Abstract
Colorectal carcinoma represents an immense problem worldwide with medical, individual and economical impacts as well. The Czech Republic belongs to the countries with the highest incidence of this malignant disease in the recent decades.
Etiopathogenesis is multifactorial, however, large bowel microbiota play a key role. Human large bowel contains over 800 species of bacteria, from which only about 20% can be cultivated.
No microbial pattern, which could be typical for colorectal cancer patients, has been identified yet. However, some particular bacteria seem to be associated with this disease.
The impact of bowel microbiota can be beneficial/protective or unbeneficial/ harmful. With respect to colorectal carcinoma, binding of potential mutagens and production of short chain fatty acids (where butyrate is the major antineoplastic causing component) belong to the protective activites of bacteria.
On the contrary, production of bacterial toxins, activation of procarcinogens, synthesis of carcinogenic and genotoxic agents and activation of bacterial enzymes (e.g. betaglucuronidase) belong to harmful effects of bacteria. Type of dietary substrates and qualitative and quantitative representation of bacterial species determine the final impact of large bowel microbiota on the host.