Huge government fines mean cases of a notorious hospital bug may be going unreported, it has been claimed.
More than half of specialist clinicians questioned for a survey believe the true number of deaths associated with Clostridium difficile is higher than official figures suggest.
A fifth claim this is because doctors under-report cases to avoid financial penalties on NHS trusts.
Tough fines are imposed on trusts that fail to meet targets for reducing C.diff infections.
In December last year, the Birmingham Post revealed hospitals in the West Midlands were facing fines of up to £45 million after a surge in cases.
C.diff is spread on the hands and contaminated surfaces. It causes diarrhoea and, in some cases, severe inflammation of the bowel. Its hardy spores can survive on the body and clothes for long periods of time.
Around three per cent of healthy adults and 66 per cent of infants harbour C.diff without suffering any ill effects. But in vulnerable individuals, such as hospital patients, the bacteria can produce serious and recurrent infections.
According to the latest Health Protection Agency figures, C.diff infection rates in English hospitals have fallen five-fold since 2006 from two per cent to 0.4 per cent of patients.
Since 2007/08, the total number of reported cases of C.diff in patients aged two and over in England has dropped from almost 55,500 to 21,695. In the whole of the UK, there were 24,751 reported cases in 2010/11 which cost the NHS an estimated £250 million.
But many of the 101 clinicians polled say the real picture is less rosy. Nearly a third thought incidence of C.diff infection had “flatlined” or even increased over the past few years.
In total, 41 per cent felt there was pressure within NHS trusts to under-report cases of C.diff to avoid fines.
More than a third of this group thought samples were sometimes not sent for laboratory tests when C.diff infection was suspected. And 63 per cent suggested that recurrent cases were going untested.
The nationwide survey was conducted by the Open Plan market research agency on behalf of two patient groups, C-Diffsupport and the National Concern for Healthcare Infections (NCHI).