MRSA is still the superbug most feared by patients -- but in recent years Irish hospitals are increasingly conquering its spread.
Outbreaks in maternity hospitals or units are rare -- but have occurred in Portlaoise and Letterkenny.
It is a clear signal that basic infection control measures have fallen down. But the puzzling recurrence of the bug in Mayo General shows that, despite attempts to eradicate it, there is much about MRSA we may yet not know.
What is certain is that the news will be a cause of concern to mothers of very sick babies, as well as women who undergo caesarean sections.
It is worrying that despite the best of expertise, it has not been eradicated at the hospital over the past seven months.
The failure of the hospital to be open about the ongoing threat for such a long time runs contrary to the need for open disclosure.
People can carry MRSA bacteria on their skin or in their nose and it does not cause harm. Infection only happens when it gets into the body through a break in the skin.
The bacteria is usually spread through skin-to-skin contact with someone who has has it on their skin or bloodstream.
However, it can also be spread through contact with towels, bed clothes and dressings. It can also survive for a long time on door handles, stair rails, floors and cleaning equipment.
The Health Protection Surveillance Centre of Ireland said MRSA is not prevalent in most maternity and neonatal units in Ireland but vigilance is needed.
Use of soap, water and hand gel, are key weapons in the fight against the bug.