ANTIPATHOGENIC ACTION AND ANTIBIOTIC SENSITIVITY PATTERN OF THE “BORHANI”-ASSOCIATED LACTIC ACID BACTERIUM WEISSELLA CONFUSA LAB-11

Abstract

Assessment of the beneficial and safety properties of food-associated microbes is inevitable since they engage in direct interactions with their host via the digestive system. In this view, we have studied the pathogen inhibitory activity and antibiotic susceptibility pattern of a newly isolated lactic acid bacterium obtained from the traditional beneficial beverage borhani. 16S rRNA gene based taxonomic and phylogenetic analysis combined with sugar fermentation tests identified the isolate as Weissella confusa; strain LAB-11. Antimicrobial activity of the lactic acid bacterium was examined using its culture supernatant against ten bacterial pathogens by agar diffusion technique. The isolate inhibited species of Acinetobacter, Bacillus, Escherichia, Klebsiella, Pseudomonas, Salmonella, Shigella and Staphylococcus which indicated a broad spectrum of its antimicrobial activity. Further investigation by coincubation assay revealed a prolonged effect of the antibacterial activity against the above pathogens. The inhibitory activity was found highly effective on the fungal pathogen Candida albicans as well. Antibiotic susceptibility assay revealed that the isolate was sensitive to most of the tested antibiotics while resistant against four antibiotics including ciprofloxacin, cloxacillin, ofloxacin, and vancomycin that might be ascribed to intrinsic resistance. The ability to inhibit a wide range of pathogens while itself being relatively safe concerning the transfer of antibiotic resistance suggests that dairy beverages like borhani which carry such beneficial lactic acid bacteria can be of particular benefits to the consumers exerting preventive effects on associated diseases.