In severe cases, C. difficile can cause critical illness and death in elderly or very sick patients. (CBC)

Two patients at Nanaimo Regional General Hospital have died after an outbreak of the C. difficile bacterium.

Thirteen other patients are also infected with the so-called superbug, according to the Vancouver Island Health Authority.

The authority said Wednesday that the two patients who died were elderly and had underlying medical conditions.

The latest death occurred Tuesday and is suspected to be due to the bacterium, while the other patient died April 1 from a confirmed C. difficile infection.

The bacterium causes flu-like symptoms and severe diarrhea.

This is the third outbreak of C. difficile at the hospital in the past two years.

Hospital staff are now wearing protective clothing such as gloves and gowns, and cleaners are using stronger disinfectants to try to contain the outbreak.