Rapid Identification and Susceptibility Testing of Pathogens From Blood Cultures

Rapid Identification and Susceptibility Testing of Pathogens Growing in Blood Culture Bottles - A Quality Improvement Theragnostic Stewardship Project

National Institute of Allergy and Infectious Diseases (NIAID), National Center for Advancing Translational Sciences (NCATS)

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.

Standard Mayo practices (bacterial culture and susceptibility testing) will be used. FilmArray testing will not be performed.

Standard Mayo practices will be used AND FilmArray testing will be performed. Results of the FilmArray Blood Culture ID Panel test will be communicated to the service by phone in real-time, 24 hours a day, 7 days a week.

Standard Mayo practices will be used. FilmArray testing will be performed and reported as above, for intervention group 1. IN ADDITION, an expert will review the subject's FilmArray Blood Culture ID Panel result and medical record and contact the primary service if a modification of antimicrobial therapy may be appropriate.

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.

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.

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.

From positive Gram stain to start of active antibiotic among patients not on active therapy at enrollment; excludes subjects with contaminated blood cultures.

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.

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.

If records of death were incomplete, mortality was determined using Accurint (LexisNexis, Philadelphia, PA), an internet research and location service.

This included all adverse events that occurred within 2 weeks following enrollment and were documented in the medical record.

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.

Percentage of Patients Who Acquired Clostridium Difficile or Multidrug-resistant Organisms Within 30 Days After Enrollment

Multidrug-resistant organisms included vancomycin-resistant enterococci, methicillin-resistant Staphylococcus aureus, extended-spectrum cephalosporin-resistant Enterobacteriaceae, and Pseudomonas aeruginosa and Acinetobacter species resistant to greater than or equal to 3 antibiotic classes.

Inclusion criteria: Positive blood culture during the study period. No positive blood cultures in prior 7 days Minnesota state research authorization provided Exclusion criteria: No Minnesota state research authorization Deceased or transitioned to comfort care within 24 hours of enrollment Positive blood culture in prior 7 days Previously enrolled in this study Negative Gram stain

Banerjee R, Teng CB, Cunningham SA, Ihde SM, Steckelberg JM, Moriarty JP, Shah ND, Mandrekar JN, Patel R. Randomized Trial of Rapid Multiplex Polymerase Chain Reaction-Based Blood Culture Identification and Susceptibility Testing. Clin Infect Dis. 2015 Oct 1;61(7):1071-80. doi: 10.1093/cid/civ447. Epub 2015 Jul 20.