Two hospital patients who contracted the Clostridium difficile (C.diff) bug have died and 14 other cases are being investigated, a health board has confirmed.

NHS Lothian revealed the pair, who were patients at Edinburgh Royal Infirmary (ERI), died from underlying conditions but had tested positive for the infection.

The 14 other cases of the bug - described by health chiefs as a "cluster" - are also being investigated at the same hospital in the city's Little France area. The health board said the affected patients are being cared for in isolation and infection prevention and control procedures have been reinforced.

Samples are being tested to establish if any of the cases are linked. The wards currently remain open.

Melanie Johnson, executive nurse director at NHS Lothian, said: "We have identified a cluster of C.diff at the hospital and an investigation is ongoing to establish if there is a link between the cases.

"As is usual practice, we isolate symptomatic patients, emphasise the importance of infection control precautions and undertake additional cleaning. 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."

Any affected patients in the ward and their relatives have been told about the infection, the health board said.

Last month, an inquiry into the deadly Vale of Leven C.diff outbreak found the bug was a factor in the deaths of 34 out of 143 patients who had tested positive for the infection at the hospital in 2007 and 2008.

Levels of the C.diff bug among hospital patients have, however, fallen in recent years, statistics show.

Meanwhile, a ward at the Dumfries and Galloway Royal Infirmary has been shut temporarily due to an outbreak of sickness and diarrhoea.

Ward 16 has been closed to new admissions, transfers and routine visiting, NHS Dumfries and Galloway confirmed.

Five patients and one member of staff have symptoms of sickness and/or diarrhoea, health chiefs said.

Norovirus is not confirmed at this stage.

The hospital's infection control team is monitoring the situation and appropriate infection control procedures have been put in place, the health board said.

Elaine Ross, infection control manager, said: "Our priority is always patient, public and staff safety.

"We appreciate that this temporary visiting restriction to Ward 16 may cause some frustration. This measure will allow us to help prevent further spread of the infection and ensure safe patient care."

Where relatives feel the need to visit people in Ward 16, they are asked to contact staff before going to the hospital.

Ms Ross added: "We are aware of a number of circulating viruses in the community and to ask people not to visit if they have been feeling unwell."