The following release is a summary of a presentation at the 100th General Meeting of the American Society for Microbiology. Additional information on this and other presentations can be found in the General Meeting Press Kit online at http://www.asmusa.org/pcsrc/gm2000/presskit.htm.
Embargo Date/Time: Thursday, May 25, 10:30 a.m.
Primary Author:
Chitra Wendakoon, University of Alberta
(780)492-0381
[email protected]
Abstract
We have found that milk fermented with Lactobacillus casei (dairy starter bacteria) can destroy Helicobacter pylori, the ulcer bug, under laboratory conditions. Some components in the fermented milk containing L. casei are very active in this action. Our results would lead to the development of new, safe and effective therapeutic regimen (such as yogurt drink) against Helicobacter infection.
Our research team led by Dr. L. Ozimek, together with Dr. C. N. Wendakoon, has been working on inhibitory effects of dairy starter bacteria on the growth of Helicobacter for the last three years. We have found that several starter cultures are effective in the inhibition. L. casei is one of the most promising strain, and we decided to work on this strain further. Also we have started developing a fermented dairy product for the patients who are infected with Helicobacter. This research was funded by Alberta Agricultural Research Institute and Dairy Farmers of Canada.
Helicobacter pylori is a small bug, living in the stomach and causes chronic gastritis and peptic ulcer diseases in humans. It is sometimes involved in certain forms of gastric cancer. H. pylori has special adaptations to survive and difficult to wipe out from the stomach. H. pylori infection is a major public health concern all over the world.
Current treatment for H. pylori infection is antibiotic therapy. Two or three antibiotics are given for 2-4 weeks. However, these antibiotics frequently produce adverse effects. Also, H. pylori is becoming resistant to a number of antibiotics, particularly to metranidazole and clarythromycin. Therefore, there is a need for simple and inexpensive alternatives to antibiotics based therapies to control H. pylori infection.
We evaluated six Lactobacillus casei strains against Helicobacter in order to see the growth inhibitory effects of L. casei strains. We examined inhibitory activity of L. casei cells, heat killed cells, skim milk fermented with L. casei and the supernatant fractions of skim milk cultures using a standard well assay method. In addition, the supernatants subjected to proteolytic enzyme treatments (proteinase K and /or trypsin) were also tested.
According to our results, whole skim milk cultures with L. casei were the most inhibitory to H. pylori. Addition of proteinase K to skim milk cultures increased the inhibitory action of the culture. The supernatant fraction of the cultures alone did not show any inhibitory activity. However, treating the supernatant either with proteinase K or trypsin produced strong inhibitory action suggesting that smaller peptides derived from enzyme action are important in the inhibitory action.. Neither live cells nor heat killed cells showed any growth inhibitory activity against H. pylori.
Lactic acid bacteria (LAB) have been proven to be useful in gastrointestinal disease prevention and treatment as well as health restoration and maintenance. The products derived from the bacterial fermentation and peptides derived from the enzyme action could be used as anti-Helicobacter compounds.
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