Introduction: The aim of this study was to evaluate the antagonistic activity of Lactobacillus strains against clinical C. difficile strains isolated from faecal samples of adults patients with diarrhea. A total 61 strains of C. difficile randomly selected isolated in the period 2007-2008 from the gastrointestinal tract of hospitalized patients in three hospitals province Mazovia, Poland. To determination of antagonistic activity ofprobiotic Lactobacillus spp. strains used four reference strains: Lactobacillus plantarum 2017405, Lactobacillus fermentum 353, Lactobacillus acidophilus DSM 21007 and Lactobacillus rhamnosus GG.
Methods: Isolation of C. difficile was performed on selective Columbia agar supplemented with cycloserine/cefoxitine and amphothericin B (CLO medium, bioMérieux, France). The plates were incubated in an anaerobic chamber for 48 h at 37 degrees C. Isolates were identified as C. difficile by the characteristic morphology of the colonies and horse-like odour, green yellow fluorescence under UV. Toxigenicity of of C. difficile strains was determined in PCR to detection of fragments of genes encoding toxin A (tcdA), toxin B (tcdB) and binary toxin (cdtA and cdtB). The study of antagonistic activity four Lactobacillus spp. strains against 61 clinical C. difficile strains was performed according to standard methods. Lactobacillus strains were inoculated on MRS medium and incubated in oxygen-free atmosphere and cut the bars of MRS agar and applied to the plate with cultures of C. difficile strains.
Results: Assessment of antagonist activity of Lactobacillus spp. strains was performed by measuring the zone of inhibition of grown of C. difficile strains. The study shows that of probiotic Lactobacillus spp. strains interacted antagonistically in vitro against all toxigenic (A+B+CDT- and A+B+CDT+) of C. difficile strains.
Conclusions: The differences in the antagonistic activity of Lactobacillus spp. strains against different toxigenic clinical C. difficile strains were not observed.