Ten patients at Antrim Area Hospital have been isolated following an outbreak of superbug Clostridium difficile.
The Northern Health and Social Care Trust last night confirmed that 10 patients in a ward at the hospital were suffering from C-difficile-related diarrhoea - four of whom were admitted with it.
"In order to prevent the spread to other patients the trust has isolated these patients in one ward and the appropriate infection control precautions are in place," a spokesperson said.
"All 10 patients are receiving treatment and their condition is improving."
C-difficile symptoms can range from diarrhoea to colitis and ulceration, possibly even causing perforation of the colon and peritonitis, according to a University of Ulster expert on the disease.
The bacterium produces two toxins which produce the symptoms, the expert said.
"Young people would tend to shrug it off, but elderly patients would be a weakened state and this thing can run riot on them," he said.
There are a number of antibiotics to which C-difficile still has no resistance and they are used as a last line of defence. The disease is prevented from spreading by isolating patients and using bleach-based detergents to wash hands and hospital equipment.
Lab reports of C-difficile in Northern Ireland increased from 412 in 1996 to 1,486 to 2006. The disease is cited in more deaths than the better known MRSA superbug, the expert said.