Three more deaths have been linked to the hospital bug Clostridium difficile in hospitals in the Northern Trust area.
There were 40 more cases of C. Diff reported in the Northern area in March.
In a statement, the Trust said it would take time to bring the ongoing outbreak under control.
There are nine hospitals in the Northern area and the outbreak mostly affects the Antrim Area and Causeway hospitals.
The Trust said they were beginning to see a downward trend, but warned that figures may still fluctuate.
"The Trust is currently conducting an analysis of every case recorded during March to identify the causes of these cases, including patient factors, admission rates to hospitals and effectiveness of infection control procedures," it said.
There has been a major intensive cleaning regime in all their hospitals and the Trust will shortly introduce a newly recruited, rapid response team to provide a round-the-clock cleaning service for Antrim and Causeway hospitals.
"In association with the Belfast Trust we have employed a piece of specialist equipment that allows for intensive cleaning of vacated ward areas," the Trust said.
The vaporised hydrogen peroxide machine will eliminate C. Diff spores when used in a sealed room over a 10 hour period.