Can I get an antibiotic? – Virus v. Bacteria and Their Treatment

Flu season is coming up! As a reminder, lets think about the reasons behind antibiotics, and why they are only used for certain cases.

Before we dive into antibiotics and their requirements, let’s think about the different types of infections we see- viral and bacterial. These infections are caused by two very different types of organisms, and the way to combat symptoms is dependent on the type of infection present. To understand why medications only work for certain infections, you first need to understand the differences between bacteria and viruses.


Bacteria are small, single-celled organisms that are surprisingly present in our everyday life. In our intestines, we have our own bacteria culture that helps us break down food during digestion so we can receive the nutrients we consume. However, bacteria can also be infective, causing common illnesses like strep throat or urinary tract infections.

When we look to treat a bacterial infection, the simple solution is an antibiotic. Antibiotics work to fight bacteria in our bodies either by killing them or stopping their growth and reproduction. One component of bacteria is the cell wall that surrounds the bacteria and protects the cell from the environment. Antibiotics can break through this cell wall, killing the bacteria, or may enter the bacteria through this wall and stop protein production within the cell. If protein production is halted, the cell can no longer grow and reproduce, ultimately leading to the end of an infection.


Viruses are smaller organisms than bacteria, but the big difference is that they require a host to survive. This means that once in your body, a virus invades cells and uses your own cells to reproduce itself. A virus cannot survive on its own without a host cell, as the virus itself lacks many components of a cell, such as the cell wall we see in bacteria. Most commonly, we see viral infections like the common cold, the flu, or COVID-19.

Since viruses lack the main structural components of a cell, antibiotics have nothing to act on to kill a virus. Remember that antibiotics commonly target protein production or the bacterial cell wall, but these features are not present in a virus due to the nature of their infection. Because of this, we treat viral infections in other ways, such as an antiviral drug or using medications that reduce symptoms. Generally, we are forced to let our immune system fight the virus off ourselves, which is why taking precautions for these infections can be super important for those with weaker immune systems. This includes getting your annual flu shot or wearing masks in the case of COVID-19. Since fighting this infection is left solely to your immune system, its best to help build it in any way possible- like giving it a weak version of an infection to build antibodies from a vaccine.


Now back to antibiotics-

So as long as you take your antibiotic, you’re all good? No! This brings us to the idea of antibiotic resistance, where some bacteria we encounter are unaffected by antibiotics. For bacteria resistant to common antibiotics, this means that they can’t be controlled by an antibiotic and this form of treatment is ineffective. For most bacteria, an antibiotic will stop the infection by killing off the bacteria invading your body. Remember we said this could happen by destroying the cell wall- well, what would happen if the next bacteria had an even stronger, thicker cell wall? The antibiotic may not be able to break through, thus leading to an antibiotically resistant bacteria.

Well, how can we limit antibiotic resistance? Simply by taking antibiotics properly! This means not taking them when they are not needed, which may be in the case of a viral infection, or by taking them for too short/long of a period, or if you happen to take your leftover antibiotic but don’t have enough for a full dose. Long story short- take your antibiotic as your physician prescribes you!

this blog post was guest-written by Alexa Geist, a Clemson University 2022 Graduate with a BS in Chemistry and a minor in Mathematical Sciences and the new Medical Office Assistant at Cardona Direct Primary Care

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