What are the principles of antimicrobial resistance?

The chance discovery of the antibiotic penicillin by British bacteriologist Dr. Alexander Fleming in 1928 is recognised as one of the the true turning points in global medical history.

But while the development of antimicrobial agents has revolutionised our understanding of the treatment of infections and infectious diseases, the growing rate of antimicrobial resistance (AMR) represents a significant threat to public health.

Antimicrobial resistance refers to an organism’s ability to grow in the presence of a chemical or drug that would normally kill it or inhibit its growth.

The first signs of antimicrobial resistance were identified in the 1950s, just a decade after the initial mass production of penicillin, when strains of Staphylococcus aureus were found to have developed resistance to penicillin. And in 1963, the first case of Meticillin-resistant Staphyococcus aureus (or what we now commonly know as MRSA) was reported.

Over the past fifty years the global medical community has continued to see an even greater number of microorganisms that have developed resistance to antimicrobial agents.

In some cases this resistance in inherent, which means it is part of the organism’s genetic makeup.

In other cases, the resistance is acquired or occurs naturally over time, whether as the result of a genetic mutation or a genetic recombination.

So what do we know about the reasons for the development and spread of antimicrobial resistance?

The overuse and misuse of antibiotics

A significant factor is the way in which antibiotics have been overused or misused, both in people and in animals.

This can be due to indiscriminate prescribing or the increase in over-the-counter availability of antibiotics in some countries.

There is the prescription of antibiotics where a genuine need hasn’t been indicated or where they have been used as a prophylactic or preventative measure for longer than recommended.

An inadequate dose of antibiotics or an insufficient period of antibiotic treatment can mean that an infection isn’t able to fully resolve.

The veterinary use of antibiotics in animals that have been bred for human consumption can also raise the risk of resistant bacteria being transferred to humans via the food chain.

The healthcare environment

Antimicrobial resistance can also be influenced by factors in the hospital environment or healthcare setting.

Higher bed occupancy rates, or increased patient to staff ratios are both factors that can increase the risk of cross-infection.

Human activity can contaminate the environment with antimicrobials, which in turn can accelerate the rate of antimicrobial resistance.

Environmental contamination can occur in a variety of ways – where there is an inadequate sanitation infrastructure or insufficient sanitation strategies, or where resistant microbes are able to persist and grow within plumbing systems such as sink drains.

The breakdown of infection prevention and control practices such as hand hygiene or environmental decontamination can also create a threat.

And then there are factors related to the patients themselves – whether it’s the common expectation that antibiotics will be freely prescribed, the intense or long-term exposure to broad spectrum antibiotics, or our propensity to travel to countries where there are higher rates of resistant organisms.

Government action to combat antimicrobial resistance

In 2013, the UK Department of Health (DH) together with the Department for Environment, Food and Rural Affairs (DEFRA) formulated a five-year antimicrobial resistance strategy that targeted seven key areas:

1. The improvement of infection prevention and control practices at both a national and international level
2. The optimising of prescribing practices to ensure the use of the right drug at the right time and for the correct duration
3. The improvement of professional education, training and public engagement to dispel some of the myths around the expectations and effectiveness of antibiotics
4. The development of new diagnostics, treatments and drugs to help differentiate between viral and bacterial conditions and to enable faster identification of drug-resistant strains
5. The provision of better access to surveillance data at local, regional and national level to facilitate understanding of emerging issues in human and animal health
6. Improved identification and increased prioritisation of antimicrobial resistance
7. A greater level of international cooperation to combat the problem

Animal health and welfare

Responsible use of antibiotics in livestock is another important piece of the puzzle in tackling antimicrobial resistance.

In November 2018, the UK Government announced the establishment of an International Reference Centre for Antimicrobial Resistance. Working with vets and farmers, the aim is to reduce the use of antibiotics in animals by 25% by 2020.

Antimicrobial resistance is a complex global problem that affects not only human health but also animal health, welfare and security.

Coordinated action plans, greater innovation and investment will all continue to be key pieces of the puzzle in the development of new antimicrobial medicines, vaccines and diagnostic tools.