Distribution and ecology of the generalist lactic acid bacterium Carnobacterium maltaromaticum in different freshwater habitats: Metabolic and antagonistic abilities

Abstract

We explored the distribution, metabolic and antagonistic activities of Carnobacterium maltaromaticum, isolated from freshwater locations in Denmark during winter or early spring. This species was widely distributed in such habitats although it was relatively rare in low pH locations. Isolates possessed a diverse metabolism, potentially enabling functional capacities independent of habitat. The intraspecies competition showed a relatively high degree of mostly low‐intensity interactions, which overall were not correlated with phylogeny or location. Only a few isolates exhibited broad‐spectrum inhibition activity, targeting species from other genera and families, including one isolate that exhibited a broad inhibitory activity due to H2O2 production. Bioinformatic analyses revealed that the frequency of bacteriocinogenic systems was low, and only one unmodified bacteriocin, piscicolin 126, correlated with phenotypic antagonistic activity. Furthermore, most potential bacteriocin gene complexes were not complete. Overall, this study showed C. maltaromaticum to be a generalist (nomadic) species with a constant presence in freshwater habitats, especially those with pH values >5. General metabolic properties did not suggest a strong degree of adaptation to the freshwater environment, and bacteriocin‐mediated antagonistic activities appeared to play a minimal ecological role.

Complete genome sequence of Listeria seeligeri strain 43-1 isolated from a Danish forest freshwater swamp

“…We examined the presence of Listeria spp. in 22 Danish freshwater habitats while mapping the distribution of lactic acid bacteria ( 1 ). One milliliter of water sample was cultured in 9 ml of Half Fraser Broth (Thermo Scientific, USA) at 30°C overnight and subsequently on RAPID’L.mono medium (Bio-Rad, USA) at 37°C for 1–2 days.…”

“…One milliliter of water sample was cultured in 9 ml of Half Fraser Broth (Thermo Scientific, USA) at 30°C overnight and subsequently on RAPID’L.mono medium (Bio-Rad, USA) at 37°C for 1–2 days. Colonies were subcultured on Tryptone Soya Agar (Oxoid, Thermo Scientific, USA) with 5% bovine blood at 37°C for 1 day and identified by matrix-assisted laser desorption/ionization-time of flight mass spectrometry ( 1 ). Compared to other studies ( 2 – 4 ), the frequency of Listeria spp.…”