Healthcare associated infections
February 2006
Introduction
Healthcare associated infections (HCAIs) are infections acquired as a result of contact with the healthcare system in its widest sense – from care provided in the home, to primary care, nursing home care and acute care in hospitals. [Go to note 1]. Accordingly, HCAIs include both hospital acquired infections (HAIs) Hospital acquired infections (HAIs) are also known as nosocomial infections which are infections that develop in a patient 48 hours or more after admission to a hospital; and community acquired infections (CAIs) that refer to any infection from which a patient is suffering when they come into a hospital or occurs within the first 48 hours of admission (ie acquired in the community). For some viral infections where it is known that the incubation period is longer (eg varicella-zoster virus), CAIs can be diagnosed after 48 hours. HCAIs are mainly acquired during a patient’s stay in hospital, although it is important to acknowledge that infections occur in community and primary, as well as, secondary healthcare settings.
The occurrence of HCAIs is not a new phenomenon and to some degree it is inevitable in any healthcare setting. HCAIs now pose significant problems in all developed healthcare systems and necessitate monitoring, control and regulation. A report published by the Department of Health (DH) indicates that between 5 and 10 per cent of hospitalised patients in the United States of America (USA), Australia and most European countries contract an HCAI (see box 1). The recent resurgence in HCAIs is to some extent a result of advances in medical technology and treatment, and the development of healthcare in the primary, secondary and community settings. The ageing population and the ability to treat more severe and chronic disease mean that, although more patients are being treated than ever before, they are often more vulnerable to infections because of the use of invasive procedures and/or as a result of suppression of the immune system. The spread of HCAIs is facilitated by high bed occupancy rates, the increasing movement and turnover of patients, and poor standards of hygiene in healthcare settings.
Box 1: Estimated prevalence of HCAIs
| • Australia | 6% | • France | 6-10% |
| • Norway | 7% | • Netherlands | 7% |
| • England | 9% | • Spain | 8% |
| • USA | 5-10% | • Denmark | 8% |
The need to control the level of HCAIs is compounded by the emergence of antimicrobial-resistant micro-organisms. The development of resistance is a natural response to the selective pressure generated by antimicrobial treatment of infections. Increasing use of antimicrobials within and outside the healthcare setting has resulted in the emergence of ‘super-bugs’ that are resistant to multiple antimicrobials. Infections have become increasingly difficult and expensive to treat. The antimicrobials that are needed to treat drug-resistant infections are potentially more toxic, which complicates efforts to control the spread of infection. This problem has been highlighted by the dramatic increase in the proportion of Staphylococcus aureus (SA) bacteraemias that are resistant to the antibiotic methicillin [Go to note 2].