Monitoring of tetrodotoxin in shellfish and screening of Toxins biosynthesis genes in bacteria isolated from Northwest of Spain

Tetrodotoxin (TTX) is a neurotoxin that has been reported from diverse organism, although the biogenic origin of TTX is still controversial, TTX biosynthesis by host-associated bacteria has been reported. The presence of TTX... [ view full abstract ]

Tetrodotoxin (TTX) is a neurotoxin that has been reported from diverse organism, although the biogenic origin of TTX is still controversial, TTX biosynthesis by host-associated bacteria has been reported. The presence of TTX in some shellfish harvesting areas of Europe has been recently reported mostly associated to high concentrations of Vibrio parahaemolyticus although the association with phytoplankton has been also suggested. The aim of this study is focused in the isolation of the major Vibrio spp and other enterobacterial populations  and to determine some pathways genes (PKS and NRPS) involved in the biosynthesis of toxins. It is also an objective of this work to investigate the possible presence of TTX in shellfish samples positive for Vibrios spp being LC-MS/MS the analytical tool used for this purpose. From January- 2017 a total of 60 samples from Galician Rias located on the Atlantic west coast of Spain have been investigated. PCR screening has been used to detect genes associated to biosynthesis of toxins. HILIC Chromatography coupled to Tandem Mass spectrometry (LC-MS/MS) has been used for the screening of TTX in the selected samples. To date, none of the samples from the harvesting areas were positive for TTX despite to the detection of the presence of Vibrio parahaemolyticus. Future work is still in progress to detect the TTX production for the NRPS positive strain, as well as to continue with the screening of the different harvesting area during annual period to correlate the presence of Vibrio spp with different environmental variables.