The number of deaths in which the superbug MRSA has been cited as a cause has doubled in four years, official statistics show.
Some of the MRSA increase could be down to better reporting
The Office for National Statistics said in 2003 MRSA was mentioned on 955 death certificates - up from 487 in 1999.
But the figures suggested some of the rise may be down to better reporting of the bug.
Other statistics revealed the number of HIV diagnoses seems to have levelled off after a decade of increases.
However, it was the MRSA figures which have proved most controversial.
Mortality rates were highest among older people with more men than women dying.
MRSA was involved in two out of 1,000 deaths in hospitals and three out of 1,000 deaths in NHS nursing homes, compared to an overall figure of one out of 1,000 deaths for the years 1999 to 2002.
But laboratory reporting of MRSA cases only increased by 7% in the last year compared to a 19% rise in deaths.
Tony Field, chairman of patient group MRSA Support, said the figures were worrying.
"This again illustrates the MRSA rate is on the increase and the authorities still haven't got to grips with it.
"However, I think these figures underestimate the scale of the problem.
"MRSA host on other causes of death. A cancer patient may get MRSA and die but cancer will be cited as the cause of death, but MRSA would have played a contributing role.
"I would expect the true figure to be much more than 955."
And Karen Jennings, of the health care union Unison, added: "That is far too many tragedies.
"There is a solution to it. We need a proper strategy to make cleaning central to policy development."
She said the contracting out of cleaning services has meant the quality of service has decreased.
The government has launched a drive to combat the superbug and last year Health Secretary John Reid ordered hospitals to slash rates of MRSA bloodstream infection by half by March 2008.
But Conservative Party leader Michael Howard blamed the government's "obsession with targets".
"It is a fact that doctors and nurses are prevented from closing wards they know to be infected with the super bug because of Tony Blair's targets.
"No other country has seen the super bug infection take over its hospitals in the same way as we have in Britain."
And Liberal Democrats health spokesman Paul Burstow added the figures were "only the tip of the iceberg".
"A clearer picture is beginning to emerge of the uphill task we face in tackling MRSA in our hospitals."
Chief Nursing Officer Chris Beasley said fighting the superbug was a top priority and part of the increase was because of better reporting.
She added: "By improving reporting of MRSA like this it will help us identify avoidable factors and learn useful lessons."
Meanwhile, experts cautiously welcomed the news that the rise in new HIV diagnoses seemed to be levelling off.
Since 1995, the number of new diagnoses has increased each year.
The provisional figure for 2004 was 5016, compared to 5047 at the time in 2003, according to the Health Protection Agency (HPA).
The 2003 figure eventually rose to just under 7,000 after late reports were received and a similar increase is expected for last year.
Lisa Power, head of policy at the Terrence Higgins Trust, said: "No-one can afford to be complacent about HIV."
And she added it was important to remember the rate of sexually transmitted infections was still rising.
HPA chairman Sir William Stewart said people should not jump to conclusions about the HIV figure, adding: "The number of diagnoses remains high."