Analysis: it's a matter of huge concern to humans, animals and the environment, but what is antibiotic resistance all about?

By Sarah Delaney, Sinéad Murphy and Ciara Tyrrell, Maynooth University

Let’s start at the beginning

In 1928, Alexander Fleming accidentally discovered a mould that could kill bacteria. This mould was producing the now well-known antibiotic penicillin. Antibiotics are drugs which fight infections which are caused by bacteria. Penicillin was first prescribed to patients in the 1940s and was used to successfully treat bacterial infections in soldiers during the first World War.

But on the day he collected his Nobel Prize, Fleming warned that overuse of antibiotics could lead to antibiotic resistance and their subsequent ineffectiveness. Bacteria are really clever and want to survive. If they are constantly exposed to low doses of antibiotics they can change parts of themselves to fight off the antibiotic. Sure enough, by the 1950s, resistance to penicillin had become a huge problem. In response to this, more advanced antibiotics were discovered and developed. However, regardless of this, resistance to these antibiotics still emerged.

A RTÉ Brainstorm video on this article

How this happens

A common mistake people make that leads to antibiotic resistance is not finishing the full course of antibiotics. If you don’t complete the treatment, even if you feel better after a few days, only the bacteria sensitive to the antibiotic will be killed. This then allows the stronger resistant bacteria to grow and multiply. This is also why you shouldn’t keep antibiotics for future use. Different types of antibiotics treat different types of bacterial infections, so it’s also a bad idea to share antibiotics with other people.

Antibiotics are only effective against bacterial infections. If you have a sore throat which is being caused by a virus, for example, antibiotics will not kill the virus and won’t make you feel any better. If you take antibiotics when they aren’t needed, you can also end up killing the "good" bacteria which lives in your gut. This then allows the resistant bacteria to grow and take over, which can be very harmful.

From RTÉ Radio 1's Morning Ireland, Dr John Stephens from Maynooth University on new research which may lead to the development of antibiotics to combat superbugs such as MRSA

Increasing rates of antibiotic resistance means decreasing availability of antibiotics to treat infections. The amount of new antibiotics being discovered has slowed drastically due to reduced economic incentives and strict regulations for pharmaceutical companies. This has, and will, continue to have dire consequences for organ transplants, surgeries, hospital infections and more.

Antibiotics and animals

It’s not just overuse and misuse in human medicine that has caused the problem of antibiotic resistance. The same antibiotics, or very similar antibiotics to those used in human medicine, are used in agriculture. This could be to treat sick animals but, they are also used in some countries to prevent the animals getting sick in the first place or to help them to grow bigger. Just like in humans, this same exposure to antibiotics in animals can result in bacteria developing resistance to antibiotics and this resistance can possibly spread to humans through the food chain.

From RTÉ Radio 1's Countrywide, Ella McSweeney reports on hiw what happens on the farm matters when it comes to antibiotic resistance

Antibiotics and food

If you consume undercooked meat carrying antibiotic resistant bacteria, it could give you food poisoning and make you very sick. And because the infection is caused by resistant bacteria, the antibiotics prescribed by the doctor might not work. The resistance could also transfer to the "good" bacteria living in our gut and possibly reduce the success of future antibiotic treatment. Therefore, it is important that meat is cooked thoroughly.

And it’s not only undercooked meat we need to be concerned about. Food which we eat raw, such as lettuce, can also carry antibiotic resistant bacteria. So how does it get there? The spreading of manure is an important process, as it recycles the vast quantities of manure produced by agricultural animals into organic fertiliser that introduces important nutrients into agricultural land. However, due to the amounts of antibiotics used in animals, the manure that they produce can introduce antibiotic resistant bacteria into the environment. This manure can also runoff into water systems. As a result, antibiotic resistant bacteria can end up on our vegetables through contaminated irrigation water.  

From RTÉ Radio 1's Mooney Goes Wild, UCD lecturer in wildlife conservation Barry McMahon on the consequences of sophisticated antibiotics for wildlife and nature

The future

Some types of bacteria have become resistant to nearly all types of antibiotics. Resistance has even developed to last-resort antibiotics, the only remaining treatment option for some infections. If this continues, it is estimated that antibiotic resistant infections will kill more people than cancer by 2050.

So what can be done to prevent this from happening? By reducing the amount of antibiotics which we currently use, in both human medicine and agricultural practices. It is imperative that people are made aware that antibiotics can’t be used to treat viral infections, such as colds and flus. This can be done through antibiotic stewardship, a program in which antibiotics are only used when needed, and the antibiotic is administered at the appropriate dose and duration in every case. Without action, it is very possible that we will run out of antibiotics to treat even a sore throat, making the simplest of infections these days deadly in the future.

Sarah Delaney is a PhD student with the Antimicrobial Resistance and Microbiome Research Group at the Department of Biology at Maynooth University. Dr Sinéad Murphy is a postdoctoral researcher with the Antimicrobial Resistance and Microbiome Research Group at the Department of Biology at Maynooth University. Ciara Tyrrell is a PhD student with the Antimicrobial Resistance and Microbiome Research Group at the Department of Biology Maynooth University and with Teagasc


The views expressed here are those of the author and do not represent or reflect the views of RTÉ