Whole genome sequencing of promising Lactobacillus delbrueckii subsp. bulgaricus strains isolated from Egyptian dairy products for probiotic characteristics

Probiotics are living microorganisms that, when given in an adequate dose, have a healthy impact on human well-being. With global interest in self-care, dietary supplements especially probiotics is expanding rapidly due to their supported health effects. In this study, a total of twenty-two samples were collected from dairy products in Egypt's markets, firstly isolated then identified and screened for probiotic properties under stressful conditions as NaCl, acid and bile salt conditions. After evaluation of the antimicrobial effect against widespread gram negative and gram positive human infecting bacteria, besides the antiviral assessment against (SARS-CoV-2) virus which has disturbed the world, the antibiotic susceptibility test was done. Only three promising isolates were subjected for whole genome sequence with high-output next generation technology and the obtained data was subjected to a full bioinformatics analysis. The results obtained stated the advance of our isolates to tolerate the stress factors that can struggle in the human gut as well as the antimicrobial effects. All these bright characteristics were confirmed and illustrated in detail through different and reliable genome analysis tools. Our isolates were founded to have stable genome through containing mobile genetic elements like phages and CRISPR clusters that confirm the safety and quality for human health.