In vitro study of the antimicrobial effect of selected probiotics combined with prebiotics on Campylobacter jejuni.

The present study investigated the antimicrobial effect of Lactobacillus acidophilus, Lactobacillus fermentum, Bifidobacterium bifidum and Bifidobacterium longum with and without 1 % inulin or 1 % oligofructose on the survival and growth of antibiotic-resistant as well as susceptible C. jejuni strains (n = 6) using the co-culture experiments in vitro. The pH of the medium and certain organic acids produced by probiotic bacteria were also measured. High performance liquid chromatography (HPLC) was used to determine the concentrations of lactic and acetic acid. L. acidophilus with 1 % inulin or 1 % oligofructose and Bifidobacteria combined with 1 % oligofructose inhibited the growth of all the tested C. jejuni strains and none of the tested C. jejuni strains were detectable in 48 hours of coincubation. C. jejuni did not affect the growth of the probiotic strains. The antimicrobial activity of probiotics combined with prebiotics against C. jejuni was most probably associated with the reduction of pH via the production of organic acids in liquid media.