ABSTRACT
Bacteria are able to form carcinogens, mutagens, or promoters of carcinogenesis or mutagenesis either by releasing them from conjugates or by forming them as accidental byproducts of their catabolic activity. Carcinogens or tumor promoters are formed by bacterial action on a number of amino acids including methionine, tyrosine, and tryptophan. Tryptophan is metabolized to a wide range of metabolites, all of which have been demonstrated in normal human urine either as a result of bacterial, or of hepatic metabolism. A number of the carcinogens/tumor promoters discussed in the previous section have yet to be implicated in human cancer. B. Hicks et al. studied the possible role of /V-nitroso compounds in the causation of the bladder cancer associated with bilharzia infection. Bilharzial infection of the urinary bladder was shown to be associated with bacterial overgrowth; the urinary flora was mixed containing a large number of species of both aerobic and anaerobic bacteria.
