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Understand  –  Antibiotic resistance

Health care-associated infections

Health care-associated infections are a threat to patient safety, and the ever-escalating problem of antibiotic resistance in bacteria is complicating the prevention and treatment of such infections even further.

Understanding health care-associated infections

Health care-associated infections are infections that patients get during the course of receiving treatment for another conditions within a healthcare setting, or from a treatment as an out-patient (a person receiving care at a health care facility but not staying over night). Common and important examples of bacterial health care-associated infections are catheter-related urinary tract infections, bloodstream infections related to intravenous cannulas and other devices, post-operative wound infections, and ventilator associated pneumonia. A viral infection that is contracted during a hospital stay, like influenza illness or norovirus gastroenteritis also counts as a health care-associated infection.

In bacterial health care-associated infections, the bacteria can come from anywhere in the health care setting, such as from the hands of a health care worker or from the patient’s own hand or skin flora. Either way, it counts as a health care-associated infection. The infection may be caused directly, for example if the urinary catheter or gloved hands of the surgeon is contaminated at the moment of the intervention. However, health care-associated infections more commonly arise from the patient’s own bacterial flora. Both susceptible and resistant bacteria can cause health care-associated infections, but resistant infections may complicate treatment and may prolong the recovery time for the patient. Multidrug-resistant bacteria are especially troublesome to treat.

Multidrug-resistant bacteria and health care-associated infections

Patients in hospitals are often exposed to multiple risk factors for acquisition of multidrug-resistant bacteria. This can be underlying chronic diseases, surgery, indwelling catheters and antibiotic use. The spread of multidrug-resistant bacteria (such as MRSA) from one person/patient to another most often occurs when someone who is colonized with resistant bacteria, but not ill, transmits them to another person, who then also becomes colonized. The bacteria may for example be carried on the person’s skin (as is most common with MRSA) or in the bowel (as is most common with various ESBL-producing bacteria or vancomycin-resistant enterococci). That is, colonization by multidrug-resistant bacteria does not necessarily have to happen at the time of the infection, they may sit silently doing no harm. Yet, if a health care-associated infection does arise from a multidrug-resistant bacterium the care for the patient becomes more difficult as options for treatment are limited.

An example to clarify

A patient comes to the hospital. On the second day, MRSA (or other multidrug-resistant bacteria) is transferred to the patient from another patient, for example via the hands of a health care worker, and silently colonizes the skin of him/her. On the fifth day, there is an operation performed, and the multidrug-resistant bacteria get into the wound, like other skin bacteria. The other skin bacteria are killed by the prophylactic antibiotic dose that was given before the operation, but the multidrug-resistant bacterium is not. It grows, and in a few days causes a health care-associated infection with pus and fever.

Some patients like premature babies and patients with malignancies treated with cytotoxic agents are especially vulnerable to infections, and get health care-associated infections more often. If the infection is caused by a multidrug-resistant bacterium the patient’s chances to get effective antibiotic treatment goes down, and consequently the risk of dying of the infection is higher.

Thus, it is very important to take measures to prevent and control:

  • The occurrence of health care-associated infections
  • The transmission or colonization of bacteria and resistant bacteria in health care settings.

Read more about how to do this under PREVENT INFECTION.

Selected Resources

Resource Description

IFIC Basic Concepts of Infection Control

This book provides a scientific foundation for basic infection control principles mainly to countries with limited resources. The 2016 Edition available in English. The 2011 Edition is available in Spanish, Italian, French, Hungarian, Arabic and Bulgarian. Several chapters may be useful including:

  • Chapter 3: Epidemiology of Healthcare-Associated Infections
  • Chapter 7: The Role of the Microbiology Laboratory (the tables describe the characteristics of the main groups of microbes potentially causing health care-associated infections)