Identification and characterization of Vibrio species

Potentially pathogenic Vibrio spp. in the marine environment are regarded to as emerging health risk in Europe, particularly infections caused by V. parahaemolyticus, V. vulnificus and non-O1/non-O139 V. cholerae strains. Thus, the inclusion of Vibrio spp. in surveillance programs and studies about the distribution of Vibrio spp. are urgently needed. This thesis contributes both: the evaluation of Matrix-assisted laser / desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) as tool for species identification in environmental samples and the analysis of spatial patterns of Vibrio spp. populations in the North and Baltic Seas. Regarding MALDI-TOF MS, the specific reference database VibrioBase was developed. VibrioBase revealed Vibrio spp. identification agreements of 96.9% compared to the approved rpoB-sequence based identification method as well as higher identificions scores and a better discrimination for closely related Vibrio spp. compared to the general BiotyperTM database of the manufacturer. Thus, the cost-effective and rapid method MALDI-TOF MS achieves accurate Vibrio spp. identification when used in combination with VibrioBase. In addition, single mass peaks were used to allow species identifications based on sensitive peaks (SIBOPS). The SIBOPS approach achieved 98% identification agreements with the conventional MALDI-TOF MS / VibrioBase system and is independend of the respective mass spectrometric eqipment and software tools. Furthermore, mass spectrometric biomarker were found, that might be used for the direct identification of Vibrio spp. in environmental samples. Using ERIC-PCR genotyping, general patterns were not observed for the distribution of V. cholerae, V. parahaemolyticus and V. vulnificus in the North and Baltic Seas. Particularly the latter two species were separated into distinct regions, which are however not linked to geographical aspects and, to a minor extent, are asscociated with environmental paramters such as salinity. In consequence, MALDI-TOF MS was confirmed as a promising tool for species identifications from environmental samples. VibrioBase and SIBOPS are important steps towards the implementation of Vibrio spp. in monitoring programs conducted by health authorities. Future reseach has to be done to acquire knowledge about ecological aspects of Vibrio spp. in temperate waters, in particular the linkage of Vibrio spp. to certain plankton species in the North and Baltic Sea.