Transcriptome of three-species biofilm with and without Listeria monocytogenes

The transcription of Listeria monocytogenes in the context of a pre-grown meat-related three-species biofilm community was analyzed. The three species included Brochothrix thermosphacta (B), Carnobacterium maltaromaticum (C), and Pseudomonas fragi (P). They were pre-grown on stainless steel slides inserted in diluted tryptic-soy-broth for 24h hours (at 10 degree C with 100 rpm). The initial inoculum consisted of equal amounts of the three species (pre-grown in tryptic soy broth 1:2 for 16 hours and adjusted to an optical density of 0.1). The biofilm was grown for 24 hours. After this time period, we added L. monocytogenes and allowed it to colonize the biofilm for two hoursand removed unattached cells by changing the medium. The biofilms were further cultivated for four hours and harvested. To obtain sufficient RNA amounts, we pooled eight slides per condition. Three biological replicates were sequenced. We investigated the transcription of the different inoculums (multi-species: BCP and Listeria-only) and the two different biofilms, the one to which Listeria was introduced, and the one without Listeria addition, to determine the potential influence of Listeria presence on established biofilm communities.