Lactobacillus acidophilus autolysins inhibit Helicobacter pylori in vitro

Antibacterial activity of 17 strains of lactobacilli was tested against 10 strains of H. pylori. The inhibition observed was related to the acid produ ction and the low pH attained. No relationship between CagA phenotype of H, pylori strains and tolerance to lactic acid was observed. In mixed culture s, L. acidophilus CRL 639 showed an autolytic behavior after 24 h of cultur e. At this moment, H. py[ori CCUG17874 showed a decrease of 2 log-cycle, an d no viable count was detected after 48 h, The bactericidal effect of L. ac idophilus CRL 639 in mixed cultures is related to a proteinaceous compound released after cell lysis.