In-vitro antibacterial activity of commercially available probiotics on food-borne pathogens along with their synergistic effects with synthetic drugs

BACKGROUND: Probiotics are put forward as food to ensure the maintenance of the equilibrium of the intestinal flora. Prolonged usage of probiotics in food ingredients for human as well as in animal feed has not exposed any side effects yet. Present study attempted to justify the effects of some commercially available probiotics (Good-gut, Lubenna, Probio and Protein restro) and commonly used antibiotics (Streptomycin, Gentamycin, Ampicillin, Methicillin, Azithromycin, Erythromycin, Ceftrizone, Imepenem, Ciprofloxacin and Tetracycline) on the bacteria which were previously isolated from food samples. METHODS: The anti-bacterial potential of the probiotics was aimed to be checked through the agar well diffusion method and the antibiogram of the synthetic drugs was determined by disc-diffusion method (Kirby Bauer technique). The minimum inhibitory concentration (MIC) of the probiotics were examined through broth micro dilution assay. RESULTS: Almost all the probiotic samples exhibited antibacterial activity against the tested bacteria within the range of 10 mm–30 mm except Bacillus spp. and Salmonella spp. The lowest MIC values 3 mg/ml was determined with Luvena for Pseudomonas spp. and Shigella spp. while the maximum MIC 20 mg/ml was recorded for Good gut and Probio against Salmonella spp. and E. coli. Meanwhile, majority of the tested pathogens were detected to be resistant against more than one antibiotic as MDR strains except gentamycin, streptomycin and azithromycin. During the combination method, the zone diameter increased remarkably with a clear indication of synergistic effects compared to their individual activity. CONCLUSION: This study substantiated that the deployment of a combination of two antibacterial medications in order to combat the multi-drug resistant bacteria would rather be efficacious than the application of either antimicrobial agent alone.