Antimicrobial Resistant Microorganisms

Unique identifier / Notation

BI0025

Synonyms

Superbugs.

Antimicrobial resistant microorganisms are those microorganisms (such as bacteria, fungi, viruses, and parasites) that change when they are exposed to antimicrobial drugs (such as antibiotics, antifungals, antivirals, antimalarials, and anthelmintic). Microorganisms that develop antimicrobial resistance are sometimes referred to as ‘superbugs’. As a result, the medicines become ineffective and infections persist in the body, increasing the risk of spread to others (WHO, 2020).

Primary reference(s)

WHO, 2020. Antimicrobial resistance. World Health Organization (WHO). Accessed 27 September 2020.

Additional scientific description

Antimicrobial resistance occurs naturally over time, usually through genetic changes. However, the misuse and overuse of antimicrobials is accelerating this process. In many places, antibiotics are overused and misused in people and animals, and often given without professional oversight. Examples of misuse include when antibiotics are taken by people with viral infections like colds and flu, and when they are given as growth promoters in animals or used to prevent diseases in healthy animals (WHO, 2020).

Antimicrobial resistant organisms, sometimes referred to as ‘superbugs’, are found in people, animals, food, and the environment (in water, soil and air). They can spread between people and animals, including from food of animal origin, and from person to person. Poor infection control, inadequate sanitary conditions and inappropriate food-handling encourage the spread of antimicrobial resistance (WHO, 2020).

Present situation (WHO, 2020): Antimicrobial resistance is an increasingly serious threat to global public health that requires action across all government sectors and society. It threatens the effective prevention and treatment of an ever-increasing range of infections caused by bacteria, parasites, viruses and fungi. New resistance mechanisms are emerging and spreading globally, threatening our ability to treat common infectious diseases, resulting in prolonged illness, disability, and death. Without effective antibiotics, the success of major surgery and cancer chemotherapy would be compromised. The cost of health care for patients with resistant infections is higher than care for patients with non-resistant infections due to longer duration of illness, additional tests and use of more expensive drugs. Antimicrobial resistance endangers achievement of the Sustainable Development Goals (UNDESA, 2021).

Resistance in bacteria (WHO, 2020): Patients with infections caused by drug-resistant bacteria are at increased risk of worse clinical outcomes and death and consume more health-care resources than patients infected with non-resistant strains of the same bacteria. Resistance in E. coli to one of the most widely used medicines for the treatment of urinary tract infections (fluoroquinolone antibiotics) is very widespread. Treatment failure to the last resort of medicine for gonorrhoea has been confirmed in at least 10 countries (Australia, Austria, Canada, France, Japan, Norway, Slovenia, South Africa, Sweden, United Kingdom). Resistance to first-line drugs to treat infections caused by Staphylococcus aureus – a common cause of severe infections in health facilities and the community – is widespread. People with MRSA (methicillin-resistant Staphylococcus aureus) are estimated to be 64% more likely to die than people with a non-resistant form of the infection.

Resistance in tuberculosis (TB) (WHO, 2020): In 2016, an estimated 490,000 people developed multi-drug resistant TB (MDRTB), globally. MDR-TB is a form of tuberculosis that is resistant to the anti-TB drugs. It requires treatment courses that are much longer and less effective than those for non-resistant TB. Globally, only half of MDR-TB patients were successfully treated in 2014. Extensively drug-resistant tuberculosis (XDR-TB), a form of tuberculosis that is resistant to at least four of the core anti-TB drugs, has been identified in 105 countries. An estimated 9.7% of people with MDR-TB have XDR-TB.

Resistance in malaria (WHO, 2020): As of July 2016, resistance to the first-line treatment for P. falciparum malaria (artemisininbased combination therapies, also known as ACTs) has been confirmed in five countries of the Greater Mekong subregion (Cambodia, the Lao People’s Democratic Republic, Myanmar, Thailand, Viet Nam). The spread of resistant strains to other parts of the world could pose a major public health challenge and jeopardise important recent gains in malaria control. A WHO Strategy for Malaria Elimination in the Greater Mekong subregion (2015-2030) was endorsed by all five countries, as well as China (WHO, 2015).

Resistance in human immunodeficiency virus (HIV) (WHO, 2020): In 2010, an estimated 7% of people starting antiretroviral therapy in developing countries had drug-resistant HIV. In developed countries, the same figure was 10–20%. Some countries have recently reported levels at or above 15% among those starting HIV treatment, and up to 40% among people re-starting treatment. This requires urgent attention.

Resistance in influenza (WHO, 2020): Antiviral drugs are important for treatment of epidemic and pandemic influenza. So far, virtually all influenza A viruses circulating in humans are resistant to one category of antiviral drugs – M2 Inhibitors (amantadine and rimantadine). Antiviral susceptibility is constantly monitored through the WHO Global Influenza Surveillance and Response System (WHO, 2021).

Metrics and numeric limits

Not applicable.

Key relevant UN convention / multilateral treaty

International Health Regulations (2005), 3rd ed. (WHO, 2016).

Examples of drivers, outcomes and risk management

Need for coordinated action (WHO, 2020): Antimicrobial resistance is a complex problem that affects all of society and is driven by many interconnected factors. Single, isolated interventions have limited impact. Coordinated action is required to minimise the emergence and spread of antimicrobial resistance. All countries need national action plans on Antimicrobial resistance. Greater innovation and investment are required in research and development of new antimicrobial medicines, vaccines, and diagnostic tools.

WHO response (WHO, 2020): The World Health Organization (WHO) is providing technical assistance to help countries develop their national action plans and strengthen their health and surveillance systems so they can prevent and manage antimicrobial resistance. It is collaborating with partners to strengthen the evidence base and develop new responses to this global threat. The WHO is working closely with the Food and Agriculture Organization of the United Nations (FAO) and the World Organisation for Animal Health (OIE) in a ‘One Health’ approach to promote best practices to avoid the emergence and spread of antibiotic resistance, including optimal use of antibiotics in both humans and animals. A political declaration endorsed by Heads of State at the United Nations General Assembly in New York in September 2016 signalled the world’s commitment to taking a broad, coordinated approach to address the root causes of antimicrobial resistance across multiple sectors, especially human health, animal health and agriculture (UNGA, 2016). The WHO has been leading multiple initiatives to address antimicrobial resistance including the following: world Antimicrobial Awareness Week (18–24 November each year); global Antimicrobial Resistance Surveillance System (GLASS); global Antibiotic Research and Development Partnership (GARDP); and the interagency Coordination Group on Antimicrobial Resistance (IACG).