Clinical Impact of Laboratory Implementation of Verigene BC-GN Microarray-Based Assay for Detection of Gram-Negative Bacteria in Positive Blood Cultures.
Gram-negative bacteremia is highly fatal, and hospitalizations due to sepsis have been increasing worldwide. Molecular tests that supplement Gram stain results from positive blood cultures provide specific organism information to potentially guide therapy, but more clinical data on their real-world impact are still needed. We retrospectively reviewed cases of Gram-negative bacteremia in hospitalized patients over a 6-month period before (n = 98) and over a 6-month period after (n = 97) the implementation of a microarray-based early identification and resistance marker detection system (Verigene BC-GN; Nanosphere) while antimicrobial stewardship practices remained constant. Patient demographics, time to organism identification, time to effective antimicrobial therapy, and other key clinical parameters were compared. The two groups did not differ statistically with regard to comorbid conditions, sources of bacteremia, or numbers of intensive care unit (ICU) admissions, active use of immunosuppressive therapy, neutropenia, or bacteremia due to multidrug-resistant organisms. The BC-GN panel yielded an identification in 87% of Gram-negative cultures and was accurate in 95/97 (98%) of the cases compared to results using conventional culture. Organism identifications were achieved more quickly post-microarray implementation (mean, 10.9 h versus 37.9 h; P < 0.001). Length of ICU stay, 30-day mortality, and mortality associated with multidrug-resistant organisms were significantly lower in the postintervention group (P < 0.05). More rapid implementation of effective therapy was statistically significant for postintervention cases of extended-spectrum beta-lactamase-producing organisms (P = 0.049) but not overall (P = 0.12). The Verigene BC-GN assay is a valuable addition for the early identification of Gram-negative organisms that cause bloodstream infections and can significantly impact patient care, particularly when resistance markers are detected.
Department of Pathology, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA.
Tamar
T
Walker
University of Southern California School of Pharmacy, Los Angeles, California, USA.
Sandrea
S
Dumadag
University of Southern California School of Pharmacy, Los Angeles, California, USA.
Christine Jiyoun
CJ
Lee
Department of Pathology, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA.
Seung Heon
SH
Lee
Department of Pediatrics, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA.
Jeffrey M
JM
Bender
University of Southern California School of Pharmacy, Los Angeles, California, USA.
Jennifer
J
Cupo Abbott
Department of Pathology, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA rosemary.she@med.usc.edu.
Rosemary C
RC
She
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016470:Bacteremia / Q000175:diagnosis*; D000071997:Blood Culture; D042241:Early Diagnosis; D005260:Female; D006090:Gram-Negative Bacteria / Q000235:genetics / Q000302:isolation & purification*; D016905:Gram-Negative Bacterial Infections / Q000175:diagnosis*; D006801:Humans; D008297:Male; D046228:Microarray Analysis / Q000379:methods*; D008875:Middle Aged; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D012189:Retrospective Studies; D055502:Secondary Prevention; D013997:Time Factors; D055815:Young Adult