Differentiation of Cronobacter spp. by tryptic digestion of the cell suspension followed by MALDI-TOF MS analysis

Lukáš Krásný; Eva Rohlová; Helena Růžičková; Jiří Santrůček; Radovan Hynek; Igor Hochel

doi:10.1016/j.mimet.2014.01.008

Differentiation of Cronobacter spp. by tryptic digestion of the cell suspension followed by MALDI-TOF MS analysis

J Microbiol Methods. 2014 Mar:98:105-13. doi: 10.1016/j.mimet.2014.01.008. Epub 2014 Jan 23.

Authors

Lukáš Krásný¹, Eva Rohlová², Helena Růžičková², Jiří Santrůček², Radovan Hynek², Igor Hochel²

Affiliations

¹ Institute of Chemical Technology in Prague, Technická 5, 166 28 Prague 6, Czech Republic; Institute of Microbiology, AS CR, v.v.i., Vídeňská 1083, 142 20 Prague 4, Czech Republic. Electronic address: krasnyl@vscht.cz.
² Institute of Chemical Technology in Prague, Technická 5, 166 28 Prague 6, Czech Republic.

PMID: 24462807
DOI: 10.1016/j.mimet.2014.01.008

Abstract

Intact cell MALDI-TOF mass spectrometry is a rapid tool for the identification and classification of microorganisms, now widely used even in clinical laboratories. However, its distinctive power is not sufficient for some closely-related species. The genus Cronobacter, formerly known as Enterobacter sakazakii, contains such species. In this work, a new method for the differentiation of five Cronobacter species is presented involving the tryptic digestion of cytoplasmatic proteins followed by MALDI mass spectrometry analysis. A database was developed for use in Bruker Biotyper software including 52 reference spectra and tested on a set of 45 samples with an overall accuracy of about 80%. The possibility of measurement automation and the short time and low cost requirements of this method compared to those of biochemical tests or PCR methods make it a supplementary option to intact cell MALDI, providing additional information about the differentiation of problematic species.

Keywords: Biotyper; Cronobacter; MALDI-TOF; Mass spectrometry; Trypsin.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Bacterial Typing Techniques / methods*
Bacteriological Techniques / methods
Cronobacter / isolation & purification*
Cronobacter sakazakii / isolation & purification
Polymerase Chain Reaction / methods
Software
Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / methods*