She spoke out after her 22-month-old suffered irreparable kidney failure and was left blind and partially deaf after contracting the potentially lethal bug.
She has barely left his hospital bedside since he was struck down at the Rose Lodge Nursery in Aboyne almost five months ago.
And the mother – who does not want her child to be identified – criticised an NHS report which this week revealed the spread of the bacterial infection could be linked to issues with handwashing at the facility.
She is now considering taking legal action. Four children and three adults contracted the illness.
While the others recovered, one child has remained at Royal Hospital for Sick Children at Yorkhill in Glasgow since May 19.
His mother said: "An MRI scan has indicated there has been some damage to the brain. He has lost his sight and has severe hearing loss. He has complete kidney failure. His kidneys will not function again.
"This has had a massive effect on his bowel."
The NHS Grampian report stated the bug may have been transferred through a private drinking water supply contaminated with animal faeces from a nearby farm or through a lack of thorough handwashing after nappy changes.
A spokeswoman for Rose Lodge Nursery School said: "We have co-operated fully with the investigation."