Listeria seeligeri isolates from food processing environments form two phylogenetic lineages.

Seven different actA subtypes forming two phylogenetic lineages could be distinguished by sequencing the actA gene of Listeria seeligeri isolates from different habitats. Isolates of the two lineages differ in hemolytic as well as phospholipase activities and in the arrangement of the virulence gene cluster. The presence of a serine protease gene resembling orf2110 of L. monocytogenes in some isolates further supports the hypothesis that L. seeligeri is subject to ongoing adaptation to changing environments.