Whole-cell MALDI-TOF: Rapid screening method in environmental microbiology

The rapidly developing field of environmental microbiology seeks reliable and fast methods for the identification of microorganisms. This work compared three methods for taxonomical identification of bacterial isolates obtained from sediment samples contaminated with polychlorinated biphenyls (PCBs). The methods compared were: biochemical set NEFERMtest 24, MALDI-TOF MS, and the sequencing of 16S rRNA genes.Use of NEFERMtest 24, which belongs to classical biochemical tests, showed a limited application. The MALDI-TOF method of mass spectrometry inferred existence of four different bacterial groups among the selected isolates. All the isolates were identified after sequencing of 16S rRNA genes in the Ribosomal Database Project. The sequencing method also proved the existence of four different taxonomical units among the isolates. This work showed a high potential of the mass spectrometry MALDI-TOF for screening and discrimination of different bacterial isolates with minimal time demand, reduced costs, and handling of the samples.

► Three identification methods for environmental bacterial isolates are compared.
► MALDI-TOF MS permits rapid determination of similarities between bacterial isolates.
► 16S rRNA genes has established its position of accurate bacterial identification.
► Biochemical tests showed limitations due to their high specialization.