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Medical School Hot Topic: Antimicrobial Resistance
Antimicrobial resistance is dubbed a global health and development threat by the World Health Organisation - in fact one of the top 10 global public health threats facing humankind. It is driven by the overuse or misuse of antimicrobials, permitting the development of drug-resistant pathogens. This in turn is exacerbated by poor infection control or unsafe water supplies, allowing the propagation of resistant microbes. Over time the financial burden of antimicrobial resistance will only increase as new and expensive medicines must be developed, trialled and purchased, hospital stays increased or novel therapies attempted, and those that become ill finding themselves out of work. We must therefore ensure that we continue to have a supply of antimicrobial drugs that function well - which requires taking action against resistance. An antimicrobial drug is any that prevents infection, be it against viruses, parasites, funguses or (most typically bacteria.
Defining AMR & Acting Against It
AMR (antimicrobial resistance) is due to the change and mutation of microbes over time, resulting in their becoming unresponsive to the medicines used to treat them - and in turn the diseases that they cause becoming far more serious to those afflicted by them. As drug resistant pathogens acquire novel mechanisms of resistance, we should consider in particular the rise of so-called ‘superbugs’ - bacteria that are ‘pan-resistant,’ meaning they cannot be treated with existing antimicrobials.
Antimicrobial resistance will develop naturally given time, as the genetics of the microbes change. Antimicrobial resistant organisms will be found in you, in the food that you eat, and in the earth that you walk on. They may be zoonotic (spreading from animal to person), spread from person to person, or come from food.
To look more specifically at what causes antimicrobial resistance, we should consider the use of prophylactic antibiotics (in both the medical profession and indeed in the veterinary profession as well), lack of access to clean water specifically in third world countries, and farms that fail to offer sufficient mechanisms of disease prevention and control, allowing microbes to spread with ease throughout their stock and in turn enter the food chain, infecting people - or passing directly from stock to farmer. We should also consider the role of legislation and enforcement - perhaps governments are too lax currently to crack down effectively on the overuse of antimicrobials and the underuse of procedures that slow and prevent infection. Lastly, awareness of the issue should be emphasised through public health campaigns, and education of the population from an early age.
Some of the most common bacterial infections - urinary tract infections, sepsis, STIs, and diarrhoea exhibit high rates of resistance against the antibiotics most commonly used to treat them - across the planet.
We should also be aware of the concept of antiviral resistance in particular as well as antibiotic resistance - for immunocompromised patients (e.g. those undergoing chemotherapy) antiviral therapies used over a long period of time in conjunction with viral replication combine efficiently to produce antiretroviral resistant strains of these viruses.
There are few new antimicrobial drugs in production. There are around 30 new antibiotics in clinical development addressing the most pressing list of pathogens, although only a handful of these have been labelled as truly innovative. We must also consider that for many across the world obtaining access to antimicrobials - any antimicrobials, let alone new and innovative ones suitable for resistant microbes - meaning that strategies need to be developed not just for the careful use of antimicrobials in developed countries, but accessibility to the correct new ones in less developed countries as well.
We must change the way in which antibiotics are used - otherwise even newly developed ones will over time become as inefficient as those that have already become so. How can we do this? We need more effective processes for the prevention of drug-resistant infections, and much improved access to new antimicrobials - otherwise many medical therapies that rely on antimicrobials (not just those suffering from infectious disease) will become more risky - think of having a knee operation or caesarean, without the safety net of prophylactic antibiotics.
Example Interview Questions
● What is antimicrobial resistance?
● How does antimicrobial resistance develop?
● What classes of drugs might be considered antimicrobial?
● How can we prevent antimicrobial resistance developing?
● Where in the world might AMR be a particular problem?
Interview Questions & Example Answers
What is antimicrobial resistance?
Antimicrobial resistance - known as AMR - is the change of microorganisms (bacteria, viruses, fungi, and parasites) in ways that will render the medications normally used to act against them ineffective. Microbes will change and evolve naturally over time - if these changes make them impervious to medication then the diseases that they cause will in turn become far more serious.
Antimicrobial resistance gives rise to ‘superbugs’ - pan-resistant microbes that cannot be treated with existing drugs.
How does antimicrobial resistance develop?
Antimicrobial resistance develops naturally, as microbes evolve, and their genetics change. Therefore, antimicrobial resistant organisms can be found anywhere - on you, on your food, on animals around you. However, humans’ use of antibiotics and antimicrobials has often led to the acceleration of the process, with prophylactic antibiotics used in both Medicine and Veterinary Medicine being thought to be particularly to blame - as exposure to antibiotics will in turn lead to the survival of resistant strains, and their subsequent dominance vs other microbes of the same strain. Additionally, lack of adherence to antibiotic regimens can cause AMR, as the drug is not taken properly until the end of its course, allowing certain more resistant bacteria to survive and grow in number. Antiviral resistance develops easily in context of antiviral therapies being used for an extended period of time and fast and inaccurate viral replication allowing the virus to evolve and change quickly.
What classes of drugs might be considered antimicrobial?
An antimicrobial is any agent that kills, or prevents the growth of, microorganisms. Antibiotics are used against bacteria, antivirals against viruses, and antifungals against fungi. An agent that kills microbes is a microbicide, or a bactericidal agent if used on bacteria specifically, whilst one that inhibits growth only is labelled a bacteriostatic agent.
Disinfectants - like bleach - kill a range of microbes and are used on non-living surfaces. Antiseptics are used on living tissue to reduce infection risk. Antibiotics are used to destroy microorganisms within the body itself. Antibiotics is a term that is now given to both antibacterial drugs and antimicrobial drugs in general (i.e. an antibiotic doesn’t just act on bacteria, it can also be a term given for an antifungal drug).
How can we prevent antimicrobial resistance developing?
We must consider the use of prophylactic antibiotics in Medicine and Veterinary Medicine. We should consider whether governments ought to do more to act against AMR, through preventing the overuse of antimicrobials. We should ensure that public health campaigns illustrate the potential danger of the issue, to increase compliance when using antibiotics and ensure that courses are finished. We should develop new antimicrobial drugs and ensure that these are used correctly in the future - and improve access to them for those that need them most.
Basic measures like immunisations, hand washing and safe food preparation, the correct use of personal protective equipment, or practising safe sex will all act to reduce the incidence of infection, and in turn reduce the amount of antibiotics that are used, and the number of microbes that come into contact with these antibiotics - and that may therefore develop resistance.
Where in the world might AMR be a particular problem?
AMR is an issue across the world. Many infections are becoming harder to treat globally. Whilst certain countries might not have standard treatment guidelines for the use of antibiotics, or for their prophylactic use in the veterinary profession, the result of this - an antimicrobial resistant strain - will often be felt across a wide area. Pneumonia, TB, gonorrhoea and some foodborne diseases are all becoming much harder to treat worldwide. We should therefore be aware of AMR as a global issue, rather than one which affects certain countries. As the WHO says, ‘without urgent action, we are heading for a post-antibiotic era, in which common infections and minor injuries can once again kill.’