Biodiversity and Phylogenetic Relationships of Novel Bacteriocinogenic Strains Isolated from Animal's Droppings at the Zoological Garden of Lille, France.

This study aimed at exploring droppings of animals living in captivity in the zoological garden (Zoo) of Lille (France), as novel sources of bacteriocinogenic strains. A collection of 295 bacterial isolates was constituted from droppings of capybara, alpaca, muntjac, zebra, tapir, rhinoceros, binturong, armadillo, saki monkey and cockatoo. Of 295 isolates, 51 exhibited antagonism against a panel of pathogenic target bacteria like Escherichia coli MC4100, Clostridium perfringens DSM 756 and Salmonella enterica subsp. enterica Newport ATCC6962. Remarkably, within this collection, only 2 Gram-negative bacilli exhibited activity against E. coli MC4100 strain used as target organism. Then, the 16S rDNA sequencing revealed these thereafter cited species, Pediococcus pentosaceus, Weissella cibaria, E. coli, Lactobacillus reuteri, Enterococcus hirae and Enterococcus faecalis. Characterization of this antagonism has revealed 11 strains able producing extracellular protease-sensitive inhibitory compounds. These strains included E. coli ICVB442 and ICVB443, Ent. faecalis ICVB472, ICVB474, ICVB477 ICVB479, ICVB481, ICVB497 and ICVB501 and Ped. pentosaceus ICVB491 and ICVB492. The genomes of the 5 most promising bacteriocinogenic strains were sequenced and analysed with Bagel4 software. Afterwards, this bioinformatics analysis permitted to locate genes encoding bacteriocins like colicin Y (E. coli), enterocin 1071A, enterocin 107 B (Ent. faecalis) and penocin A (Ped. pentosaceus), associating the above-mentioned antibacterial activity of proteinaceous nature to possible production of bacteriocins. All these results enabled us to select different bacteriocinogenic strains for a further characterization in terms of beneficial traits.

Compatibility, Cytotoxicity, and Gastrointestinal Tenacity of Bacteriocin-Producing Bacteria Selected for a Consortium Probiotic Formulation to Be Used in Livestock Feed.

Bacteriocin-producing Escherichia coli ICVB442, E. coli ICVB443, Enterococcus faecalis ICVB497, E. faecalis ICVB501, and Pediococcus pentosaceus ICVB491 strains were examined for their pathogenic risks and compatibility and hence suitability as consortium probiotic bacteria. Except for E. coli ICVB442, all were inclined to form biofilm. All were gelatinase-negative, sensitive to most of the antibiotics tested and not cytotoxic to porcine intestinal epithelial cells (IPEC-1) when tested at a multiplicity of infection (MOI) of 1. P. pentosaceus ICVB491 stood apart by inhibiting the other four strains. Both E. coli strains and E. faecalis ICVB497 strain were ß-hemolytic. Survival in the TIM-1 dynamic model of the human digestive system was 139% for the tested E. coli ICVB443 strain, 46% for P. pentosaceus ICVB491, and 32% for the preferred E. faecalis ICVB501 strain. These three potential probiotics, which are bacteriocin-producing strains, will be considered for simultaneous use as consortium with synergistic interactions in vivo on animal model.

In silico analyses of the genomes of three new bacteriocin-producing bacteria isolated from animal's faeces.

Here, we have analysed and explored the genome sequences of three newly isolated bacteria that were recently characterised for their probiotic activities and ability to produce bacteriocins. These strains, isolated from faeces of animals living in captivity at the zoological garden of Lille (France), are Escherichia coli ICVB443, Enterococcus faecalis ICVB501 and Pediococcus pentosaceus ICVB491. Their genomes have been analysed and compared to those of their pathogenic or probiotic counterparts. The genome analyses of E. coli ICVB443 and Ent. faecalis ICVB501 displayed similarities to those of probiotics E. coli 1917 Nissle, and Ent. faecalis Symbioflor 1, respectively. Furthermore, E. coli ICVB443 shares at least 89 genes with the enteroaggregative E. coli 55989 (EAEC), and Ent. faecalis ICVB501 shares at least 315 genes with the pathogenic Ent. faecalis V583 strain. Unlike Ped. pentosaceus ICVB491, which is devoid of virulence genes, E. coli ICVB443 and Ent. faecalis ICVB501 both carry genes encoding virulence factors on their genomes. Of note, the bioinformatics analysis of these two genomes located the bsh gene, which codes for bile salt hydrolase (BSH). The presence of BSH is of major importance, as it can help to increase the viability of these two strains in the gastrointestinal tract (GIT). The genome analysis of Ped. pentosaceus ICVB491 confirmed its GRAS status (Generally Recognised As Safe), as no genomic virulence factor determinant was found.