Impact of Bacillus cereus on the Human Gut Microbiota in a 3D In Vitro Model

Abstract

In vitro models for culturing complex microbial communities are progressively being used to study the effects of different factors on the modeling of in vitro-cultured microorganisms. In previous work, we validated a 3D in vitro model of the human gut microbiota based on electrospun gelatin scaffolds covered with mucins. The aim of this study was to evaluate the effect of Bacillus cereus, a pathogen responsible for food poisoning diseases in humans, on the gut microbiota grown in the model. Real-time quantitative PCR and 16S ribosomal RNA-gene sequencing were performed to obtain information on microbiota composition after introducing B. cereus ATCC 14579 vegetative cells or culture supernatants. The adhesion of B. cereus to intestinal mucins was also tested. The presence of B. cereus induced important modifications in the intestinal communities. Notably, levels of Proteobacteria (particularly Escherichia coli), Lactobacillus, and Akkermansia were reduced, while abundances of Bifidobacterium and Mitsuokella increased. In addition, B. cereus was able to adhere to mucins. The results obtained from our in vitro model stress the hypothesis that B. cereus is able to colonize the intestinal mucosa by stably adhering to mucins and impacting intestinal microbial communities as an additional pathogenetic mechanism during gastrointestinal infection.

Animal and In Vitro Models as Powerful Tools to Decipher the Effects of Enteric Pathogens on the Human Gut Microbiota

“…The names of bacterial taxa in the lists are presented in descending order from the highest to the lowest taxonomical rank and in alphabetical order within the same rank, regardless of the relevance of increases or reductions in microbial abundances. ↓ Enterobacter [57] In vitro ↑ Bifidobacterium, Clostridium, Mitsuokella ↓ Total bacterial load, Pseudomonadota, Akkermansia, Escherichia-Shigella, Faecalibacterium, Lactobacillus [58] Abbreviations: 1 CDI: Clostridioides difficile infection; 2 2 ′ -FL: 2 ′ -fucosyllactose.…”

“…The impact of B. cereus on gut communities was also investigated in vitro by Calvigioni and colleagues [ 58 ]. Following a combined approach of 16S rDNA-targeting real-time qPCR and Illumina sequencing, microbial consortia of in vitro cultured fecal samples were analyzed after the addition of vegetative cells or culture supernatants of the pathogenic B. cereus strain ATCC 14579.…”

“…Following a combined approach of 16S rDNA-targeting real-time qPCR and Illumina sequencing, microbial consortia of in vitro cultured fecal samples were analyzed after the addition of vegetative cells or culture supernatants of the pathogenic B. cereus strain ATCC 14579. The obtained results showed that B. cereus was able to reduce the total bacterial load, Pseudomonadota , Akkermansia , Escherichia-Shigella , Faecalibacterium , and Lactobacillus and increase the amount of Bifidobacterium , Clostridium , and Mitsuokella [ 58 ]. The increase in Bifidobacterium spp.…”