A Comparative Study of MALDI-TOF MS and Conventional Culture Methods for Bacterial Species Identification

Abstract

Identification of bacteria to species level is based on culturing in different media which takes 48 to 72 h 
from the time of isolation. Matrix-assisted desorption ionization-time of flight mass spectrometry (MALDI
TOF MS) is a new technology in bacteria identification. We evaluated MALDI-TOF-MS system with 101 
consecutively isolated bacteria colonies under routine laboratory conditions by comparing its 
identification efficiency with conventional culturing and biochemical tests. The MALDI-TOF MS identified 
bacteria 
colonies as Escherichia coli 44(43.5%), Klebsiella pneumoniae 56(55.4%) and 
Stenotrophomonas maltophila 1(1.4%) while cultural and biochemical method identified bacteria colonies 
as E. coli 43(42.5%), K. pneumoniae 56(55.4%) and failed to identify one bacteria colony which was 
identified as S. maltophila by MALDI-TOF MS. Our data suggests that although both methods are good 
for bacteria identification, MALDI-TOF MS is better than conventional culturing and biochemical tests 
because of its short turn around time with no loss of accuracy.