Ugh. Your nose feels stopped up. You are coughing
and sneezing. You swear the top of your head is going to pop off, if you
sneeze one more time. Sounds like all the symptoms of a sinus infection.
You finally cannot take it anymore, so off to the doctor you go to get
some medicine. For a sinus infection, most likely you would be
prescribed antibiotics. So what are these wonderful medicines and how do
Bacteria are tiny single celled organisms. Most
bacteria do not cause illness, but some can. If an illness-causing
bacteria does get past your immune system and start reproducing, it can
cause an illness. We want to kill these bacteria to eliminate the
disease. Essentially, antibiotics are selective poisons used to kill
Certain bacteria produce chemicals that damage or
disable parts of our bodies. In a sinus infection, for example, bacteria
have gotten into the sinuses. The body works hard to fight off the
bacteria, which cause inflammation. The inflammation in your sinuses is
what makes it feel like your head could pop off. The antibiotic kills
the bacteria, which reduces the inflammation, and then you feel better.
Antibiotics work by either killing the bacteria
completely, called bactericidal, or by disrupting the membrane of
bacterial cells, called bacteriostatic. Antibiotics can also inhibit
bacterial growth by keeping bacterial cells from making proteins and
acids that they need for survival and reproduction. The overall goal of
the antibiotic, which can be made from naturally occurring fungi or
chemical compounds, is to harm bacterial cells without harming human
In order to understand how antibiotics work, we
need to explore the structure of bacterial cells. Bacterial cells differ
significantly from most plant and animal cells. Proteins and
cells are targeted using antibiotics and only select bacteria for
In medicine, verifying that a person has a
bacterial infection prior to prescribing antibiotics is very important.
Antibiotics only work on bacteria. They do not work on viruses, because
a virus is not alive. A bacterium is a living, reproducing organism. A
virus is essentially just a piece of genetic material. It injects its
genetic material into a living cell, and then the infected cell
reproduces more infected cells. With a virus, there is nothing to kill,
so antibiotics do not work on them.
If you have been prescribed a course of
antibiotics, finish the entire course--even if you feel better. When you
do not finish the entire course, there may still be some bacteria that
have survived, but are too low in numbers to cause symptoms. These
remaining bacteria are the “fittest,” having survived this long. If you
stop the antibiotics early, these “fit” bacteria are able to reproduce.
This can cause antibiotic resistant bacteria, which require more
specialized antibiotics that are more harmful to human cells.