All patients entering NHS hospitals in England will be screened for MRSA and Clostridium difficile, the PM has said.
Hand washing is the most effective way of battling MRSA
Gordon Brown told BBC One's Andrew Marr Show that tackling hospital-acquired infections was an "absolute priority".
A programme of deep cleaning hospitals had begun and would continue across the country in the coming months, he said.
Health Secretary Alan Johnson would publish detailed plans for tackling the so-called superbugs later in the week, the prime minister added.
Mr Brown said the government was setting aside £50m to pay for the deep-clean programme. It had doubled the number of matrons on NHS wards, and introduced stiffer penalties for hospitals where cleaning is not done properly, he added.
The prime minister said: "We are doing everything in our power to root out this problem.
"It is something that I regard as an absolute priority because the National Health Service has got to be able to offer people clean hospitals that are safe for patients to come to."
A spokeswoman for the Department of Health said all patients attending hospital for routine operations will be screened for MRSA by 2008-9, with screening for emergency patients introduced over the next three years.
She said: "We have reduced the rates of MRSA blood stream infections significantly and we are beginning to see improvements in C difficile rates."
But the Conservatives dismissed Mr Brown's pledge as "spin". They claim the money to pay for the deep-cleaning programme would be taken from other parts of the NHS.
Tory health spokesman Andrew Lansley said: "In spite of Brown's claims, we know that money is being taken from the local NHS to pay for it. This is unacceptable.
"Infections are a major problem in our hospitals. Gordon Brown's one-off gimmicks won't solve this.
"We need a comprehensive, long-term strategy to root out infections, including screening when people are admitted to hospital and isolating those who are infected."
The Conservatives have proposed large fines for hospital trusts who fail to bring down infection rates.
Liberal Democrat health spokesman Norman Lamb said health minister Ann Keen had told the Commons as recently as last month that there was no evidence that screening for C difficile would be clinically effective.
He added: "The screening of patients for MRSA when they enter hospital is crucial in the fight against superbugs, which is why we called for the immediate introduction of a screening programme last year.
"But too often, Gordon Brown talks tough only for the plans to be exposed as ill-considered and undeliverable."