title: Identification of Gram-Negative Bacteria and Genetic Resistance Determinants from Positive Blood Culture Broths by Use of the Verigene Gram-Negative Blood Culture Multiplex Microarray-Based Molecular Assay.
abstract: Bloodstream infection is a serious condition associated with significant morbidity and mortality. The outcome of these infections can be positively affected by the early implementation of effective antibiotic therapy based on the identification of the infecting organism and genetic markers associated with antibiotic resistance. In this study, we evaluated the microarray-based Verigene Gram-negative blood culture (BC-GN) assay in the identification of 8 genus or species targets and 6 genetic resistance determinants in positive blood culture broths. A total of 1,847 blood cultures containing Gram-negative organisms were tested using the BC-GN assay. This comprised 729 prospective fresh, 781 prospective or retrospective frozen, and 337 simulated cultures representing 7 types of aerobic culture media. The results were compared to those with standard bacterial culture and biochemical identification with nucleic acid sequence confirmation of the resistance determinants. Among monomicrobial cultures, the positive percent agreement (PPA) of the BC-GN assay with the reference method was as follows; Escherichia coli, 100%; Klebsiella pneumoniae, 92.9%; Klebsiella oxytoca, 95.5%; Enterobacter spp., 99.3%; Pseudomonas aeruginosa, 98.9%; Proteus spp., 100%; Acinetobacter spp., 98.4%; and Citrobacter spp., 100%. All organism identification targets demonstrated >99.5% negative percent agreement (NPA) with the reference method. Of note, 25/26 cultures containing K. pneumoniae that were reported as not detected by the BC-GN assay were subsequently identified as Klebsiella variicola. The PPA for identification of resistance determinants was as follows; blaCTX-M, 98.9%; blaKPC, 100%; blaNDM, 96.2%; blaOXA, 94.3%; blaVIM, 100%; and blaIMP, 100%. All resistance determinant targets demonstrated >99.9% NPA. Among polymicrobial specimens, the BC-GN assay correctly identified at least one organism in 95.4% of the broths and correctly identified all organisms present in 54.5% of the broths. The sample-to-result processing and automated reading of the detection microarray results enables results within 2 h of culture positivity.
authors.affiliation: The Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
authors.forename: Nathan A
authors.initials: NA
authors.lastname: Ledeboer
authors.affiliation: Intermountain Medical Center, Murray, Utah, USA.
authors.forename: Bert K
authors.initials: BK
authors.lastname: Lopansri
authors.affiliation: med fusion, Lewisville, Texas, USA.
authors.forename: Neelam
authors.initials: N
authors.lastname: Dhiman
authors.affiliation: med fusion, Lewisville, Texas, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Cavagnolo
authors.affiliation: Johns Hopkins, Baltimore, Maryland, US.
authors.forename: Karen C
authors.initials: KC
authors.lastname: Carroll
authors.affiliation: Laboratory Alliance of Central New York, LLC Hospital, Fayetteville, New York, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Granato
authors.affiliation: NorthShore University Health System Evanston, Evanston, Illinois, USA.
authors.forename: Richard
authors.initials: R
authors.lastname: Thomson
authors.affiliation: University of Washington, Seattle, Washington, USA.
authors.forename: Susan M
authors.initials: SM
authors.lastname: Butler-Wu
authors.affiliation: University of Washington, Seattle, Washington, USA.
authors.forename: Heather
authors.initials: H
authors.lastname: Berger
authors.affiliation: Henry Ford Hospital, Detroit, Michigan, USA.
authors.forename: Linoj
authors.initials: L
authors.lastname: Samuel
authors.affiliation: The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.
authors.forename: Preeti
authors.initials: P
authors.lastname: Pancholi
authors.affiliation: The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.
authors.forename: Lettie
authors.initials: L
authors.lastname: Swyers
authors.affiliation: Hennepin County Medical Center, Minneapolis, Minnesota, USA.
authors.forename: Glen T
authors.initials: GT
authors.lastname: Hansen
authors.affiliation: University of California-Davis Medical Center, Sacramento, California, USA.
authors.forename: Nam K
authors.initials: NK
authors.lastname: Tran
authors.affiliation: University of California-Davis Medical Center, Sacramento, California, USA.
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Polage
authors.affiliation: Creighton University School of Medicine, Omaha, Nebraska, USA.
authors.forename: Kenneth S
authors.initials: KS
authors.lastname: Thomson
authors.affiliation: Creighton University School of Medicine, Omaha, Nebraska, USA.
authors.forename: Nancy D
authors.initials: ND
authors.lastname: Hanson
authors.affiliation: MRIGlobal, Kansas City, Missouri, USA.
authors.forename: Richard
authors.initials: R
authors.lastname: Winegar
authors.affiliation: The Medical College of Wisconsin, Milwaukee, Wisconsin, USA bbuchan@mcw.edu.
authors.forename: Blake W
authors.identifier: http://orcid.org/0000-0002-4111-048X
authors.initials: BW
authors.lastname: Buchan
mesh_terms: D016470:Bacteremia / Q000175:diagnosis* / Q000382:microbiology; D001431:Bacteriological Techniques / Q000379:methods; D024881:Drug Resistance, Bacterial; D006090:Gram-Negative Bacteria / Q000235:genetics* / Q000302:isolation & purification*; D016905:Gram-Negative Bacterial Infections / Q000175:diagnosis* / Q000382:microbiology; D006801:Humans; D046228:Microarray Analysis / Q000379:methods; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D011446:Prospective Studies; D012189:Retrospective Studies; D013997:Time Factors