title: Performance Evaluation of the Verigene Gram-Positive and Gram-Negative Blood Culture Test for Direct Identification of Bacteria and Their Resistance Determinants from Positive Blood Cultures in Hong Kong.
abstract: BACKGROUND
  A multicenter study was conducted to evaluate the diagnostic performance and the time to identifcation of the Verigene Blood Culture Test, the BC-GP and BC-GN assays, to identify both Gram-positive and Gram-negative bacteria and their drug resistance determinants directly from positive blood cultures collected in Hong Kong.
  
  
  RESULTS
  A total of 364 blood cultures were prospectively collected from four public hospitals, in which 114 and 250 cultures yielded Gram-positive and Gram-negative bacteria, and were tested with the BC-GP and BC-GN assay respectively. The overall identification agreement for Gram-positive and Gram-negative bacteria were 89.6% and 90.5% in monomicrobial cultures and 62.5% and 53.6% in polymicrobial cultures, respectively. The sensitivities for most genus/species achieved at least 80% except Enterococcus spp. (60%), K.oxytoca (0%), K.pneumoniae (69.2%), whereas the specificities for all targets ranged from 98.9% to 100%. Of note, 50% (7/14) cultures containing K.pneumoniae that were missed by the BC-GN assay were subsequently identified as K.variicola. Approximately 5.5% (20/364) cultures contained non-target organisms, of which Aeromonas spp. accounted for 25% and are of particular concern. For drug resistance determination, the Verigene test showed 100% sensitivity for identification of MRSA, VRE and carbapenem resistant Acinetobacter, and 84.4% for ESBL-producing Enterobacteriaceae based on the positive detection of mecA, vanA, blaOXA and blaCTXM respectively.
  
  
  CONCLUSIONS
  Overall, the Verigene test provided acceptable accuracy for identification of bacteria and resistance markers with a range of turnaround time 40.5 to 99.2 h faster than conventional methods in our region.
authors.affiliation: Department of Health technology and Informatics, The Hong Kong Polytechnic University, Hong Kong SAR, China.
authors.forename: Gilman K H
authors.initials: GK
authors.lastname: Siu
authors.affiliation: Department of Microbiology, Queen Mary Hospital, The University of Hong Kong, Hong Kong SAR, China.
authors.forename: Jonathan H K
authors.initials: JH
authors.lastname: Chen
authors.affiliation: Department of Pathology, Princess Margaret Hospital, Hong Kong SAR, China.
authors.forename: T K
authors.initials: TK
authors.lastname: Ng
authors.affiliation: Department of Clinical Pathology, Pamela Youde Nethersole Eastern Hospital, Hong Kong SAR, China.
authors.forename: Rodney A
authors.initials: RA
authors.lastname: Lee
authors.affiliation: Department of Pathology, United Christian Hospital, Hong Kong SAR, China.
authors.forename: Kitty S C
authors.initials: KS
authors.lastname: Fung
authors.affiliation: Department of Microbiology, Queen Mary Hospital, The University of Hong Kong, Hong Kong SAR, China.
authors.forename: Sabrina W C
authors.initials: SW
authors.lastname: To
authors.affiliation: Department of Pathology, United Christian Hospital, Hong Kong SAR, China.
authors.forename: Barry K C
authors.initials: BK
authors.lastname: Wong
authors.affiliation: Department of Pathology, Princess Margaret Hospital, Hong Kong SAR, China.
authors.forename: Sherman
authors.initials: S
authors.lastname: Cheung
authors.affiliation: Department of Clinical Pathology, Pamela Youde Nethersole Eastern Hospital, Hong Kong SAR, China.
authors.forename: Ivan W F
authors.initials: IW
authors.lastname: Wong
authors.affiliation: Department of Pathology, United Christian Hospital, Hong Kong SAR, China.
authors.forename: Marble M P
authors.initials: MM
authors.lastname: Tam
authors.affiliation: Department of Health technology and Informatics, The Hong Kong Polytechnic University, Hong Kong SAR, China.
authors.forename: Swing S W
authors.initials: SS
authors.lastname: Lee
authors.affiliation: Department of Microbiology, Queen Mary Hospital, The University of Hong Kong, Hong Kong SAR, China.
authors.forename: W C
authors.initials: WC
authors.lastname: Yam
mesh_terms: D016470:Bacteremia / Q000235:genetics* / Q000382:microbiology*; D001431:Bacteriological Techniques / Q000379:methods; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D016983:Enterococcus / Q000235:genetics; D006090:Gram-Negative Bacteria / Q000235:genetics*; D006094:Gram-Positive Bacteria / Q000235:genetics*; D006723:Hong Kong; D006801:Humans; D025202:Molecular Diagnostic Techniques / Q000379:methods; D012680:Sensitivity and Specificity