The number of deaths linked to the hospital bug Clostridium difficile has outstripped those due to MRSA, latest figures show.
Hospital acquired infections can kill
Deaths involving Clostridium difficile rose by 69% to 3,800 from 2004-05, the Office for National Statistics said.
In the same period, MRSA mentions on certificates increased by 39% to 1,629.
The government said better recording had given a "more accurate picture", but accepted cutting deaths linked to both bugs was a "major challenge".
Being mentioned on a certificate does not necessarily mean a hospital acquired infection was the cause of death, but it does mean it was considered a contributing factor.
Most of the deaths from both C.difficile and MRSA were in the older age groups.
The ONS figures also showed that between 2001 and 2005 MRSA was mentioned on one in every 500 death certificates in England and Wales. For C. difficile it was one in every 250.
The ONS said greater awareness and high public profile of the disease may have contributed to an increase in the reporting of C. difficile on death certificates.
Health Minister Lord Hunt agreed, saying: "We are now getting a far more accurate picture of the number of deaths from C. difficile and MRSA with vastly improved recording.
"It is a major challenge for the NHS and a top priority for government."
He said that tough hygiene targets meant the NHS was starting to see significant reductions in rates of MRSA infections.
"We now want to see similar progress in relation to C. difficile," he said.
C. difficile is a bacterium found in the gut of up to 3% of healthy adults and 66% of infants, where it rarely causes problems.
However, it can cause illness when its growth goes unchecked.
For example, treatment with certain antibiotics can disturb the balance of "normal" bacteria in the gut, allowing C. difficile to thrive.
And efforts to combat MRSA, such as alcohol hand-rubs, have had no impact on C. difficile.
C. difficile forms spores which means it can survive for long periods in the environment, such as on floors and around toilets, and spread in the air.
Rigorous cleaning with warm water and detergent is the most effective means of removing spores from the contaminated environment and the hands of staff, say experts.
Head of health at Unison, Karen Jennings, said: "These shocking figures show that MRSA and C difficile have a deadly grip on our NHS. Dirt is not cheap.
"We need to wage war on these superbugs and cleaning and cleaners should be on the front line as an integral part of the infection control team.
"No one wants to be treated in a dirty hospital but sadly the culture of cleaning was sold off at the same time as compulsory competitive tendering was brought in.
"It's time for hospitals to set safe minimum staffing levels for their cleaning services - patients and staff deserve nothing less."
A spokeswoman for the Patients Association said: "Our worry is that these figures will continue to rise as other priorities take precedence
"The government promised to make infection control one of its top priorities. Yet its own announcement to further reduce waiting times by 'round the clock operations' will inevitably harm these efforts," she said.