The NHS in Wales is failing to implement "simple but important" steps for preventing hospital-acquired infections, a report has warned.

Thursday's study by the Wales Audit Office said that the cost of infections such as MRSA was around £50m a year.

But health trusts should be taking more action, much of it described as "straightforward", to reduce the risk of infection.

The watchdog said that just over six per cent of patients in Welsh hospitals have a healthcare-associated infection at any one time.

That rate is lower than in England and Scotland, but higher than Northern Ireland and the Republic of Ireland.

Welsh ministers have published a strategy for addressing the problems, and many trusts are said to have put action plans and targets in place.

However the report called for further steps to be taken, such as making infection control responsibilities clear in job descriptions.

It also said that NHS trusts should make cleaners part of specific ward teams, while trusts should be required to measure the cost and impacts of infections.

Auditor general for Wales Jeremy Colman said: "It is unacceptable to the public that patients should run the risk of acquiring infections as a result of their interaction with the NHS.

"Everyone in the NHS should be taking personal responsibility to minimise infections.

"Simple, but important, steps need to be taken and the recommendations in my report point to a number of ways to tighten prevention and control.

"Improvements are already evident since the Welsh Assembly Government launched its strategy, but further work is needed - particularly around education, guidance, measurement and evaluation."