St. Joseph's Healthcare spokeswoman Kyla Kumar says an elderly patient died July 11 at the hospital's Charlton Campus, which has 11 C. difficile cases.
She says the hospital is reviewing the death but it appears the bacteria did not play a "significant role."
The hospital declared the outbreak Saturday at its Charlton Campus.
Infected patients have been placed in isolation rooms which are double-cleaned daily with bleach-based cleaners.
C. difficile, which causes diarrhoea, is one of the most common infections in hospitals and long-term care facilities.
Note to readers: This is a corrected story. An earlier version identified C. difficile as a virus.