Our Lady's Children's Hospital in Crumlin in Dublin has apologised to 18 families who were wrongly identified as being at the centre of a contamination scare over a medical scope.

In a statement the hospital says contact has been made with 7 new patients - separate from the 18 who have now been given the all clear - to notify them that their children may have caught a bug as a result of a cracked medical scope.

It emerged on Tuesday night that colonoscopes at the hospital had cracks in them but only one contained a bug that can cause infection and cannot be cleared by antibiotics.

When the hospital carried out quality assurance checks on the scopes there were two that did not pass the test. One of them was contaminated with ESBL and the hospital says that due to an error, the contamination was attributed to the wrong scope.

Investigation underway

A formal investigation is being undertaken by the hospital with the full support of the HSE.

ESBL is an enzyme produced by bacteria that breaks down some commonly used antibiotics. A healthy person normally carries 1,000's of harmless bacteria in their gut. ESBL producing bacteria may become part of this without causing any infection. This is colonisation but not infection.

A positive screen has no immediate impact for patients: however an ESBL positive status may affect the first line antibiotics chosen to treat the child if they show signs of severe infection.

The hospital has confirmed that follow-up letters, an information pack and a testing kit is also being issued to the families potentially affected.

It adds that all families will be given the choice of taking the samples themselves or attending the hospital.

Results will be notified to the families immediately. If any child is found to be positive, the hospital says it will provide them and their family with all the necessary information and support.

It stresses that there is no immediate impact on children's health.