Antimicrobial resistance
Introduction
Antimicrobial resistance (AMR) is a global health concern that threatens the effective prevention and treatment of an ever-increasing range of infections caused by bacteria, parasites, viruses and fungi. It occurs when microorganisms change in ways that render the medications used to cure the infections they cause ineffective. When the microorganisms become resistant to most antimicrobials they are often referred to as "superbugs". This is a significant concern because a resistant infection may kill, can spread to others, and imposes huge costs to individuals and society.
Mechanisms of Antimicrobial Resistance
The mechanisms of antimicrobial resistance are complex and varied. They can be broadly classified into three groups: natural resistance, acquired resistance, and clinical resistance.
Natural Resistance
Natural resistance is an inherent ability of an organism to resist the effects of an antimicrobial agent through its inherent structural or functional characteristics. This type of resistance is generally predictable and is a standard consideration in the choice of antimicrobials in the treatment of infectious diseases.
Acquired Resistance
Acquired resistance refers to resistance that is gained through mutation or receipt of resistance genes. This can occur through one of three mechanisms: mutation, gene transfer, or acquisition of a resistance plasmid.
Mutation
Mutation is a change in the DNA sequence of a cell's genome. When it occurs in the germ line cells, the change can be passed on to future generations. In bacteria, mutations are the primary means of resistance to antimicrobial agents.
Gene Transfer
Gene transfer is the process by which bacteria can acquire genes from other bacteria in a number of ways. This can occur through conjugation, transformation, or transduction.
Acquisition of a Resistance Plasmid
Plasmids are small, circular pieces of DNA that are separate from the chromosomal DNA. They can replicate independently and can be transferred from one bacterium to another. Some plasmids carry genes that confer resistance to antimicrobial agents.
Clinical Resistance
Clinical resistance is resistance that is evident in the clinical setting but not necessarily in the laboratory. This can occur when an organism is resistant in vivo (in the body) but not in vitro (in the lab). This is often due to the fact that the conditions in the body are much more complex and variable than those in the lab.
Factors Contributing to Antimicrobial Resistance
There are several factors that contribute to the development and spread of antimicrobial resistance. These include misuse and overuse of antimicrobials, lack of infection prevention and control, lack of robust surveillance systems, and poor quality medicines.
Misuse and Overuse of Antimicrobials
The misuse and overuse of antimicrobials are key factors in the development of antimicrobial resistance. This can occur in healthcare settings, in the community, and in agriculture.
Healthcare Settings
In healthcare settings, antimicrobials are often overused. This can be due to a lack of rapid diagnostic tests, fear of failure to treat a potentially serious infection, or pressure from patients to receive antibiotics.
Community
In the community, antimicrobials are often misused. This can be due to self-medication, use of leftover prescriptions, or use of antimicrobials for non-bacterial infections.
Agriculture
In agriculture, antimicrobials are often used inappropriately to promote growth and prevent disease in healthy animals.
Lack of Infection Prevention and Control
Lack of infection prevention and control measures can contribute to the spread of antimicrobial resistance. This can occur in healthcare settings, in the community, and in agriculture.
Healthcare Settings
In healthcare settings, lack of infection prevention and control measures can lead to the spread of resistant organisms. This can be due to poor hygiene, inadequate sterilization of medical equipment, or inadequate isolation of patients.
Community
In the community, lack of infection prevention and control measures can lead to the spread of resistant organisms. This can be due to poor hygiene or inadequate sanitation.
Agriculture
In agriculture, lack of infection prevention and control measures can lead to the spread of resistant organisms. This can be due to poor animal husbandry or inadequate veterinary oversight.
Lack of Robust Surveillance Systems
Lack of robust surveillance systems can contribute to the spread of antimicrobial resistance. This can occur when there is inadequate monitoring of antimicrobial resistance and use, or when there is a lack of coordinated action.
Poor Quality Medicines
Poor quality medicines can contribute to the development of antimicrobial resistance. This can occur when medicines are of poor quality, are counterfeit, or are not stored or transported properly.
Impact of Antimicrobial Resistance
The impact of antimicrobial resistance is significant and wide-ranging. It threatens the effective treatment of an ever-increasing range of infections, increases healthcare costs, threatens food production and security, and undermines many of the advances in healthcare.
Threat to Effective Treatment
Antimicrobial resistance threatens the effective treatment of an ever-increasing range of infections. When infections become resistant to first-line antimicrobials, more expensive therapies must be used. The longer duration of illness and treatment, often in hospitals, increases healthcare costs.
Increased Healthcare Costs
The cost of healthcare for patients with resistant infections is higher than for patients with non-resistant infections due to longer duration of illness, additional tests and use of more expensive drugs.
Threat to Food Production and Security
Antimicrobial resistance threatens food production and security. The use of antimicrobials in agriculture, especially in food-producing animals, is a major driver of resistance. Resistant organisms can be transmitted to humans through the food chain, posing a serious threat to food security.
Undermining Advances in Healthcare
Antimicrobial resistance undermines many of the advances in healthcare. Many of the advances in medical treatment – such as organ transplantation, cancer chemotherapy, diabetes management and major surgery – are dependent on the ability to treat infections. If that ability is lost, the ability to safely offer these treatments is also lost.
Strategies to Combat Antimicrobial Resistance
There are several strategies to combat antimicrobial resistance. These include improving the use of antimicrobials, developing new drugs and diagnostic tests, improving infection prevention and control, and strengthening surveillance systems.
Improving the Use of Antimicrobials
Improving the use of antimicrobials is a key strategy in combating antimicrobial resistance. This can be achieved through stewardship programs that promote the appropriate use of antimicrobials.
Developing New Drugs and Diagnostic Tests
The development of new drugs and diagnostic tests is crucial in the fight against antimicrobial resistance. New drugs are needed to treat resistant infections, and new diagnostic tests are needed to rapidly identify infections and to determine their resistance profiles.
Improving Infection Prevention and Control
Improving infection prevention and control is a key strategy in combating antimicrobial resistance. This can be achieved through the implementation of basic hygiene practices, the use of vaccines, and the isolation of patients with resistant infections.
Strengthening Surveillance Systems
Strengthening surveillance systems is a key strategy in combating antimicrobial resistance. Robust surveillance systems are needed to monitor the spread of resistant infections and to guide the use of antimicrobials.
Conclusion
Antimicrobial resistance is a global health concern that requires a coordinated, multifaceted approach to address. It threatens the effective treatment of an ever-increasing range of infections, increases healthcare costs, threatens food production and security, and undermines many of the advances in healthcare. Strategies to combat antimicrobial resistance include improving the use of antimicrobials, developing new drugs and diagnostic tests, improving infection prevention and control, and strengthening surveillance systems.
