Our Lady of Lourdes Hospital in Drogheda has been forced to close three wards following an outbreak of the hospital infection, C Diff (Clostridium Difficile).
The hospital, which is the largest in the northeast, is also closed to visitors.
The HSE has confirmed that two patients who had contracted C Diff in the hospital have died in the past week.
However, they say it is not clear yet whether the bacteria was a contributory factor in their deaths.
Dr Dominic O'Brannigan, Clinical Director for the Health Service Executive in Louth/Meath, said ten cases have so far been confirmed and results on two other patients are awaited.
He said that nine other patients have been given the all clear.
As a result of the outbreak, Infection Control Procedures have been implemented which means all elective admissions, including elective tests and examinations, have been suspended.
In addition, the hospital has gone on 'protective call' where only certain admissions can be made to the Emergency Department.
Most ambulance and GP referrals are being sent to other hospitals around the region.
A number of hospital beds have been closed as a result of the outbreak and members of the public are being asked not to visit the hospital.
If a visit is unavoidable, people are asked to phone ahead to make arrangements with the hospital staff.
It is likely these measures will be in place for several days.