Feed Insects as a Reservoir of Granadaene-Producing Lactococci.

Insects are a component of the diet of different animal species and have been suggested as the major source of human dietary protein for the future. However, insects are also carriers of potentially pathogenic microbes that constitute a risk to food and feed safety. In this study, we reported the occurrence of a hemolytic orange pigmented producing phenotype of in the fecal microbiota of golden lion tamarins () and feed larvae (). Feed insects were identified as a regular source of based on a reanalysis of available 16S rRNA gene libraries. Pan-genome analysis suggested the existence of four clusters within the group. The presence of cluster indicated that some strains of the group produced a pigment similar to granadaene, an orange cytotoxic lipid produced by group B streptococci, including . Pigment production by strains was dependent on the presence of the fermentable sugars, with no pigment being observed at pH <4.7. The addition of buffering compounds or arginine, which can be metabolized to ammonium, restored pigment formation. In addition, pigment formation might be related to the source of peptone. These data suggest that edible insects are a possible source of granadaene-producing lactococci, which can be considered a pathogenic risk with zoonotic potential.