Would rapid identification of bacteria and rapid detection of methicillin-resistant S. aureus (MRSA) and vancomycin-resistant enterococci (VRE) (using an FDA-cleared assay) in positive blood culture bottles improve patient care at Mayo Clinic Rochester (or just lead to increased cost)?
We hypothesize that the FilmArray Blood Culture ID Panel will reduce the duration of empiric broad-spectrum antimicrobial therapy typically administered in patients who have positive blood cultures, improving clinical outcome and reducing cost. To test this hypothesis we propose a prospective, randomized controlled study comparing outcomes among patients with positive blood cultures who receive either: Standard culture and antimicrobial susceptibility testing (AST) of positive blood culture bottles as is done today (control), standard culture and AST of positive blood culture bottles plus the FilmArray Blood Culture ID Panel (intervention group 1), or standard culture and AST of positive blood culture bottles plus the FilmArray Blood Culture ID Panel testing along with expert infectious diseases phone consultation (intervention group 2). In both intervention groups, results of the FilmArray test will be communicated by phone to the primary service, along with templated comments about optimal antimicrobial therapy, based on the result. (Templated comments will also be used in the control group). In intervention group 2, an infectious diseases pharmacist or physician will provide patient-specific recommendations to modify antimicrobial therapy, if appropriate, based on microbiology results and clinical information obtained through medical record review and discussion with the primary service.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
DIAGNOSTIC
Masking
SINGLE
Enrollment
743
FilmArray Blood Culture Identification (BCID) Panel is a polymerase chain reaction (PCR) panel that identifies 19 types of bacteria, 5 types of fungi, and select antimicrobial-resistance genes.
Real time antimicrobial stewardship: an infectious diseases pharmacist or physician will provide patient-specific recommendations to modify antimicrobial therapy.
This test identifies the pathogen responsible for an infection.
Mayo Clinic in Rochester
Rochester, Minnesota, United States
Duration of Antimicrobial Therapy (Hours)
Difference between the date and time of the antibiotic start order (or Gram stain-positive blood culture, if antibiotics were started prior to the positive culture result) and the date and time of the antibiotic stop order. Shorter duration of broad spectrum antibiotics and longer duration of narrow-spectrum antibiotics were considered favorable outcomes.
Time frame: Approximately 4 days after enrollment
Time From Positive Gram Stain to First Active Antibiotic
From positive Gram stain to start of active antibiotic among patients not on active therapy at enrollment; excludes subjects with contaminated blood cultures.
Time frame: Approximately 14 days after positive blood culture
Time to First Appropriate De-escalation or First Appropriate Escalation of Antibiotics
De-escalation included discontinuation of 1 or more antibiotics and/or switching from a broad- to a narrow spectrum antibiotic. Escalation included initiation of 1 or more antibiotics and/or switching from a narrow- to a broad-spectrum antibiotic.
Time frame: Positive Gram stain, 96 hours after enrollment
Percent of Contaminated Blood Cultures Not Treated or Treated for Less Than 24 Hours
Contaminated blood cultures were defined as growth of organisms such as coagulase-negative staphylococci from a single blood culture set when greater than or equal to 2 blood culture sets were collected, except among subjects suspected to have true bacteremia associated with central venous catheters or devices.
Time frame: Within 14 days after positive blood culture
Time to Pathogen Identification
Time frame: Approximately 14 days after positive blood culture
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Antibiotic susceptibility testing determines the susceptibility of a bacterial strain to a specific antibiotic or a panel of antibiotics. Antibiotic susceptibility testing determines the susceptibility of a bacterial strain to a specific antibiotic or a panel of antibiotics.
Number of Subjects Who Had Negative Blood Cultures Within 3 Days After Enrollment
Time frame: 3 Days after enrollment
Length of Entire Hospitalization (Days)
Time frame: Participants were followed for the duration of hospital stay, approximately 15 days
All-cause and Attributable Mortality
If records of death were incomplete, mortality was determined using Accurint (LexisNexis, Philadelphia, PA), an internet research and location service.
Time frame: 30 days after positive blood culture
Number of Subjects With Antibiotic-Associated Toxicities/Adverse Events
This included all adverse events that occurred within 2 weeks following enrollment and were documented in the medical record.
Time frame: Approximately 14 days after positive blood culture
Percentage of Subjects With Infectious Disease Consultation Within 72 Hours of Enrollment
Time frame: Approximately within 72 hours of positive blood culture
Mean Total Hospitalization, Laboratory Test, and Antimicrobials Costs Per Subject
Costs were calculated using a standardized inflation-adjusted estimate of costs for each service or procedure performed in constant dollars. This approach adjusts for hospital-billed charges with Medicare Cost Report department-level cost-to-charge ratios. Physician services were proxied with Medicare reimbursement rates based on Current Procedure Terminology (CPT)-4 codes using the Medicare Fee Schedule. We did not include the cost of the stewardship program in the cost analysis, as it is not a billed service. As there was no Medicare reimbursement rate for the rmPCR test at the time of the study, test cost was proxied using the FilmArray respiratory panel. These costs were varied in sensitivity analysis with rmPCR test cost ranging from a 50% decrease to a 300% increase.
Time frame: Approximately 7 days after positive blood culture and for duration of entire hospitalization