Health Secretary Stephen Barclay has been asked to draw up new rules to make hospitals safer from infections after the death of Ipswich mother Karen Starling following a lung transplant in Cambridge.
Mrs Starling, 54, died in February 2020 after having a lung transplant at the Royal Papworth Hospital in Cambridge in May the previous year.
The inquest also examined the death of 65-year-old Anne Martinez from Hertfordshire who died in December 2020, also after a lung transplant at the Royal Papworth in 2019.
An inquest in Cambridge found that both women had been infected with Mycobacteria Abscessus (M abscessus) which was in the water system at the hospital - and that neither would have died without being infected.
Coroner Keith Morton KC has now sent a copy of his findings to the Secretary of State for Health and Social Care as a "Report to Prevent Future Deaths."
This requires the department to say what action it is taking to prevent a repetition of such deaths at the Royal Papworth and hospitals across the country.
The deadline for the report is January 2 next year - although it is possible this could be exptended, especially as the time period includes the Christmas holidays.
In his report to the government Mr Morton said: "During the course of the inquest the evidence revealed matters giving rise to concern.
"In my opinion, there is a risk that future deaths could occur unless action is taken. In the circumstances it is my statutory duty to report to you."
He lists a number of issues that should be addressed, including getting a better understanding of how the bacteria can enter and survive in the hospital's water system.
Mr Morton said a total of 34 patients had been diagnosed with the infection, and this was continuing - although the number of cases being found was declining.
He concludes his report: "In my opinion action should be taken to prevent future deaths and I believe you and your Department of State have the power to take such action."
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