title: The IRIDICA BAC BSI Assay: Rapid, Sensitive and Culture-Independent Identification of Bacteria and Candida in Blood.
abstract: Bloodstream infection (BSI) and sepsis are rising in incidence throughout the developed world. The spread of multi-drug resistant organisms presents increasing challenges to treatment. Surviving BSI is dependent on rapid and accurate identification of causal organisms, and timely application of appropriate antibiotics. Current culture-based methods used to detect and identify agents of BSI are often too slow to impact early therapy and may fail to detect relevant organisms in many positive cases. Existing methods for direct molecular detection of microbial DNA in blood are limited in either sensitivity (likely the result of small sample volumes) or in breadth of coverage, often because the PCR primers and probes used target only a few specific pathogens. There is a clear unmet need for a sensitive molecular assay capable of identifying the diverse bacteria and yeast associated with BSI directly from uncultured whole blood samples. We have developed a method of extracting DNA from larger volumes of whole blood (5 ml per sample), amplifying multiple widely conserved bacterial and fungal genes using a mismatch- and background-tolerant PCR chemistry, and identifying hundreds of diverse organisms from the amplified fragments on the basis of species-specific genetic signatures using electrospray ionization mass spectrometry (PCR/ESI-MS). We describe the analytical characteristics of the IRIDICA BAC BSI Assay and compare its pre-clinical performance to current standard-of-care methods in a collection of prospectively collected blood specimens from patients with symptoms of sepsis. The assay generated matching results in 80% of culture-positive cases (86% when common contaminants were excluded from the analysis), and twice the total number of positive detections. The described method is capable of providing organism identifications directly from uncultured blood in less than 8 hours.
  
  
  CONCLUSIONS
  The IRIDICA BAC BSI Assay is not available in the United States.
authors.affiliation: Ibis Biosciences, an Abbott Company, Carlsbad, California, United States of America.
authors.forename: David
authors.initials: D
authors.lastname: Metzgar
authors.affiliation: Ibis Biosciences, an Abbott Company, Carlsbad, California, United States of America.
authors.forename: Mark W
authors.initials: MW
authors.lastname: Frinder
authors.affiliation: Department of Emergency Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America.
authors.forename: Richard E
authors.initials: RE
authors.lastname: Rothman
authors.affiliation: Department of Emergency Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America.
authors.forename: Stephen
authors.initials: S
authors.lastname: Peterson
authors.affiliation: The Johns Hopkins Hospital Clinical Microbiology Laboratory, Baltimore, Maryland, United States of America.
authors.forename: Karen C
authors.initials: KC
authors.lastname: Carroll
authors.affiliation: The Johns Hopkins Hospital Clinical Microbiology Laboratory, Baltimore, Maryland, United States of America.
authors.forename: Sean X
authors.initials: SX
authors.lastname: Zhang
authors.affiliation: Department of Emergency Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America.
authors.forename: Gideon D
authors.initials: GD
authors.lastname: Avornu
authors.affiliation: Ibis Biosciences, an Abbott Company, Carlsbad, California, United States of America.
authors.forename: Megan A
authors.initials: MA
authors.lastname: Rounds
authors.affiliation: Ibis Biosciences, an Abbott Company, Carlsbad, California, United States of America.
authors.forename: Heather E
authors.initials: HE
authors.lastname: Carolan
authors.affiliation: Ibis Biosciences, an Abbott Company, Carlsbad, California, United States of America.
authors.forename: Donna M
authors.initials: DM
authors.lastname: Toleno
authors.affiliation: Ibis Biosciences, an Abbott Company, Carlsbad, California, United States of America.
authors.forename: David
authors.initials: D
authors.lastname: Moore
authors.affiliation: Ibis Biosciences, an Abbott Company, Carlsbad, California, United States of America.
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Hall
authors.affiliation: Ibis Biosciences, an Abbott Company, Carlsbad, California, United States of America.
authors.forename: Christian
authors.initials: C
authors.lastname: Massire
authors.affiliation: Ibis Biosciences, an Abbott Company, Carlsbad, California, United States of America.
authors.forename: Gregory S
authors.initials: GS
authors.lastname: Richmond
authors.affiliation: Ibis Biosciences, an Abbott Company, Carlsbad, California, United States of America.
authors.forename: Jose R
authors.initials: JR
authors.lastname: Gutierrez
authors.affiliation: Ibis Biosciences, an Abbott Company, Carlsbad, California, United States of America.
authors.forename: Rangarajan
authors.initials: R
authors.lastname: Sampath
authors.affiliation: Ibis Biosciences, an Abbott Company, Carlsbad, California, United States of America.
authors.forename: David J
authors.initials: DJ
authors.lastname: Ecker
authors.affiliation: Ibis Biosciences, an Abbott Company, Carlsbad, California, United States of America.
authors.forename: Lawrence B
authors.initials: LB
authors.lastname: Blyn
mesh_terms: D000465:Algorithms; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D001419:Bacteria / Q000302:isolation & purification*; D001424:Bacterial Infections / Q000097:blood*; D001681:Biological Assay / Q000379:methods*; D002175:Candida / Q000302:isolation & purification*; D002177:Candidiasis / Q000097:blood*; D017931:DNA Primers; D024881:Drug Resistance, Bacterial; D025141:Drug Resistance, Fungal; D006801:Humans; D057230:Limit of Detection; D016133:Polymerase Chain Reaction; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D018805:Sepsis / Q000097:blood* / Q000382:microbiology; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D000900:Anti-Bacterial Agents; D017931:DNA Primers