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 coli44(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.

Key words: Bacteria identification, MALDI- TOF MS, culture, biochemical test, bacteria colony.