Listeria aquatica identified with MALDI TOF MS

Listeria aquatica

Listeria aquatica was first described in 2014 together with L. floridensis, L. cornellensis, L. riparia and L. grandensis by M. Wiedmann et. al.
It is a Gram-positive, facultatively anaerobic, nonmotile, non-spore-forming rod-shaped bacterium. Interestingly, it is not pathogenic and belongs to the so called Listeria sensu lato species. The species was discovered in running water in Florida. The name “aquatica” comes from Latin, meaning “found in water, aquatic”.

One unique characteristic of Listeria aquatica is that it is the only member of the genus Listeria that can ferment maltose. It is also the only nonmotile Listeria that can ferment D-tagatose.
The type strain of Listeria aquatica is BEI NR-42633; DSM 26686; FSL S10-1188; LMG 28120.

Moreover, three sensu lato species (L. fleischmannii, L. floridensis, and L. aquatica) are unable to grow at low temperatures, one of the major characteristics of the genus Listeria. According to their phylogenetic and phenotypic characteristics a reclassification of L. fleischmannii, L. aquatica, and L. floridensis into the novelle genus Mesolisteria (referring to the mesophillic nature of species within this genus) is proposed.

It is crucial to monitor the presence of Listeria species in aquatic environments, including L. aquatica, as a potential indicator organism for the presence of L. monocytogenes and other pathogenic Listeria species.