The aim of this study was to use of probiotic Lactobacillus species as a potential alternative treatment to control some foodborne pathogens isolated from different sources of retail food such as (yogurt, green salad, and sausage). The predominant bacterial isolates were Staphylococcus aureus, Bacillus cereus, Klebsiella sp., Escherichia coli, Proteus sp., Pseudomonas sp., and Shigella sp. Isolates were identified by gram stain reaction, culture morphology on selective and differential media and motility test. The antibiotic sensitivity was determined using 12 antibiotics based on their mode of action using the disc diffusion method. Isolated probiotics were identified as five species of namely: Lactobacillus pentosus strain K50, Lactobacillus plantarum strain KK518, Lactiplantibacillus argentoratensis strain LSM1-4, Lactobacillus plantarum subsp. Plantarum strain Ni1243, Lactiplantibacillus plantarum strain Gm6 using the molecular technique. These species were tested and confirmed as potential probiotic by acid tolerance, bile salt resistance, antibiotic susceptibility testing, phenol resistance, and antimicrobial activity against isolated pathogenic bacteria. The adhesion of isolated probiotic strains to intestinal epithelium was determined in vitro using Caco-2 cell line. The results showed that Lactiplantibacillus plantarum strain Gm6 had the strongest adhesion ability to the Caco-2 cell line, and the least was Lactiplantibacillus argentoratensis strain LSM1-4. Using the agar spot test and displacement assay probiotic strains showed strong antagonistic activity toward many pathogenic bacteria isolated from many retail foods collected from local markets as Staphylococcus aureus, Klebsiella, Escherichia coli and might be useful as a natural alternative to antibiotics.
Key words: Antibiotics, antimicrobial activity, gastrointestinal tract, Lactic acid bacteria, Pathogenic bacteria
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