A trio of Midland hospitals have been "named and shamed" in a report into the threat posed to patients by superbug Clostridium Difficile.
According to the report by Tory MP Grant Shapps, more than 25,000 of all cases - nearly one in six - went unreported last year as the Government only logged cases in patients over 65.
Figures obtained under the Freedom of Information Act revealed that University Hospital of North Staffordshire was ranked fourth worst in the UK, where 1,027 cases of C.Diff were recorded by trust bosses during 2006/07.
University Hospital of Coventry and Warwick, a PFI-funded superhospital which opened last July to replace the ageing Walsgrave Hospital, is rated eighth with 896 cases.
Heart of England NHS Foundation Trust - which runs Heartlands, Good Hope and Solihull hospitals - is the tenth worst trust, with 827 cases.
But a spokesman for University Hospital of North Staffordshire disputed the MP's findings, claiming they recorded just 893 C.Diff infections last year, across all age groups.
He said: "I suspect Mr Shapps has been given figures for our pathology lab, which carries out tests for all cases across our patch, rather than the trust itself.
"We have seen an increase in cases here: last year we had 679, but we are working with local primary care trusts to tackle the spread of C.Diff."
Mr Shapps' study C-Difficile: The Complete Germ Map of Britain, cites University Hospitals of Leicester where 1,739 cases were reported, as having the worst record on tackling the potentially fatal superbug.
His figures reveal that C.Diff, which is latent in the gut from birth, infects more than eight times as many people in British hospitals as MRSA and kills twice as many.
The infection causes diarrhoea ranging from mild cases to severe illness and can be fatal. Elderly patients treated with broad-spectrum antibiotics are at the greatest risk.
Mr Shapps said: "This investigation reveals that the number of C.Diff cases in Britain's hospitals has been dramatically underestimated with the Government simply ignoring anyone who contracts the infection, but happens to be under the age of 65.
"I'm calling on the Government to recognise and then get to grips with the true scale of the problem.
"The Government is constantly trying to convince us that the NHS is safe in their hands, but C-Diff infections continue to rise across the entire age range and are up by over 40 per cent in the last three years alone.
"It is an absolute scandal that I had to go these lengths to get the true figures revealed."
Cases of MRSA are around 7,000 a year and are currently falling, but figures show C.diff is a growing problem as the rate of infections continues to soar, his study claims.