Evaluation of the FilmArray Blood Culture Identification Panel: Results of a Multicenter Controlled Trial.

Sepsis is a major cause of morbidity, mortality, and increased medical expense. Rapid diagnosis improves outcomes and reduces costs. The FilmArray blood culture identification panel (BioFire Diagnostics LLC, Salt Lake City, UT), a highly multiplexed PCR assay, can identify 24 etiologic agents of sepsis (8 Gram-positive, 11 Gram-negative, and 5 yeast species) and three antimicrobial resistance genes (mecA, vanA/B, and blaKPC) from positive blood culture bottles. It provides results in about 1 h with 2 min for assay setup. We present the results of an eight-center trial comparing the sensitivity and specificity of the panel with those of the laboratories' standard phenotypic identification techniques, as well as with molecular methods used to distinguish Acinetobacter baumannii from other members of the A. calcoaceticus-A. baumannii complex and to detect antimicrobial resistance genes. Testing included 2,207 positive aerobic blood culture samples, 1,568 clinical and 639 seeded. Samples were tested fresh or were frozen for later testing within 8 h after the bottles were flagged as positive by an automated blood culture system. At least one organism was detected by the panel in 1,382 (88.1%) of the positive clinical specimens. The others contained primarily off-panel organisms. The panel reported multiple organisms in 81 (5.86%) positive clinical specimens. The unresolved blood culture identification sensitivity for all target detections exceeded 96%, except for Klebsiella oxytoca (92.2%), which achieved 98.3% sensitivity after resolution of an unavoidable phenotypic error. The sensitivity and specificity for vanA/B and blaKPC were 100%; those for mecA were 98.4 and 98.3%, respectively.

Nonculture techniques for the detection of bacteremia and fungemia.

Bacteremia and fungemia account for a substantial proportion of all cases of severe sepsis. Antibiotic resistance is a contributing factor in many hospital-acquired infection deaths. Traditional phenotypic methods for the identification of bacteria and yeasts from positive blood cultures and determining antimicrobial susceptibility require 48-72 h, delaying optimal therapy and negatively impacting patient outcomes. Molecular methods, including nonamplified DNA probe panels and peptide nucleic acid probes, and nucleic acid amplification methods such as PCR, proteomic methods (matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry) and direct biochemical tests provide more rapid identification of bacteria and fungi, and in some cases antimicrobial resistance markers, from positive blood cultures, as well as directly from whole blood. These methods vary in the breadth of organisms that they detect, and equally important, their ease of use. This article examines the principles, performance and practicality of the various rapid, nonculture techniques for the detection of bacteremia and fungemia.