[Effect of antibiotics on intestinal microflora and production of metabolites]

Methodical approaches to detection of relation between intestinal microflora and its metabolites are described. The microbial origin of certain compounds can be asserted by a decrease in their production after exposure to antibacterial drugs or the absence of their production in microbe-free animals. The authors consider that parallel investigation of intestinal microflora and its metabolites after exposure to various agents e.g. narrow spectrum antibiotics or specific substrates is the most accurate methodical approach to detection of their interrelations. Data on the effect of four drugs i.e. kanamycin, metronidazole, cefotaxime and bactrim on production of 10 bacterial metabolites: p-cresol, phenol, indican, acetic, propionic, butyric, isobutyric, valeric, isovaleric and caproic acids in rats are presented. Correlation between the metabolites and the intestinal microflora composition was revealed. It is concluded that detection of microorganisms responsible for production of definite metabolites requires at the maximum: (1) exposure to drugs of different spectra, (2) detection of changes in intestinal microflora by biotope++ and (3) investigation of mucosa microflora which more exactly characterizes metabolism of definite biotops.