The New Concept
A different explanation proposed by C. De Simone is based on the observations that particular strains are antagonistic against pathogenic bacteria through the production of antimicrobial substances, by promoting a reduced luminal colonic pH, and modulation of a variety of substances that are involved in healing of inflammation (such as interleukins, metalloproteinases and nitric oxide synthase [NOS]). Furthermore, it is based on the observation that the colon can be considered a "fermentation chamber", whose metabolic activity is profoundly altered by the bacterial composition and concentration. The colonization of the colon with beneficial bacteria modifies the intestinal content and this can exert an effect even on the activity and function of distant organs. These observations and the potential therapeutic benefits of manipulating the enteric microflora using probiotics has become an area of active investigation (7).
This new concept led to the formulation of the probiotic product VSL3 (Table II) in high bacterial concentration (450 billion live bacteria per sachet). The probiotic VSL#3 preparation is formulated in sachets
Table II: Bacterial probiotics used in hermophilus.
with a daily dose of 1 sachet of vsl3 b.i.d., depending on the severity of the disease and the number of stools per day (27).
There is very important evidence that not all probiotic preparations are equivalent in terms of efficacy, since they include many different preparations (71) and differ also in the concentration of bacteria depending on the colony-forming units per gram. Furthermore, some probiotic preparations' are made of a single bacterial~ strain and others with two or more strains. In addition to this, clinical studies with lactobacillus as a probiotic have shown variable results, which will be discussed below.