The NHS has been attacked for failing to monitor the full extent of the hospital superbug crisis.
Handwashing is still key to reducing hospital infections
The National Audit Office says incomplete data means the crisis cannot be accurately assessed.
It estimates 5,000 die each year from infections such as MRSA, but warns the true figure could be much higher.
Data published on Wednesday on one form of MRSA - bloodstream infections - shows some of the most prestigious hospitals have some of the worst rates.
The issue featured heavily in Prime Minister's Questions on Wednesday.
Tory leader Michael Howard asked why the NHS "still doesn't have a proper grasp of the extent and cost of hospital acquired infections".
He added: "Government targets have made dealing with hospital superbugs more difficult."
Charles Kennedy, Liberal Democrat leader, attacked the government for setting a new target for improving hospital hygiene and reducing infection rates
"That should be a given. It should be taken as read by patients."
Tony Blair said: "This is a serious problem. We are not the only country with it, however, and we are working very hard to eradicate it."
The NAO says progress since it last reported in 2000 has been "patchy".
MRSA (methicillin resistant staphylococcus aureus) first appeared in the 1960s
Some strains are resistant to almost all known antibiotics
Cases have increased by 600% in the past decade
Cases are expected to double again in the next six years
Efforts to combat it cost the NHS £1bn a year
Based on their findings then, the Commons Public Accounts Committee made a series of recommendations about how HAI rates could be cut. This report looks at progress since.
The NAO says, if all the recommended measures had been brought in across the NHS in England, infections and deaths could have been cut by around 15% - around 750 deaths a year.
MRSA (Methicillin Resistant Staphylococcus aureus) is just one of the infections patients can develop in hospital, but it is the focus of public, government and the health service because of its resistance to treatment.
The government announced on Monday it was bringing in further measures, such as bringing in overseas experts and publication of infection rates, in a bid to reduce rates.
The UK has one of the highest levels of hospital infections in Europe.
They are estimated to cost the NHS around £1 billion a year.
The NAO report says many hospitals have made significant progress in introducing ways to improve the prevention and control of hospital acquired infection.
But it says the NHS still does not have enough information on the extent and cost of hospital acquired infection.
Launching the report, its author Karen Taylor said the lack of comprehensive information about the extent of the problem hampered the introduction of changes which could reduce rates.
"The dissemination of good practice is very poor. It's difficult to get the message to frontline staff.
"The lack of information hides what's actually happening. Without it, you can't target action."
Currently, the only kind of MRSA hospitals have to report is bloodstream infections, which have increased from 7,250 in 2001-02 to 7,647 in 2003-04.
However neither MRSA wound or urinary tract infection rates are collected.
The NAO also warns many doctors and nurses still fail to wash their hands between patients - even though this is thought to be the key factor in preventing the spread of infections between patients.
It said many staff still see the issue as a problem for the infection control team alone, and do not take responsibility for it themselves.
Other factors which have affected hospital acquired infection rates include high bed occupancy levels, and a lack of side rooms, which mean infected patients cannot be isolated as easily.
The NAO warns antibiotic resistance is also an increasing problem, and calls for better education and training in infection control and better compliance with hand hygiene measures.
Sir John Bourn, head of the NAO, said "The Department of Health has made important progress in raising the profile in NHS trusts of the control of hospital-acquired infection.
"However, I am concerned that, four years on from my original report, the NHS still does not have a proper grasp of the extent and cost of hospital-acquired infection in trusts."
Edward Leigh MP, chairman of the Public Accounts Committee, said the NAO report uncovered an "appalling lack of progress by the Department of Health and the NHS".
He added: "Four years from the original NAO report in 2000 - and the picture is bleak.
"The department has launched a number of initiatives but remains at sea on the cost and extent of hospital acquired infection in general.
"And, despite my Committee's recommendations, there is still no mandatory surveillance and reporting scheme for all hospital acquired infection."
He added: "It is a matter of shame that our MRSA infection rate is among the worst in Europe."
Health Secretary John Reid said government plans would help to bring all hospitals up to the level of the best.
He said: "It is clear that some parts of the NHS have to do more to control this threat
and match the achievements of hospitals which maintain low MRSA rates."