The parents of 24 babies at a Belfast hospital are waiting to find out if their children are free from the infection that caused the deaths of three newborns there.
Results will be available tomorrow after babies who were treated in the neonatal unit of the Royal Maternity Hospital in Belfast underwent tests.
Meanwhile, Northern Ireland's health minister Edwin Poots has revealed the number of confirmed cases of pseudomonas in babies at the Royal is six, not seven as previously believed.
Three babies have died and three others have contracted the infection, which affects the chest, blood and urinary tract.
A deep clean of the hospital was expected to be completed last night, and a helpline set up to support expectant mothers worried about giving birth at the neonatal unit has been extended due to demand.
The service was due to end yesterday, but continuing calls from panic-stricken women forced the Belfast Health and Social Care Trust to keep lines open.
Mr Poots reassured concerned parents that the Department for Health, Social Services and Public Safety was doing its best to control the outbreak.
"I fully understand the anxiety of parents and the wider community; however, we are doing everything we can to ensure safe continuity of care for the babies and support for their families," said Mr Poots.
He added that expectant mothers should attend their appointments at the hospital as normal.
"Ensuring that we eradicate the source of infection and are able to fully reopen the neonatal unit at the Royal Jubilee Maternity Hospital as quickly as possible remains a key priority," he went on.
Pseudomonas lives in water or moisture and patients can carry it on their skin. The infection can be treated with the right antibiotic, but the third baby who died failed to respond to the treatment.
There are usually fewer than 80 cases of it annually across Northern Ireland.
Overall numbers in Northern Ireland, England and Wales have declined over the last few years.
There were a total of 3,807 cases of all strands of pseudomonas reported in 2010, a slight drop from 3,888 in 2009 and 3,957 cases in 2008.
One expert said the number of cases has fallen due to an increased awareness and better hygiene in hospitals.
Dr Martin Wiselka, a consultant in infectious diseases, said the tragic cases in Belfast do not indicate a rise in the infection.
"There's always more that can be done but actually we've made really good progress in the last few years," Dr Wiselka said.
"We've reduced the rates of MRSA nationally over the last few years and rates of Clostridium difficile have come down a great deal."
The Belfast trust spokesman said staff were carrying out a staged approach towards cleansing the maternity suite of all traces of the infection.
The large intensive care room, which holds up to 13 babies, has already been cleared and the infants moved into separate small rooms.
A different - and apparently unlinked - strain of the infection also claimed the life of another baby in Altnagelvin hospital in Londonderry last month.
The infection was subsequently eradicated and health officials said there was no evidence to suggest it was linked to the strain that has hit the Royal's maternity unit.
Mr Poots stressed that the neonatal unit is the only part of the hospital affected by the pseudomonas outbreak.
Delivery wards and all other services at the hospital are operating as normal, and expectant mothers have been advised they should attend their appointments as scheduled.
Trust chief executive Colm Donaghy said a full investigation into whether anything else could have been done would be carried out.
Two women were forced to make the 100-mile journey to Dublin to have their babies because of the outbreak.