Antibiotics

All over the world, people will resort to antibiotics whenever they have a bacterial infection, rather than letting their immune system deal with the bacteria. This has been made easy as antibiotics can literally be sold to anyone over the counter in thousands of stores across the world, without any prescriptions or doctors notes needed. Antibiotics work by many ways, one way is by dissolving the cell membrane of a bacterium, causing it to deteriorate and basically die as nothing will be there to contain it's genetic information. Another way is by stopping a bacterium’s cell wall from building, and without a cell wall the inside pressure of the bacterium will become too much causing it to burst. [1] Sadly, the helpful bacteria within our bodies will also be affected by antibiotics, which is why its not good to have antibiotics on a regular basis, to allow time for the recuperation of the 'good' bacteria.

DNA Replication- gene mutations

When bacteria replicates, just like any other animal cell, there are many bases in just one strand of DNA, which all need to be copied perfectly to make an identical bacterium (or two identical daughter cells). This process is called binary fission, as bacteria do not need to sexually reproduce to make another bacterium[2]. This complicated process of DNA replication is bound to have errors made in it as there are so many bases that some could be replaced by another, and bases can even be deleted, causing something called a frameshift, which will cause a lot of problems when it comes to protein synthesis as different proteins could be made, which are unwanted, but they also could be advantageous[3]. These ‘errors’ are called gene mutations, and gene mutations will happen to every organism within its life span, including us humans, but most of the time gene mutations will do little to nothing.

Evolution and Natural Selection

Gene mutations are the cause for evolution and becoming ‘better’ at survival within a certain environment. Evolution happens when a gene mutation gives an organism a better characteristic necessary for survival, which can then lead to them surviving for longer periods and reproducing, passing on this advantageous characteristic to their offspring, until overtime natural selection happens, and all the animals without this advantageous characteristic die out, whilst the others survive and keep reproducing.

What could happen:

Now let’s put everything I have said above in context of bacteria that has entered the human body. This person won’t know the bacteria is in him until enough toxins are released from them, and enough of them have reproduced to form a lot more bacteria (this is when the symptoms will start to appear). This person will find out what they have by asking a doctor or searching up their symptoms and will respond by taking antibiotics to help get rid of bacteria in the body. But, a single bacterium has managed to become resistant because of a gene mutation that means antibiotics can’t dissolve the cell membrane of that bacterium. So, all other bacteria will be killed off but that one (natural selection). Then this bacterium will of course reproduce rapidly, making identical copies of itself, and spreading the resistant and hard to get rid of bacteria through the person’s body. This is how the rise of resistant strains of bacteria come around, which are literally called ‘superbugs’, emphasising how big of an issue they are, like MRSA for example.

People with ‘superbugs’ in hospital are treated with very special care as bacteria is contagious, and could spread to other patients within the hospital, so even doctors need to take extra precautions to ensure nobody gets diseased.

There is a way to avoid any of this happening and it is simply to reduce the antibiotics intake and only resort to them when extremely necessary, not when you have a small cough or something along those lines.

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References:
[1]: http://learn.genetics.utah.edu/content/microbiome/antibiotics/
[2]: http://microbiologyonline.org/about-microbiology/introducing-microbes/bacteria
[3]: http://www.wwnorton.com/college/anthro/our-origins2/ch/04/answers.aspx

Image credits:
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Thank you for reading.