امیر عباس برزگری سرخه

Background and Aim : Probiotics may be a good alternative to antibiotics in fighting pathogenic bacteria. The current study aimed to evaluate the antibacterial activity of Lactobacillus rhamnosus cell-free supernatant against Staphylococcus aureus and Escherichia coli. Methods : L.􀀃 rhamnosus􀀃 ATCC􀀃 7469􀀃 was􀀃 cultured􀀃 in􀀃 the􀀃 MRS􀀃 broth􀀃 medium􀀃 at􀀃 37˚C.􀀃 The􀀃 medium was transferred to the tube after 48 h and centrifuged at 8000 rpm for 20 minutes. The supernatant was passed through a filter􀀃 with􀀃 0.2􀀃 μm􀀃 pores􀀃 under􀀃 sterile􀀃 conditions.􀀃 The􀀃 antibacterial activity of the filtered supernatant was determined against S. aureus ATCC 25923 and E. coli ATCC 8739 by minimum inhibitory concentration (MIC) method. Results : The minimum inhibitory concentration of L. rhamnosus cell-free supernatant against S. aureus and E. coli was 25 and 12.5 microliter/ml, respectively. Conclusion : The cell-free supernatant of L. rhamnosus had a good antibacterial effect on S. aureus and E. coli.