Researchers from Spain have identified a strain of probiotic（益生菌） bacteria that may be useful in treating ulcers¹（溃疡） caused by Helicobacter pylori. They report their findings in the February 2011 issue of the journal Applied² and Environmental Microbiology. "H. pylori is considered one of the major risk factors underlying³ the development of gastritis（胃炎） and gastric⁴ and duodenal（十二指肠的） ulcers," write the researchers. "Currently, antibiotic-based treatment for H. pylori infection is neither sufficient nor satisfactory, with the most successful treatments reaching 75 to 90% eradication⁵ rates. The use of probiotics is a potentially promising⁶ tool to prevent H. pylori."

According to an expert consultation⁷ conducted by the Food and Agriculture Organization and the World Health Organization probiotics are "live microorganisms which when administered in adequate amounts confer a health benefit to the host." The regular intake⁸ of probiotic microoganisms has been demonstrated to prevent several disorders⁹ including diarrhea and inflammatory bowel¹⁰ disease.

Among probiotics Bifidobacterium is one of the favorite genera in studies focused on the prevention of gastrointestinal infection and is often used in fermented¹²（酿造） dairy products or food supplements. Some studies have been done in vitro (in test tubes or petri dishes) showing bifidobacterial activity against H. pylori.

In this study, the researchers tested numerous strains of bifidobacteria isolated¹³ from the feces of breast-fed infants for activity against H. pylori. They identified one strain (Bifidobacterium bifidum CECT 7366) that under certain conditions had an inhibition level of nearly 95% in vitro and tested its activitity against infection in mice.

After 21 days, mice treated with the potentially probiotic strain developed significantly less ulcers than the control group. Additional tests suggest that treatment partially¹⁴ relieved damage to gastric tissue caused by H. pylori infection. Ingestion of the bacteria did not induce any disease or mortality in both healthy and immunocompromised（免疫功能不全的） mice.

"The results presented here confer to strain B. bifidum CECT 7366 the status of a probiotic bacterium¹¹ with functional¹⁵ activity against H. pylori," write the researchers. "Human clinical trials must be performed before commercialization of this strain can be approved."