PetriKey

Bacterium

Streptococcus gallolyticus (bovis)

Group D strep linked to colon cancer

strep-tuh-KOK-us gal-oh-LIT-ih-kus

Gram positivegram-positivecoccigroup-dendocarditiscolon-cancer

High-yield clue

Streptococcus gallolyticus (bovis) bacteremia and endocarditis carry a strong study association with colorectal adenomas and carcinoma.

Overview

A group D, non-enterococcal streptococcus (formerly Streptococcus bovis) whose bacteremia and endocarditis carry a strong study association with colorectal neoplasia. It is a classic 'bug and body-site link' teaching point.

Classification

  • Gram-positive
  • Cocci in chains
  • Group D streptococcus
  • Non-enterococcal
  • Bile-esculin positive

Lab & identification clues

  • Bile-esculin positive
  • Group D antigen
  • Grows in bile
  • Does not grow in 6.5% NaCl (contrast with Enterococcus)

Associations

  • Colorectal adenoma / carcinoma association
  • Infective endocarditis in older adults
  • Gastrointestinal colonization

Commonly confused with

  • Enterococcus (also group D)
  • Viridans streptococci

Your notes

Original student-study summary. Sources checked: OpenStax Microbiology 2e, NCBI Bookshelf Medical Microbiology, and CDC topic pages where applicable; reviewed 2026-06. Educational only; no diagnosis, treatment, dosing, or specimen-handling guidance.

OpenStax: Microbiology 2e organism classification foundationssourceNCBI Bookshelf: Medical Microbiology organism chapterssourceCDC: CDC disease and public-health topic pagessource