Epsom and St Helier hospitals are facing a fine of at least £1.4million after failing to hit their hospital infection reduction targets.
Between April 2012 and January 6 this year, 55 patients have developed Clostridium difficile, a bacterial infection which commonly occurs in hospital patients who have recently had a course of antibiotics.
This is already three above the maximum target of 52 set by the Department of Health for the trust this financial year and there are still two and a half months to go.
As the size of the fine escalates the more the target is broken, the trust could have to pay many millions.
Just four more cases could result in a £3.7million fine, with this rising to £5.7million if 63 cases are recorded. It is at the discretion of primary care trusts, which enforce the fines, as to how much a trust must actually pay for exceeding its targets.
In December, the trust’s chief executive, Matthew Hopkins, said the potential for a £5.7million fine for infection control was included as part of the financial projections for Epsom Hospital’s deficit - one of the main reasons cited for the collapse of its proposed merger with Ashford and St Peter’s.
A trust spokesman said it had made "significant process" in cutting infection rates and has seen a 75 per cent overall reduction in the number of cases of C difficile in the last five years.
He said: "We recognise that just one healthcare-associated infection is one too many and we are absolutely committed to driving down the number of these cases even further.
"We work hard to ensure our patients are protected from infections like C difficile and do all we can to keep the number of cases to an absolute minimum."
He said the measures in place to do this includes mandatory training for staff on infection prevention and control, and the recruitment of nurses to support and educate staff about the management of diarrhoea which is associated with the condition.
Pharmacists have also been recruited to work with staff to ensure antibiotics are prescribed in the most appropriate way.
A Department of Health spokesman said: “Fines have been a part of the NHS standard contract for a number of years.
"In 2012-13 tighter thresholds have been issued for organisations which have not met their objectives.
“They are not meant to penalise, but to encourage improvement.
“They are designed to encourage organisations which report a large number of C difficile infections to stay within their set objectives within the year.
“The PCTs do not have discretion to amend the objectives which trigger a fine but if a trust is given a financial penalty, they can negotiate with the trust as to how the money can be used within the organisation for service improvement.
“Fines were introduced to help organisations provide the highest level of patient care and where breaches are identified, which cannot be clinically justified, we would expect the sanctions to be imposed.”