A paediatrician’s “mad idea” that a mother was deliberately poisoning her own son with faeces resulted in her being dragged through the criminal justice system for six years, it has been claimed.

The 39-year-old is now likely to be acquitted after prosecutors admitted that there was not enough evidence to prove their claims that she had injected faecal matter into a cannula while the boy was being treated at Sydney’s Westmead Hospital.

He had originally returned a number of sterile blood cultures and urine cultures following his admission in September 2014.

But several weeks later, while still in hospital, the boy’s blood sample tested positive for e.coli and another bowel organism; a result which alarmed one of the hosptial’s senior doctors, paediatrician and infectious diseases specialist Professor David Isaacs.