Investigations are continuing into a cluster of cases of Clostridium difficile infection in wards at the Royal Infirmary of Edinburgh.
The NHS said no new cases had been identified in the last 24 hours.
Fourteen patients were affected by the infection, commonly known as C-diff, and two patients died from underlying conditions after also testing positive for the infection in the days before their death.
Since the cluster was identified in early November, four patients have recovered and been discharged home.
The eight patients who remain in hospital are being cared for in isolation, and NHS Lothian said two very seriously ill, but stressed while they had tested positive for the infection,C-diff was not the cause of their condition.
Infection prevention and control procedures have been reinforced at the hospital to help protect them, other patients, staff and visitors. The five affected wards remain open.
Samples are currently being tested to establish if any of the identified cases are linked, although it is understood results are not expected until January.
Melanie Johnson, Executive Nurse Director, NHS Lothian, said: “Investigations are ongoing to establish if there is a link between the cases, but we always act as if cases are linked and implement action to prevent cross transmission.
“Our robust surveillance procedures meant that we were able to identify these cases quickly and take the appropriate action.”
Affected patients in the ward and their relatives have been told about the infection and the actions that have been taken so far have been explained to them.
Nursing and medical staff are on hand to answer any other questions or concerns from visitors and patients themselves
The latest “cluster of cases” comes despite experts from Health Protection Scotland being parachuted in to drive down rising infection rates in the Lothians. Three additional infection control nurses have been brought in – and increased ward inspections are being carried out – to curb the rise, which peaked at 52 cases in October last year.
Labour Lothian MSP Sarah Boyack said the latest flare-up had come as a shock.
“Given last month’s publication of the public inquiry into the outbreak of C.difficile at the Vale of Leven hospital, clear lessons should have been learnt across the NHS,” she said. “We urgently need to find out why this happened.”
C.diff is an infection of the gut which often causes diarrhoea, but can be life-threatening when it leads to severe inflammation of the bowel. It is notoriously difficult to treat because of its resistance to antibiotics.
Good hand hygiene, careful prescription of antibiotics and high cleaning standards can prevent infection and recurrence.
Last year there were 403 recorded cases in Lothian, with almost three-quarters of people affected aged over 65.
Tom Waterson, Unison branch chairman for Lothian, said the prevalence of the infection was a “huge concern”.
He said: “We are working alongside NHS Lothian, the infection control teams and Consort as much as possible to try to assist in eradicating the problem. It is worrying that it is still happening but the senior management team is taking it very seriously and I am reassured by their response.”