2020 Volume 69 Issue 4 Pages 608-614
Although matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has proven its high accuracy and rapidity for microorganism identification, the differentiation between Klebsiella oxytoca and Raoultella spp. by MALDI-TOF MS is difficult because of their highly similar mass spectra. Thus, the aim of this study was to evaluate the capability of MALDI Biotyper (Bruker Daltonics) to identify K. oxytoca and Raoultella spp. using biochemical tests. We tested a collection of 124 clinical isolates previously identified as K. oxytoca or Raoultella spp. by MALDI Biotyper and two ATCC strains. MALDI Biotyper correctly identified 100% of K. oxytoca isolates to the species level. For Raoultella spp., 100% of their isolates were identified to the genus level and only 8 (23.5%) isolates were identified to the species level. The use of additional phenotypic tests is recommended for the reliable identification of this genus.
