Ian Ramage, consultant nephrologist at Yorkhill Children’s Hospital in Glasgow, has treated Bo since he first arrived from Aberdeenshire in May 2012.
He said the “darkest days” in the youngster’s treatment were when it became clear how seriously the infection had damaged him.
Mr Ramage said: “I think the darkest days were not the times when he was most unwell, but when we realised that he would pull through and that he would be blind and require a stoma.
“All our energies had gone into keeping him alive, then we realised the burden his health would have on him and on Lucy.”
He said most children make a full recovery from E. coli, but added that those who do not generally suffer renal failure – as Bo did – and require a kidney transplant
However, the state of Bo’s bowel, which was left with five holes in it after being attacked by the bacteria, further complicated his case.
Meanwhile, new guidelines on managing the risks of E.coli have been hailed as a victory for common sense.