Two patients have died and another has had emergency surgery in cases linked to infections, a hospital has revealed.
C difficile causes severe diarrhoea
The clostridium difficile (C diff) outbreak occurred at Leicester's Glenfield Hospital cardiac unit in the last month.
The bug, which causes severe diarrhoea, is especially dangerous to the elderly and is commonly contracted in hospital.
An isolation ward is in place and a dedicated nursing team is tackling the spread of the infection.
All three patients underwent surgery to have all or part of their bowel removed to eradicate the infection.
The first patient died some days ago while the second death was confirmed on Wednesday.
A spokesman said no new cases have been reported in the unit from last week and the unit is still operating on cardiac patients.
New patients are being admitted to a completely sterile area and looked after by nursing staff, who have not been in contact with infected patients.
Dr David Jenkins, director of infection prevention and control said: "Unfortunately whenever patients are very poorly and treated with antibiotics there is a risk of infection.
"Because Glenfield is recognised as being one of the nation's top heart hospitals, we take very poorly patients who often have a higher risk of infection.
"The fact that we care for the most poorly patients means we would perhaps expect to see more of the bug than other hospitals - but that's not the case, our rate of infection here is comparable to other hospitals."
C diff was linked to just under 1,000 deaths in the UK in 2003. It is a common hospital-acquired infection.
In 2004 the Leicester Royal Infirmary, Leicester General Hospital and Glenfield Hospital, recorded 728 C diff cases - 0.71% of patients treated.