Injured soldiers returning from Iraq have brought back a superbug that has been linked with outbreaks in NHS hospitals where they have been treated, a health minister has confirmed. The links between casualties brought back from Iraq and outbreaks in the NHS have caused alarm within the health service and led to renewed demands for more dedicated wards for Britain's armed forces to enable wounded soldiers to be isolated more effectively.

The Health Protection Agency has urged NHS hospitals to step up their infection control measures as a result of the outbreaks of a strain of the superbug Acinetobacter baumannii which is resistant to many types of antibiotics.

"A multi-resistant strain of A. baumannii known as the 'T strain' has been isolated from casualties returning to the UK from Iraq," the Health minister Andy Burnham said in a Commons written answer.

He said the exact source of the infection had not been identified but US casualties returning to America had also been found to be carrying the superbug.

Experts in microbiology who were studying the links between the infection and those wounded in Iraq, said an injured soldier thought to have caught the infection in Iraq may have caused a large outbreak of the superbug in an intensive care unit in an NHS hospital in south-east England.

They reported that the superbug was also found in two hospitals in the Midlands in soldiers who had been injured while serving in Iraq. The HPA said last night it was thought the T-strain survived in soil and sand in warm climates such as Iraq.

There was criticism last month of the treatment of injured soldiers on NHS wards after reports that a paratrooper wounded in Afghanistan was threatened by a Muslim visitor at Selly Oak Hospital in Birmingham, where many soldiers are treated. A campaign for a dedicated hospital for the armed forces was mounted with the support of forces' families. Tony Blair partially bowed to the pressure by announcing that troops would be given a dedicated ward at Selly Oak.

Reg Keys, whose son Tom was killed by a mob in Majar al-Kabir, Iraq, in June 2003, said the existence of the new strain of the infection underlined the need for dedicated facilities for the armed forces. "These lads are giving their lives for their country," he said. "The least they deserve is to be treated in military hospitals, not civilian hospitals, for reasons of security, but the existence of this superbug is very worrying. It proves the case even more for their own medical facilities."

Harry Cohen, the Labour MP for Leyton and Wanstead, who tabled questions about the superbug, said: "It is a worry that this bug which is infecting some of the wounded in Iraq is coming back to this country and could infect other patients in NHS hospitals. It does show that we need more separate wards for the armed forces."

At one hospital in Birmingham the bacteria is reported to have infected 93 people, 91 of them civilians. Thirty-five died, although the hospital was not able to establish whether the superbug was a contributory factor.

A. baumannii is resistant to most common antibiotics and, if left untreated, can lead to pneumonia, fever and septicaemia. It has been identified in more than 240 military personnel in the US since the 2003 invasion of Iraq, and has been associated with five deaths.