Regular articleRapid Identification of Pathogens with the hemoFISH Test Applying a Novel Beacon-Based Fluorescence in Situ Hybridization (bbFISH) Technology in Positive Blood Culture Bottles

Rapid and accurate identification of pathogens responsible for sepsis is essential for early and targeted antimicrobial therapy. Blood cultures are the current reference standard for detection of pathogens in blood, but culture-based identification methods are time consuming. We evaluated the hemoFISH assay by using the novel bbFISH technology for rapid and accurate identification of a broad range of microorganisms in positive blood cultures. A total of 103 positive blood culture bottles were investigated. In total, 106 bacterial species were detected in the blood cultures and subsequently identified with conventional methods. The Gram-staining indicated monomicrobial growth in 95.1% (98/103) and polymicrobial growth in 4.9% (5/103) blood cultures. In 65.0% (67/103) cultures Gram-positive, 32.0% (33/103) Gram-negative, and 3.0% (3/103) both Gram-positive and Gram-negative bacteria were identified. Depending on the Gram-staining results, either the hemoFISH Gram-positive or the hemoFISH Gram-negative panel was used. In case of a polymicrobial infection, both panels were applied. The hemoFISH assay showed a sensitivity and specificity of 100% (95% CIs of 96.34% to 100% and 30.48% to 100%, respectively). Of the 106 bacterial species, the hemoFISH assay correctly identified 55.7% (n = 59) to species level, 34.0% (n = 36) to genus level, and 7.5% (n = 8) to family level. The novel hemoFISH using bbFISH technology appears to be a valuable rapid tool for the identification of a broad range of microorganisms in positive blood cultures.