Direct identification of microorganisms from positive blood cultures using the lysis-filtration technique and matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS): a multicentre study.
Microbial identification from blood cultures is essential to institute optimal antibiotic therapy and improve survival possibilities. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has been successfully applied to identify bacteria and yeasts from positive blood cultures broths. The aim of this multicentre study was to evaluate the reliability of the lysis-filtration technique associated with MALDI-TOF MS to directly identify microorganisms from 765 positive blood cultures collected in six Italian hospitals. Overall, 675/765 (78.1%) blood isolates were correctly identified at the species level, with significant differences between Gram-negative and Gram-positive bacteria (92.6%, and 69.8%, respectively). Some difficulties arise in identifying Streptococcus pneumoniae, Staphylococcus aureus, yeasts and anaerobes. The lysis-filtration protocol is a suitable procedure in terms of performance in identifying microorganisms, but it is quite expensive and technically time-consuming since the time of filtration is not regular for all the samples. The application of the MALDI-TOF MS technique to the direct microbial identification from positive blood cultures is a very promising approach, even if more experience must be gained to minimize errors and costs.
Microbiology Laboratories of AO "Papa Giovanni XXIII" (formerly "Ospedali Riuniti di Bergamo"), Bergamo.
Claudio
C
Farina
Department of Medical Biotechnologies, University of Siena, Siena.
Fabio
F
Arena
Local Health Authority 4, Prato.
Patrizia
P
Casprini
IRCCS San Raffaele Hospital, Milan.
Paola
P
Cichero
IRCCS San Raffaele Hospital, Milan.
Massimo
M
Clementi
Microbiology Laboratories of AO "Papa Giovanni XXIII" (formerly "Ospedali Riuniti di Bergamo"), Bergamo.
Marina
M
Cosentino
Local Health Authority 4, Prato.
Roberto
R
Degl'Innocenti
Department of Medical Biotechnologies, University of Siena, Siena.
Tommaso
T
Giani
Manzoni Hospital, Lecco.
Francesco
F
Luzzaro
Campo di Marte Hospital, Lucca.
Romano
R
Mattei
Manzoni Hospital, Lecco.
Carola
C
Mauri
Campo di Marte Hospital, Lucca.
Maria
M
Nardone
Department of Medical Biotechnologies, University of Siena, Siena; Siena University Hospital, Siena; Department of Experimental and Clinical Medicine, University of Florence, Florence.
Gian Maria
GM
Rossolini
Microbiology Laboratories of AO "Papa Giovanni XXIII" (formerly "Ospedali Riuniti di Bergamo"), Bergamo.
Paula Andrea
PA
Serna Ortega
Microbiology Laboratories of AO "Papa Giovanni XXIII" (formerly "Ospedali Riuniti di Bergamo"), Bergamo.
Francesca
F
Vailati
D001419:Bacteria / Q000737:chemistry / Q000145:classification / Q000302:isolation & purification*; D001424:Bacterial Infections / Q000097:blood / Q000382:microbiology*; D015373:Bacterial Typing Techniques / Q000379:methods*; D001769:Blood / Q000382:microbiology*; D006801:Humans; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
Blood culture; Identification; Lysis-filtration technique; MALDI-TOF