What is Antimicrobial Resistance?

Antimicrobial resistance, what is it?

Antimicrobial resistance, or simply AMR, is a formidable threat to global health, but healthcare professionals, veterinarians, policy-makers, and individuals can unite to preserve these lifesaving drugs.

What are Antimicrobials?

Antimicrobials are groups of medicines that are critical tools in the prevention and treatment of infections in humans, animals, and plants. These infections are caused by microorganisms, also known as microbes, which are single-cell organisms, or colonies of cells, like bacteria, fungi, viruses, and parasites.

Antimicrobial agents function by either destroying or inhibiting the growth of microbes and are typically classified according to which type of microbe is primarily targeted i.e. antibiotics are used against bacteria, antifungals are used against fungi, and so on. Antimicrobials are a cornerstone of modern medicine, as well as underpinning the functioning of societies, and many common healthcare, veterinarian and agricultural practices rely on their use.

What is Antimicrobial Resistance?

AMR is the ability of a microorganism to withstand the action of an antimicrobial agent. It is an evolutionary phenomenon that occurs when microbes are exposed to antimicrobials; certain cells can respond to this exposure by advantageously adapting through various means.

Microorganisms are some of the oldest known life forms and have been present on earth for 3.5 billion years – nothing stays around that long without learning how to survive external threats!

Not all resistant cells are created equal and there are different ways in which cells can develop resistance. 

Innate resistance is when the structure of the microbe naturally resists the drug, such as when the membrane of the cell becomes too large to be crossed.

Acquired resistance, however, is when only a specific resistance pattern is found in some populations of microbes.

Resistant cells can then share genetic information to sensitive cells, cells that antimicrobials are still effective against, so they can also develop resistance. This can happen through three different mechanisms:

  1.  Transformation, where DNA is exchanged without direct contact; 
  2.  Transduction, where a viral vector transmits resistance information;  
  3. Conjugation, where genetic information is exchanged through cell-to-cell contact.

Through these different sharing processes, sensitive cells can develop resistance even if they have never been directly exposed to any antimicrobial agents. A key takeaway is that microbes can develop resistance when exposed to antimicrobials – and not the individual humans, animals, or plants that consume these drugs, as commonly mistaken.

Although AMR is an evolutionary adaptation, the rate in which microbes develop resistance is accelerated through our extensive use of these medicines across human and animal sectors.

Why is AMR a threat to global health?

The era of antimicrobials has been paramount to the advancement of public health. The doubling of life expectancy in the latter half of the 20th century has been partly attributed to the rise of antimicrobials (Ventole, 2015). The efficacy and safety of modern medical advancements—like organ transplantation, hip replacement surgery, and cesarean section—all depend on antimicrobials to ward off the risk associate with pathogenic microbes (WHO, 2020).

People who are immunocompromised, such as patients undergoing treatment for cancer or HIV/AIDs, are also often prescribed antibiotics to prevent secondary infections from occurring (WHO, 2020). Across the medical sphere, antimicrobials form a fundamental component in the delivery of safe and effective healthcare interventions.

However, the impact of AMR is already taking shape, implicating the ability for many treatments to be carried out to the same degree of safety and efficacy. When looking at the numbers, the World Health Organization (2019) announced that at least 700,000 people die each year due to drug-resistant diseases. These are often referred to as ‘superbugs,’ such as multi-drug-resistant Tuberculosis (WHO, 2019).

If we do not shift the way in which we consume antimicrobials, annual deaths are projected to jump to 10 million by 2050 (WHO, 2019). In addition, the short- and long-term economic impact of AMR is projected to push 28.3 million people into extreme poverty by 2050 with countries from the global south most implicated (Ahmed and Khan, 2019).

superbug antimicrobial resistance drug-resistant disease infections

Antimicrobials are not only vital for the prevention and treatment of infectious diseases in humans, but also in our pets and farm animals alike, as well as managing the threat of zoonosis (Ma, et al. 2020). Zoonosis is the transfer of infectious diseases from non-human animals to humans. The recurring E. Coli outbreaks in the United States, for example, have infected 474 people, leading to 219 hospitalizations and a total of six deaths (FDA, 2020).

Investigators from the Food and Drug Administration (FDA) discovered that specific lettuce farms had been contaminated with a strain of E. Coli which could be traced back to cattle facilities (FAO, 2018; FDA, 2020). The bacteria were present in the irrigation systems, mud, manure, water and soil on and surrounding the feedlots which hold upwards of 100,000 cows (FDA, 2019). It is believed that the bacteria could have spread through any number of environmental vectors, such as leaking out from waste systems (i.e. fecal matter) to groundwater systems, subsequently contaminating lettuce fields that were in close by (FDA, 2020)

Antimicrobial-resistant bacteria have already been recorded in the waste management systems throughout multiple animal agricultural facilities (He, et al. 2020; Kirchhelle, 2018; Ma, et al. 2020). These drug-resistant pathogens pose the threat of novel and/or untreatable infectious diseases entering our food chain, either by leaking into the environment or through humans eating the animals directly. As experienced with the current COVID-19 pandemic, it does not take long for microbes to travel across the world and affect the stability of economies and the livelihoods of people far and wide.

Preserve Antimicrobials, Prevent Drug Resistance

AMR is a multi-sectoral issue and cannot be adequately addressed using a solutions framework that views problems, such as the aforementioned E. Coli outbreaks, in a singular dimension. The WHO (2017) has called for a One Health approach, whereby the designing and implementing of programmes, policies, legislation and research mobilizes professionals across sectors to work together to come up with solutions. 

The WHO’s 2015 Global Action Plan states that bridging the awareness and knowledge gap on AMR is one of the first steps that can be taken. That is one of the reasons why Flemingo is developing online courses to help stakeholders continue their education in the field of infectious diseases and infections medicine.

The combined future of human, animal, and planetary health rest on implementing medical, veterinary, and agricultural standards that safeguard antimicrobials.  Healthcare professionals, veterinarians, individuals, and policy-makers alike can have a huge impact on preserving these vital agents, ensuring that they are still effective in the years to come.