UK soldiers returning from Iraq bring along superbugs too, it is feared. And newer, more drug-resistant, varieties are spawned.
Eight patients died of a new strain of the bug at a hospital where soldiers injured in Iraq are treated, BBC reports.
The University Hospital Birmingham NHS Foundation Trust revealed the deaths happened between 2005 and 2007.
But the trust's medical director David Rosser has said the bug, which is still present in the hospital, is "not a significant problem".
The bug - multi-resistant Acinetobacter baumannii - is one of the Gram-negative superbugs, which is more resistant to antibiotics than Gram-positive superbugs like MRSA.
Records obtained by the BBC show the bug spread rapidly in 2003 from the trauma theatres onto the trauma wards and then into the burns unit, where two children were infected.
Doctors believe the new strain was introduced by injured soldiers flown back from Iraq because it was found on one when he was admitted to the hospital in 2004.
The T-strain was responsible for the majority of MDR-AB infections in the hospital and is thought most likely to have led to the subsequent deaths.
The registered deaths at the hospital from the bug date from 2005 onwards after the infection spread onto the respiratory medicine wards.
Three elderly patients with breathing problems died from the bug that year, another four patients died a year later and one died last year.
In 2007, of the 108 patients infected with Acinetobacter baumannii, 26 were from the military.
The latest outbreak of six cases took place in the neurosurgical critical care unit last September.
Scientists have linked the bug to returning soldiers. Dr Martin Gill, writing in the Journal of Clinical Microbiology in 2006, said it was "the T-strain that has been most strongly associated with these casualties and that has, in the United Kingdom at least, caused the most infections".
He added: "It has been isolated from at least one soldier immediately on admission to the United Kingdom hospital, ruling out the possibility that it was acquired in that hospital."
Dr Gill works as a microbiologist at the hospital.
The link has also been made by doctors writing in the Lancet Infectious Diseases journal in 2006.
The MDR-AB bug is more resistant to antibiotics than MRSA.
Only one old antibiotic, colistin, is still effective, but it is toxic to kidneys and is becoming less effective.
Professor Peter Hawkey, of Heartlands Hospital, Birmingham, said bugs of this type thrived in intensive care units.
He said: "They have developed a lot of antibiotic resistance. This has become increasingly a problem particularly in intensive care and burns patients.
"As they are very resistant, we are very limited. Sometimes we have only one, sometimes no antibiotics to treat them.
"They also survive well in the environment."
The University Hospital trust put in place a strict action plan investigating trauma theatres seven and eight, restricting staff movements and isolating infected patients.
But the minutes of the infection control meetings show concerns that staff were not washing their hands.
There were also concerns about beds coming up from the stores uncleaned and equipment such as bronchoscopes not being cleaned adequately.
Staff were also using the route between adult and children's burns units as a thoroughfare, potentially spreading the infection from the soldiers to children.
The children's burns unit is no longer based at Selly Oak.
Death from the superbug can take many forms, such as fevers, pneumonia, meningitis and septicaemia, while patients who survive often face longer hospital stays due to the complications.
It is difficult to control in the environment because it is airborne and can survive for long periods in dry places.
The hospital actually removed curtains after finding that they were harbouring the bacteria.
But Professor Tom Elliot, deputy director of the hospital, insisted the bug was easier to eradicate than MRSA.
He added that it was still not proven that the T-strain of the bug is imported by soldiers into the hospital.
He said MDR-AB existed long before the Iraq War and is low on the radar in terms of priorities.
This was endorsed by the medical director David Rosser, who said: "Some of the wounded evacuated patients do come back colonised with bugs that we would not normally see in civilian practice.
"We have a very clear idea of what these bugs are likely to be and are able to deal with it.
"It is not a significant problem."