Abstract
We evaluated the performance of the Verigene Gram-Negative Blood Culture Nucleic Acid Test (BC-GN; Nanosphere, Northbrook, IL, USA), an automated multiplex assay for rapid identification of positive blood cultures caused by 9 Gram-negative bacteria (GNB) and for detection of 9 genes associated with β-lactam resistance. The BC-GN assay can be performed directly from positive blood cultures with 5 minutes of hands-on and 2 hours of run time per sample. A total of 397 GNB positive blood cultures were analyzed using the BC-GN assay. Of the 397 samples, 295 were simulated samples prepared by inoculating GNB into blood culture bottles, and the remaining were clinical samples from 102 patients with positive blood cultures. Aliquots of the positive blood cultures were tested by the BC-GN assay. The results of bacterial identification between the BC-GN assay and standard laboratory methods were as follows: Acinetobacter spp. (39 isolates for the BC-GN assay/39 for the standard methods), Citrobacter spp. (7/7), Escherichia coli (87/87), Klebsiella oxytoca (13/13), and Proteus spp. (11/11); Enterobacter spp. (29/30); Klebsiella pneumoniae (62/72); Pseudomonas aeruginosa (124/125); and Serratia marcescens (18/21); respectively. From the 102 clinical samples, 104 bacterial species were identified with the BC-GN assay, whereas 110 were identified with the standard methods. The BC-GN assay also detected all β-lactam resistance genes tested (233 genes), including 54 bla CTX-M, 119 bla IMP, 8 bla KPC, 16 bla NDM, 24 bla OXA-23, 1 bla OXA-24/40, 1 bla OXA-48, 4 bla OXA-58, and 6 bla VIM. The data shows that the BC-GN assay provides rapid detection of GNB and β-lactam resistance genes in positive blood cultures and has the potential to contributing to optimal patient management by earlier detection of major antimicrobial resistance genes.
Highlights
Sepsis caused by drug-resistant Gram-negative bacteria (GNB) often results in serious clinical outcomes in patients [1]
Bacterial strains A total of 268 stored clinical isolates at the National Center for Global Health and Medicine (NCGM) were used in the study: 23 Acinetobacter baumannii; 1 Acinetobacter oleivorans; 4 Citrobacter freundii; 14 Enterobacter cloacae; 2 Enterobacter hormaechei; 1 Enterococcus faecalis; 30 Escherichia coli; 6 Klebsiella oxytoca; 43 Klebsiella pneumoniae; 1 methicillin-resistant Staphylococcus aureus (MRSA); 1 methicillinsensitive Staphylococcus aureus (MSSA); 1 methicillin-resistant Staphylococcus epidermidis (MRSE); 1 Morganella morganii; 4 Proteus mirabilis; 4 Proteus vulgaris; 116 Pseudomonas aeruginosa; 15 Serratia marcescens; and 1 Stenotrophomonas maltophilia
Higher rates of misidentification in K. pneumoniae and S. marcescens isolates were likely to be due to the probes used in the BC-GN assay
Summary
Sepsis caused by drug-resistant Gram-negative bacteria (GNB) often results in serious clinical outcomes in patients [1]. Early administration of appropriate antibiotics improves survival of sepsis patients [3]. To improve diagnosis of causative organisms of sepsis, automated continuous-monitoring blood culture systems were developed and introduced into clinical microbiological laboratories during the 1990s [5]. These early systems and subsequent generations of automated blood culture systems remain key diagnostic tools in the diagnosis of sepsis [5]. There has been an unmet need for rapid and automated technology to identify bacterial species as well as detection of drug resistance genes
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
