclosures
All Authors: No reported disclosures
265. Common Organisms of Parotid abscess in Cambodian Children
Authors: Farrilend Prak 
Published: November 2023

Abstract

Background
Our aim is to determine the most common pathogens to cause parotid abscess and some epidemiology on children under 15 years of age who were admitted at Angkor Hospital for Children and consider where the children lived in order to aid critical thinking for quick diagnosis and proper treatment

Methods
Our study is retrospective study chart review of all the children who had parotid abscess that was confirmed during surgery. The 42 patients were all under 15 years of age and lived in Cambodia. The duration of the study was 5 years, from 01-Jan-2017 to 01-Jan-2022

Results
Of the 42 patients with parotid abscess, the most common pathogen found was Burkholderia Pseudomallei in 76% (32 of cases), of which 60% (19 cases) affected the right side and 40% affected the left side (13 cases) and we less commonly saw bilaterally. Staphylococcus aureus was the second most common cause and found in 24% (9 cases) of which 77% (7 cases) were on left side and only 23% (2 cases) on the right side. Cheek swelling was a chief complaint in 99% of cases and fever was a presenting feature in 90% of cases. They are from multiple different provinces in Cambodia that lie around the Tonle Sap River, primarily Siem Reap 77% (33), then Kampong Thom 9.5% (4), Battambang 5% (2), Phnom Penh 2.3% (1), and Banteay Meanchey 2.3% (1).

Conclusion
The most common cause of parotid abscess in children under 15 years of age in our study was Burkholderia Pseudomallei which is Gram negative rod shape, and mostly involved the right side and was not seen in bilaterally. The other pathogen is Staphylococcus Aureus which more commonly effected the left side. The children all live in provinces surrounding the Tonle Sap River region.
For the regional of their living were from different province and place in that we found from the surrounding the Tonle Sap River, Siem reap 77% (33), Kampong Thom 9.5% (4), Phnom Penh2.3% (1), Battambang 5% (2), Banteay Meanchey 2.3% (1).

Disclosures
All Authors: No reported disclosures
280. A cross-sectional pilot study on the relationship of gut microbiota pattern to immunogenicity of influenza vaccine in lupus patients
Authors: Kiewsanuan Nathathai , Ngamjanyaporn Pintip , Pisitkun Prapaporn , Payungporn Sunchai , Sawaswong Vorthon , Chanchaem Prangwalai , Maiuthed Arnatchai , Rotjanapan Porpon 
Published: November 2023

Abstract

Background
Immunosuppressive therapy, the nature of the autoimmune disease, and different gut microbiome patterns may affect influenza vaccination responses of lupus patients. Thus far, the gut microbiome patterns in this population in response to influenza vaccination have yet to be studied extensively. So, this study aims to evaluate the gut microbiome pattern associated with influenza vaccination response and assess the associated factors that may affect different gut microbiome patterns among lupus patients.
The bar plot shows relative abundances of gut microbiome at the phylum level in lupus patients and healthy controls.

Methods
The cross-sectional pilot study was conducted at Ramathibodi Hospital during 2021-2022. This study is a substudy of another cohort study investigating influenza vaccination response to different dosing regimens, randomly into the high-dose (HD) and standard-dose (SD) quadrivalent influenza vaccination. The patient’s demographics and other relevant information were retrieved. Fecal samples were collected at enrollment for microbiota study. Immunogenicity to vaccination was determined via seroprotection and seroconversion rates.

Results
A total of 62 participants were enrolled. Most patients were female (93.55%). The median (IQR) ages among SD and HD groups were 35.5 (28-42.5) and 34 (25-43) (P=0.878) years old. 18 (29.03%) were taking high-level immunosuppressive treatment (HI) received SD, and 18 (29.03%) were taking low-level immunosuppressive treatment (LI) received SD. There was no significant difference in gut microbiota patterns among all patient groups. Firmicutes were the most abundant phylum, and Bacteroides were the most abundant genera in all patient groups. The alpha diversity was more prominent in the seroconversion groups but no statistical differences (P=0.260 in Shannon indexes). Multivariate logistic regression analysis revealed the LI group (AOR: 7.39, 95% CI 1.11 to 49.36; P=0.039), presence of Bacteroides (AOR 1.16, 95% CI 1.01 to 1.33; P=0.031) were associated with seroconversion of influenza vaccine.

Conclusion
The gut microbiota patterns of lupus patients were not different from healthy controls nor vaccination response. Therefore, the immunosuppressive therapy did not affect the gut microbiota patterns in lupus patients, and an HD of influenza vaccine may not be necessary.

Disclosures
All Authors: No reported disclosures
285. The Pediatric Urinary Microbiome: A Comparison of infants under 12 months with and without Urinary Tract Infection in South Korea
Authors: Hyen Lee Ji , Won Lee Jung 
Published: November 2023

Abstract

Background
The microbiome of the urinary tract plays a significant role in maintaining health through its impact on bladder homeostasis. Urobiota helps maintain the urothelial integrity and prevents urinary tract infection (UTI), regulating neurotransmission and promoting local immune function. However, the number of studies on the pediatric population, especially those in the infant age group in Asia, is limited.

Methods
We prospectively analyzed the urine microbiome of 15 Infants under 12 months between Jan. 2022 and Dec. 2022, grouped as UTI and control groups. UTI group was defined with fever (body temperature ≥38°C), pyuria (≥5 WBC/ high power field), significant bacteriuria (positive urine culture with pure growth 50,000 colony forming unit (CFU)/mL in catheterized urine culture) and control group was recruited from healthy infants who came to our hospital for vaccination but were uninfected. The urine samples underwent DNA extraction and 16S ribosomal RNA gene sequencing, urinalysis and urine culture. The Shannon diversity, the relative abundances of genus and species level, was analyzed with a Mann-Whitney U test and Kruskal-Wallis test.

Results
The number of subjects was fifty and the mean age of the pediatric subjects was 6.2 months old. Ten of the subjects were in the control group (the ratio of male to female was 5:5), and five of the subjects in the UTI group (the ratio of male to female was 2:3). Most common genus are streptococcus, bacteroids, prevotella, citrobacter, and bifidobacterium in control group, while UTI group are frequently dominated by the genus Escherichia coli, streptoccus, bacteroids, prevotella, and bifidobacterium. There was no difference in genus lactobacillus between the two groups. In the analysis of the Shannon diversity, those with UTIs had significantly decreased diversity compared to the control group (P =0.037).
The top 20 genus in pediatric urine specimens
The comparison of Shannon diversity of control group and pediatric Urinary tract infection group in South Korea

Conclusion
A urinary microbiome was identified in infants under 12 months and we observed the differences in microbiome diversity and composition. The pediatric urinary microbiome has just begun to be explored, and further research and investigation must be conducted into about different ethic and demographic pediatric population characteristics.

Disclosures
All Authors: No reported disclosures
286. The Effect of Fecal Microbiota Transplantation on Decolonization of Multidrug-resistant Organisms in the gut
Authors: Soon Lee Seung , Tae Suk Ki , eun Yong Dong 
Published: November 2023

Abstract

Background
Gut colonization of multidrug-resistant organisms (MDROs), such as carbapenemase-producing Enterobacteriaceae (CPE) and vancomycin-resistant Enterococci (VRE), precedes clinical infections. It increases the risk of patient-to-patient transmission of MDROs as well as clinical infections such as bacteremia. Therefore, decolonization of MDROs in the gut by restoring colonization resistance through fecal microbiota transplantation (FMT) could be an effective infection control strategy for MDROs.

Methods
From March 2019 to November 2022, FMT for CPE and VRE decolonization in the gut was conducted at Hallym University Chuncheon Sacred Heart Hospital. Frozen or capsulized stool (MicroBiotix FMT Delivery Microbiota Preparation) from unrelated pre-screened healthy donor was used for each FMT. The rates of and the time to successful decolonization, defined as 3 consecutive negative results from rectal swab culture repeated with 3-day intervals after the initial FMT, were investigated in CPE and VRE rectal colonizers, respectively.

Results
FMT was performed in 60 CPE rectal carriers (KPC=55, KPC & NDM=2, KPC & IMP=1, NDM=1, NDM & OXA=1) and in 15 VRE rectal carriers (E. faecium=14, E. faecalis=1). Among patients with follow-up data after initial FMT, decolonization success rates for CPE and VRE rectal carriers were 44.8% (26/58) and 66.7% (10/15) at 1 month, 77.1% (37/48) and 92.9% (13/14) at 3 months, 95.5% (42/44) and 100% (14/14) at 6 months, respectively. Median and mean times to decolonization after initial FMT were 30 and 43 days in CPE rectal colonizers and 14 and 29 days in VRE rectal colonizers, respectively.
FMT results for decolonization of MDROs in the gut of Chuncheon Sacred Heart Hospital (ClinicalTrials.gov number, NCT04583098)

Conclusion
FMT as a microbiome restoration therapy is an effective method to control CPE and VRE colonization (ClinicalTrials.gov number, NCT04583098).

Disclosures
All Authors: No reported disclosures
291. A Longitudinal Study of The Effect of Fecal Microbiota Transplantation on Klebsiella pneumoniae and its Bacteriophages in a Patient with Long-Term Colonization
Authors: Manuel Joshua , Forsstrom Sarah , Berryhill Brandon A , Burke Kylie , Smith Andrew , Woodworth Michael H , Levin Bruce 
Published: November 2023

Abstract

Background
Live biotherapeutic products such as fecal microbiota transplantation (FMT) show promise as therapies for conditions associated with gut microbiome composition and function, including colonization and recurrent infection with multidrug resistant organisms (MDRO). Although FMTs can reduce colonization with MDROs, much is still unknown about the mechanisms responsible for successful treatment with FMTs. The observation that bacteriophages (phages) are ubiquitous in all microbial communities including FMT doses and are being developed as therapies for MDROs suggests that phages contribute to FMT efficacy. We present results of a case study employing experimental and metagenomic analyses to test the hypothesis that phages contribute to the clinical efficacy of FMTs.
A patient with recurrent urinary tract infections (UTI) with a multidrug resistant Klebsiella pneumoniae was treated with an FMT delivered by retention enema as part of a recent clinical trial (NCT02922816). Metagenomic analyses showed that this patient had baseline K. pneumoniae intestinal domination with relative abundance of 90%. At Day 2 post FMT, the relative abundance of K. pneumoniae was 0.5% and follow-up stool cultures with Klebsiella selective and differential media were negative.

Methods
We competitively aligned reads from the stool metagenomes to the gut phage database using bowtie2 and inStrain. We isolated K. pneumoniae and phages from the donor and patient samples and bacteria susceptibility.
Methods For K. pneumoniae/Phage Isolation and Metagenomic Analysis

Results
We found 76 potential K. pneumoniae phages in the patient before treatment, of which 58 have a breadth of coverage &gt; 0.10. Among these, 39/58 (67%) are known to be temperate and are able to incorporate in the host bacterial genomes as prophages.
Breadth of Coverage of K. pneumoniae Phages in the Patient Prior to FMT
Solid bars represent unknown free phages identified in the sample. Dashed bars represent phages that are known to be temperate found in the patients metagenome.

Conclusion
As resistance to host phages quickly emerges, we postulated that phages in the FMT dose contribute to the elimination of K. pneumoniae in this patient. To test the hypothesis, we follow the changes in relative densities of gut K. pneumoniae phages with metagenomic coverage analyses in longitudinally collected fecal samples post FMT. To further test this hypothesis, we isolated phages and bacteria from the FMT and sequential fecal samples from the patient and tested the susceptibility of the K. pneumoniae to the phages from both the FMT dose and the patient.

Disclosures
All Authors: No reported disclosures
306. Determining natural killer cell responses to JC polyomavirus
Authors: Tan C Sabrina , Ahn Jenny , Chen Sarah , Lee Esther , Gikundiro Eunice , Craemer Melissa , Gressens Simon , Yoder Taylor , Lifton Michelle , Jost Stephanie 
Published: November 2023

Abstract

Background
JC polyomavirus (JCPyV) infects oligodendrocytes and causes progressive multifocal leukoencephalopathy (PML), a potentially fatal complication of monoclonal antibody treatments for cancer and autoimmune diseases, and a rare but often-fatal disease in people living with HIV. There is currently no effective treatment against JCPyV and novel immunotherapies for PML are urgently needed. Natural killer (NK) cells play critical roles in defense against viral infections, yet NK cell responses to JCPyV remain largely unexplored.

Methods
Intracellular cytokine staining (ICS) of NK and T cells stimulated with overlapping peptide pools covering the JCPyV capsid VP1 was performed. A novel flow cytometry-based assay was created to determine NK cell killing efficiency of infected SVG-A cells. Blocking antibodies were used to determine NK cell receptors responsible for immune recognition of JCPyV-infected cells. Single cell cloning was used to expand a homogenous population of NK cells.

Results
Using ICS, about 40% of healthy donors demonstrated NK cell responses, with CD107a upregulation and robust IFNy production by NK cells extending beyond T cell responses(Fig 1). Next, we showed that co-culture of NK cells and JCPyV-infected SVG-A cells leads to, on average, a 65% reduction of infected cells (Fig2). Expression of ligands for the activating NK cell receptor NKG2D was modulated in JCPyV-infected cells, with overall enhanced expression of ULBP-2. Accordingly, NKG2D blockade resulted in decreased NK cell degranulation. Interestingly, we also identified JCPyV-derived peptides that elicit dominant responses by NK cells and can stabilize HLA-E, the ligand for the inhibitory NKG2A and the activating NKG2C receptors. Blockade of NKG2A enhanced NK cell response to JCPyV-infected targets. Finally, we have isolated and expanded single NK cell clones with potent cytotoxic functions against autologous target cells pulsed with JCPyV-derived peptides (Fig 3) and JCPyV-infected SVG-A cells.Fig 2.Fig. 3

Conclusion
Altogether, these findings suggest NKG2D-mediated activation and the NKG2/HLA-E axis may play key roles in controlling JCPyV replication and targeting these receptors and/or expansion of JCPyV-specific NK cells may be promising NK cell-based immunotherapeutic for PML.

Disclosures
All Authors: No reported disclosures