Baylor University Medical Center Proceedings April 2015 - (Page 144)
The SUCCESS model for laboratory performance and
execution of rapid molecular diagnostics in patients
with sepsis
Mhair Dekmezian, MD, Stacy G. Beal, MD, Mary Jane Damashek, MT (ASCP) SM, Raul Benavides, MD,
and Neelam Dhiman, PhD
Successful performance and execution of rapid diagnostics in a clinical laboratory hinges heavily on careful validation, accurate and timely
communication of results, and real-time quality monitoring. Laboratories
must develop strategies to integrate diagnostics with stewardship and
evidence-based clinical practice guidelines. We present a collaborative
SUCCESS model for execution and monitoring of rapid sepsis diagnostics
to facilitate timely treatment. Six months after execution of the Verigene
Gram-Positive Blood Culture (BC-GP) and the AdvanDx PNA-FISH assays, data were collected on 579 and 28 episodes of bacteremia and
fungemia, respectively. Clinical testing was executed using a SUCCESS
model comprising the following components: stewardship, utilization
of resources, core strategies, concierge services, education, support,
and surveillance. Stewardship needs were identified by evaluating the
specialty services benefiting from new testing. Utilization of resources
was optimized by reviewing current treatment strategies and antibiogram
and formulary options. Core strategies consisted of input from infectious
disease leadership, pharmacy, and laboratory staff. Concierge services
included automated Micro-eUpdate and physician-friendly actionable
reports. Education modules were user-specific, and support was provided through a dedicated 24/7 microbiology hotline. Surveillance was
performed by daily audit by the director. Using the SUCCESS model, the
turnaround time for the detailed report with actionable guidelines to the
physician was ~3 hours from the time of culture positivity. The overall
correlation between rapid methods and culture was 94% (546/579).
Discrepant results were predominantly contaminants such as a coagulase-negative staphylococci or viridans streptococci in mixed cultures.
SUCCESS is a cost-effective and easily adaptable model for clinical laboratories with limited stewardship resources.
B
acteremia is a major cause of severe sepsis and septic
shock, accounting for 30% to 40% of cases, with an estimate of about 250,000 cases occurring annually in the
United States (1). A significant proportion of causative
organisms are gram-positive bacteria, most commonly Staphylococcus species (2). Multiple studies have established that timely
administration of appropriate antibiotics significantly reduces
the mortality of severe sepsis and septic shock. Use of inappropriate empiric antibiotics is a common factor associated with
mortality rates as high as 75% (3, 4). Delays in initiating antimicrobial treatment are correlated with a progressive increase
144
in mortality (5). The choice of initial antibiotics for treatment
of bacteremia must currently be determined empirically. A
reduction in time to an accurate identification and susceptibility results may lead to improved patient outcomes, although
literature on the magnitude of such an effect is mixed (6, 7).
Current standard blood culture procedures consist of inoculating a blood culture bottle and placing it on an automated
continuous monitoring and alert platform (8). Upon positivity,
the contents are Gram stained, plated on appropriate media, and
allowed to grow for 18 to 42 hours or longer, with subsequent
subcultures and susceptibility testing as appropriate. The temporal delay between collection of a blood sample from a patient
and availability of traditional identification and susceptibility
results has obvious implications regarding patient care.
Newer technologies such as nucleic acid amplification tests,
fluorescence in situ hybridization (FISH), and matrix-assisted
laser desorption ionization time-of-flight mass spectrometry
(MALDI-TOF MS) provide rapid identification of pathogens
and codetection of key resistance markers directly from positive blood cultures. The Verigene Gram-Positive (BC-GP) and
Gram-Negative (BC-GN) blood culture assays are approved by
the Food and Drug Administration (FDA) to detect common
gram-positive and gram-negative organisms, respectively, and
associated resistance markers within 3 hours from positive blood
cultures (9). The Verigene assays are nonamplified tests that rely
on nucleic acid extraction from positive blood cultures followed
by microarray-based detection using capture and detection
probes. BC-GP is specific for 12 gram-positive bacterial identification targets and 3 associated resistance markers (mecA, vanA,
and vanB), while BC-GN is specific for 8 gram-negative bacterial identification targets and 6 resistance markers (blaCTX-M,
blaKPC, blaNDM, blaVIM, blaIMP, and blaOXA). The turnaround
time from positive blood culture to results can be markedly reduced compared with traditional methods, potentially providing
From med fusion Laboratory, Lewisville, TX (Dekmezian, Beal, Damashek,
Benavides, Dhiman), and the Department of Pathology and Laboratory Medicine,
Baylor University Medical Center at Dallas, Dallas, Texas (Dekmezian, Beal,
Benavides).
Corresponding author: Neelam Dhiman, PhD, Technical Director, Molecular
Diagnostics, med fusion, 2501 South State Highway 121, Suite 1100, Lewisville,
TX75067 (e-mail: ndhiman@medfusionsvs.com).
Proc (Bayl Univ Med Cent) 2015;28(2):144-150
Table of Contents for the Digital Edition of Baylor University Medical Center Proceedings April 2015
Antibiotic utilization improvement with the Nanosphere Verigene Gram-Positive Blood Culture assay
The SUCCESS model for laboratory performance and execution of rapid molecular diagnostics in patients with sepsis
Impact of the DASH diet on endothelial function, exercise capacity, and quality of life in patients with heart failure
A survey-based analysis of symptoms in patients with postural orthostatic tachycardia syndrome
An interactive web-based project to stimulate internal medicine resident reading using board-type questions
The acute respiratory distress syndrome
History of neurologic examination books
Cecal adenocarcinoma presenting as colonic intussusception in adulthood
Large-volume barium aspiration
Effect of resection of an orbital arteriovenous malformation on central venous pressure
Acute nonrheumatic streptococcal myocarditis resembling ST-elevation acute myocardial infarction in a young patient
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Cardiac arrhythmias during myocardial infarction
Takotsubo cardiomyopathy associated with hyperthyroidism treated with thyroidectomy
Ventricular tachycardic storm with a chronic total coronary artery occlusion treated with percutaneous coronary intervention
Myocardial ischemic hyperacute T-wave oversensing leading to a defibrillator shock storm
Usefulness of percutaneous closure of patent foramen ovale for hypoxia
Mitral stenosis and acute ST elevation myocardial infarction
Eff ectiveness of exclusion of a persistent sciatic artery aneurysm with an Amplatzer™ plug
Immune thrombocytopenia associated with consumption of tonic water
Paraneoplastic cerebellar ataxia and the paraneoplastic syndromes
Carcinoma of the lungs causing enlarged kidneys
Mixed epithelial and stromal tumors of the kidney discovered incidentally at autopsy
Superior sagittal sinus thrombosis as the initial presentation of renal cell carcinoma
Hepatocellular carcinoma with extension to the heart via the inferior vena cava
Leprosy in a Texan
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