[Colicinogeny in nonspecific intestinal inflammations and colorectal cancer]

Colicins are proteinaceous substances produced by Escherichia coli strains and related bacteria of Enterobacteriaceae family. They are considered to be an important factor in preserving the balance of the intestinal microflora. Their antibiotic action on susceptible bacteria is supplemented with cytotoxicity for several pro- and eukaryotic cells. The large bowel is a natural site of their action. Besides of enhancing oxidoreductive activity of leukocytes in vitro, colicins are also believed to influence inflammatory reaction in vivo. For these reasons, the first part of the present work was concerned with studying colicinogeny in nonspecific inflammatory bowel diseases (IBD). No significant difference has been found out in colicinogeny between a total of 93 IBD-related and 160 healthy controls. In testing leukocyte migration inhibition, colicins of autologous E. coli were used as antigens. The migration index out of normal range showed 36% patients with ulcerative colitis (5/14), 80% patients with Crohn's disease (12/15), and only one clinically healthy control subject (1/16; 6%). The obtained results are considered to be proof of cellular hypersensitivity of IBD patients to colicins of their own E. coli strains. In several colicins the antitumorous effect has been reported in both the in vitro and in vivo experimentation. The second part of this work was concerned with colicinogeny in colorectal cancer. Colicinogenic E. coli were evidenced in 42 subjects (40%) from 105 patients with colorectal carcinoma. Controls showed colicinogenic E. coli in 102/160 clinically healthy subjects (64%), and the difference was as significant as p less than 0.05. In colorectal cancer group, the subjects with proved colicinogeny showed lesser amounts of colicinogenic E. coli strains in contrast with non-colicinogenic ones. In colorectal cancer patients with colicinogenic E. coli strains, B and M colicins were of most frequent occurrence in them no antitumorous effect has been experimentally stated. If changes of colicinogeny were only either the manifestation or consequence of tumor disease, so both the presence or absence of colicinogenic E. coli would have been dependent of clinical patients's condition, stage of disease (in accord with Dukes) or correlated with the tumor markers. For these accounts, a total of 28 colorectal cancer patients underwent a colicinogenic study. However, no colicinogeny dependence was evidenced of either clinical condition or Dukes stage, showing no correlation with any of cancer markers investigated (carcinoembryonic antigen, CA 19-9, alfa-1-fetoprotein, alfa-1-orosomucoid, Cancer serum index, sialic acid, lysozyme).(ABSTRACT TRUNCATED AT 400 WORDS)