Identification of Waterborne Microbial Pathogens by Matrix-assisted Laser-desorption/ionization Time-of-flight Mass Spectrometry and the Biotyper 2.0 Databases

On the basis of various guidelines for drinking-water quality, five species of bacteria (Helicobacter pylori, Salmonella typhimurium, Yersinia enterocolitica, Legionella pneumophila, and Campylobacter jejuni) were selected as representatives of waterborne microbial pathogens. Matrix-associated laser-desorption/ionization timeof-flight mass spectrometry (MALDI-TOF MS) analysis was conducted to identify the five bacteria, and the MALDI-TOF MS results were compared with results obtained through 16S rRNA identification. The MALDI-TOF MS analysis yielded score values of 1.60 ± 0.19, 2.41 ± 0.09, 2.37 ± 0.16, 2.19 ± 0.15, and 1.85 ± 0.08 for H. pylori, S. typhimurium, Y. enterocolitica, L. pneumophila, and C. jejuni, respectively. In addition, the MALDI-TOF identification results were well-correlated with those from the 16S rRNA identification. This study suggests that MALDI-TOF-based identification is an inexpensive, rapid, reproducible, and accurate alternative method for the identification of waterborne microbial pathogens in aquatic environments.