Antimicrobial resistance (AMR) occurs when microorganisms develop or possess mechanisms that allow them to survive or multiply despite exposure to an antimicrobial medicine that would normally inhibit their growth or kill them.
Antimicrobial resistance can affect bacteria, viruses, fungi, and parasites. Resistance may arise through genetic changes, such as mutations, or through the acquisition of resistance genes from other microorganisms. When antimicrobial medicines are used, susceptible microorganisms may be eliminated or suppressed while resistant ones survive and multiply. This process, known as selection pressure, can increase the proportion of resistant microorganisms in a population.
Resistant microorganisms can spread between people, animals, and through the environment. Factors contributing to the emergence and spread of antimicrobial resistance include inappropriate or unnecessary antimicrobial use, incorrect prescribing or dispensing, failure to follow appropriate treatment instructions, inadequate infection prevention and control, poor sanitation, and the circulation of substandard or falsified medicines. Resistance can also emerge and spread despite appropriate antimicrobial use, because it is a natural biological process that can be accelerated by selection pressure.
Antimicrobial resistance can make infections more difficult to treat, increase the risk of treatment failure, prolong illness and hospital stays, raise healthcare costs, and increase the risk of complications and death. It can also limit the effectiveness of medical procedures that depend on reliable infection prevention and treatment, including surgery, cancer treatment, and organ transplantation.
QUICK FACT
It is the microorganism, not the patient’s body, that becomes resistant to an antimicrobial medicine. A person can carry or develop an infection caused by a resistant microorganism, making that infection harder to treat with certain medicines.
COMMONLY CONFUSED WITH
- Antibiotic resistance: Resistance specifically involving bacteria and antibiotics. It is one type of antimicrobial resistance.
- Drug resistance: A broader term describing reduced susceptibility to a medicine. Depending on the context, it may refer to antimicrobial resistance or resistance to other types of medicines.
- Treatment failure: When treatment does not achieve its intended outcome. Antimicrobial resistance can cause treatment failure, but other factors, including an incorrect diagnosis, inadequate drug exposure, poor adherence, or complications of the disease, can also contribute.
- Drug tolerance: A term used in different medical and biological contexts for a reduced response to a substance. It is not interchangeable with antimicrobial resistance.
SEE ALSO
- Antimicrobial
- Antibiotic
- Antibiotic Resistance
- Antimalarial
- Drug Resistance
- Infection
- Antimicrobial Stewardship
