bluuebunny/crossref_metadata_2025 huggingface dataset:
472. Corticosteroid Exposure as a Risk Factor for Pneumocystis jirovecii Pneumonia Mortality in HIV-Negative Patients: A Multicenter Retrospective Case-Control Study with a Global Research Network Validation
Authors: Vargas Barahona Lilian , Molina Kyle C , Pedraza-Arévalo Laura C , Sillau Stefan , Tagawa Alex , Scherger Sias , Chastain Daniel B , Shapiro Leland , Franco-Paredes Carlos , Hawkins Kellie , Henao-Martínez Andrés F
Published: December 2022

Background

HIV-negative patients have higher mortality from PJP compared to patients with HIV, however, we lack data on predictors of PJP-associated mortality in HIV-negative patients. We aim to characterize the role of previous corticosteroid exposure in PJP-related mortality.

Methods

A multicenter retrospective case-control study was performed on HIV-negative patients tested for PJP within the UCHealth system from 2000 to 2021. Cox proportional-hazards model was used for survival analysis. We queried TrinetX, a global research network, to validate mortality risk differences among HIV-negative patients with PJP with prior corticosteroid exposure versus those without. We used propensity score matching to assess independent corticosteroid risk of 1-year mortality.

Results

We identified 105 cases of PJP and 71 controls without PJP. HIV-negative patients with steroid exposure in the previous 6 months were more likely to have a history of malignancy (26.5% vs 11.9%, p=0.026), solid organ transplant (14.8% vs 3.4%, p=0.023), inflammatory disease (27.6% vs 8.5%, p=0.03), or use of other immunosuppressive drugs (83.8% vs 13.6%, p< 0.0001). The median prednisone equivalent dose was higher in patients who died at 7 weeks (33.7 vs. 21.5 mg/d) and 1 year (33.7 vs. 20 mg/d). Adjusted Cox proportional-hazard model found an increased rate of death at 10 weeks (HR: 3.8, CI: 1.6-9.26, p=0.003)(Figure 1) and 1 year (HR: 4.8, CI: 2.2-10.7, p< 0.0001) among patients previously on steroids. A TrinetX-based propensity score matching of 2176 HIV-negative patients found a significantly increased 1-year mortality (OR: 1.9 CI: 1.6-2.2, p< 0.0001) after PJP diagnoses in the group with corticosteroid exposure in the previous year compared to those with PJP without corticosteroid exposure. The mean β-d-glucan (203±154 vs. 82± 35.8 pg/mL, p=0.025) and ferritin levels (1591±5576 vs. 1041± 1300 mcg/L, p=0.02) were higher in those with prior steroid use. Figure 1.Adjusted 70-days mortality among HIV negative patients with PJP by corticosteroid exposure

Conclusion

HIV-negative patients with PJP and corticosteroid use preceding diagnosis have higher mortality than those without corticosteroid use. A higher fungal burden may influence corticosteroid mediated mortality.

Disclosures

All Authors: No reported disclosures.
475. Does Metabolite Matter? Defining Target Itraconazole and Hydroxy-itraconazole Serum Levels for Blastomycosis
Authors: Hess Danielle , Abu Saleh Omar M , Enzler Mark , Jannetto Paul J , Mara Kristin , Stevens Ryan W , Vergidis Paschalis , Rivera Christina G
Published: December 2022

Background

Itraconazole is first-line treatment for mild-moderate blastomycosis and consolidation of moderate-severe disease. Itraconazole is metabolized to 3 metabolites, including an active metabolite hydroxy-itraconazole. The sum of itraconazole and hydroxy-itraconazole levels > 1.0 mcg/mL is guideline recommended for treatment of invasive fungal infections; conversely, some experts suggest targeting a parent compound level alone > 1.0 mcg/mL. This study aims to compare clinical outcomes and adverse drug reactions (ADRs) of combined itraconazole and hydroxy-itraconazole levels > 1.0 mcg/mL versus itraconazole parent compound alone > 1.0 mcg/mL in patients with blastomycosis.

Methods

This study is a single-center, retrospective chart review of patients ≥ 18 years with probable or proven Blastomyces infection who received itraconazole with at least one documented serum itraconazole level. The primary outcome was rate of partial or complete treatment response in patients with a combined itraconazole and hydroxy-itraconazole level > 1.0 mcg/mL versus itraconazole parent compound > 1.0 mcg/mL for > 75% of measured levels. ADRs attributable to itraconazole were compared between the groups. Treatment response rates and ADRs were compared between groups using two proportion z-tests.

Results

Total of 80 patients were included: 36 = combined itraconazole and hydroxy-itraconazole > 1.0, 32 = itraconazole parent alone > 1.0, 12 = 75% of all levels < 1.0. No statistically significant difference was observed between groups for blastomycosis rate of partial or complete treatment response (94.3% combined vs 96.6% parent, p=0.99). Significantly higher mortality was observed in patients failing to achieve itraconazole or itraconazole/hydroxy-itraconazole > 1.0 (2.8% combined vs 0% parent vs 25% neither, p=0.01). There was no significant difference in total ADRs between the three groups (p=0.56).

Conclusion

This limited evidence supports an itraconazole therapeutic target combining itraconazole and hydroxy-itraconazole > 1.0 for blastomycosis treatment.

Disclosures

Paschalis Vergidis, MD, AbbVie: DSMB|Cidara: Grant/Research Support|Scynexis: Grant/Research Support Christina G. Rivera, PharmD, Gilead: Grant/Research Support|Gilead: Honoraria|Insmed: Honoraria.
494. Enteric bacteria are immune-reactive in patients with Crohn's disease with extraintestinal manifestations
Authors: Maldarelli Grace A , Metz Maeva , Funez-dePagnier Gabriela , Lavergne Alexa , Lai Daniel , Chang Adrienne , Malik Fardina , de Vlaminck Iwijn , Longman Randy S
Published: December 2022

Background

Bacterial constituents of the intestinal microbiota can contribute to local and systemic inflammatory diseases. Crohn's disease (CD), a type of inflammatory bowel disease, can result in extraintestinal manifestations (EIM) including peripheral (CD-SpA) and axial spondyloarthritis (CD-AxSpA). Microbial contributors to CD pathogenesis can be identified by flow cytometric sorting and 16S sequencing of bacteria recognized by mucosal IgA. We expand this technique by incubating fecal samples with autologous sera, capturing bacterial species recognized by circulating IgG in a process called IgG-seq. We hypothesize that these systemically-recognized enteric bacteria are linked to development of CD-EIM.

Methods

Fecal samples from individuals with CD were sorted into IgG-positive and negative populations. DNA was extracted from each population, 16S sequencing performed, and sequences processed with QIIME2. Intestinal coating index (ICI) was calculated at the genus level. Serum cell-free DNA sequencing (cfDNA) was performed for a subset of samples.

Results

IgG-seq was conducted on 86 CD, 41 CD-SpA, and 16 CD-AxSpA samples. PCoA analysis demonstrates significant differences in microbiome composition in the three groups (P = 0.013, PERMANOVA). Relative abundances of Escherichia-Shigella and Ruminococcus are positively correlated with joint disease activity. Analysis of IgG ICI for genera present in > 10% of patients demonstrates overrepresentation of Ruminococcus, Escherichia-Shigella, and Bacteroides in IgG-recognized fractions. IgG recognition of bacteria does not cluster specifically by CD or EIM severity. cfDNA sequencing demonstrates no Ruminococcus DNA in serum, whereas E. coli DNA was detected in multiple patient sera.

Conclusion

IgG-seq is a robust method for identifying immune-reactive enteric bacteria; our results highlight the link between immune response to enteric bacterial genera, such as Escherichia-Shigella and Ruminococcus, and joint disease activity in CD-SpA and CD-AxSpA. While Escherichia-Shigella may induce immunity by breaching the mucosal barrier, the absence of Ruminococcus in serum cfDNA suggests immune activation at barrier sites. Further studies are needed to characterize the strain-specific features that underlie our findings.

Disclosures

Fardina Malik, MD, Pfizer: Advisor/Consultant Iwijn de Vlaminck, PhD, GenDX: Advisor/Consultant|GenDX: Board Member|Kanvas Biosciences: Board Member|Kanvas Biosciences: Ownership Interest|Karius Inc.: Board Member|Karius Inc.: Ownership Interest|Viracor Eurofins: Advisor/Consultant Randy S. Longman, MD, PhD, Pfizer: Advisor/Consultant.
496. Epidemiology, virulence and antimicrobial resistance of hypervirulent Klebsiella pneumoniae and K. pneumoniae complex member in western New York, 2017-2020
Authors: Tesini Brenda L , Taffner Samantha , Cameron Andrew , Pecora Nicole
Published: December 2022

Background

Klebsiella pneumoniae is a leading cause of nosocomial infections, and hypervirulent K. pneumoniae (hvKp) is an increasingly recognized community-associated pathogen. However, the epidemiology and pathogenicity of hvKp and K. pneumoniae complex infections in the US remains poorly understood. We characterized the tissue tropism, antimicrobial resistance, and virulence factors associated with K. pneumoniae complex members and hvKp using whole genome sequencing.

Methods

We analyzed all Klebsiella pneumoniae isolates from liver sources from 2017-2020 and isolates from other sterile tissue sites from 2018-2019 in a western New York regional academic microbiology laboratory by whole genome sequencing. Only one isolate per patient was included. Basic clinical and demographic data was obtained from the medical chart. Virulence factors and antibitoic resistance genes were identified using Kleborate version 2.0. Hypervirulence was defined as the presence of rmpA or rmpA2 and the aerobactin gene cluster (iuc).

Results

We sequenced 25 Klebsiella pneumoniae isolates from liver sources from 2017-2020 and an additional 29 isolates from other non-blood sterile sites from 2018-2019. 80% of the hepatic K. pneumoniae complex isolates were K. pneumoniae sensu stricto (n=20). The remaining isolates were identified as K. quasipneumoniae (n=3) and K. variicola (n=2). Non-hepatic tissue isolates contained only one K. variicola; the remainder were K. pneumoniae sensu stricto. Seven isolates met criteria for hypervirulence; all were K. pneumoniae sensu stricto isolated from liver abscesses (28% of such isolates). All were community onset infections, and only 2 patients with hvKp had prior international travel identified. None had additional sites of infection documented. Four isolates were identified as ESBL phenotypically and all had blaCTX-M-15 detected; one of which was K. quasipneumoniae.

Conclusion

This study suggests that hypervirulent K. pneumoniae hepatic abscesses may be more prevalent in the US than previously appreciated. Non-sensu stricto K. pneumoniae complex members were infrequently isolated from bodily tissues, less likely to carry hypervirulence genes but may harbor extended antibiotic resistance.

Disclosures

All Authors: No reported disclosures.
497. Fecal cytokine profiling and markers of intestinal inflammation in Aotus nancymaae diarrhea model for enteropathogens
Authors: Lizewski Rhonda A , Carlos Gaspar Juan , Nuñez Roza , Nieto Monica , Espinoza Nereyda
Published: December 2022

Background

Naval Medical Research Unit 6 (NAMRU-6) established an animal model that closely resembles diarrheal diseases caused by Shigella, Campylobacter, and enterotoxigenic Escherichia coli (ETEC) in humans. These enteropathogens cause considerable mortality due to diarrhea in children and morbidity in travelers and military personnel deployed to regions of high prevalence. The successful oral challenge model developed in Aotus nancymaae, a New World monkey species, for Shigella, Campylobacter, and ETEC results in reproducible diarrhea attack rates of ≥70%. This model has been fundamental for the development and evaluation of new vaccine candidates. Many new approaches in vaccine development focus on stimulating antibodies against specific antigens expressed by these enteropathogens. Recent studies use the Aotus diarrhea model to evaluate new passive therapeutic and prophylactic treatments to prevent infection, inflammation, or diarrhea. However, the immune response and intestinal inflammation by the main enteropathogens are not clearly defined.

Methods

This study investigates how the cytokines and fecal markers of intestinal inflammation respond to gastroenteritis caused by Shigella, Campylobacter and ETEC in Aotus. Twenty-nine fecal cytokines (FC) were measured during diarrhea induced by Shigella flexneri (N = 8), Campylobacter jejuni (N=8), and ETEC (N = 8).

Results

Of note, both IL-1β and IL-15 were significantly increased at 24 hours after ETEC challenge. In contrast, when an infection with Shigella flexneri occurs, a significant increase in cytokines and chemokines such as MIF, MIP-1α and MIP-1β are observed 24 hours after challenge. While animals challenged with Campylobacter jejuni produce an increase in IL-1β 24 hours after challenge and an increase in cytokines MIF, MIP-1α and MIP-1β 4 days after challenge.

Conclusion

There is nonspecific upregulation of TH1/TH17 effector cytokines and those known to mediate intestinal barrier damage. The FC profiles have a different behavior between the three enteropathogens. This provides new insights into gut-specific immune alterations in the Aotus diarrhea model, which will help improve the design of new prophylactic and therapeutic treatments against diarrhea.

Disclosures

All Authors: No reported disclosures.
499. Immunotherapy with Pattern Recognition Receptor Agonists Improves Morbidity and Mortality in a Corticosteroid-Immunosuppressed Murine Model of Influenza-Associated Pulmonary Aspergillosis
Authors: Wurster Sebastian , García Jezreel Pantaleón , Albert Nathaniel D , Evans Scott , Kontoyiannis Dimiitrios P
Published: December 2022

Background

Corticosteroids are known to increase the incidence and worsen the outcomes of influenza-associated pulmonary aspergillosis (IAPA) in patients with severe influenza pneumonia. Adjunct immunomodulatory strategies might improve the treatment of this emerging entity, but in-vivo data in validated corticosteroid-immunosuppressed animal models of IAPA is scarce.

Methods

8-10-week-old female BALB/c mice were infected with 7.5% LD90 of a mouse-adapted influenza A/H3N2/Hong Kong/1968 strain, delivered by aerosolization on day (d) 0. On d5 and d8, mice received two intraperitoneal injections of 10 mg cortisone acetate (CA) or mock injections. On d9, mice were intranasally challenged with 50,000 Aspergillus fumigatus (AF) conidia. Infection severity was scored using the viral pneumonia score (VPS, 0 = healthy to 12 = moribund) and the murine sepsis score (MSS, 0 = healthy to 3 = moribund). For therapeutic studies, mice received a 30-minute nebulization of the toll-like receptor (TLR) 2/6/9 agonists Pam2+ODN (PMID: 34153197; 4 µM/1 µM) or PBS (mock treatment) on d8 (single-dose) or d8+12 (dual-dose). Therapeutic studies used a combined morbidity/mortality endpoint, with an event defined as either death or reaching a VPS ≥ 7.

Results

CA-immunosuppressed mice with IAPA had 64% 16-day mortality and survivors had severe morbidity (median MSS 2.7). In contrast, all non-immunosuppressed mice with IAPA survived and showed consistently low morbidity (median d16 MSS 0.5). All mock-treated CA-immunosuppressed mice with IAPA reached the combined morbidity/mortality endpoint by d11. Single-dose Pam2+ODN treatment led to universal event-free survival until d13 but all mice deteriorated by d16. Dual-dose Pam2+ODN treatment before and after AF infection led to 75% event-free survival until d21, with all survivors fully recovering (VPS = 0, p < 0.001, Figure 1). Figure 1

Conclusion

Aligned with clinical evidence, we found detrimental outcomes of IAPA in CA-immunosuppressed mice. Treatment with TLR agonists significantly improved morbidity and mortality of CA-immunosuppressed mice with IAPA. Next, we will study the impact of synergistic anti-infective and immunotherapeutic interventions on the course and immunopathogenesis of IAPA.

Disclosures

Dimiitrios P. Kontoyiannis, MD, ScD, PhD (hon), AbbVie: Advisor/Consultant|Astellas Pharma: Advisor/Consultant|Astellas Pharma: Grant/Research Support|Astellas Pharma: Honoraria|Cidara Therapeutics: Advisor/Consultant|Gilead Sciences: Advisor/Consultant|Gilead Sciences: Grant/Research Support|Gilead Sciences: Honoraria|Merck: Advisor/Consultant.
507. Peripheral blood RNA signatures associated with human babesiosis, quality of life and neurological symptoms
Authors: Marcos Luis A , Lamba Pooja , Gary Evan , Hou Wei , Spitzer Eric , Mordue Dana
Published: December 2022

Background

Human babesiosis is an emerging tick-borne disease in the US that is primarily caused by the protozoan Babesia microti (Bm). Although Babesiosis can cause life-threatening infections, the pathophysiology including host and parasite determinants associated with disease severity are largely unknown. The aim of this study is to identify parasite and host signatures of human babesiosis and correlate these with disease severity and long-term symptoms.

Methods

We enrolled prospectively patients with acute babesiosis (microcopy positive blood smear for Bm, confirmed by PCR) at Stony Brook University Hospital during 2020-2021. Blood samples and surveys were completed at initial diagnosis (Visit=1;V1) and at months 1, 6 and 12 (V2,V3,V4). Total RNA from whole peripheral blood was isolated using the PAXgene Blood RNA Kit from individuals infected with Bm and healthy controls. Quality of life (QOL) surveys were administered to patients.

Results

Peripheral blood transcriptome analysis of 17 patients (median age: 63 years, range 42-78; 24% female) who presented with babesiosis were distinctly different from uninfected individuals (n=9). Babesiosis was associated with a peripheral blood Type I and Type II Interferon transcriptional signature. Other dominant transcriptional signatures included those involved in activation of mononuclear cells, oxidative phosphorylation, inducible nitric oxide synthase and regulation of homeostasis as well as inducible nitric oxide synthase. Ingenuity Pathway Analysis for clinical chemistry and hematology also highlight changes associated with cardiotoxicity, hepatotoxicity, and nephrotoxicity as well as increased levels of red blood cells. Patients with babesiosis showed a persistent deterioration of QOL in cognition [mean V1=33.1; V3=36.3] and satisfaction [mean V1=28.4; V3=34]. Also a decrease in QOL over time despite effective treatment [mean at V1 82 (SD: 5.9), V2 80 (8.1), V3 76 (4.7) (p >0.05).

Heat Map Summary.

Volcano Plot

Gene Pathways Analysis

Conclusion

Babesiosis is associated with a marked alteration in the peripheral blood transcriptome of patients that may also provide insight into both the pathophysiology of the disease including severity and complications. Furthermore, even after successful treatment, babesiosis may result in long-term impacts on quality of life indicators.

Disclosures

All Authors: No reported disclosures.
514. Association Between Antibiotic Exposure and Clinical Outcomes of Immune Checkpoint Inhibition
Authors: Wilson Grant , Zhang Jiajia , Spence Emma , White Maxwell , Allen Jawara , Fan Christopher , Queen Jessica , Naidoo Jarushka , Sears Cynthia L , Shaikh Fyza
Published: December 2022

Background

Recent studies have suggested that antibiotic (ABX) use and resulting changes in the gut microbiome alter the efficacy of immune checkpoint inhibitors (ICIs) in cancer treatment, but detailed data are lacking. We performed a retrospective analysis of the impact of ABX timeframe of administration on overall survival (OS) and progression-free survival (PFS) in non-small cell lung cancer (NSCLC) patients treated with ICIs.

Methods

We assembled a cohort of stage IV NSCLC patients treated with ICIs at Johns Hopkins Medicine between 1/1/2013 and 12/31/2019 (n=154). Patient demographics, ICI and ABX (intravenous and/or oral, n=100) treatments, tumor characteristics, and progression and survival data was extracted from the electronic medical record (EMR) and verified by chart review. Progression was defined by radiological evidence or provider notes. Univariate analysis was performed with Kaplan-Meier curves with log-rank tests and multivariate analysis was performed with Cox regression.

Results

Demographic data indicated that most patients were white (n=109), smokers (n=130), and had Eastern Cooperative Oncology Group (ECOG) performance statuses of zero to one (n=128). The median age was 67 years old and slightly under half of patients (n=65) received ICIs as first line therapy. Analysis with Kaplan-Meier curves for OS and PFS revealed significantly worse OS for patients with exposure to any ABX vs. not exposed in the 2.8 years before to 4.8 years after ICI start (Median OS: 14 vs. 21.5 months, p = 0.019; Median PFS: 4.4 vs. 7.7 months, p = 0.24). ABX exposure in the 2 months before to 2 months after ICI start also negatively impacted OS (Median OS: 7.5 vs. 17.4 months, p = 0.05; Median PFS: 3.3 vs. 5.8 months, p = 0.39). Decreased OS with any ABX use in the 2.8 years before to 4.8 years after ICI start was supported by multivariate analysis controlling for age, race, ECOG performance status, tumor histology, prior lines of therapy, and prior treatment types (Adjusted Hazard Ratio: 2.0, 95% CI: 1.3-3.3).

Kaplan-Meier survival analysis of antibiotic exposure

Overall survival (A) and progression-free survival (B) in stage IV NSCLC patients treated with ICIs, with or without exposure to ABX in the 2.8 years before to 4.8 years after ICI start. P-values calculated with log-rank tests.

Conclusion

Our study indicates a negative association of ABX on OS of ICI-treated NSCLC patients in both a broad and narrow timeframe around ICI start. Further work defining ABX impact on therapeutic outcomes in a larger cohort of patients across multiple tumor types is ongoing.

Disclosures

Grant Wilson, BS, Infectious Diseases Society of America G.E.R.M. Grant: Grant/Research Support Cynthia L. Sears, MD, Bristol Myers Squibb: Grant/Research Support Fyza Shaikh, MD, PhD, Bristol Myers Squibb: Grant/Research Support.
519. DeepLPI: A Novel Drug Repurposing Model based on Ligand-Protein Interaction Using Deep Learning
Authors: Wei Bomin , Zhang Yue , Gong Xiang
Published: December 2022

Background

Drug repurposing has gained increased attention because it proposes to find effective cures for new diseases from approved drugs to lower development costs and time, and computational prediction of protein-ligand interactions (PLI) can provide accurate and fast drug screening. The shortcomings of existing machine learning-based methods for PLI prediction include 1) using human-selected features leads to loss of information and therefore lower accuracy and 2) using limited 3D structure data for input leads to lower generalizability.

Methods

To address the shortcomings, I proposed DeepLPI, a novel deep learning-based model that takes as input the raw sequences of drug molecules and proteins. DeepLPI applied pre-trained embedding models to encode the raw sequences into dense vector representations, which were then fed into 1D-CNN and biLSTM to obtain predictions. BindingDB dataset was used for model training and performance evaluation that is compared with a start-of-the-art method DeepCDA. Fig 1.Principle of NLP-inspired deep learning-based methods to embed drug SMILES strings (Mol2vec) and protein sequences (ProSE). Similar drugs or proteins will be in close distance after the embedding because these methods can capture contextual information.Fig 2.Model architecture from input to output of DeepLPI.

Results

Results showed that the DeepLPI reached an overall AUROC of 0.79 based on the BindingDB internal test, 76% better than DeepCDA. DeepLPI also outperformed DeepCDA using the external Davis dataset (AUROC=0.53) and COVID-19 3CL Protease dataset (AUROC=0.61). Figure 3.A randomly reserved part of the BindingDB dataset was grouped into four cases for testing, according to whether the drug molecules or the proteins are seen in the training set. (Note that the drug-target pairs in the test set are excluded from the training set.)Fig 4.We compare with DeepCDA, a recently published DTI prediction model that reported to be better than previous models. DeepLPI is 76% better in accuracy metric AUROC in classification tasks.Fig 5.As a preliminary attempt, the model trained on BindingDB was applied to a recent COVID-19 dataset targeting the 3CL-protease, which reported 897 small molecule drugs. Our model is better than the baseline method by 25%.

Conclusion

The high performance of DeepLPI suggests that our model has the potential to identify new COVID-19 drugs when applied to approved drugs. The generalizability of the model also promises applications to diseases in a wider scope.

Disclosures

All Authors: No reported disclosures.
520. Development of Cefepime-taniborbactam MIC Antimicrobial Susceptibility Test (AST) for Enterobacterales and Pseudomonas aeruginosa on MicroScan Dried Gram-negative MIC Panels
Authors: Fernandez Enrique J , Williams Robert L , Carr Vasna , Carr Vasna , Renae Miller
Published: December 2022

Background

Automated AST devices are critical to inform appropriate care of patients with bacterial infections. Cefepime-taniborbactam is an investigational agent under development to treat infections due to multidrug-resistant bacteria, including carbapenem-resistant Enterobacterales and Pseudomonas aeruginosa. Development of a cefepime-taniborbactam antimicrobial susceptibility test was completed for the MicroScan Dried Gram-negative MIC (MSDGN) Panel when compared to CLSI broth microdilution reference panels.

Methods

Development was conducted by comparing MICs obtained using the MSDGN panel to MICs using a CLSI broth microdilution reference panel. The concentration range of cefepime-taniborbactam evaluated was 0.12/4-64/4 µg/mL. A total of 1376 isolates (1256 Enterobacterales and 120 P. aeruginosa) were tested at 16, 18, and 20 hours incubation times (for visual read and autoSCAN-4). A total of 917 isolates (837 Enterobacterales and 80 P. aeruginosa) were tested at 16 and 18 hours incubation time for the WalkAway System. All isolates were tested using turbidity and Prompt® methods of inoculation. MSDGN panels were incubated at 35 ± 1°C. Reference panels, prepared according to ISO methodology, were inoculated using the turbidity inoculation method. All frozen reference panels were incubated at 35 ± 2°C and read visually. Rates of essential agreement (MicroScan MIC within ± 1 doubling dilution of reference MIC) were determined for each combination of inoculation method and read method.

Results

Essential agreement rates ranged from 93.0% to 98.8% for all isolates tested during development. Essential agreement rates for each inoculation and read method are presented in Table 1. Table 1- Results

Conclusion

Cefepime-taniborbactam MIC results obtained with the MSDGN panel correlated well with MIC results obtained using reference panels. Rates of essential agreement were ≥93.0% for all inoculation and read methods. These development data support the continued evaluation of MSDGN panel with cefepime-taniborbactam in a multicenter trial.

Pending submission and clearance by the United States Food and Drug Administration; not yet available for in vitro diagnostic use in the US. For Investigational Use Only. The performance characteristics of this product have not been established.

Disclosures

Enrique J. Fernandez, BS, Beckman Coulter, Inc.: Employee of Beckman Coulter Robert L. Williams, PhD, Beckman Coulter, Inc.: Employee of Beckman Coulter Vasna Carr, BS, Beckman Coulter, Inc.: Employee of Beckman Coulter Vasna Carr, BS, Beckman Coulter, Inc.: Employee of Beckman Coulter Miller Renae, BS, Beckman Coulter, Inc.: Employee of Beckman Coulter.
521. Investigating the Gram-Positive Selective Spectrum of Ibezapolstat, a First-in-Class DNA Polymerase IIIC (Pol IIIC) Inhibitor
Authors: Jahangir Alam M , Begum Khurshida , Karim Md Ekramul , Hu Chenlin , Basseres Eugenie , Lancaster Chris , Garey Kevin W
Published: December 2022

Background

Ibezapolstat (IBZ) is a non-absorbable antimicrobial currently in phase 2 clinical trials for the treatment of Clostridioides difficile infection (CDI). In vitro and human studies have shown potent activity of IBZ against C. difficile but selective activity against other beneficial Gram-positive gut microbiota shown to reduce the risk of recurrent CDI. As the target DNA Pol IIIC enzyme is present in most Gram-positive species, the reasons for this selectivity are unclear. The purpose of this study was to assess the selectivity of IBZ against Gram-positive gut microbiota.

Methods

Using stool samples and microbiome data from the phase 1 and 2 studies, changes in proportional abundance of gut microbiome species were analyzed over time in healthy volunteers or patients with CDI given IBZ. Using a separate collection of gut microbiota species, MIC determinations against a variety of Gram-positive gut species were assessed by broth microdilution.

Results

Baseline gut microbiota from healthy volunteers were primarily Firmicutes, Bacteroidetes, or Actinobacteria. Actinobacteria increased in abundance after starting IBZ (primarily Bifidobacteriales or Coriobacteriales) and persisted for the entire dosing period. In comparison to the phase 1 study, the phase 2a CDI study baseline microbiota had a lower proportion of Actinobacteria and Firmicutes and increased Bacteroidetes. In CDI patients, Actinobacteria increased in abundance after starting IBZ (primarily Coriobacteriales) followed within 2-3 days by decreased abundance of Bacteroidetes, and an increased abundance of Lachnospiraceae and Ruminococcaceae. Using isolated gut microbiota species, IBZ was inactive (MIC >64 µg/mL) against representative Actinobacteria (Bifidobacteriaceae and Coriobacteriaceae) and certain Firmicutes (Lachnospiraceae and Lactobacillaceae) but highly active against strains of C. difficile (MIC<2 µg/mL).

Conclusion

Microbiome changes with IBZ were dependent on underlying composition of the baseline microbiome but consistently demonstrated increased abundance of Actinobacteria after starting therapy. IBZ microbiome data coupled with in vitro MIC determinations demonstrated persistence or regrowth of healthy microbiota associated with beneficial physiologic effects.

Disclosures

Kevin W. Garey, PharmD, MS, Acurx Pharmaceuticals: Grant/Research Support|Paratek Pharmaceuticals: Grant/Research Support|Seres Therapeutics: Grant/Research Support|Summit Pharmaceuticals: Grant/Research Support.
534. Evaluation of a Rapid Multiplex PCR Diagnostic Device for the Detection of Microorganisms from Nasopharyngeal and Throat Swab Specimens in the Near Patient Setting
Authors: Bastar Jeffrey , Ky Ashley , Holmberg Kristen , Bay Hana , Drobysheva Daria , Davis Thomas , Selvarangan Rangaraj , Doran Kathryn , Sifers Laura , Cohen Daniel M , Enne Virve , Steele Mark , Andjelic Cynthia
Published: December 2022

Background

Limited availability of multiplex molecular tests in the near-patient setting can impact the rapid diagnosis and treatment of patients experiencing symptoms of respiratory tract infections, including pharyngitis. The BioFire® Respiratory/Sore Throat (R/ST) Panel (bioMérieux, Salt Lake City, UT), designed for use with the BioFire® SpotFire System, is a PCR-based sample-to-answer diagnostic test that identifies four bacteria and 10 viruses (including SARS-CoV-2) from nasopharyngeal swab (NPS) or throat swab (TS) specimens in about 16 minutes. This study evaluated the performance of an Investigational Use Only (IUO) version of the BioFire R/ST Panel in the near patient setting.

Methods

NPS and TS specimens were prospectively enrolled from symptomatic consented/assented volunteers of all ages, or obtained as residual leftover specimens. Enrollment was conducted between December 2020 and September 2021 at five study sites in the US and UK (adult and pediatric emergency departments or urgent care clinics) with testing performed by personnel representative of the intended users (non-laboratory professionals). Several analytes that were not circulating during the COVID-19 pandemic were supplemented with archived specimens of known analyte composition. Performance was determined for both sample types by comparison to FDA cleared multiplex PCR tests or culture and PCR followed by sequencing of isolates (Streptococcus from throat swabs).

Results

A total of 1131 NPS and 452 TS prospectively collected specimens and 542 NPS and 128 TS archived specimens were tested with the BioFire R/ST Panel. For NPS specimens (prospective and archived) overall positive percent agreement (PPA) was 98.7% and negative percent agreement (NPA) was 99.1%, and for TS specimens (prospective and archived) overall PPA was 95.9% and NPA was 99.2%.

Conclusion

The BioFire R/ST Panel is a sensitive, specific, and robust test for rapid detection of a wide range of organisms in NPS and TS specimens in the near-patient setting. This test is expected to aid in the timely diagnosis and appropriate management of pharyngitis and other respiratory infections.

Data presented are from assays that have not been cleared or approved for diagnostic use.

Disclosures

Jeffrey Bastar, PhD, MSCI, bioMerieux: Employee|bioMerieux: Stocks/Bonds Ashley Ky, MLS(ASCP), bioMérieux: Employee|bioMérieux: Stocks/Bonds Kristen Holmberg, n/a, bioMerieux: Employee Hana Bay, BS, Biomerieux: Employee|Biomerieux: Stocks/Bonds Daria Drobysheva, PhD, bioMerieux: Employee Rangaraj Selvarangan, BVSc, PhD, D(ABMM), FIDSA, F(AAM), BioFire: Grant/Research Support|Luminex: Grant/Research Support Virve Enne, BSc PhD, Biomerieux: Advisor/Consultant Cynthia Andjelic, PhD, bioMerieux: Employee.
535. Evaluation of the BioFire Blood Culture Identification (BCID2) panel for transplant recipients with a bloodstream infection
Authors: Palacios Carlo Foppiano , Peaper David , Malinis Maricar F , Malinis Maricar F , Perreault Sarah , Cohen Elizabeth A , Vogel Joshua , Azar Marwan M
Published: December 2022

Background

In patients with bloodstream infections (BSI), the BioFire blood culture identification (BCID2) multiplex PCR panel is associated with decreased time to organism identification and antimicrobial susceptibility results needed to guide optimal therapy. While the performance of BCID2 has been evaluated in the general population, data for transplant recipients are limited. We sought to identify the utility of the BCID2 panel in transplant recipients.

Methods

A retrospective chart review was conducted to identify all solid organ recipients (SOTR) and bone marrow transplant recipients (BMTR) within 2 years of transplantation with BSI for whom BCID2 was performed from 06/2021 to 01/2022. Demographic and microbiological data were collected. Positive blood cultures for the same patient and same organism(s) occurring within 14 days of the initial test were considered a single BSI event. Descriptive statistics were performed.

Results

A total of 29 transplant recipients with 45 positive blood cultures underwent BCID2 testing. Mean age was 54 years, 69% were BMTR and 53% of cultures were from peripheral sites. A total of 51 organisms were recovered from 45 blood cultures. Organisms identified by blood cultures included Enterobacterales (45%), Enterococcus spp (20%), Candida spp (8%), non-Enterobacterales gram negative rods (14%), Streptococcus spp (8%), and other gram positives (5%). No anaerobic organisms were isolated. BCID2 did not detect 7/51 (14%) organisms identified by blood cultures including monomicrobial (n=6/39) and polymicrobial (n=1/6) cultures. All 7 organisms not identified by BCID2 were not in the BCID2 database. All occurred in BMTR; 4 were considered pathogenic and treated with antimicrobials vs. 3 contaminants (Table 1). BCID2 detected CTX-M or Van A/B in all 15 samples with ceftriaxone (n=9) or vancomycin resistance(n=6).

Conclusion

In transplant recipients, BCID2 detected 86% of organisms and 100% of resistance markers identified by conventional testing. All 7 (14%) missed cases involved off-target organisms, of which 4 were considered pathogenic. BCID2 is a useful tool for BSI detection in transplant recipients, but providers should consider the possibility of off-target pathogens when clinically appropriate.

Disclosures

David Peaper, MD, Tangen Biosciences: Stocks/Bonds Maricar F. Malinis, MD, Aicuris: Primary Investigator of Clinical Trial at Yale Site|Takeda: Primary investigator of clinical trial at Yale Site Maricar F. Malinis, MD, Aicuris: Primary Investigator of Clinical Trial at Yale Site|Takeda: Primary investigator of clinical trial at Yale Site.
541. In Silico Modeling by Causal Inference for Identifying Biomarkers of Sepsis
Authors: Carvalho Walisson , Silvério-Machado Rita , Couto Bráulio R G M , Zarate Luis Enrique
Published: December 2022

Background

“Every 3 seconds, someone in the world dies of sepsis” (https://sepsistrust.org/about/). We used causal inference theory as a in silico method to identify biomarkers of sepsis. Causal Inference is a theory in Machine Learning that seeks for the root causes of an event.

Methods

In the study it was used transcription profile data downloaded from http://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE12624. This dataset has 70 samples, being 34 sepsis and 36 non-sepsis samples. Data set contains 8,519 attributes: 7,672 genes obtained after preprocessing of the mRNA expression profile data. The method applied in the dataset was a modification in the HEISA, a local learner of two stages algorithm (Figure 1). In the first stage HEISA identifies variables that compounds the set of parents, children, parents of parents and children of children of a target. During the second stage is calculated the causal effect using do-calculus method, of the selected variables of the first stage in the target. At end of the second stage, features with causal effect greater than 0.2 is selected. After selecting the features mRNA expression, it was applied two algorithms of classification, Random Forest and K-means, in order to evaluate the ability of the selected variables of identifying the occurrence of sepsis. Figure 1- Causal inference HEISA algorithm.

Results

As shown in Table I, after applying the algorithm, it was select six mRNA expressions that better explains whether sepsis occurs, or not. Analyzing these genes it was possible to observe that three of them are known biomarkers, they are related to sepsis: NM_017526, NM_004649 and NM_006099. It is important to stress that the second one, Homo sapiens leptin receptor overlapping transcript (LEPROT) transcript variant 1 mRNA, is known to be inversely proportional to sepsis (its causal effect is negative). The other three biomarkers, NM_017526, NM_001274, and NM_001071 also are inversely proportional to sepsis. Their relationship with sepsis is still unknown. Regarding the classification task, using only those six mRNA expressions, the accuracy of the task of classification was 100%. Table I- Sepsis biomarkers candidates.

Conclusion

In a big set of 7,672 genes, only six were returned as sepsis biomarkers candidates. This is a very promising in silico discovery, made by a novel mathematical method, the Causal Inference theory.

Disclosures

All Authors: No reported disclosures.
553. Designing and evaluating a facilitation workshop for antimicrobial stewardship teams to de-implement inappropriate perioperative antibiotic use in pediatric hospitals
Authors: Malone Sara , McKay Virginia , Saito Jacqueline M , Rangel Shawn , Bono Kelly , Newland Jason
Published: December 2022

Background

In pediatric hospitals, approximately 20% of inappropriate antibiotic use results from unnecessary postoperative antibiotic prophylaxis (POP). Facilitation, an implementation strategy focused on using individuals as change agents, may be an effective strategy. No standard facilitation training has been provided for individuals leading antimicrobial stewardship programs (ASP). We describe the development and evaluation of a virtual facilitation workshop to increase antimicrobial stewards’ ability to reduce POP.

Methods

This work was conducted in the Optimizing Perioperative Antibiotic in Children (OPERATIC) trial, a stepped wedge randomized controlled trial with 9 pediatric hospitals to test strategies with ASPs to reduce POP. After comprehensive literature review, we developed a theoretically supported facilitation training workshop. Four modules were presented weekly that targeted evidence against POP use, data visualization, understanding local context, and enhancing interpersonal skills. After workshop completion, participants completed an electronic survey consisting of 13 Likert questions (scale 1-5; 1=very poor) questions adapted from a published measure for practice facilitation and four open ended questions. Responses were analyzed descriptively.

Results

A total of 10 physicians, 7 pharmacists, and 1 other staff affiliated with ASPs completed the survey for a 75% response rate. Participants rated the overall workshop as a 4.5 on average. Participants stated they were likely to use workshop information in the future. Individuals stated they gained skills regarding communication/conflict style (4.45), implementation science principles (4.3), and data visualization (4.1). Three individuals believed the workshop could be shorter. In free text responses, participants highlighted the usefulness of examples and role play as well as the conceptual shift in viewing the ASP as an active facilitator in the surgical setting.

Conclusion

Virtual facilitation training is feasible and useful for ASP teams. This workshop method could enable skill development within the context of a clinician’s schedule, while still promoting evidence-based strategies for better de-implementation of unnecessary prescribing.

Disclosures

Sara Malone, PhD, LCSW, AHRQ: Grant/Research Support|NIH: Grant/Research Support Jason Newland, MD, AHRQ: Grant/Research Support|Merck: Grant/Research Support|NIH: Grant/Research Support|PEW Charitable Trust: Grant/Research Support|Pfizer: Grant/Research Support.
558. Increasing Safety Net Antibiotic Prescriptions (SNAP) for Acute Otitis Media Treatment in Pediatric Urgent Care Clinics
Authors: McKinsey Jennifer , Nedved Amanda , Wyly Donna , Austin Holly B , Dosdos Dinah , Murdock Emily , Lee Brian R , Patel Aimy T , El Feghaly Rana E
Published: December 2022

Background

Acute otitis media (AOM) is the most common diagnosis for which antibiotics are prescribed in pediatrics. National guidelines recommend offering a safety net antibiotic prescription (SNAP) to select patients, to be filled if symptoms worsen or do not improve within 48-72 hours. However, clinicians continue to prescribe immediate antibiotics for most cases of AOM. Our goal was to increase the percentage of eligible patients diagnosed with AOM in our pediatric urgent care (PUC) clinics who are offered a SNAP from our baseline of 7.7% to 40% within nine months.

Methods

A multidisciplinary team of PUC clinicians, an Infectious Diseases physician, and a data analyst, used quality improvement (QI) methodology to identify barriers to offering SNAP (Figure 1). Patients without chronic ear conditions were considered eligible for SNAP if they had no or mild otalgia for < 48 hours, fever < 39oC, no otorrhea, and for patients ≤ 24 months old, if they had only unilateral AOM. We analyzed all encounters of patients ≥ 6 months old with a discharge diagnosis of AOM from three PUC clinics during baseline (October 2020 – September 2021) and study (October 2021 – March 2022) periods. Interventions included clinician education, standardized discharge instructions, electronic health record updates to improve documentation, and educational flyers for clinicians and families. Our outcome measure was the percentage of eligible encounters during which SNAP was offered. Our process measure was the percentage of AOM encounters in which SNAP eligibility was documented. Our balancing measure was the percentage of patients returning with AOM symptoms within 14 days.

Results

We reviewed 12,502 encounters from October 2020 through March 2022. At baseline, clinicians documented SNAP eligibility in 5.5% of AOM encounters and offered SNAP to 7.7% of eligible patients. By March 2022, clinicians documented SNAP eligibility in 58.9% of AOM encounters and offered SNAP to 40.7% of eligible patients (Figure 2). There was no change in our balancing measure.

UCL: Upper control limit. LCL: Lower control limit.

Conclusion

Using QI methodology, we increased the percentage of eligible patients with AOM who were offered SNAP, reducing antibiotic exposure in PUC clinics. Efforts are ongoing to further improve this process.

Disclosures

Brian R. Lee, PhD, MPH, CDC: Grant/Research Support|Merck: Grant/Research Support.
561. Methicillin-Resistant Staphylococcus aureus is Decreasing in Community-Onset Pediatric Infections Treated at a Mid-Atlantic Health System
Authors: Prochaska Erica , Milstone Aaron , Sick-Samuels Anna , Xiao Shaoming , Schumacher Christina , Tamma Pranita , Carroll Karen C , Gadala Avi
Published: December 2022

Background

Hospitalizations due to soft tissue methicillin resistant S. aureus (MRSA) infections are decreasing nationally. Analyzing trends in pediatric community-onset (CO) S. aureus infections is needed to inform empiric antibiotic selection in the Emergency Department and outpatient settings.

Methods

We identified all cultures growing S. aureus between January 1, 2014 and December 31, 2020 in the Johns Hopkins Hospital microbiology laboratory that services an academic medical center, a mid-level teaching hospital, and a community hospital. Patients were included if they were ≤18 years of age or treated in a pediatric location. Cultures that likely represented colonization, such as nasal swabs, throat swabs, or sputum were excluded. Patients hospitalized within 2 calendar days of culture collection were defined as treated in-hospital. All others were defined as treated outpatient. CO infection was defined as a culture obtained within 3 days of hospitalization or from children not hospitalized. Only the first culture per patient per quarter was included. Cochran Armitage test was used to analyze trends in antibiotic susceptibilities.

Results

3517 cultures obtained from 3078 patients were included. 3208 cultures (91%) were CO. Of CO cultures, 2517 (78.5%) were treated in an outpatient setting and 691 (21.5%) were treated in-hospital. There was a 74% decrease in the number of CO S. aureus cultures during the study period: 751 in 2014 to 191 in 2020. Comparing CO cultures from 2014 and 2020, methicillin susceptibility increased from 59.5% to 67% overall (p = 0.007), 59.4% to 63.8% in outpatient treated cultures (p = 0.07), and 60% to 76% among in-hospital treated cultures (p =0.02). Methicillin susceptibility from CO soft tissue sources remained about 60% during the study period with no significant change in trend. When soft tissue sources were excluded from CO cultures, methicillin susceptibility increased from 61.7% in 2014 to 84.1% in 2020 (p = 0.01). Within CO blood cultures, methicillin susceptibility increased from 86.7% to 92.3% (p = 0.4).

Conclusion

In a regional health system, CO pediatric MRSA incidence is decreasing. Although the majority of CO bloodstream S. aureus infections are methicillin susceptible, MRSA continues to cause up to 40% of S. aureus soft tissue infections.

Disclosures

Aaron Milstone, MD, Merck: Grant/Research Support Karen C. Carroll, MD, Abbott Diagnostics: Advisor/Consultant|BD Diagnostics: Advisor/Consultant|BD Diagnostics: Grant/Research Support|BioRad, Inc: Grant/Research Support|Meridian Biosciences: Grant/Research Support|Roche Diagnostics: Advisor/Consultant|Scanogen, Inc: Advisor/Consultant|Scanogen, Inc: Grant/Research Support|Thermo Fisher, Inc: Advisor/Consultant.