Karen Morrisroe-Clutton, a librarian, who has an 11-week-old baby, is in a medically induced coma in intensive care at Wrexham Maelor Hospital, North Wales.
A second victim is being treated at the hospital and another two people have been taken ill with the pathogen. The chip shop in Llay, Wrexham, has been closed.
Ms Morrisroe-Clutton’s mother, Rose Morrisroe, told the BBC that her daughter fell ill last Tuesday after eating a vegetarian burger she bought at the chip shop. “She started with diarrhoea, then developed sickness and was passing blood," she said.
Dr Judy Hart, consultant in communicable disease control at the National Public Health Service for Wales (NPHS), said: “The NPHS and Wrexham Council’s environmental health officers are investigating four cases of E. coli O157:H7 in three families from the Wrexham area. “Two people have been hospitalised. As a precautionary measure, a food premises in Llay was closed by the council on July 30 while investigations are carried out.”
Earlier this year, a public inquiry found that a butcher from South Wales was responsible for one of the largest outbreaks of E. coli in Britain. A public inquiry found that William Tudor showed disregard for food safety that led to multiple cases of E. coli disease and the death of a five-year-old boy in 2005. The inquiry called for more safety checks and urged food producers to “get to grips” with safety management.