摘要：Aim: The intestinal flora may be washed out after bowel cleansing and may be beneficially influenced by probiotics during recolonization. In this randomized placebo-controlled double-blind study, the effect of bowel cleansing with or without subsequent inoculation by Lactobacillus plantarum 299v was assessed. Patients and methods: Patients who underwent bowel cleansing were included. After colonoscopy, patients consumed a drink with or without L. plantarum 299v (10<sup>11</sup> cfu/day). Faecal samples were collected: before bowel cleansing (week 0), the first sample after colonoscopy (week 1), after 2 and 4 weeks of consumption (week 2 and week 4), and 4weeks after cessation of the drinks (week 8).Total colony forming units (cfu) of bacteria per gram faeces were counted. Denaturing gradient gel electrophoresis (DGGE) was used to analyse the dominant flora, expressed as ‘similarity values’. Results: Twenty-two patients completed the study (12 probiotic, 10 placebo). The mean concentration of lactobacilli increased (p<0.05) from 4.7+-1.9 at week 0 to 6.59+-0.8 at week 2 in the probiotic group and returned back to 4.6+-1.4 at week 8 (p<0.05). DGGE profiles demonstrated high similarity values within subjects over time: mean value 86.5%+-2.6. No significant differences in similarity values were seen after bowel cleansing (week 2) or between probiotic and placebo groups. Conclusions: Although counts of faecal lactobacilli increased during probiotic consumption, no further changes in culture and DGGE results were observed. Therefore, the faecal flora can be considered as relatively stable over time: bowel cleansing or probiotic consumption had no major influence on the composition of the faecal flora.Key words: randomized double-blind placebo-controlled study, Lactobacillus plantarum 299v, probiotics, bowel cleansing procedure, PCR/DGGE
