Microorganisms and Health [7]: Antibiotics and Resistance (High band Biology)

Microorganisms and Health [7]: Antibiotics and Resistance (High band Biology)

A Level Biology: Microorganisms and Health
7 – Antibiotic and Resistance Hi! Welcome to my seventh video on the series
about Microorganisms and Health. Today, we are going to be talking about Antibiotics
and antibiotic resistance. So the first thing to establish is what antibiotics
actually do. They’re chemicals, which usually in the case of penicillin can actually punch
holes in the cell walls of bacteria. This is very important about antibiotics is the
fact they’re ineffective against viruses. They only have an effect on bacteria and some
fungi. By punching holes in the cell wall, the penicillin
causes stuff like osmotic lysis; stuff leak out of the inside of the cell and therefore,
the cell can’t reproduce. Other types of antibiotics work in other ways by stopping
reproduction and therefore, slowing down the growth rate, particularly of bacteria. Without modern antibiotics here, it would
be safe to assume that most people who’d listen to this video wouldn’t be here because
some of your relatives would have died from infections. They were able to treat a number
of different diseases very, very effectively. The problem that is being produced is the
fact that by overuse and by over-prescription and by incorrect use, we have actually ended
up improving the bacteria that we are actually trying to kill. It can work in these several
ways. One way to produce resistant strains of bacteria
is to actually, simply take antibiotics. You can pretty much guarantee that by taking antibiotics,
you are going to end up with resistant strains. The general cause of action is when bacteria
are able to reproduce. Some of those will mutate and some of those mutations might potentially
lead to drug resistance. By taking the drugs, you actively promote the ones that are resistant
to survive. If the only ones that are able to survive are the drug resistant ones, then
the next time they’ll go to reproduce, they’ll pass that gene on to the next generation and
therefore, they will then thrive. So when you want to take another antibiotic
in the future for a certain infection, then it would be ineffective against those bacteria
because it has drug resistance. Another way to produce drug resistant bacteria
is to take an antibiotic again, for a different condition. What the antibiotic may do is it
may wipe out a number of the pretty much beneficial bacteria that you have living within your
system. What this may do is it may promote the survival of the resistant bacteria because
of lack of competition. If there are no normal bacteria there that are not resistant, they
may not be able to complete for food sources with the resistant strains. So the less normal or non-resistant bacteria
there are, the better is the survival changes of the resistant bacteria. Therefore, their
numbers can increase and can cause problems within a person. Another way to promote resistance is this
method by which bacteria can use to swap genetic information between the same species of bacteria
and in between different species of bacteria. They do it via this organelle here called
a plasmid. A plasmid is basically a circular piece of DNA and on these circular pieces
of DNA, they can carry genes for resistance. It is very, very possible that these plasmids
can exchange between different bacteria and they can exchange resistance. Therefore, a
species or a type of bacteria that wasn’t resistant that comes into contact with a resistant
strain could possibly gain resistance via these plasmids. Part of the problem comes from over-prescription
of antibiotics and specifically, over-prescription for an incorrect diagnosis. You should never
give an antibiotic for viral infection. Also, you should use them with caution. For minor infections, it is probably not the
best idea to be promoting loads and loads of antibiotics because you are essentially
asking for trouble. You are going to promote the survival of resistant strains. If it is
something that your body can normally clear up by itself, then it is probably preferential
to do so. One of the most high profile cases of antibiotic-resistant
bacteria is this better called MRSA which stands for Methicillin-Resistant Staphylococcus
Aureus. Staphylococcus is the type of bacteria and methicillin is a type of antibiotic similar
to penicillin. So because we have been using a great number of different types of antibiotics,
this promoted the survival of this MRSA. Particularly in certain hospitals and particularly people
who are already frail or have an impaired immunity, MRSA can be lethal. In summary, antibiotics can work by rupturing
the cell walls of bacteria or stopping them reproducing. The antibiotic resistance can
develop when antibiotics are not used properly. They’ll aid in the promotion of resistant
strains. Part of the problem comes from over-prescription and incorrect prescription of antibiotics.
In order to reduce this, we need to use less and we need to use it sparingly. Only for
the very conditions that actually require it should it be prescribed. [end of audio – 05:30]
A Level Biology: Microorganisms and Health 7 – Antibiotics and Resistance


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