Using minimum inhibitory concentration to evaluate the effect ofBacillus subtilis natto as a probiotic on enteropathogenic bacteria

BACKGROUND AND ABJECTIVEProbiotics play a critical role to treat the diarrhea caused by bacteria is a progressingphenomenon. in which probiotics play an essential role. The aim of this study is to investigatethe antibacterial effect of the probiotic Bacillus subtilis natto on a number of commonpathogens of the digestive system.MATERIALS AND METHODSIn this study, Bacillus subtilis natto strain ATCC G۸S۳ was selected as probiotic. itsantimicrobial effect on four gastrointestinal pathogens, including Bacillus cereus, Salmonellatyphimurium ATCC ۱۴۲۹, Shigella flexneri ATCC ۱۱۲۲۲ and Escherichia coli ATCC ۲۵۹۲۲was investigated. The minimum inhibitory concentration or MIC method was used to detectthe antibacterial activity of Bacillus subtilis natto as a probiotic. In this method, ۵ differentsupernatant concentrations including ۱۰۰, ۵۰, ۲۵, ۱۲.۵ and ۶.۲۵ (μg⁄ml) were used. In the nextstep, minimum bactericidal concentration were performed according to microbiology standardswith four repetitions.RESULTS AND DISCUSSIONMIC concentration for Escherichia coli ATCC ۲۵۹۲۲ was ۵۰, while no antibacterial effect wasobserved on Bacillus cereus ATCC ۱۱۷۷۸, Salmonella typhimurium ATCC ۱۴۲۹ and Shigellaflexneri ATCC ۱۱۲۲۲. Therefore, the results showed that Bacillus subtilis natto ATCC G۸S۳ hasan inhibitory effect on some pathogens, including Escherichia coli.CONCLUSIONBecause Bacillus subtilis natto ATCC G۸S۳ is safe and resistant as a probiotic and it was ableto show inhibitory results on the pathogen Escherichia coli, it can be used for some bacteria inthe future

کلیدواژه ها:

Probiotics ، Bacillus subtilis ، MIC ، Gastrointestinal pathogens