Evaluating the Safety of Potential Probiotic Enterococcus durans KLDS6.0930 Using Whole Genome Sequencing and Oral Toxicity Study

Abstract

Enterococcus durans KLDS6.0930 has previously been shown to have probiotic potential. However, being a potential clinical pathogen, it becomes necessary to evaluate its safety status for novel potential probiotic use. The purpose of this study is to systematically evaluate the safety of E. durans KLDS6.0930 based on its genomics, phenotypic characteristics and oral toxicity. The complete genome of E. durans KLDS6.0930 was sequenced and analyzed for safety-related genes. Antibiotic susceptibility and the production of harmful metabolites were tested. A 28-day repeated oral dose toxicity test was implemented in rats. In vitro, E. durans KLDS6.0930 was resistant to five antibiotics, with intrinsic resistances to four antibiotics and no identified genes for the last. E. durans KLDS6.0930 was not hemolytic and virulence factors were non-functional in its genome. E. durans KLDS6.0930 produced a small amount of tyramine and phenethylamine; genes encoding tyramine decarboxylase were identified. In addition, genotype and phenotype analyses showed that the strain did not have the ability to generate D-lactic acid, indole, or nitroreductase. In vivo, E. durans KLDS6.0930 did not induce adverse effects on the organs, hematological and serum biochemical parameters, or cecal bacterial populations in the oral toxicity test. These results indicate that E. durans KLDS6.0930 can be safely used as a potential probiotic for human consumption and animal feed.

Complete genome sequence and comparative analysis of two potential probiotics Bacillus subtilis isolated from honey and honeybee microbiomes

“…Also, the genes encoding for virulence factors such as hemolysin BL, non-hemolytic enterotoxin NHE, enterotoxin T, cytotoxin T, and cereulide were not present in either of the two strains. Recently, the whole-genome sequencing has been used for the safety assessment of potential probiotic strains and prediction of the presence or absence of genes associated with virulence and adverse metabolite [ 38 – 40 ]. Therefore, in future, the complete genome sequencing would be a crucial and accurate approach for evaluating the safety and control the quality of probiotic strains.…”

Molecular detection, phylogenetic analysis, and antibacterial performance of lactic acid bacteria isolated from traditional cheeses, North‐West Iran

“…hirae (Adnan, Patel, & Hadi, 2017) and Ent. durans (Li et al, 2018). These strains have the ability to produce a variety of antimicrobial compounds, such as organic acids and bacteriocins (Hassanzadazar et al, 2014 farciminis as a feed additive would help to improve ruminal fermentation digestibility without any adverse effect on the pH of rumen and enhance ruminant productivity through manipulation of the rumen microbial ecosystem (Elghandour et al, 2019).…”

“…hirae (Adnan, Patel, & Hadi, 2017) and Ent. durans (Li et al., 2018). These strains have the ability to produce a variety of antimicrobial compounds, such as organic acids and bacteriocins (Hassanzadazar et al., 2014).…”

Lactobacillus xylosus isolated from butter showed potentiality to be used as probiotic and biopreservative

“…LAB are gram positive, non-sporing, catalase negative, cocci-shaped, usually non-motile organisms that are devoid of cytochrome C and are nonaerobic, but are aerotolerant and acid tolerant which produce lactic acid as the major end product (Agrawal, 2005;Nami et al, 2019;Chowdhury et al, 2012). These microbes are ubiquitous in nature and are indigenous inhabitants of the human gastrointestinal tract, vagina and human skin, but are also found in soil, water, vegetables products, meats, fermented and cooked meat and dairy products (Andersson et al, 2001;Li et al, 2018). LAB deploy strong antagonistic activity against pathogenic, non-pathogenic and spoilage organisms in fermented milk, foods and beverages (Gilliland et al, 1975) and demonstrate antimutagenic properties through reducing the activity of β-glucornidase, nitro reductase and azoreductase which convert precarcinogen into its active form (Guarner et al, 2003).…”