Ryan K. Shields
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View article: Incidence and factors associated with rapid blood culture sterilization among patients receiving ertapenem combination therapy for MSSA bacteremia
Incidence and factors associated with rapid blood culture sterilization among patients receiving ertapenem combination therapy for MSSA bacteremia Open
Ertapenem combination therapy has been shown to expedite the time to blood culture sterilization among patients with MSSA bacteremia. The purpose of this study was to define what proportion of patients sterilizes blood cultures within 72 h…
View article: Allele-specific effects of mutations in the rifampin resistance-determining region (RRDR) of RpoB on physiology and antibiotic resistance in <i>Enterococcus faecium</i>
Allele-specific effects of mutations in the rifampin resistance-determining region (RRDR) of RpoB on physiology and antibiotic resistance in <i>Enterococcus faecium</i> Open
Enterococcus faecium is a member of the human gut microbiota that has evolved into a problematic nosocomial pathogen and a leading cause of infections in hospitalized patients. Treatment of E. faecium infections is complicated by antibioti…
View article: Effectiveness of imipenem-relebactam for multidrug-resistant <i>Pseudomonas aeruginosa</i> in pneumonia and bloodstream infections in the United States (MIRAGE)
Effectiveness of imipenem-relebactam for multidrug-resistant <i>Pseudomonas aeruginosa</i> in pneumonia and bloodstream infections in the United States (MIRAGE) Open
Imipenem-relebactam demonstrates in vitro activity against multidrug-resistant (MDR) Pseudomonas aeruginosa , but real-world effectiveness data are limited. MIRAGE was a multicenter, retrospective, observational study of imipenem-relebacta…
View article: <i>In vitro</i> evolution of durlobactam resistance in NDM-producing <i>Escherichia coli</i> due to a single mutation in <i>mrdA</i> encoding penicillin-binding protein 2
<i>In vitro</i> evolution of durlobactam resistance in NDM-producing <i>Escherichia coli</i> due to a single mutation in <i>mrdA</i> encoding penicillin-binding protein 2 Open
Durlobactam, a diazabicyclooctane β-lactamase inhibitor, exhibits direct antibacterial activity by binding to penicillin-binding protein 2 (PBP2). We generated a mutant strain of New Delhi metallo-β-lactamase-producing Escherichia coli wit…
View article: Current and future options for the treatment of serious infections due to carbapenem-resistant <i>Pseudomonas aeruginosa</i>
Current and future options for the treatment of serious infections due to carbapenem-resistant <i>Pseudomonas aeruginosa</i> Open
SUMMARY Pseudomonas aeruginosa is a frequent cause of hospital-acquired infections and is notable both for its virulence and its resistance to multiple antibiotics. In the absence of head-to-head clinical trials and availability of all pot…
View article: Within-Patient Evolution of <i>Pseudomonas aeruginosa</i> Populations During Antimicrobial Treatment
Within-Patient Evolution of <i>Pseudomonas aeruginosa</i> Populations During Antimicrobial Treatment Open
Multidrug-resistant (MDR) Pseudomonas aeruginosa infections pose a major challenge to effective treatment. Understanding genomic adaptations during antimicrobial therapy in patients infected with this pathogen is crucial for preventing the…
View article: Allele-Specific Effects of Mutations in the Rifampin Resistance-Determining Region (RRDR) of RpoB on Physiology and Antibiotic Resistance in <i>Enterococcus faecium</i>
Allele-Specific Effects of Mutations in the Rifampin Resistance-Determining Region (RRDR) of RpoB on Physiology and Antibiotic Resistance in <i>Enterococcus faecium</i> Open
Enterococcus faecium is a member of the human gut microbiota that has evolved into a problematic nosocomial pathogen and leading cause of infections in hospitalized patients. Treatment of E. faecium infections is complicated by antibiotic …
View article: Population pharmacokinetics of meropenem-vaborbactam in acutely ill hospitalized patients with various degrees of renal dysfunction including continuous renal replacement therapy
Population pharmacokinetics of meropenem-vaborbactam in acutely ill hospitalized patients with various degrees of renal dysfunction including continuous renal replacement therapy Open
Real-world meropenem-vaborbactam (MVB) pharmacokinetic-pharmacodynamic (PK/PD) attainment data in patients with renal dysfunction including continuous renal replacement (CRRT) are lacking. We evaluated MVB PK in patients with renal dysfunc…
View article: Functional Genomics of Antibiotic Susceptibility in <i>Enterococcus faecalis</i> From Infective Endocarditis
Functional Genomics of Antibiotic Susceptibility in <i>Enterococcus faecalis</i> From Infective Endocarditis Open
Enterococcus faecalis is an opportunistic pathogen that causes infective endocarditis. Despite in vitro synergy of the recommended combination ampicillin-ceftriaxone (AC), E faecalis infective endocarditis (EFIE) mortality remains high. We…
View article: Pharmacokinetic and pharmacodynamic evaluation of sulbactam‐durlobactam in a critically ill patient on continuous venovenous hemofiltration infected with carbapenem‐resistant <i>Acinetobacter baumannii‐calcoaceticus</i> complex
Pharmacokinetic and pharmacodynamic evaluation of sulbactam‐durlobactam in a critically ill patient on continuous venovenous hemofiltration infected with carbapenem‐resistant <i>Acinetobacter baumannii‐calcoaceticus</i> complex Open
Background Drug databases currently do not provide dosing guidance for sulbactam‐durlobactam in continuous renal replacement therapy. Herein, we present the first in vivo pharmacokinetic (PK) evaluation of sulbactam‐durlobactam during cont…
View article: Comparative <i>in vitro</i> activity of sulbactam with avibactam or durlobactam against carbapenem-resistant <i>Acinetobacter baumannii</i>
Comparative <i>in vitro</i> activity of sulbactam with avibactam or durlobactam against carbapenem-resistant <i>Acinetobacter baumannii</i> Open
Objective To determine the in vitro activity of sulbactam in combination with avibactam or durlobactam with and without meropenem or imipenem against carbapenem-resistant Acinetobacter baumannii clinical isolates. Methods Standardized susc…
View article: Epidemiology, Treatment, and Outcomes of Gram‐Negative Bacteremia in a Multicenter Cohort of Solid Organ Transplant Recipients
Epidemiology, Treatment, and Outcomes of Gram‐Negative Bacteremia in a Multicenter Cohort of Solid Organ Transplant Recipients Open
Introduction Little is known about the epidemiology and management of gram‐negative bloodstream infections (GN‐BSIs) in patients after solid organ transplant (SOT). We describe epidemiology, treatment approaches, and outcomes in a subset o…
View article: 209. Population Pharmacokinetics of Meropenem-Vaborbactam in Acutely Ill Hospitalized Patients with Various Degrees of Renal Dysfunction
209. Population Pharmacokinetics of Meropenem-Vaborbactam in Acutely Ill Hospitalized Patients with Various Degrees of Renal Dysfunction Open
Background Pharmacokinetic-pharmacodynamic (PK/PD) target attainment rates for meropenem-vaborbactam (MV) in real-world acutely ill patients are poorly defined. We sought to evaluate target attainment rates for MV in patients with various …
View article: P-1227. Population Pharmacokinetics (PK) of Cefiderocol (FDC) during Acute Pulmonary Exacerbations (APE) in Adult Persons with Cystic Fibrosis (CF)
P-1227. Population Pharmacokinetics (PK) of Cefiderocol (FDC) during Acute Pulmonary Exacerbations (APE) in Adult Persons with Cystic Fibrosis (CF) Open
Background FDC has potent activity against many Gram-negative rods associated with CF APE. Due to metabolic changes seen in CF as well as frequent infection with resistant bacteria, persons with CF (PwCF) frequently have altered PK and may…
View article: P-1826. Genomic Epidemiology and Clinical Characteristics of <i>Stenotrophomonas maltophilia</i> at an academic medical center
P-1826. Genomic Epidemiology and Clinical Characteristics of <i>Stenotrophomonas maltophilia</i> at an academic medical center Open
Background S. maltophilia is an opportunistic pathogen in critically-ill and immunocompromised patients. Distinguishing between colonization and infection is challenging and genomic surveillance data are scarce. This study seeks to define …
View article: P-2320. Clinical Significance of Colonization with Fluoroquinolone-Resistant Enterobacterales in Hematopoietic Cell Transplant Recipients and Patients with Acute Leukemia
P-2320. Clinical Significance of Colonization with Fluoroquinolone-Resistant Enterobacterales in Hematopoietic Cell Transplant Recipients and Patients with Acute Leukemia Open
Background Hematopoietic cell transplant (HCT) recipients and patients with acute leukemia are at high risk of Gram-negative bacteremia during neutropenia. Fluoroquinolone (FQ) prophylaxis is used to prevent bacterial infections during neu…
View article: P-1495. Antibiotic and Phage Susceptibility of Pseudomonas aeruginosa Clinical Isolates From Phage Therapy Patients
P-1495. Antibiotic and Phage Susceptibility of Pseudomonas aeruginosa Clinical Isolates From Phage Therapy Patients Open
Background Antibiotic resistance is a rising issue, with the World Health Organization predicting that by 2025, around 10 million deaths annually will be caused by resistant infections. Phage therapy is an alternative form of treatment for…
View article: P-1253. Validating and Comparing the Predictiveness of Cefepime Pharmacokinetic Models Used in Bayesian Dosing
P-1253. Validating and Comparing the Predictiveness of Cefepime Pharmacokinetic Models Used in Bayesian Dosing Open
Background Bayesian software may enhance beta-lactam dosing. Therefore, we analyzed the predictiveness of cefepime pharmacokinetic (PK) models for use as Bayesian priors. Methods Data on adult patients receiving cefepime intravenous therap…
View article: 211. Defining Optimal Sampling Times for Cefepime Therapeutic Drug Monitoring in Clinical Practice
211. Defining Optimal Sampling Times for Cefepime Therapeutic Drug Monitoring in Clinical Practice Open
Background Clinicians performing beta-lactam therapeutic drug monitoring (TDM) lack evidence on when levels should ideally be drawn after a dose. Herein, we define the optimal timing (i.e., optimal sampling) for cefepime using real-world T…
View article: 311. Defining the magnitude of desirability of outcome ranking (DOOR) differences in effectiveness of Ceftazidime-Avibactam (CZA) versus Ceftolozane-Tazobactam (C/T) for multidrug-resistant (MDR) <i>Pseudomonas aeruginosa</i> infections in the United States (CACTUS)
311. Defining the magnitude of desirability of outcome ranking (DOOR) differences in effectiveness of Ceftazidime-Avibactam (CZA) versus Ceftolozane-Tazobactam (C/T) for multidrug-resistant (MDR) <i>Pseudomonas aeruginosa</i> infections in the United States (CACTUS) Open
Background CACTUS is a retrospective, matched, multicenter study comparing the efficacy of C/T and CZA for the treatment of bacteremia or pneumonia due to MDR P. aeruginosa. We previously demonstrated that treatment with C/T resulted in hi…
View article: P-1075. Treatment Patterns among Hospitalized Patients with Gram-Negative Infection Treated with Imipenem/Cilastatin/Relebactam (I/R): Retrospective US-based EHR Medical Chart Review
P-1075. Treatment Patterns among Hospitalized Patients with Gram-Negative Infection Treated with Imipenem/Cilastatin/Relebactam (I/R): Retrospective US-based EHR Medical Chart Review Open
Background Real world evidence with I/R is limited. This study describes the patient, treatment, and clinical outcomes of hospitalized adult patients with a suspected gram negative (GN) infection who were treated with I/R for ≤48hrs.Table …
View article: P-1105. Effectiveness of Imipenem-Relebactam for Multidrug-resistant <i>Pseudomonas aeruginosa</i> in Pneumonia and Bloodstream Infections in the United States (MIRAGE)
P-1105. Effectiveness of Imipenem-Relebactam for Multidrug-resistant <i>Pseudomonas aeruginosa</i> in Pneumonia and Bloodstream Infections in the United States (MIRAGE) Open
Background Imipenem/relebactam (I/R) demonstrates potent in vitro activity against multidrug-resistant (MDR) Pseudomonas aeruginosa. The objective of this study is to evaluate the real-world effectiveness of I/R for treatment of MDR Pseudo…
View article: P-1766. Evaluation of a Comprehensive Antimicrobial Stewardship Initiative for Gram-Negative Bacteremia in 21 Acute Care Hospitals
P-1766. Evaluation of a Comprehensive Antimicrobial Stewardship Initiative for Gram-Negative Bacteremia in 21 Acute Care Hospitals Open
Background Shorter antibiotic courses are non-inferior to longer for treatment of uncomplicated gram-negative bacteremia (GNB). This study evaluated the impact of a pharmacist-driven stewardship effort to use clinical decision support soft…
View article: 312. Impact of Patient Subgroups on the Efficacy of Ceftazidime-Avibactam (CZA) versus Ceftolozane-Tazobactam (C/T) for Multidrug-resistant (MDR) <i>Pseudomonas aeruginosa</i> infections in the United States (CACTUS)
312. Impact of Patient Subgroups on the Efficacy of Ceftazidime-Avibactam (CZA) versus Ceftolozane-Tazobactam (C/T) for Multidrug-resistant (MDR) <i>Pseudomonas aeruginosa</i> infections in the United States (CACTUS) Open
Background CACTUS is a retrospective, matched, multicenter study comparing the efficacy of C/T and CZA for treatment of bacteremia or pneumonia due to MDR P. aeruginosa. We found that treatment with C/T resulted in higher rates of clinical…
View article: P-661. Impact of Optimal β-lactam Treatment on the Outcomes of Patients with <i>Pseudomonas Aeruginosa</i> Pneumonia
P-661. Impact of Optimal β-lactam Treatment on the Outcomes of Patients with <i>Pseudomonas Aeruginosa</i> Pneumonia Open
Background P. aeruginosa is the most common cause of nosocomial pneumonia and accounts for a large proportion of antibiotic use in the ICU. Despite this, there are limited comparative-effectiveness data for β-lactam agents. Our objective w…
View article: Restoring ceftolozane susceptibility: a role for diazabicyclooctane β-lactamase inhibitors?
Restoring ceftolozane susceptibility: a role for diazabicyclooctane β-lactamase inhibitors? Open
Paired baseline and post-exposure isolates from 34 patients who developed ceftolozane–tazobactam (TOL-TAZ) resistance following treatment of multidrug-resistant (MDR) Pseudomonas aeruginosa infections were analyzed to determine if ceftoloz…
View article: Cefiderocol pharmacokinetics during acute pulmonary exacerbations in hospitalized adult persons with cystic fibrosis
Cefiderocol pharmacokinetics during acute pulmonary exacerbations in hospitalized adult persons with cystic fibrosis Open
Persons with CF (pwCF) present altered pharmacokinetics (PK) and are often infected with multidrug-resistant (MDR) bacteria. Herein, we describe the PK of cefiderocol, a siderophore cephalosporin with potent activity against MDR Gram-negat…
View article: Clinical outcomes of a twice-daily metronidazole dosing strategy for Bacteroides spp. bloodstream infections
Clinical outcomes of a twice-daily metronidazole dosing strategy for Bacteroides spp. bloodstream infections Open
In the largest study to date of patients with Bacteroides spp. bacteraemia treated with metronidazole, twice-daily dosing strategies were not associated with worse outcomes compared with thrice-daily dosing strategies.