The Vale of Leven Hospital was the focus of the C.diff outbreak
Clostridium difficile infection is a greater contributory factor to deaths in Scottish hospitals than currently recorded, an expert has warned.
It follows a BBC Scotland investigation into the death of 18 patients at the Vale of Leven Hospital, Dunbartonshire.
Professor Hugh Pennington said: "C.diff should appear on a death certificate more often than it does."
Health Secretary Nicola Sturgeon said procedures had failed but action was being taken to tackle C.diff.
General Register Office for Scotland statistics showed C.diff was a factor in 597 deaths last year, compared with 313 deaths in 2005.
A total of 55 people were affected by the bug at the Vale of Leven Hospital between December of last year and June this year.
C.diff was the primary cause of death in nine patients there and was also a contributory factor in another nine.
An independent investigation commissioned by the Scottish Government found that there was no clear surveillance system in place, infection control procedures had failed and there were failings in leadership and accountability.
Information obtained by the BBC investigations unit through freedom of information requests also revealed that across the country almost half of hospitals which responded had seen cleaning budgets go down in real terms this year, while almost a third had beds closer together than recommended guidelines.
'Nasty as you can get'
Prof Pennington is an emeritus professor of bacteriology and has carried out work into deadly E.coli outbreaks in Scotland and Wales, where he headed a public inquiry.
He said C.diff was about "as nasty as you can get" in terms of killing people and that the key element to battling the infection was stopping it spreading and isolating infected patients.
"I think it's very reasonable to suppose that more than 18 people died at the Vale," he added.
"My experience of hospital acquired infections, and I've looked at many cases, is that very often when it's abundantly clear from looking at the clinical notes of the patient a hospital acquired infection, maybe C.diff, maybe MRSA, was material in causing their death - it doesn't appear on their death certificate.
"So it may be a substantial number more."
The professor also said the Vale of Leven report had not been afforded the time to properly analyse how the outbreak had actually occurred and was just a start.
Ms Sturgeon told BBC Scotland: "The key failure at the Vale of Leven is that the surveillance systems weren't robust enough to pick up what was happening there and I think that is a matter of enormous regret and something that I never, ever want to see happen again.
"But I feel pretty dreadful about every single case of infection in our hospitals - I watched my own grandmother battle C.difficile before she died a few years ago, I know how absolutely dreadful it is and I don't want to see any patient or any relative have to go through that."
Ms Sturgeon dismissed suggestions that the report into the Vale of Leven outbreak was not comprehensive enough, amid concerns that it did not question key frontline staff.
The health secretary said: "If there is a feeling that any frontline staff wants to make their views known they are absolutely entitled to do that and they should do that, but this report has laid bare significant and serious failings that are now being acted upon."
A statement from NHS Greater Glasgow and Clyde Health Board said: "The Vale of Leven Hospital was fully compliant with the requirements of the mandatory Health Protection Scotland National Clostridium difficile Surveillance System.
"However, the national system was designed to monitor trends but not pick up individual outbreaks at the ward and/or hospital level."
The Labour MSP for Dumbarton, Jackie Baillie, said it was now time for the Scottish Government to "listen to the families and order a full public inquiry into C.difficile as a matter of urgency".
"The BBC's revelations are deeply disturbing," she said.
"Professor Cairns Smith admits that the short investigation he led during the summer did not have enough time to get to the bottom of every aspect.
"We need a public inquiry because the families who lost loved ones at the Vale of Leven deserve answers and other Scottish hospitals need help to avoid a similar serious outbreak."
Liberal Democrat health spokesman Ross Finnie said: "The findings by the BBC prove, beyond any doubt, that there is no argument for not having a full public inquiry into C.diff. Such an inquiry should not be limited to the Vale of Leven hospital, but must cover the whole of Scotland."
Health boards across Scotland are to be given tougher targets to tackle C.diff, with NHS boards expected to reduce the rate of the infection in hospitals by at least 30% by 2011.
Issues arising from the Vale of Leven have also been referred to the procurator fiscal for consideration.