Reliability of Acinetobacter baumannii Identification with Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry

Abstract

Background:The purpose of this study was to evaluate the reliability of identification with the strains of Acinetobacter baumannii and non-baumanni Acinetobacter spp, determined with matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), compared to the molecular genetic method. Methods: A total of 225 blood isolates of A. baumannii and non-baumanni Acinetobacter spp. were included in this study. Species identification was performed using MALDI-TOF MS, blaOXA-51 polymerase chain reaction (PCR), and RNA polymerase β-subunit (rpoB) PCR-sequencing. Results:The MALDI-TOF MS results showed 100% category agreement with that of blaOXA-51 PCR, which clearly distinguished A. baumannii from nonbaumanni Acinetobacter spp. The species-concordance rate of non-baumanni Acinetobacter spp. was 73.7% (14/19) on the basis of rpoB sequence results. Conclusions: MALDI-TOF MS is very useful in distinguishing between A. baumannii and non-baumanni Acinetobacter spp. accurately, which is useful information on the choice of therapeutic agents. However, there was a limitation in correctly identifying non-baumanni Acinetobacter spp.