A fourth patient who contracted an infection after having heart surgery in Nottingham has died, health officials have said.
Earlier this year 14 people who had heart valve surgery were recalled after three patients died.
Nottingham University Hospitals NHS Trust contacted the patients, who all underwent the procedure at the Trent Cardiac Centre at the City Hospital.
A trust spokesman said staphylococcal infections were linked to one surgeon.
The Nottingham University Hospitals NHS Trust said it had been analysing the cases and surgery and had established a pattern.
All of the patients who developed the valve infection were operated on by the same surgeon.
In a statement the trust said: "The surgeon concerned has not performed any valve operations since we became aware of the problem in July.
"He will not return to doing valve operations unless and until we and external experts and regulatory bodies are absolutely sure it is safe for him to do so."
The trust said there were "compelling scientific grounds" why the risks of infection in the surgeon's patients only occured in valve operations.
"The cluster of endocarditis cases was caused by a bacterium called Staphylococcus epidermidis.
"This is normally a harmless bacteria carried on people's skin. It is very rarely the cause of infection unless it sticks to a foreign body such as a line, joint replacement or artificial heart valve.
"In this outbreak a single strain of Staphylococcus epidermidis was identified to be the cause of the infections and an identical strain was found to be carried on the skin of the surgeon."
The surgeon, who was not named, would not be carrying out valve surgery "until it is absolutely safe for him to so", the statement concluded.