MRSA was found on door handles and taps
Scientists have discovered a way of cleaning wards to ensure surfaces are virtually free of the MRSA superbug.
But the researchers from St Thomas' Hospital, London stress they do not know if better cleaning will reduce the numbers of patients infected.
Experts agree the main way to prevent transmission is for staff to wash their hands between patients.
But it is thought staff may also pick up MRSA from surfaces such as taps and door handles and then infect patients.
Hospital-acquired infections like MRSA (methicillin resistant Staphylococcus aureus) affect around 100,000 people in England each year, costing £1 billion and causing an estimated 5,000 deaths.
'Patients infect rooms'
St Thomas' researchers looked at isolation rooms and bathrooms used by patients with MRSA and general wards and bathrooms used by patients who had not been infected.
MRSA was found to be present in all the rooms tested.
The researchers, led by Professor Gary French, said it was not surprising that the isolation rooms were contaminated, because the patient was likely to infect the room.
But researchers also found four different types of MRSA present on beds examined in the open ward, and in a shared bathroom.
MRSA was also present on a fifth of door handles to 21 rooms used by infected patients, and 7% of door handles to 175 non-MRSA rooms.
The researchers compared traditional cleaning, using special detergents, with a hydrogen peroxide vapour - which could be used where rooms could be sealed off and treated.
The study was partly funded by Bioquel, the company which produces the vapour cleaner.
It was found only 1% of sites cleaned using the hydrogen peroxide vapour remained contaminated with MRSA, compared to 66% of those cleaned using detergents.
Writing in the Journal of Hospital Infection, Professor French, head of the infection department at Guy's and St Thomas' NHS Trust, said: "The distribution of the contamination and the isolation of multiple strains suggest that the environment may be an important source of hospital cross-infection."
But he stressed researchers now need to look at whether having cleaner surfaces reduces the number of patients infected with MRSA.
"The research has demonstrated that used in certain situations, for example where we can seal off a side room which has been occupied by a patient with MRSA, this technique is extremely effective in removing MRSA from equipment and surfaces.
"The next - and very important - step is to understand the impact that removing MRSA from the environment might have on patient infection rates."
A spokeswoman for the Health Protection Agency said: "MRSA is currently thought to be primarily transmitted to patients by hands and equipment.
"The spread of MRSA and other infections on hospital wards can be limited and controlled by following good infection control procedures.
"The hospital environment such as floors and furniture and are not currently considered to be a major source of MRSA transmission.
"As the authors rightly point out further investigation of the clinical significance of hospital environmental contamination and of more effective cleaning methods are required."