Healthcare associated infections
February 2006
Healthcare associated infections
A wide variety of micro-organisms can be transmitted in healthcare settings, including bacteria, viruses, fungi and mycoplasmas, producing in turn a wide range of different diseases. The majority of HCAIs are caused by bacteria, many of which are carried harmlessly by healthy people. They most commonly affect the urinary tract, lower respiratory tract, surgical wounds, skin and the bloodstream. These account for three-quarters of all HCAIs while less common causes include specific infectious diseases such as influenza and viral gastro-enteritis (see figure 1). National Audit Office (2000) The management and control of hospital acquired infection in acute NHS trusts in England. London: The Stationery Office. While some bacteria are more difficult to treat, the type of bacteria involved is often less important, in terms of the impact on the patient, than the site and kind of infection. Many HCAIs are caused by micro-organisms susceptible to antimicrobials and can, therefore, be treated effectively. Of the main categories of HCAIs, urinary tract infections occur most frequently, while bloodstream infections have the highest associated mortality.3 HCAIs can be transmitted between persons, derived from the patient’s natural flora or spread as a result of environmental contamination.
HCAIs affect patients in a variety of ways from increased discomfort and pain to severe chronic illness, permanent disability and in some cases may cause death. Infection can also lead to extended lengths of stay of affected patients, bed and ward closure, and increased diagnostic and treatment costs, especially when infection is caused by an antimicrobial resistant micro-organism. Although HCAIs are caused by a wide variety of micro-organisms, several pathogens and their associated antimicrobial resistance are of particular significance including S.aureus, Glycopeptide-resistant enterococci (GRE), Clostridium difficile, Streptococcus pneumoniae, Acinetobacter species, Extended-spectrum Beta-Lactamases (ESBL) producing Escherichia coli, and Candida species.
Further information
- Summary information on the micro-organisms commonly causing HCAIs can be found in the appendix .
- More detailed information about the causative agents of HCAIs and their epidemiology can be found on the Health Protection Agency (HPA) website at www.hpa.org.uk - and on the National Resource for Infection Control (NRIC) website at www.nric.org.uk