Assessment of a new synbiotic preparation in healthy volunteers: survival, persistence of probiotic strains and its effect on the indigenous flora

Twelve healthy volunteers were recruited. Faecal samples were taken before and at various time points during the administration period and at day 3 in the post-treatment period. Stool culture were performed and amplified ribosomal DNA restriction analysis was used to detect L. paracasei, the major bacterial component of the synbiotic products.An increase of at least 1 log of L. paracasei-like bacteria was observed in all subjects. An increase of as much as 3 log was seen in subjects who had a low number of L. paracasei-like lactobacilli at the baseline. The counts of L. paracasei-like lactobacilli were found to persist for at least 3 days after discontinuation of intake in healthy volunteers in 7 subjects. Genetic analysis showed that the maiority of vancomicin insensitive lactobacilli were real L. paracasei, as the strains administered with the tested product.This study has shown that the strains of L paracasei administered with a synbiotic dietary supplement are able to survive through the gastrointestinal tract and to persist for at least a few days. It was also shown the efficacy of a synbiotic preparation to positively affect the microflora of healthy volunteers.For a long time colonic microflora has been considered to play an important role in the maintenance of the health and well-being of the host [1]. In addition to promote normal gastrointestinal functions and protecting against pathogenic bacteria, the microflora exerts beneficial effects on systemic metabolism and immune system [2].The ability to control the growth and the pathogenic potential of these bacteria depends on the proper function of the microflora [3].Imbalance in the colonic microflora with relative predominance of aggressive bacteria and insufficient concentration of protective species has been associated with colonic inflammation [4,5] and pouchitis[6].Intake of probiotics (living micro-organisms), prebiotics (non-digestible oligosaccharides) and synbiotics (mixture of probiotics and prebi