The "super bug" has forced the closure of two 30-bed wards in the Royal Brisbane and Women's Hospital in Australia when 21 patients tested to "super bug."
Clinical chief executive officer, Professor Keith McNeil, said staff were working to eradicate Vancomycin Resistant Enterococcus (VRE), which is resistant to antibiotics.
The medical wards are being disinfected and screened for the bug as patients leave.
Prof McNeil also said staff had been put on extra shifts to carry out the "labour-intensive" cleaning, but said the hospital was not under unusual strain.
He admitted the shutdown would stretch already limited bed availability but would not "at this stage" affect elective surgery waiting lists at the 900-bed hospital.
"Bed pressures are ever-present every day," he told reporters in Brisbane.
"We run a balance between the number of people that are coming in and the number of people who (we) are able to discharge, so we have to put in strategies to try and maintain that throughput of patients.
"At this point in time we are not having any difficulties."
Most patients who tested positive to the bug were not sick, Prof McNeil said.
However, people with low immunity - including those with chronic disease, organ transplant recipients, diabetics and elderly people - can suffer severe infection, which is difficult to treat because of the bug's resistance.
Prof McNeil said some patients receiving dialysis had tested positive but had not come down with "overwhelming illness" as yet.
The infected wards are general medical wards with no surgical patients.
However, Australian Medical Association Queensland president Ross Cartmill said the closure could reduce the hospital's ability to cope with an emergency.
"You might have a medical emergency that needs a bed and where are they going to put that patient?" Dr Cartmill said.
Professor McNeil said the wards, which make up more than 5 per cent of the hospital's beds, would not be reopened until they had been swabbed twice and cleared of VRE both times, a process that would take at least 10 days.
"We're taking the decision to do this now so that we can nip it in the bud," he said. "We don't want it to get any worse."
RBWH patients who have tested positive to VRE include people undergoing kidney dialysis who are highly vulnerable to infection. But Professor McNeil said most were already in hospital and did not need special treatment.
"The majority of them . . . are in hospital for another reason and can clear themselves once they get out of hospital," Professor McNeil said. "But we don't want it to spread to the sicker patients. We've got to try to eradicate it."
VRE could cause wound, urine and blood infections.
Scientists believe bacteria such as VRE have mutated over the years to become increasingly resistant to drugs.
He said dealing with super bugs was now part of the day-to-day management of all hospitals.
"That's part of being a big teaching hospital," he said.
"We're not unique in this - this happens all around Australia and all around the developed world."
Visitors to wards should wash their hands before entering and leaving and should avoid sitting or lying on patients' beds, doctors advise.