Twenty-six people have died from Pseudomonas in Northern Ireland over the past four years.
The Health Minister, Edwin Poots, revealed the figure on Wednesday as he briefed the assembly's health committee on the investigation.
Recently, four babies died following complications from the infection.
In December, a baby died from a Pseudomonas infection at Altnagelvin Hospital in Derry.
In January, three more died from a different strain of the infection at the Royal Jubilee Maternity in Belfast.
Neo-natal wards across Northern Ireland have conducted deep cleans and intensive checks for the bacteria that can be found in water supply units.
Taps in neo-natal units across Northern Ireland have been changed and only sterile water is being used for the direct care of patients.
Edwin Poots said that the 26 deaths in four years should be considered within the context of the number of confirmed cases each year, approximately 85.