What is antibiotic resistance and what can we do to prevent it?

Safiya Zaloum

What are antibiotics?

Antibiotics are drugs that kill bacteria. The bacteria that they are designed to kill cause illness in humans, as many bacteria live in humans and are harmless and can even be helpful, for example, those that live in your gut and help to digest your food! Bacteria aren’t the only microorganisms that cause disease in humans but antibiotics can only be used against bacteria.

Bacteria can cause a human to become ill in a number of different ways. Once inside the body, bacteria can multiply so much that they can disrupt the normal functions of human cells, or they can release a harmful substance called a toxin to make us feel unwell. Some can also kill human cells, meaning we cannot function as we normally do and this makes us feel ill.

Most humans fight off these infections as their immune system can recognise the bacteria and use special immune cells to kill the bacteria. Sometimes, us humans need a little help to kill off the bacteria which are making us feel ill. If our immune cells cannot fight off the bacteria or if we are seriously unwell, we might need antibiotics. 

Antibiotics work by attacking weakness in bacteria that aren’t present in human cells. It is important that antibiotics don’t destroy human cells as well as the bacteria, as this could make you feel even more unwell. For example, penicillin – a common antibiotic, works by preventing the bacteria from forming new cell wall. The cell wall of the bacteria needs to be constantly remade throughout the lifetime of a bacteria, and human cells do not have a cell wall, making this an ideal target for antibiotics.

What is antibiotic resistance?

Antibiotic resistance is when bacteria are no longer killed by antibiotics. It is the bacteria, not humans, that become resistant. 

Bacteria can have genes for resistance to certain antibiotics in their DNA. DNA is the instructions which tell the bacteria how to build all of its parts and what to do. A gene is like a chapter in the instructions booklet, telling you how to make a specific part of your object and in bacteria, sometimes one or more of these genes can tell the bacteria how to be resistant to a certain antibiotic. Many bacteria have plasmids, which are small loops of DNA containing just some of their genes. These can be exchanged between bacteria, meaning instructions for how to become resistant to antibiotics can be shared between bacteria.

There are many different ways that bacteria can be resistant to antibiotics. These are some of those ways:

• Restrict the access of the antibiotic by blocking the ways that antibiotics enter the bacteria
• Get rid of the antibiotics by making pumps that can pump the antibiotic outside of the bacteria
• Destroy the antibiotic so that it cannot kill the bacteria
• Change the target of the antibiotic so that it cannot work against the bacteria. If the antibiotic usually fits onto a specific receptor, like 2 puzzle pieces joining together, the bacteria can change the shape of its receptor so the antibiotic no longer fits and cannot kill the bacteria.

Antibiotic resistance occurs naturally, however misuse of antibiotics in humans and other animals is accelerating this process. The more bacteria are exposed to antibiotics, the more likely they are to develop resistance. 

Many infections caused by bacteria, such as pneumonia and tuberculosis, are now becoming harder to treat due to antibiotic resistance. There has recently been the emergence of so-called “superbugs” such as MRSA, which are resistant to many different types of antibiotics, making them very difficult to treat and sometimes these are infections that the patient has to live with. Levels of antibiotic resistance are rising around the world and this is meaning longer hospital stays for many patients and infections that were once easy to get rid of are becoming very difficult to treat.

How can we prevent antibiotic resistance?

Tightening rules on who can access antibiotics will help to stop overuse. Overusing antibiotics when they are not needed increases the exposure bacteria have to antibiotics and allows them to develop resistance mechanisms. Having stricter rules on who can be given antibiotics and ensuring that in all countries a prescription from a doctor is needed in order to get antibiotics will limit how often they are used, so that only those who truly need them get them. 

You can help by not asking for antibiotics if your doctor says you don’t need them, and educating yourself and others on when antibiotics are necessary. Most coughs and colds are caused by viruses, so you won’t need antibiotics as these only work against bacteria. It is important you take your antibiotics exactly how your doctor tells you to. Don’t stop taking them as soon as you feel better – take the whole course as this ensures no bacteria is left behind to potentially become resistant.

Reducing the spread of infection in the first place will help to reduce the need for antibiotics. Vaccinations teach your body to recognise antigens (proteins on the surface of pathogens) from a bacterium or virus, so that if you get infected, your immune system can fight it off before you feel unwell. Washing your hands regularly and covering your nose and mouth with a tissue then throwing it away when you cough or sneeze prevents the spread of infection.

Scientists are working to develop new antibiotics, however, the rate of discovery is slow. This is why it is so important that we work together to slow the spread of antibiotic resistance and only use antibiotics when they are really needed. Many common medical procedures including lots of surgeries will become much more dangerous if patients cannot receive antibiotics to treat and prevent infections.