title: Optimized Use of the MALDI BioTyper System and the FilmArray BCID Panel for Direct Identification of Microbial Pathogens from Positive Blood Cultures.
abstract: Despite the current reliance on blood cultures (BCs), the diagnosis of bloodstream infections (BSIs) can be sped up using new technologies performed directly on positive BC bottles. Two methods (the MALDI BioTyper system and FilmArray blood culture identification [BCID] panel) are potentially applicable. In this study, we performed a large-scale clinical evaluation (1,585 microorganisms from 1,394 BSI episodes) on the combined use of the MALDI BioTyper and FilmArray BCID panel compared to a reference (culture-based) method. As a result, the causative organisms of 97.7% (1,362/1,394) of the BSIs were correctly identified by our MALDI BioTyper and FilmArray BCID-based algorithm. Specifically, 65 (5.3%) out of 1,223 monomicrobial BCs that provided incorrect or invalid identifications with the MALDI BioTyper were accurately detected by the FilmArray BCID panel; additionally, 153 (89.5%) out of 171 polymicrobial BCs achieved complete identification with the FilmArray BCID panel. Conversely, full use of the MALDI BioTyper would have resulted in the identification of only 1 causative organism in 97/171 (56.7%) of the polymicrobial cultures. By applying our diagnostic algorithm, the median time to identification was shortened (19.5 h versus 41.7 h with the reference method; P < 0.001), and the minimized use of the FilmArray BCID panel led to a significant cost savings. Twenty-six out of 31 microorganisms that could not be identified were species/genera not designed to be detected with the FilmArray BCID panel, indicating that subculture was not dispensable for a few of our BSI episodes. In summary, the fast and effective testing of BC bottles is realistically adoptable in the clinical microbiology laboratory workflow, although the usefulness of this testing for the management of BSIs remains to be established.
authors.affiliation: Institute of Microbiology, Università Cattolica del Sacro Cuore, Rome, Italy.
authors.forename: B
authors.initials: B
authors.lastname: Fiori
authors.affiliation: Institute of Microbiology, Università Cattolica del Sacro Cuore, Rome, Italy.
authors.forename: T
authors.initials: T
authors.lastname: D'Inzeo
authors.affiliation: Institute of Microbiology, Università Cattolica del Sacro Cuore, Rome, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Giaquinto
authors.affiliation: Institute of Microbiology, Università Cattolica del Sacro Cuore, Rome, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Menchinelli
authors.affiliation: Institute of Microbiology, Università Cattolica del Sacro Cuore, Rome, Italy.
authors.forename: F M
authors.initials: FM
authors.lastname: Liotti
authors.affiliation: Institute of Microbiology, Università Cattolica del Sacro Cuore, Rome, Italy.
authors.forename: F
authors.initials: F
authors.lastname: de Maio
authors.affiliation: Institute of Microbiology, Università Cattolica del Sacro Cuore, Rome, Italy.
authors.forename: G
authors.initials: G
authors.lastname: De Angelis
authors.affiliation: Institute of Microbiology, Università Cattolica del Sacro Cuore, Rome, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Quaranta
authors.affiliation: Institute of Microbiology, Università Cattolica del Sacro Cuore, Rome, Italy.
authors.forename: D
authors.initials: D
authors.lastname: Nagel
authors.affiliation: Institute of Infectious Diseases, Università Cattolica del Sacro Cuore, Rome, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Tumbarello
authors.affiliation: Institute of Public Health (Section of Hygiene), Università Cattolica del Sacro Cuore, Rome, Italy bposteraro@rm.unicatt.it msanguinetti@rm.unicatt.it.
authors.forename: B
authors.initials: B
authors.lastname: Posteraro
authors.affiliation: Institute of Microbiology, Università Cattolica del Sacro Cuore, Rome, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Sanguinetti
authors.affiliation: Institute of Microbiology, Università Cattolica del Sacro Cuore, Rome, Italy bposteraro@rm.unicatt.it msanguinetti@rm.unicatt.it.
authors.forename: T
authors.initials: T
authors.lastname: Spanu
mesh_terms: D000465:Algorithms; D001769:Blood / Q000382:microbiology*; D006801:Humans; D008828:Microbiological Techniques / Q000191:economics / Q000379:methods*; D025202:Molecular Diagnostic Techniques / Q000191:economics / Q000379:methods*; D016133:Polymerase Chain Reaction / Q000379:methods*; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D018805:Sepsis / Q000175:diagnosis*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000191:economics / Q000379:methods*; D013997:Time Factors