bluuebunny/crossref_metadata_2025_split huggingface dataset:
2545. Impact of Early Dose Adjustment of Beta-Lactams in Patient with Septic Shock
Authors: Tawwater John C , Adams David T , Kaur Satwinder S , Ibragimova Nayle 
Published: November 2023

Abstract

Background
Effective antimicrobial dosing is crucial for survival in patient with septic shock. However, attaining therapeutic antimicrobial serum concentration is often problematic due to pathophysiological changes associated with critical illness. Antimicrobial concentrations can be decreased due to increased volume of distribution and augmented renal clearance. In addition, antibiotic doses are frequently adjusted per local renal dosing protocols based on creatinine clearance, resulting in suboptimal antibiotic exposures. The purpose of this study is to determine if unadjusted dosing of cefepime (CEF) and meropenem (MER) during the first 48 hours of septic shock improves clinical outcomes.

Methods
This is a retrospective observational cohort study comparing renally dose adjusted CEF and MER per institutional renal dosing protocol (pre-group, PRE) and unadjusted, full-dose CEF and MER (post-group, POST) (Figure 1). Adults aged 18-89 years with septic shock, initially treated with CEF or MER for at least 48 hours, and presenting with renal impairment are included. Patients receiving renal replacement therapies are excluded. The primary outcome is vasopressor-free days (VFD). Secondary outcomes are composite outcome of in-hospital mortality and hospice disposition, hospital length of stay (LOS), intensive care unit (ICU) LOS, and systemic inflammatory response syndrome (SIRS)-free days.Figure 1.Beta-lactam Dosing for Septic Shock - PRE and POST.

Results
Baseline demographic characteristics were similar between the groups with the exception of receipt of stress-dose steroids, which was significantly higher in PRE (p=0.019). The primary outcome of VFD was not significantly different between the groups, with a median of 9.33 days in PRE (n=40) and 9.54 days in POST (n=32) (Figure 2). The hospital LOS (PRE 12.5 days, POST 5.25 days, p=0.121), ICU LOS (PRE 5.5 days, POST 5 days, p=0.15), mortality, and SIRS-free days were not significantly different between the groups (Figure 3).Figure 2.Primary outcome - vasopressor-free days.Figure 3.Secondary outcomes - hospital LOS and ICU LOS.

Conclusion
Unadjusted beta-lactam dosing did not increase VFD, although the significantly higher use of stress-dose steroids in PRE could confound the result. There was no differences in secondary efficacy outcomes; however, an overall trend for shorter hospital LOS and ICU LOS in POST was observed.

Disclosures
All Authors: No reported disclosures
144. Impact of Rapid Identification and Resistance Gene Detection using an Algorithm-Based Approach in Gram-Negative Bacteremia
Authors: Jawanda Jasanjeet , Clarke Lloyd , Creager Hannah M , Shields Ryan K 
Published: November 2023

Abstract

Background
Time to appropriate antimicrobial therapy is the most important predictor of survival among patients with sepsis due to Gram-negative bacteria (GNB). Infections due to multidrug-resistant (MDR) pathogens often result in inappropriate empiric treatment (tx). The GenMark ePlex identifies organisms and resistance markers within 1.5 hours from blood culture positivity compared to 48-72 hours by conventional methods.

Methods
We are conducting a single-center study to assess outcomes before and after ePlex implementation. The pre-intervention period included patients with GN bacteremia from January to June 2021. Patients were excluded if they received comfort-only care within 48 hours, had polymicrobial GN bacteremia, or were infected by an organism not on the ePlex panel. Primary outcome is time to in-vitro active therapy from blood culture collection.

Results
208 patients were identified during the pre-intervention period; 154 met inclusion criteria. Median age was 64 years, 49% were male, and 28% were immunocompromised. Median (IQR) Charlson Comorbidity index and Pitt Bacteremia scores were 6 (4-8) and 2 (1-8), respectively (Table 1). 16% of patients were infected by MDR GNB and 21% received inactive empiric tx. Overall median (IQR) time to in-vitro active tx was 3.9 (1–19) hours, but was 39.5 (13.6-71.9) hours among those who received inactive empiric tx. Median (IQR) time to first antibiotic modification was 2.7 (1.0-3.4) days. 38% of patients were transitioned to oral antibiotics at a median (IQR) of 4.2 (3.1-6.1) days. The median (IQR) duration of tx was 15 (10-17) days; 4.5% of patients were treated with ≤ 7 days. Median (IQR) length of hospitalization was 15.5 (7-36) days. 7.8% were re-admitted within 30 days (Table 2). In-hospital and 30-day mortality rates were numerically higher among patients who received inactive empiric therapy (27% and 21%, respectively) when compared to patients who received active empiric therapy (16.5% and 12%, respectively) (Figure 1).
Results Table 1: Patient demographics, underlying conditions and infection and treatment characteristics in the pre-intervention group
Results Table 2
Results Figure 1

Conclusion
Our pre-intervention data highlight opportunities to improve the management of GN bacteremia. Implementation of ePlex is likely to decrease the proportion of patients treated with inactive therapy, shorten time to optimal tx and reduce lengths of stay.

Disclosures
Ryan K. Shields, PharmD, MS, Allergan: Advisor/Consultant|Cidara: Advisor/Consultant|Entasis: Advisor/Consultant|GSK: Advisor/Consultant|Melinta: Advisor/Consultant|Melinta: Grant/Research Support|Menarini: Advisor/Consultant|Merck: Advisor/Consultant|Merck: Grant/Research Support|Pfizer: Advisor/Consultant|Roche: Grant/Research Support|Shionogi: Advisor/Consultant|Shionogi: Grant/Research Support|Utility: Advisor/Consultant|Venatorx: Advisor/Consultant|Venatorx: Grant/Research Support
2562. Retrospective Analysis of Cefepime Intravenous Push versus Extended Infusion for the Treatment of Neutropenic Fever
Authors: Rust Thomas J , Krause Tracy M , Saw Stephen 
Published: November 2023

Abstract

Background
The outcomes associated with intravenous push (IVP) cefepime compared to extended infusion (EI) have not yet been studied. The objective of this study was to evaluate the effectiveness of IVP versus EI cefepime in patients with neutropenic fever.

Methods
This was a retrospective, single-center, cohort study evaluating hematopoietic stem cell transplant (HSCT) recipients who received IVP or EI cefepime for at least 48 hours for the treatment of neutropenic fever. Patients were excluded if they were admitted to an intensive care unit (ICU) at the time of cefepime initiation, required renal replacement therapy, received an IVP dose &lt; 2 grams, or grew a cefepime-resistant organism from initial cultures. Patients were grouped 2:1 EI-to-IVP according to weight &gt;100 kg and autologous or allogeneic HSCT. The primary outcome was defervescence at 72 hours. Secondary outcomes included 30-day in-hospital mortality, ICU transfer within 72 hours, ICU length of stay (LOS), hospital LOS, breakthrough infection, and escalation of gram-negative therapy within 72 hours. Data was analyzed using independent t-test or Wilcoxon Rank Sum test if continuous and chi-square test or Fisher’s Exact test if nominal.

Results
Of the 120 patients meeting eligibility criteria, 40 patients received IVP cefepime and 80 patients received EI cefepime. All baseline demographics were balanced between groups with the exception of time from cefepime order entry to first dose administration (Table 1). Concomitant medication administrations were also similar between groups apart from antipyretic administration (Table 2). Defervescence within 72 hours occurred in 28 (70%) patients treated with IVP and 51 (63.8%) patients treated with EI (p = 0.496). No patients experienced in-hospital mortality and median hospital LOS was not significantly impacted by IVP vs EI administration (18 vs 17.5 days, p = 0.158). None of the additional secondary outcomes studied were significantly different between groups (Table 3).

Conclusion
The current study showed no significant differences in clinical outcomes when administering cefepime as IVP or EI for the treatment of neutropenic fever. Larger studies and/or randomized controlled trials are necessary to confirm the findings of this study.

Disclosures
All Authors: No reported disclosures
2578. Trends in Pathogens and Antibiotic Treatment in Children with Cystic Fibrosis in 2018 and 2022: A Retrospective Multicenter Study
Authors: Stout Dayna , Fireizen Yaron , Vigers Timothy , Ahmed Mohamoud , Akong Kathryn , Ryu Julie , Hahn Andrea , Koumbourlis Anastassios , Tirakitsoontorn Pornchai , Arrieta Antonio C , Burgener Elizabeth , Towler Elinor , Keck Allison , Sagel Scott , Bradley John S 
Published: November 2023

Abstract

Background
The new Cystic Fibrosis (CF) transmembrane conductance regulator modulator therapy combination (elexacaftor/tezacaftor/ivacaftor, ETI) has significantly improved the quality of life of children with CF and decreased the rate of pulmonary exacerbations (PEx). The focus of our study was to examine the infection characteristics of PEx in children with CF before the availability of ETI (2018) and following ETI approval and during emergence from COVID-19 (2022).

Methods
We conducted a multicenter (5 sites) retrospective review collecting data on children with CF over 12-month periods in 2018 and in 2022 who were hospitalized for PEx and treated with IV antibiotics. We analyzed the number of PEx, bacterial and fungal organisms identified by CF respiratory cultures and IV antibiotics used empirically at hospital admission.

Results
The number of hospitalizations for PEx decreased from 414 in 2018 to 163 in 2022. The most common organisms identified in all centers were Pseudomonas aeruginosa (Pa), Staphylococcus aureus (Sa) and Candida species, with no apparent overall difference in the relative percentages of pathogens isolated between 2018 and 2022 (figure 1), although fewer children were infected with methicillin-resistant S. aureus (MRSA) in 2022 (2.7%) than in 2018 (10%) (p=0.014). There was variability in the type of antipseudomonal agents and antistaphylococcal agents used empirically both within and between the different centers (figure 2).

Conclusion
Pathogens isolated from respiratory culture associated with PEx demonstrated similar rates of isolation of pathogens in the 2 time periods, consistent with historical CF pathogen isolation. The decreased number of PEx in 2022 compared to 2018 is consistent with the widespread use of ETI. The variability of usage antipseudomonal agents between centers and between years of data collection requires further investigation.

Disclosures
Andrea Hahn, MD, MS, TGV Dx: Advisor/Consultant Antonio C. Arrieta, MD, FIDSA, FPIDS, Astellas Pharma Global Development, Inc.: Advisor/Consultant|Astellas Pharma Global Development, Inc.: Grant/Research Support|Astellas Pharma Global Development, Inc.: Honoraria|Cumberland Pharmaceutical: Grant/Research Support|IDbyDNA: Advisor/Consultant|IDbyDNA: Grant/Research Support|Melinta: Grant/Research Support|Merck: Advisor/Consultant|Merck: Grant/Research Support|Nabriva: Grant/Research Support|Paratek Pharmaceuticals: Grant/Research Support|Pfizer, Inc: Advisor/Consultant|Pfizer, Inc: Grant/Research Support|Roche/Genentech: Grant/Research Support|The Medicine Company: Grant/Research Support
2583. Antimicrobial Resistance Profile of Mycobacterium simiae and Treatment Trends from a Tertiary Care Center in Lebanon
Authors: Zakhour Johnny , Bitar Elio , Chalhoub Mariam , Wehbe Saliba , Harb Souad Bou , Kanj Souha S 
Published: November 2023

Abstract

Background
Mycobacterium simiae is a rare non-tuberculous mycobacterium (NTM) that is most identified in some Middle Eastern countries. It is unclear why this NTM is geographically restricted. The pathogen can either be a mere colonizer or cause significant morbidity. Patients with M. simiae infection require prolonged treatment with a combination of 3 antimicrobials. Drug resistance among M. simiae isolates can complicate the course of treatment. However, the correlation between in vitro resistance and clinical response is unknown. We aimed to report the susceptibility profile of M. simiae isolates from our institution and the prescribed treatments.

Methods
We conducted a retrospective study of M. simiae isolates from the American University of Beirut Medical Center (AUBMC) over 19 years. All isolates were cultured at AUBMC using the Lowenstein-Jensen media and the BacT/ALERT system then referred for speciation and susceptibility testing at Mayo Clinic, MN, USA.

Results
We included 72 isolates that underwent susceptibility testing from 59 patients. Most isolates were obtained from sputum samples (61.1%) and the rest from bronchoalveolar lavages (BAL). The highest rates of susceptibility were to clarithromycin (84.7%) and amikacin (73.6%). All isolates were resistant to ciprofloxacin, streptomycin, doxycycline, and minocycline (Graph 1). Median minimal inhibitory concentrations (MIC) for clarithromycin and amikacin for susceptible isolates were 8 and 16 mcg/mL respectively. Clofazimine susceptibility was performed on only 16 isolates, 10 of which had an MIC ≤ 0.06 mcg/mL and the highest was 0.25 mcg/mL. Empiric antimicrobial therapy was given to 30% of patients but was inappropriate in 80% of cases. Targeted therapy was given to 40.9% of patients. Most received triple therapy with clarithromycin (95.8%) and clofazimine (41.7%) being the most common agents. The median duration of treatment was 12 months with the longest duration being 11 years. Microbiologic cure was achieved in 73.9% of the 23 patients who underwent repeated testing.
Susceptibility of Mycobacterium simiae isolates according to the CLSI breakpoints.
TMP-SMX, trimethoprim-sulfamethoxazole. *Clofazimine was not included in this graph as there is no consensus on breakpoints for susceptibility for NTM. All our isolates had MICs ≤ 0.25 mcg/mL which is lower than breakpoints used in other studies.

Conclusion
M. simiae exhibits resistance to most available antimycobacterial agents. Further research is needed to understand resistance mechanisms of this organism and correlate in vitro and in vivo findings.

Disclosures
Souha S Kanj, MD, Gilead: Advisor/Consultant|Menarini: Advisor/Consultant|MSD: Advisor/Consultant|Pfizer: Advisor/Consultant
2587. Evaluating Seasonality & Demographic Risk Factors of Hospital Encounters in Patients with Community Acquired Pneumonia (CAP)
Authors: Lildar Taikchan , Shah Chineen , Khan Alvi , Sutaria Nishith , Miele Andrew , Chorzepa Aldona , Bozzo Thomas A , Robitsek Jonathan , Shakil Javeria , Cervellione Kelly L 
Published: November 2023

Abstract

Background
Community Acquired Pneumonia (CAP) is associated with increasing hospitalization rates and is a leading driver of morbidity and mortality. Seasonal differences associated with pathogen incidence in CAP-related hospital admissions have been found (Cilloniz et al., 2017). However, seasonal differences in CAP-related readmissions have not been studied.Table 1.Descriptive characteristics of the sample overall & by season. *percentages calculated as proportion of total pathogens identified, n=53 **calculated as proportion of total for each pathogen

Methods
This retrospective study examined 478 CAP-related admissions from 01/2017-03/2020 within an urban healthcare network in Queens, NY. The primary outcome was rates of readmission at 30 days. Predictors included demographics (e.g., age), clinical factors (e.g., Elixhauser comorbidity score), sputum culture bacteria present, and season of admission (Winter: 21 DEC-20 MAR, Spring: 21 MAR-20 JUN, Summer: 21 JUN-21 SEP, Fall: 22 SEP-20 DEC).

Results
Rates of hospital encounters due to CAP were highest in winter (33%) while rates of 30 day-readmission were highest in the spring (16%). Significant differences in total number of encounters were found by season (58% Winter, 25% Fall, 23% Spring, 19% Summer; p&lt; 0.001) but not readmissions (p=0.29). Sputum culture data was available for 314 patients, with microbial etiology identified in 53 patients. Significant seasonal variations in Klebsiella pneumoniae incidence were found (53% summer, 23% fall & summer, 0% winter, p=0.02). Patients presenting in winter were significantly older than other seasons (avg.=71.5, p=0.01). Across seasons, patients readmitted within 30 days had significantly higher Elixhauser scores (median score=9 vs. median score=3, p=0.003). No significant differences were observed between seasons or readmission in terms of gender, race/ethnicity, smoking history, or Elixhauser score.

Conclusion
Seasonal differences in CAP-related encounters were observed, in line with previous studies. Descriptive differences in rates of readmission suggest that future research about risk factors is needed. This study is limited by its retrospective nature, low sputum culture rates, and unstandardized sputum culture collection methods. Data on viral pneumonia was not collected.

Disclosures
All Authors: No reported disclosures
2590. Efficacy of Doxycycline Versus Azithromycin in Community Acquired Pneumonia
Authors: Mei Julie , Blum Sharon , Bosco Michael , Akerman Meredith , Fleming Andrew 
Published: November 2023

Abstract

Background
Guideline-based CAP treatment has consisted of 2 preferred regimens: a beta lactam with a macrolide (azithromycin), or monotherapy with fluoroquinolone or beta lactam with doxycycline as an alternative regimen. While doxycycline may represent a more attractive option due to concerns for increased cardiovascular risks associated with azithromycin, individual trials assessing efficacy

Methods
Individuals over 18, admitted for greater than 48 hours at NYU Brooklyn, NYU Long Island, and NYU Tisch from January 1, 2019 to December 31, 2022 with clinical or radiographic evidence of pneumonia treated with ceftriaxone plus either azithromycin or doxycycline were included. Subjects were excluded if received alternative antibiotics for &gt;24 hours, were hospitalization for &gt;48 hours within the last 90 days, were pregnant or breastfeeding, had history of structural lung disease, active lung cancer, suspected tuberculosis, or bloodstream infections, immunocompromising condition, ventilated, or with non-infectious cause of pulmonary infiltrates.

Results
A total of 91 patients met inclusion criteria, 42 patients in the azithromycin group and 49 patients in the doxycycline group. Primary outcomes defined as treatment failure requiring broadening of antibiotics, all-cause inpatient mortality and time to clinical stability were similar between the groups. In the azithromycin group, 11.9% of patients required broadening antibiotics compared to 6.12% in the doxycycline group (p=0.46). Time to clinical stability was 3 in the azithromycin group versus 3.14 days (p=0.6) in the doxycycline group. Secondary outcomes including time to hospital discharge, time to stepdown to oral antibiotics and length of treatment had no difference between groups. There was no difference in safety outcomes between groups.

Conclusion
Azithromycin and doxycycline were comparable in terms of efficacy and safety when treating CAP. These findings can be added to the existing body of evidence supporting doxycycline as an attractive option for atypical CAP coverage.

Disclosures
All Authors: No reported disclosures
2616. Effect of Vitamin D on Clinical Outcomes in Patients Hospitalized with Influenza: A Retrospective Study
Authors: Chan-Colenbrander Suk Yin , Wang Qi 
Published: November 2023

Abstract

Background
Seasonal influenza infection causes significant morbidity and mortality worldwide. This study evaluates the effect of vitamin D on clinical outcomes in patients hospitalized with influenza infection.

Methods
We performed a retrospective chart review of patients (age 18 years and older) admitted between January 1, 2016, and December 31, 2019, to the University of Minnesota Medical Center, who were tested positive for influenza.
Data were summarized using median and interquartile range (IQR) for continuous variables, frequency and percentage for categorical variables. Groups were compared using two-sample Wilcoxon test for continuous variables and Chi-square test (or Fisher's exact test for sparse data) for categorical variables.

Results
Out of 320 patients tested positive for influenza, 180 were vaccinated against influenza. The median age of those tested positive in the vaccinated group was 64 (IQR 49-74) and the unvaccinated, 58 (IQR 35-71) p=0.0074. 97.8% of the vaccinated and 94.3% of the unvaccinated patients received oseltamivir. Significantly more unvaccinated patients were admitted to the intensive care unit (ICU) (p=0.0029) and required ventilatory support (p=0.0097) compared to those who were vaccinated.
55% of the vaccinated and 36.4% of the unvaccinated patients were on Vitamin D (p=0.001). Vitamin D median level was significantly higher in the vaccinated group, 35 (IQR 22-46) compared to 24 (IQR 15-36) in the unvaccinated group (p=0.0001).
Vitamin D levels did not significantly affect the length of hospital stay, ICU admission, respiratory or cardiovascular complications, hospital survival, survival at 1- and 3-years post hospitalization in both the vaccinated and unvaccinated groups.

Conclusion
Vitamin D levels did not significantly affect the clinical outcomes of patients hospitalized with influenza.

Disclosures
All Authors: No reported disclosures
2625. Characteristics and Outcomes of COVID-19 in Patients with a Left Ventricular Assist Device
Authors: Fleites Jorge , Natori Yoichiro , Simkins Jacques , Butrous Hoda , Bauerlein Jospeh , Phancao Anita , Loebe Matthias , Munagala Mrudula , Anjan Shweta 
Published: November 2023

Abstract

Background
Patients with left ventricular assist devices (LVAD) infected with SARS-CoV-2 may be at increased risk of complications and mortality. The purpose of the study was to analyze the characteristics and outcomes of LVAD patients with SARS-CoV-2 infection at our center.

Methods
A retrospective review of LVAD patients diagnosed with COVID-19 via PCR between March 1st, 2020, and March 1st, 2023, was conducted. Patient demographics, clinical, laboratory, and imaging data were collected. We performed descriptive statistical analysis on the data obtained.

Results
During the study period, we were actively following 130 LVAD patients, 34 (26.2%) developed COVID-19. Our cohort consisted of 27 males (79.4%) with a median age of 63.5 years and median BMI of 27.6 (Table 1). Eighteen and 12 self-identified as African American (52.9%) and Hispanic (35.3%), respectively. The common comorbidities included hypertension (94.1%), hyperlipidemia (79.4%), atrial fibrillation (67.4%), and chronic kidney disease (61.8%). The most common presenting symptoms were shortness of breath (41.2%), cough (35.3%), and fever (29.4%). Nine (26.5%) patients were asymptomatic. Twenty-eight (82.4%) and 16 (57.1%) were admitted to the hospital and ICU, respectively (Table 2). Ten (35.7%) and 2 (7.1%) patients required supplemental oxygen via nasal canula, and mechanical ventilation, respectively. Most of the hospitalized patients were managed with Remdesivir (71.4%) and systemic corticosteroids (42.9%). No complications of pump hemolysis or thrombosis, or systemic embolisms were noted. Two deaths were reported: one patient (2.9%) died while in the hospital from COVID-19, and another patient died 16 months later secondary to acute respiratory failure in the setting of post-COVID pulmonary fibrosis.

Conclusion
This is the largest single center study analyzing outcomes of COVID-19 in LVAD patients to date. Our cohort experienced a lower mortality rate from COVID-19 infection compared to prior studies. Larger studies are needed to guide management strategies and determine optimal timing for heart transplant after COVID-19.

Disclosures
All Authors: No reported disclosures