Bacteria and viruses are very different types of organisms, and accordingly, bacterial and viral infections are handled differently by the human body and are treated differently by medication. This difference matters not only because you will want to know how to get better when you or someone you love gets sick but also because of the public health issues that arise when the infections are handled incorrectly.
Bacteria are single-celled organisms that can invade and grow within the human body. In general, our bodies mount an immune response to the bacteria; however, this immune response is usually not strong enough to kill off the infection. To cure bacterial infection, antibiotics are needed to kill the bacteria within the host body.
Bacterial infections can be treated with antibiotics because antibiotics kill bacteria.
In contrast, the body’s immune response generally can kill a viral infection. In addition, antibiotics kill only bacteria; they cannot kill viruses. Therefore, because things like the flu and colds are caused by viruses, antibiotics have no effect on them.
Using antibiotics for a viral infection has no benefit but can create problems.
Because it is not always possible to determine whether an infection (e.g., sinus infection) is caused by a virus or bacteria) and because some patients think they need to receive some sort of treatment to feel better, antibiotics have been overused and misused by doctors. Antibiotics will not have any effect on viral infections. Many think that it can’t hurt to take the antibiotics even if they aren’t do anything, however, this is not the case. As bacteria replicate their DNA, just like when DNA replicates within human cells, small changes in the DNA can occur. Some of these changes can make the bacteria resistant to antibiotics. Normally, those bacteria with that changed DNA would not be common because all the other bacteria without the changed DNA are so prevalent.
However, if antibiotics are given often, these conditions are selecting for the bacteria with a change in the DNA that makes them resistant.
All the original bacteria without the change will die. Because of this, taking antibiotics increases the chances of selecting for strains of DNA that are resistant to the antibiotic. If these strains then infect someone, treating the infection with that kind of antibiotics will not work. Infectious bacteria are everywhere. If we cannot kill infectious bacteria with antibiotics, society cannot fight these bacteria, and people will start getting sick and dying.
Check out this video to see antibiotic resistance in action.
This is what is happening right now and what the National Institutes of Health have declared a critical topic for public health. One example is methicillin-resistant Staphylococcus aureus (MRSA). Staphylococcus aureus (or “staph”) infections are usually easily treated with antibiotics, but with the introduction of MRSA, people can now get a staph infection that is difficult to treat because it is resistant to some kinds of antibiotics. If a treatment regimen cannot be found, the infected person could die.
This is also why adding antibiotics (e.g., triclosan) to soaps and toothpastes is a problem. Soaps do not work by killing bacteria; they surround dirt and bacteria to lift them off of a surface (e.g., your skin) so that they can be washed away.
Adding antibiotics to soaps does not increase their efficacy, but adding antibiotics to products increases the chances of developing antibiotic resistant bacteria. There is no benefit to balance this risk.
Companies have taken advantage of the fact that people do not understand how soaps work and will preferentially buy antibacterial soaps. This will increase the companies’ profits, not benefit the consumers, and potentially harm the environment.
Understanding the science of bacteria and viruses empowers you to make informed decisions about these issues. If you understand the dangers of antibiotic resistance and the difference between bacterial and viral infections, you can proactively choose when to use antibiotics and think carefully about the products you are buying and using.