Antagonistic effects of Lactobacillus casei subspecies casei on Helicobacter pylori

ABSTRACT

Helicobacter pylori is a gram negative curved bacterium, inhabited in gastric mucosa where it remains for years. It causes several diseases such as gastritis and peptic ulcer. Its conventional treatment is antibiotics therapy; however there are other methods under investigation by probiotic micro organisms like Lactobacilli. It is reported that Lactobacilli supernatant inhibits H. pylori growth. In the present study, inhibitory effects of a subspecies of Lactobacillus genus, L. casei casei, on H. pylori growth in a mix culture was investigated. The study was performed in 2002, using a gel stabilized system. This system consisted of two layers including a solid PYS [peptone yeast extract salt solution] medium containing 1.5% agar plus 2% glucose at the bottom and a semi-solid PYS medium [0.75% agar without glucose but certain number of washed bacterial cells] on the top, all in a 30 ml tubes. In this system, L. casei casei and H. pylori were cultivated alone and in mix cultures. Samples from cultures were taken by sterile cork borers, each core was sectioned into smaller size, on which viable counts, pH, glucose concentration and optical density were determined and compared to each other. The investigating organism in this system produced growth band in the semi-solid layer. The growth position [growth bands], number of viable cells, optical density and pH in the mix culture of H. pylori plus L. casei casei were similar to those in the culture of H. Pylori alone. Conclusions: The results indicated that, L. casei casei can not prevent H. pylori growth in the mix culture and is not a good candidate as a probiotic against H. Pylori