In Vitro Inhibition of Helicobacter pylori Growth and of Adherence of cagA-Positive Strains to Gastric Epithelial Cells by Lactobacillus paraplantarum KNUC25 Isolated from Kimchi

Abstract Lactobacillus paraplantarum KNUC25 strain was isolated from overfermented kimchi, a Korean traditional food. The strain had a broad antimicrobial activity spectrum, from Gram-positive to Gram-negative bacteria. The aim of this study was to evaluate the activity of L. paraplantarum KNUC25 against Helicobacter pylori strains. Judged by a disc agar diffusion method, the anti-H. pylori activity existed in the cell-free supernatants (CFSs) of KNUC25. The mean diameters of growth inhibition by 10, 30, and 60 μL of a 15-fold concentrated CFS per disc were 11.2, 17.7, and 23.7 mm, respectively. The neutralized CFS lost its anti-H. pylori activity, suggesting that acidic pH in CFS may be responsible for the anti-H. pylori activity. Adherence was determined by urease activity of H. pylori adhered to gastric epithelial cell line AGS cells after co-incubation of AGS cells with CFS and H. pylori strain ATCC43504 (s1m1vacA/cagA+), ATCC51932 (s2m2vacA/cagA−), or SS1 (s2m2vacA/cagA+) in vitro followed by three w...