MALDI-TOF MS Identification and Clustering Applied to Enterobacter Species in Nosocomial Setting

Enterobacter microorganisms cause important bacterial infections in humans. Recently,carbapenem resistant isolates carrying the blaKPC gene were described and theirclonal transmission in different nosocomial outbreaks reported. In this study, the relativenumbers of Enterobacter species, their antimicrobial susceptibility along 3 years ofobservation and the identification ability of the two most common MALDI-TOF platformswere evaluated. A clustering analysis was performed to identify changes in the microbialpopulation within the nosocomial environment. Enterobacter were identified using twoplatforms (MALDI-TOF Biotyper and VITEK MS). Antimicrobial susceptibility was testedby Vitek2 Compact and MIC50 and MIC90 was evaluated using GraphPad software.Clustering analysis was performed by MALDI-TOF and a dendrogram was built withboth platforms and compared. The most frequent species isolated were Enterobacter