Post-surgery infections are causing concern in Wales, UK.
Nearly a fifth (18%) of all infections take place after surgery, it has been found.
The Assembly's Audit Committee states: "This is a higher proportion than in England (13.8%), Northern Ireland (13.8%) and Scotland (15.9%), although it is lower than in the Republic of Ireland (21.5%)."
The National Public Health Service estimates the annual cost of infections in Wales is Ģ50m.
There is evidence C-difficile infections "increased significantly" in Wales between 1993 and 2005.
However, the report notes overall Wales has had more success than England or Scotland in fighting infections. While 6.4% of all patients in Welsh acute hospitals suffered an infection, this is less than England (8.2%) and Scotland (9.5%). Wales is out-performed by the Republic of Ireland (4.9%) and Northern Ireland (5.4%).
The report, by the Assembly's cross-party audit committee, is published the day after the Assembly passed its first law, designed to "make it easier and quicker for patients to claim compensation when treatment provided by the NHS in Wales has been negligent". It is intended to allow lower value negligence claims to be handled without resorting to legal action.
Health Minister Edwina Hart said: "When things do go wrong, patients should be able to raise concerns openly and know lessons will be learned by the organisation and that they will get the help and support they need or compensation, if appropriate. This important piece of legislation will build on our efforts to continually improve the care for patients and learn from any mistakes."
The audit committee's report demonstrates infections remain a challenge to the NHS in Wales. However, it praises the Welsh strategy of tackling all infections - not just those making the headlines. It claims this has lowered overall infection rates, writes David Williamson in Western Mail.
The report concludes: "This appears particularly true when comparing Welsh infection rates with England, where the national approach appears to have involved a specific focus on MRSA."
David Melding, the Conservative AM who chairs the committee, said a "cultural change" was under way but added: "[There] is still a long way to go until infection prevention and control has achieved satisfactory results. We as a committee call on the Welsh Assembly Government to do more to improve its processes in dealing with Healthcare Associated Infections to capitalise further on the progress already been made."
Martin Semple, a clinical specialist at the Royal College of Nursing (RCN) Wales, said: "Nurses have been at the forefront in tackling superbugs such as MRSA and C-difficile. We know what works and the Welsh Assembly Government must continue to invest in adequate cleaning services, training for staff in infection control and ensure the number of beds available in the NHS increases. The Government must also consider how it can support nursing and care homes. We are anticipating the outcome of the Empowering Ward Sister project, which has made a series of important recommendations that will go a long way to continue the fight against infection."
Shadow Health Minister and Cardiff North AM Jonathan Morgan said: "We welcome efforts to improve levels of cleanliness in Welsh hospitals. However, it is clear much work still needs to be done. Patients have every right to expect to be treated in clean hospitals or in an environment where their health is not threatened by illnesses picked up when they are being cared for.
Welsh Liberal Democrat AM Eleanor Burnham said: "I believe strongly that the Welsh Assembly Government needs to impress upon all who work in the health service in Wales the true importance of basic cleanliness and hygiene - and everyone, including visitors, needs to feel part of this fight against infections - to eradicate this modern-day blight."