Molecular validation of clinical Pantoea isolates identified by MALDI-TOF

PLoS One. 2019 Nov 4;14(11):e0224731. doi: 10.1371/journal.pone.0224731. eCollection 2019.

Abstract

The Enterobacterial genus Pantoea contains both free-living and host-associating species, with considerable debate as to whether documented reports of human infections by members of this species group are accurate. MALDI-TOF-based identification methods are commonly used in clinical laboratories as a rapid means of identification, but its reliability for identification of Pantoea species is unclear. In this study, we carried out cpn60-based molecular typing of 54 clinical isolates that had been identified as Pantoea using MALDI-TOF and other clinical typing methods. We found that 24% had been misidentified, and were actually strains of Citrobacter, Enterobacter, Kosakonia, Klebsiella, Pseudocitrobacter, members of the newly described Erwinia gerundensis, and even several unclassified members of the Enterobacteriaceae. The 40 clinical strains that were confirmed to be Pantoea were identified as Pantoea agglomerans, Pantoea allii, Pantoea dispersa, Pantoea eucalypti, and Pantoea septica as well as the proposed species group, Pantoea latae. Some species groups considered largely environmental or plant-associated, such as P. allii and P. eucalypti were also among clinical specimens. Our results indicate that MALDI-TOF-based identification methods may misidentify strains of the Enterobacteriaceae as Pantoea.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Typing Techniques / methods*
  • Diagnostic Errors
  • Enterobacteriaceae Infections / diagnosis
  • Enterobacteriaceae Infections / microbiology*
  • Humans
  • Pantoea / classification*
  • Pantoea / genetics
  • Pantoea / isolation & purification
  • Phylogeny
  • Plants / microbiology
  • Reproducibility of Results
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization

Grants and funding

This research was funded by a Discovery Grant (#2015-06417) to JS by the Natural Sciences and Engineering Council of Canada. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.