Streptococcus bovis does not selectively colonize colorectal cancer and polyps.

The objective was to determine if Streptococcus bovis selectively colonizes colorectal cancer and polyps. Stools were submitted before colonoscopy; fluid and selected tissue biopsies obtained during colonoscopy were cultured for S. bovis. The setting was a large multispecialty clinic. Outpatients undergoing colonoscopy for suspected colorectal cancer and polyps were the participants. Forty studies on 35 patients were performed. One of 35 stools (2.9%) obtained before colonoscopy yielded S. bovis. S. bovis was cultured from three of 40 fluid aspirations (7.5%), one of 33 adenomas biopsied (3%), none of six adenocarcinomas, none of 14 nonneoplastic polyps, one of 40 (2.5%) biopsies from normal mucosa adjacent to an adenoma, and none of 40 mucosal biopsies remote from any lesion. These data do not support selective colonization of colorectal neoplasms by S. bovis.