Comparison of MALDI-TOF MS Biotyper and 16S rDNA sequencing for the identification of Pseudomonas species isolated from fish.

Effective and reliable methods of identification of Pseudomonas species are important for the characterization of microorganisms. Freshwater ecosystems are an important source of Pseudomonas species, including those pathogenic to fish and humans. The aim of the present study was to compare the identification conducted with MALDI-TOF MS Biotyper and 16S rDNA sequencing of fish-borne Pseudomonas spp. Altogether, 13 different Pseudomonas spp. were isolated from freshwater fish. Phylogenetic analysis showed a clear taxonomic placement only for 13 out of 15 Pseudomonas isolates. Accordance of identification method was found only in 6 out of 15 isolates. The human pathogenic Pseudomonas spp. were not found in our study, indicating that the fish could be considered as safe for consumption. The present study revealed a high discriminatory power of the mass spectra investigation and 16S rDNA gene sequencing technology for the identification of Pseudomonas spp. associated with freshwater fish.