Synergistic Inhibitory Activities and Enhancing Antibiotic Sensitivities of Lactobacilli from Rajshahi Traditional Curd

Abstract

Context: Lactic acid bacteria particularly Lactobacilli are considered to be the most useful group of microorganisms for potential uses as biopreservatives. Lactobacilli preserve dairy foods like curds by producing various organic and inorganic compounds that are antagonistic to other microorganisms. Objective: The current study is designed to evaluate the synergistic inhibitory activity of Lactobacilli against pathogenic bacteria which is important for increasing safety and better quality of curds. As probiotic bacteria have great potential as adjunct or alternative therapy in a range of infectious, inflammatory and allergic diseases, assessment of co-cultures of Lactobacilli is also important for the eradication of pathogenic bacteria by conventional antibiotics. Materials and Methods: The co-cultures of Lactobacilli were screened for their inhibitory activities and antibiotic sensitivities against six pathogenic bacteria such as Shigella sonnei, Staphylococcus aureus, Bacillus cereus, Shigella dysenteriae, Escherichia coli and Bacillus subtilis by disc diffusion and broth microdilution methods.  Results: Synergistic inhibitory effects of Lactobacilli co-cultures were observed against several tested pathogenic bacteria and significantly antibacterial activities were observed against S. aureus and S. dysenteriae. The tested Lactobacilli were shown to produce various antimicrobial compounds marked as bacteriocin-like inhibitory substances. The co-cultures of Lactobacilli prominently increased antibiotic sensitivities to various pathogenic bacteria. Discussion and Conclusion: The antimicrobial compounds producing ability of Lactobacilli in co-culture inhibited common pathogenic organisms will help in producing safe and delicious dairy products. Co-culture with Lactobacilli can reveal novel treatment strategies for infectious diseases that are being increasingly more difficult to treat due to the global spread of antibiotic resistance.