Detection of Escherichia coli sequence type 131 by matrix-assisted laser desorption ionization time-of-flight mass spectrometry: implications for infection control policies?

Background: Sequence type 131 (ST131) is a predominant lineage among extraintestinal pathogenic Escherichia coli. It plays a major role in the worldwide dissemination of extended-spectrum beta-lactamase (ESBL)-producing E. coli. The ST131 pandemic is mainly the result of clonal expansion of the single well-adapted subclone H30-Rx, which is acquired in hospitals more frequently than other ESBL-producing E. coli clones. Aim: To develop a rapid method using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) to identify ST131 for infection control purposes. Methods: Peak biomarkers of ST131 were identified from the mass spectrum profiles of 109 E. coli isolates (including 50 ST131 isolates). Findings: The models accurately identified ST131 isolates from mass spectrum profiles obtained with and without protein extraction. Conclusions: The rapid identification of ST131 isolates with MALDI-TOF MS can be easily implemented in the laboratory, and could help to target infection control measures in patients carrying multi-drug-resistant E. coli that are more likely to spread. (C) 2015 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.