Faecal bacterial flora in patients with colon cancer and control subjects.

Faeces from 10 colon cancer patients and from 10 control subjects were studied by quantitative and qualitative aerobic and anaerobic techniques using a variety of non selective, selective and differential media. In several cases, there were significantly different numbers of organisms of specific types recovered from the two groups studied. Most prominent and meaningful findings were the higher frequency of isolation and counts of Bacteroides species (especially B. fragilis group) and of C. paraputrificum in the patient group. Apart from the demonstration of the altered faecal bacterial flora in colon cancer patients and of the possible etiologic role of C. paraputrificum and B. fragilis in colon carcinogenesis, the bacteriological data, confirmed by more extensive studies, could be used as an index for colon cancer or for populations at high risk.