POTENTIAL IN VITRO ANTI-HELICOBACTER ACTIVITY OF BACTERIOCIN AND BACTERIOCIN-LIKE COMPOUNDS PRODUCED BY LACTOBACILLI

The study was designed for screening of the potential activity of lactic acid bacteria against Helicobacter pylori and other enteropathogenic organisms. A total of 40 samples including natural cow milk and fresh infant stools were tested for the presence of lactic acid bacteria. Of these samples, 73 lactic acid bacterial isolates were recovered on MRS agar medium using the streak-plate method. Isolates inducing probiotic effect were tested under microaerophilic conditions against standard cultures of H. pylori, Esherichia coli and Salmonella enteritidis. The data obtained showed that five isolates of lactic acid bacteria were able to produce bacteriocin or bacteriocin-like compounds. Sequencing of 16S rRNA gene revealed that five isolates belonged to Lactobacillus rhamnosus and Lactobacillus plantarum in addition to other lactic acid bacteria. The most effective isolate (LAB1) showed a marked large inhibition zone against H. pylori. The bacteriocin or bacteriocin like compound(s) produced by lactobacilli were further analyzed and characterized. We can conclude that probiotics might be useful in the prophylaxis or as co-therapy for treatment of H. pylori infections.