What are healthcare associated infections ?

A healthcare associated infection is acquired when providing healthcare. When this happens in a hospital, the infection is called a hospital infection or nosocomial infection. Nowadays, the term ‘healthcare associated infection’ is most often used.

When microbes settle for a longer period of time in/on the body, multiplying without appreciable damage or discomfort, this is called colonisation or carriership. This turns into an infection as soon as disease symptoms occur. The term ‘infection’ implies microbial transmission. When an inflammation occurs, the body reacts in a certain way to the presence of microbes.

An inflammation can be caused by microbes that are already present on/in your own body. But microbes can also be transmitted by one patient to another. For instance, when healthcare providers do not disinfect their hands at the right moments. Hand hygiene is indeed the easiest and most effective way to prevent the transmission of microbes.

The term ‘healthcare associated infection’ covers a wide range of infections. The most common healthcare associated infections are urinary tract infections, infections of the lower respiratory tract, surgical site infections and blood infections (see figure). The risk factors of a healthcare associated infection vary depending on the type of the infection.

Source: WHO, numbers for Belgium based on the prevalence study of ECDC 

Different types of microbes can cause healthcare associated infections. It mostly concerns bacteria, but also fungi/yeasts (e.g. Candida) and viruses (e.g. the flu virus). Healthcare associated infections in hospitals are often caused by bacteria that are resistant to one or more types of antibiotics. These are called ’multi-resistant’ bacteria and they reduce the effectiveness of antibiotic treatments.  

The figure shows the transmission of microbes in a schematic way.

The core elements of microbe transmission by the are:

• Donor surface ’A’ contains microbes ‘a’

E.g. : the patient’s skin, the bed(linen) of the patient, bedside table, …

• Receptor surface ‘B’ contains microbes ‘b’

E.g.: skin/body part of another patient, medical equipment of another patient

• A hand picks up a micro-organism ‘a’ from donor surface ‘A’ and carries it over to receptor surface ‘B’, no hand hygiene action is performed.
• Receptor surface ‘B’ is now cross-contaminated with microorganism ‘a’ in addition to original flora ‘b’.
• The patient and/or his/her environment has now been infected with microbes and this can  possibly cause  a healthcare associated infection.

Source : My five moments for hand hygiene (H. Sax - Journal of hospital infection 2007)

Every person carries bacteria on his/her body, among others on the skin, in the mouth and in the intestines. These are harmless guest germs (also called ‘commensal’ bacteria) that normally do not cause infections. However, pathogenic or harmful bacteria do cause infections. They are spread, for instance, by sick people or by eating infected food (Salmonella). A patient at the hospital is more vulnerable to contract infections, both from pathogenic and commensal bacteria. Indeed, these two kinds of bacteria more easily infect a patient weakened by disease, an organ transplantation, after an operation or when he/she has a blood catheter or a bladder tube. 

In modern healthcare institutions, 5 to 10% of patients acquire a healthcare associated infection. Surveys reveal that in Belgium, some 7.1% of the patients contract a healthcare associated infection during their hospital stay. This amounts to more than 100 000 patients a year. The situation in Belgium is comparable to other European countries. The European Centre for Disease Prevention and Control (ECDC) estimates that every year, around 4 million patients get a healthcare associated infection in the member states of the European Union. Between 25 000 and 37 000 patients would die due to these infections. 

A healthcare associated infection demands additional diagnoses and treatment, which may extend the hospital stay. In serious cases, the infection can lead to long term invalidity and even to the death of the patient. It often concerns vulnerable and/or very ill patients for whom the additional healthcare associated infection was too much to take. Additionally, healthcare associated infections cause an augmentation of healthcare costs for both the patient and the society.

A survey by the Belgian Federal Knowledge Centre for Public Health (KCE) shows that healthcare associated infections in Belgium are responsible for 720 757 extra days of hospitalisation, 384.3 million EUR extra healthcare costs, and 2625 extra casualties every year. 

Unfortunately, only one out of three  healthcare associated infections can be prevented, even if all preventive measures are applied by the book.  Hospitals are indeed crowded with people that are very receptive to infections: weakened elderly people, patients with a strongly challenged immune system (e.g. patients having had an organ transplantation or chemotherapy) and patients needing far-going treatments for life threatening diseases (e.g. patients on intensive care or neonatal departments). However, we have to do all we can to avoid healthcare associated infections as much as possible. Hand hygiene is one of the most effective ways to do so. 

Each hospital in Belgium has a hospital hygiene team consisting of a physician and one or more nurses with specific expertise in infection management. Along with the hospital hygiene committee, the chief of medical staff and the chief of the nursing department, they are responsible for the prevention of healthcare associated infections in the hospital.

Practise shows that a good prevention policy can drastically reduce the number of healthcare associated infections. Such a policy is based on general preventive measures including hand hygiene, personal protection (e.g. gloves) and keeping a patient with an infection risk in a separate room. Besides, there are specific measures to prevent urinary tract infections, surgical site infections, lower respiratory tract infections and blood infections. Much attention is also given to monitoring healthcare associated infections in order to quickly detect possible epidemics and to control them.