Multi-centre evaluation of mass spectrometric identification of anaerobic bacteria using the VITEK® MS system.
Accurate and timely identification of anaerobic bacteria is critical to successful treatment. Classic phenotypic methods for identification require long turnaround times and can exhibit poor species level identification. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is an identification method that can provide rapid identification of anaerobes. We present a multi-centre study assessing the clinical performance of the VITEK(®) MS in the identification of anaerobic bacteria. Five different test sites analysed a collection of 651 unique anaerobic isolates comprising 11 different genera. Multiple species were included for several of the genera. Briefly, anaerobic isolates were applied directly to a well of a target plate. Matrix solution (α-cyano-4-hydroxycinnamic acid) was added and allowed to dry. Mass spectra results were generated with the VITEK(®) MS, and the comparative spectral analysis and organism identification were determined using the VITEK(®) MS database 2.0. Results were confirmed by 16S rRNA gene sequencing. Of the 651 isolates analysed, 91.2% (594/651) exhibited the correct species identification. An additional eight isolates were correctly identified to genus level, raising the rate of identification to 92.5%. Genus-level identification consisted of Actinomyces, Bacteroides and Prevotella species. Fusobacterium nucleatum, Actinomyces neuii and Bacteroides uniformis were notable for an increased percentage of no-identification results compared with the other anaerobes tested. VITEK(®) MS identification of clinically relevant anaerobes is highly accurate and represents a dramatic improvement over other phenotypic methods in accuracy and turnaround time.
Department of Pathology and Laboratory Medicine, UCLA, Los Angeles, CA, USA.
O
O
Garner
A
A
Mochon
J
J
Branda
C-A
CA
Burnham
M
M
Bythrow
M
M
Ferraro
C
C
Ginocchio
R
R
Jennemann
R
R
Manji
G W
GW
Procop
S
S
Richter
J
J
Rychert
L
L
Sercia
L
L
Westblade
M
M
Lewinski
D001421:Bacteria, Anaerobic / Q000737:chemistry / Q000145:classification* / Q000302:isolation & purification*; D001424:Bacterial Infections / Q000175:diagnosis*; D001431:Bacteriological Techniques / Q000379:methods*; D006801:Humans; D012680:Sensitivity and Specificity; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
Anaerobe; VITEK-MS; bacterial identification; clinical microbiology; matrix-assisted laser desorption ionization time-of-flight mass spectrometry