Inhibitory effect of lactic acid bacteria isolated from kimchi against murine norovirus

Human norovirus causes gastroenteritis through a fecal-oral route. However, there are no effective therapeutic agents owing to the lack of culture systems. Alternatively, antiviral food extracts and beneficial microorganisms could be developed as antiviral agents. Here, we investigated the inhibitory effects of 142 lactic acid bacteria (LAB) or LAB-free filtrate from kimchi products against murine norovirus-1 (MNV-1) in RAW264.7 cells. LAB strains were identified through 16S rRNA gene sequencing. Cells were pre-treated with LAB or LAB-free filtrate, and co-treated with LAB and MNV-1 at 5 degrees C for 21 days. Among the 56 coccus-shaped LAB, pre-treatment of Pediococcus pentosaceus (CAU170229-2 and CAU170230-3) and Weissella cibaria (CAU170231-1 and CAU170231-3) significantly reduced MNV-1 by 1.93 +/- 0.21-3.49 +/- 0.43 to log(10) PFU/mL. Among the 86 rod shaped LAB, pre-treatment of Lactobacillus sakei (CAU170208-2 and CAU170210-4) and Lactobacillus curvatus (CAU170210-2 and CAU170235-3) significantly decreased MNV-1 by 1.42 +/- 0.26-1.70 +/- 0.63 log(10) PFU/mL. LAB-free filtrates decreased MNV-1 by 0.26 +/- 0.07-0.50 +/- 0.18 to log(10) PFU/mL, and MNV-1 co-treated with LAB slightly reduced MNV-1 by 0.56 +/- 0.07-0.60 +/- 0.09 to logio PFU/mL. Thus, W. cibaria, P. pentosaceus, L. curvatus, and L. sakei from kimchi are promising anti-noroviral candidates.