"What am I?" microbiology of culture-positive, biofire® blood culture identification 2 panel-negative bloodstream infections
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Updated: May 13, 2025
Preparation of a Blood Culture Pellet for Rapid Bacterial Identification and Antibiotic Susceptibility Testing
Published on: October 15, 2014
Joseph Berger1, Divya Pandya1, Jordan Colson2
1Division of Infectious Diseases, Department of Medicine, University of Miami Miller School of Medicine, 1400 NW 12th Ave, Miami FL 33136, USA.
Background:
The BioFire® blood culture identification 2 panel (BCID2) detects 33 of the most common bloodstream infection (BSI) pathogens, yet it can fail to detect the causal agent of sepsis in up to 13 % of cases, mostly due to infections caused by off-panel target microorganisms. A better understanding of the microbiology of culture-positive, BCID2-negative BSI is needed.
Methods:
Single-center, retrospective study of microbiology and outcomes in 275 cases of BCID2-negative BSI between 2022 and 2024.
Results:
A total of 257 adult patients with 275 cases of culture-positive, BCID2-negative BSI were analyzed. Viable organisms were identified in 95.2 % of the cases. False negative results (i.e., in-BCID2 panel target microorganism) occurred at 3.3 % and corresponded mostly to Candida spp. (67 %). Although microorganisms considered of low clinical significance accounted for more than a third of the cases, off-BCID2 panel, clinically relevant microorganisms identified by culture included Bacteroides spp. (other than B. fragilis; 12 %), Clostridium spp. (5.8 %), Candida spp. (4.4 %), Achromobacter xylosoxidans, Pasteurella multocida, Trichosporon asahii, Fusarium spp., Rhodococcus equi, Capnocytophaga spp., and Burkholderia cepacia, among others. Only 116 (42 %) were on appropriate antibiotic therapy at the time of BCID2 result. 30-day mortality was 24 % in the entire cohort, but as high as 33 %, 44 %, and 42 % for Bacteroides spp., Clostridium spp. and Candida BSI, respectively.
Conclusions:
These results highlight the limitations of the BCID2 panel (e.g., need for inclusion of pan-Bacteroides and Clostridium spp., and optimization of sensitivity for Candida spp.); and provide useful insights on the most common causes of BCID2-negative BSI.
