bluuebunny/crossref_metadata_2025_split huggingface dataset:
P-866. Epidemiology and Risk Factors for Mortality in Clostridial Bacteremia: A Retrospective Multicenter Observational Study
Authors: Okazaki Aiko , Okugawa Shu , Kobayashi Tatsuya , Kawada Miki , Kawase Kyotaro , Nakayama Shin , Wakabayashi Yoshitaka , Kitazawa Takatoshi , Takezawa Riko , Tatsuno Keita , Koyano Saho , Higurashi Yoshimi , Ikeda Mahoko , Harada Sohei , Tsutsumi Takeya 
Published: January 2025

Abstract

Background
Clinical studies on clostridial bacteremia are scarce, and the factors associated with mortality have not been well investigated. Furthermore, the distribution of Clostridium species varied among studies. To investigate the epidemiology of clostridial bacteremia and the factors associated with mortality, we conducted a study in Japan.

Methods
This multicenter, retrospective, observational study was conducted in four Japanese hospitals. Patients with bacteremia in whom Clostridium spp. were detected in blood cultures between 2007 and 2021 were included. Only the first episode of infection was included and blood culture contamination was excluded. Clinical data were collected from the electronic medical records of each hospital. Comparisons between survival and death groups were performed to identify risk factors associated with in-hospital mortality.

Results
A total of 278 patients were included in the study. C. perfringens was the most common species (52.9%), followed by C. ramosum (9.7%) (Table 1). The median age of the patients was 77 years, and 61.9% were male. Comorbidities included malignancy (38.1%), diabetes mellitus (29.9%), and gallstones (18.0%). More than 50% of the infections were community-acquired (68.0%). Polymicrobial bacteremia was present in 56.8% of patients. The most common source of infection was the intestinal tract (30.2%) followed by the biliary tract (23.0%). The median Pitt bacteremia score of the patients was two. The in-hospital mortality rate was 25.9%. Of these, 34.7% died within three days of positive blood culture. Mortality rates did not differ significantly between C. perfringens and non-C. perfringens. The independent risk factors for in-hospital mortality were hepato-pancreato-biliary malignancy, chronic heart failure, Pitt bacteremia score, acute renal failure, and pneumonia as the source of infection (Table 2).

Conclusion
C. perfringens was the most common pathogen, but the distribution of other species differed from those reported in other studies. More than one-third of all in-hospital deaths occurred within three days of positive blood culture. To improve prognosis, it is necessary to elucidate the pathogenesis of bacteremia in the early acute phase and develop therapeutic strategies.

Disclosures
Sohei Harada, MD, PhD, MSD: Honoraria|Shionogi: Honoraria
P-867. Carbapenem-resistant gram-negative bacterial infections in South India: A four-year retrospective study
Authors: Dorairajan Suresh Kumar , Rajakumar Ratheesh 
Published: January 2025

Abstract

Background
Carbapenem-resistant Gram-negative bacteria (CRGNB) posed a global healthcare threat due to antibiotic resistance. In India, carbapenem resistance surged, and Ceftazidime–avibactam (CAZ-AVI) and Aztreonam (AZT) saw increased use without efficacy data. Previous international studies comparing polymyxins with CAZ-AVI plus AZT highlighted the need for region-specific evaluation. Here, we report the epidemiological, clinical, and treatment outcomes of patients admitted with CRGNB infections in a South Indian tertiary care referral hospital.
Common CRO'S reported during the study period

Methods
This retrospective study was conducted at a 250-bed tertiary care referral hospital in South India. Over the last four years (2019 to 2023), we identified all blood culture results indicating the growth of carbapenem-resistant Gram-negative bacteria (CRGNB). Subsequently, we systematically reviewed the medical records of these patients, focusing on demographical, clinical, microbiological, and outcome data. Blood cultures utilized the BacT/ALERT (Biomerieux) culture system, and species identification was accomplished with the VITEK GNI card (Biomerieux). Antibiotic susceptibility testing followed the revised Clinical and Laboratory Standards Institute performance standards. Data were entered into an Excel spreadsheet, and descriptive statistics were employed for data interpretation.

Results
The study comprised 122 patients with positive blood cultures for carbapenem-resistant Gram-negative bacteria (CRGNB), with 70.50% males and 29.50% females, averaging 58.3 years. Common CRGNBs were identified, as shown in Figure 1. Minimum Inhibitory Concentrations (MICs) for colistin were available on 34.4% occasions. CRGNBs exhibited a 41% mortality rate. Combinational therapy (n=79) for CR showed lower mortality than monotherapy (n=43), especially Colistin monotherapy (72% mortality) and Polymyxin B (20%) compared to ceftazidime avibactam + aztreonam (14%) mortality.

Conclusion
A 41% mortality rate was noted in patients with CRGNB infections in South India, with significantly higher mortality (72%) associated with colistin monotherapy. Future strategies should focus on the role of combination therapies to enhance patient outcomes in the context of CRGNB infections.

Disclosures
All Authors: No reported disclosures
365. Amoxicillin Direct Oral Challenge in Patients with High-Risk Allergic Reaction
Authors: Le Bryan , Joshi Shyam , Ham YoungYoon 
Published: January 2025

Abstract

Background
Historically, penicillin skin testing (PST) has been the first step in allergy evaluation, followed by an oral challenge (OC). Recently, there have been studies looking at the safety of direct OC in patients without a prior PST, mostly in patients with a history of a mild reaction, such as distant rash or unknown reactions. There is, however, a paucity of data for OC without a PST for patients who report a high-risk reaction to penicillin. Our hospital protocol allows for OC without PST of patients who have had a severe IgE-mediated reaction, as long as the reaction occurred more than 10 years ago.

Methods
Patients over the age of 18 admitted with a high-risk penicillin allergy who were tested with a direct OC were included. High-risk reactions include anaphylaxis, angioedema, hives, as well as shortness of breath. Patients that had a PST prior to an OC or did not have a penicillin allergy were excluded. Data collected were age at the time of challenge, reported allergy and historic reaction, presence of other high-risk allergies, onset to symptoms, time since last reaction, and result of OC. If the challenge resulted in a reaction to penicillin and inability to de-label the allergy, data on reaction and use of rescue medications were also collected.

Results
Of the 288 patients who had received an OC at our institution, 9 were excluded due to prior PST and 2 were excluded due to a non-penicillin allergy. One hundred eight were additionally excluded due to their initial allergic reaction not being high-risk. One hundred sixty-nine patients were included in the analysis. Of the 169 patients with a history of high-risk reactions, 46 patients specifically reported anaphylaxis and 34 patients reported angioedema. One hundred and fifty-nine patients (94.1%) passed the OC and had the allergy de-labeled. Of the 10 patients (5.9%) who reacted during the OC, 3 required diphenhydramine and one required albuterol. The rest did not require the use of rescue medications and were simply observed until the reaction passed. Epinephrine was not used for any patient as a rescue medicine.

Conclusion
Direct OC without a prior PST for patients who report a high-risk allergic reaction to penicillin drugs is reasonable after 10 years have passed from the initial reaction.

Disclosures
YoungYoon Ham, PharmD, Gilead: Honoraria
P-879. Predicting Antimicrobial Resistance and Empiric Treatment Failure in Hospital-Onset Sepsis Using Machine Learning on Electronic Health Records
Authors: Cohen Scott A , Morris John G , Prosperi Mattia 
Published: January 2025

Abstract

Background
Antimicrobial resistance (AMR) is a major cause of treatment failure in hospital-onset sepsis. Approaches to guide empiric antimicrobial therapy are urgently needed. We utilized machine learning to predict empiric treatment failure and AMR patterns within a high-risk hospital-onset sepsis cohort using electronic health records (EHRs).

Methods
We examined hospitalizations with documented bacterial infection from 2010 to 2023 at a tertiary-care academic hospital system. Hospital-onset sepsis was defined using CDC Adult Sepsis Event criteria. Empiric therapy was considered adequate if all pathogens isolated were susceptible to antimicrobials administered. AMR patterns included methicillin (MRSA), extended-spectrum beta-lactamase (ESBL), vancomycin (VRE), ceftriaxone, and carbapenem (CRE). Features for prediction were patient characteristics, hospitalization details, and clinical severity metrics measured within 24 hours prior to sepsis onset. Linear and non-linear machine learning models were evaluated using bootstrap validation and out-of-bag area under the receiver operating characteristic curve (AUC).

Results
Among 49,581 hospitalizations, 2019 (4%) hospital-onset sepsis encounters were identified. Mean (SD) age was 65 (16.4) years and 900 (45%) were female. At 24 hours after sepsis onset, 377 (19%) received inadequate empiric treatment and 911 (45%) infections expressed AMR. Those who received inadequate empiric treatment were 8.2 (95%CI: 6.2-10.9) times more likely to have an AMR infection. Random forest model was best-performing, with AUC (95%CI) for any AMR pattern, VRE, and CRE at 0.64 (0.63-0.64), 0.71 (0.69-0.72), and 0.70 (0.67-0.73), respectively. The AUC (95%CI) for predicting inadequate empiric antimicrobial treatment was 0.65 (0.64-0.66) with a sensitivity of 64% (58-69%) and specificity of 52% (46-68%) at optimal probability thresholds.

Conclusion
In a hospital-onset sepsis cohort with prevalent AMR, machine learning approaches utilizing limited EHR data accessible at initial sepsis recognition had moderate, but clinically insufficient, discriminatory ability in predicting AMR and empiric antimicrobial treatment failure. Future research will evaluate the utilization of large language models using unstructured EHRs.

Disclosures
All Authors: No reported disclosures
P-881. A Retrospective Review of Enterobacter cloacae complex Bacteremia: 2019-2023
Authors: Harder Samuel , Leitch Maison Z , Lee Bonita , Smith Stephanie W , Stokes William 
Published: January 2025

Abstract

Background
Enterobacter cloacae complex is one of the most common Enterobacterales considered at moderate to high risk for clinically significant AmpC production. AMP-C betalactamases confer resistance to broad spectrum cephalosporins and common beta-lactam betalactamases including Amoxicillin-Clavulanate and Piperacillin-Tazobactam. Carbapenems are often used empirically when this organism is isolated but there is a current gap in the literature regarding in which circumstances non-carbapenem antibiotics can be used safely for patients with enterobacter cloacae complex infections. The aim of this study was to examine independent predictors of mortality for patients with enterobacter cloacae complex bacteremia and identify patients which can appropriately receive non-carbapenem based therapy safely and effectively without negative impacts on mortality.

Methods
We conducted a retrospective analysis of 285 episodes of enterobacter cloacae complex bacteremia. The main outcome measure was mortality at 30 days.The χ2 or Fisher's exact test were used to compare categorical variables. To identify the independent risk factors of infection and mortality, a binary logistic regression model was used to control for the effects of confounding variables.

Results
Of 285 patients 17.5% (50) were deceased at 30 days, 110 patients received a beta-lactam betalactamase inhibitor combination initially and 80 patients received an initial broad spectrum cephalosporin. Of 209 patients for whom antibiotic data was available 73 were changed to a carbapenem within 24 hours of the initial blood culture being drawn. In univariate analysis only source was identified as a statistically significant risk factor for mortality at 30 days. In univariate and multivariate binary logistic regression analysis change to carbapenem within 24 hours of blood culture was not an independent risk factor of death at 30 days.

Conclusion
Change to carbapenem within 24 hours of cultures being taken was not an independent risk factor of 30 day mortality. Further studies are needed to determine in what group broad spectrum cephalosporins or beta-lactam betlactamase inhibitors are appropriate therapy for enterobacter cloacae.

Disclosures
All Authors: No reported disclosures
P-909. Molecular Testing Performance for the Diagnosis of Cryptococcal Meningitis in a Tertiary Care Center
Authors: Pinilla Ruth Serrano , Endo Manuel , Dallas Steven 
Published: January 2025

Abstract

Background
Cryptococcus is the most common cause of fungal meningitis worldwide and delayed diagnosis and treatment can be devastating. Diagnostic modalities include culture, antigen detection (CrAg), direct visualization in CSF and PCR. The reported sensitivity of the FilmArray® meningitis/encephalitis (ME) panel for cryptococcal meningitis compared to culture is 92-96%, and compared to CSF CrAg is 52-83%, with reported specificity of 99%. Lower CSF CrAg levels and lower quantitative growth in culture have been associated with false negative ME panel.
Characteristics of samples with false negative ME Panel

Methods
After IRB approval was obtained, a retrospective chart review of all cases of cryptococcal meningitis established by CSF Culture, CSF CrAg or ME panel from June 2017-June 2020 in a tertiary center was performed.

Results
Cryptococcus spp. was detected in 18 specimens, by either ME panel (14), CSF CrAg (12) or culture (18). These specimens were obtained from 16 patients. Their mean age was 46 years (24-73). 75% of patients were male. All the patients in this series were immunocompromised. 10 patients had HIV (PWH), half of them had CD4 counts &lt; 40 cells/mm^3, and the mean CD4 count of the rest was 99 cells/mm^3 (41-163). Three patients had a prior solid organ transplant, one had liver cirrhosis and one had idiopathic CD4 lymphopenia. The mean opening pressure was 28.1 (16- &gt;60 cm CSF). Compared to culture, the ME panel detected Cryptococcus spp. in 14/18 specimens. Of those, a total of 14 patients had a simultaneous CSF CrAG performed, 12 of those samples had a detectable CrAG, and ME panel detected the organism in all those samples. Both false negative CSF CrAG had a false negative ME Panel but were later diagnosed with a culture. There were 4 samples with false negative ME Panel. Their cultures were reported as “very light” qualitative growth. Two of them had a bloody sample and CMV detected in the ME panel, suggesting that contamination with large amount of blood can interfere with the performance of this test. This delayed treatment initiation by an average of 2 days.

Conclusion
Although the ME Panel is an excellent tool to diagnose meningitis, the lack of detection of Cryptococcus sp. in the ME panel in the right clinical context should prompt careful clinical consideration to prevent delays in treatment initiation for patients at risk of this infection.

Disclosures
All Authors: No reported disclosures
P-917. Management of pediatric focal intracranial infections: opportunities to reduce low-value care
Authors: Lu Lydia S , Dalby Allyson , Jaggi Preeti 
Published: January 2025

Abstract

Background
Focal intracranial infections are rare but life-threatening complications of sinusitis, otitis media and mastoiditis in children. Management requires collaboration between multiple specialists and prolonged antimicrobial treatment.

Methods
We retrospectively identified patients hospitalized at our tertiary care children’s hospital with focal intracranial infections from Jan 2022 - April 2024 followed in infectious disease clinic. Patient charts were reviewed to inventory imaging, surgical interventions and antibiotic treatment received. We further identified complications in each case requiring intervention, including surgery, hospitalizations and emergency room visits. MRI imaging was defined as low-value if ordered over 2 weeks prior to the study in a patient without new symptoms, or ordered for a hospitalized patient who was afebrile without neurologic symptoms or parental concerns after 30 days of antibiotic therapy.

Results
Thirty-four patients were followed in pediatric infectious disease clinic for outpatient management of: subdural empyema (13, 38%), epidural empyema (11, 33%) and brain abscess (10, 29%). Patients were most likely male (68%) and Black or African American (74%), with a median age of 12 (range: 2-18). Nearly all (94%) had at least one MRI; 19 (56%) had a repeat MRI during hospitalization, 22 (65%) had a repeat MRI after discharge. About one-third of MRIs (31%) after discharge required sedation. In our cohort 18 patients had a low-value MRI (53%) and 5 of these (28%) had more than one low-value MRI. No low-value MRI led to a finding requiring surgical intervention. The mean duration of antibiotic treatment was 42 days (SD 10.8 days). Four patients (12%) returned to the ED while on antibiotic therapy for PICC line issues, with one patient returning 3 times for PICC concerns.

Conclusion
Some management strategies for pediatric focal intracranial infections may be unnecessary or have unrecognized consequences. Repeat MRI for half our cohort was of low-value, exposed many to risks of sedation, and consumed significant family and system resources. Children on prolonged IV antibiotic therapy were at risk for line complications. Routine management of these infections merits reconsideration to decrease unwarranted costs and risks to patient.

Disclosures
All Authors: No reported disclosures
P-928. The Second Heart Program: A Peer-focused, Multidisciplinary Harm Reduction Intervention to Improve Outcomes for People Who Inject Drugs After Admission for Infective Endocarditis
Authors: Atri Alisha , Lennox Robin , O’Shea Timothy , McIlveen Marcie 
Published: January 2025

Abstract

Background
Infective endocarditis (IE) is a severe and highly prevalent injection-related infection among people who inject drugs (PWID). IE is estimated to account for 5-10% of deaths among PWID. The long-term outcomes among PWID with infective endocarditis are poor, with 5-year mortality rates over 50%. Most long-term complications are related to ongoing drug use (re-infection). However, most PWID with IE are not offered treatment for their underlying substance use disorder while in hospital. The Second Heart (SH) program is the first interdisciplinary team in Canada designed specifically to meet the unique needs of PWID with IE and which transitions with patients from the hospital into the community. The six components of the SH team are: peer support worker, systems navigator, addiction medicine physician, infectious disease physician, cardiologist/cardiac surgeon, and family physician.

Methods
The Second Heart Program was a non-randomized clinical trial enrolling PWID with infective endocarditis at three tertiary care hospitals in Hamilton. It was a mixed methods study utilizing both qualitative and quantitative methods. Five quantitative surveys, two qualitative interviews, and chart review were completed over the 12-month study period.

Results
Participants felt that their involvement with SH supported their physical, mental, and social recovery from IE, improved their trust in the healthcare system, and increased their engagement with their care. Out of 20 enrolled participants, all were consulted with an addictions medicine provider during initial hospitalization, 16/20 were set up with a family doctor post-discharge, 9/20 completed their 1-month follow-up survey, one participant died within 12 months of enrolment, and 12/19 completed their 12-month follow-up survey.

Conclusion
The early success in this pilot project has led to the successful application of funding for an expanded version of the multidisciplinary intervention for people who have any injection-related infection, including Hepatitis and HIV.

Disclosures
All Authors: No reported disclosures
P-940. Diagnostic Workup of Bacteremia Post TAVR, a Single Center Experience Over a Decade
Authors: Villareal Kenneth , Zorn George (Trip) , Almoghrabi Omar , Tadros Peter , Marikanti Goutham , Li Yanming , Baddour Larry M , El Atrouni Wissam 
Published: January 2025

Abstract

Background
Prosthetic valves are considered a risk factor for endocarditis however diagnosing prosthetic valve endocarditis (PVE) is complicated by acoustic shadowing on echocardiography. In 2023, the ISCVID published an update to the Duke Criteria (Duke 2023) which intended to increase the sensitivity in diagnosing PVE. The purpose of this study was to examine how TAVR infective endocarditis (TAVR-IE) was diagnosed at our institution
90 Day Mortality Kaplan Meier Curve

Methods
HERON was utilized to match cases between ACC/STS databases and the EMR at The University of Kansas Health System (TUKHS). Patients with bacteremia occurring after a TAVR were reviewed. Each case was evaluated if they met rejected/possible/definitive endocarditis criteria in the Modified Duke Criteria (Duke 2005) and the Duke 2023 Criteria. To adjudicate the diagnosis, an expert panel reviewed all cases that met definitive endocarditis criteria in any edition of the Duke Criteria.

Results
A total of 2371 TAVRs were conducted at TUKHS from 2012 to 2023. We identified 146 cases of post procedure bacteremia. We excluded 53 cases leaving 93 in the cohort. Transeophageal echocardiography was utilized in about half of the cases (TTE 73, TEE 45). F-FDG positron emission tomography/CT was done in six patients and Cardiac CT in one patient. Cultures returning with Enterococcus spp (16). viridans group streptococci (15), and Staphylococcus spp. (15) had similar incidence. About half had either atypical organisms (40) on 2005 Duke criteria or polymicrobial growth (7). Definitive criteria were met in 18 and 21 patients for the Duke 2005 and Duke 2023 Criteria respectively. Two cases had minor microbiological criteria upgraded to major in Duke 2023. One case was promoted to definitive endocarditis based on Cardiac CT. Upon adjudication the panel agreed with Duke 2023 Criteria classification. Sensitivity was calculated 85%/100% for Duke 2005 and Duke 2023 Criteria respectively. Kaplan Meier curves calculated no significant difference of 3 month mortality between TAVR patients who had met definitive criteria and those who did not. (Figure #1)

Conclusion
The 2023 ISCVID Duke Criteria in this study appeared to have superior sensitivity for TAVR-IE when compared to the older Modified Duke Criteria published in 2005.

Disclosures
Larry M. Baddour, MD, UpToDate, Inc.: Royalty payments (authorship duties). Wissam El Atrouni, MD, ViiV Healthcare: Advisor/Consultant