Hi, I'm Cathy with Level Up RN. This is the first video in our microbiology review series.
In this particular video, I will be focusing on the history of microbiology, and I'll be discussing the key people and concepts that you likely have to know for your micro class. So I obviously won't be discussing all the people who contributed to microbiology over the years. I'll really just be focusing on the people and concepts that you are likely to get tested on.
At the end of the video, I'm going to give you guys a quiz to test your understanding of some of the key information that I'll be covering, so definitely stay tuned for that. And if you really want to crush it, be sure to follow along with our Level Up RN Microbiology Flashcards. These flashcards are available in physical format, as well as digital format via Flashables.
For more information about our flashcards, check the description below. And if you have our flashcards, pay close attention to the bold, red text on the back of the cards because those are the things that you are likely to see show up on a micro exam.
Robert Hook is the first individual that I would be familiar with. He lived from 1635 to 1703, and he was the first person to observe larger cells using his microscope.
So when he was looking at a sample of cork using his microscope, he observed structures that looked like a honeycomb or little, small rooms. So he coined the term cell, which means small room in Latin, and this marked the beginning of cell theory, and a key part of this theory is that all living things are made of cells.
Next, we have Antonie van Leeuwenhoek, who lived from 1632 to 1723. He is considered to be the father of microbiology, and he was the first person to develop a microscope lens powerful enough to observe microbes. And he was also the first person to observe live microorganisms using his microscope, and he described these microbes as animalcules or "wee, little beasties."
So with the discovery of these "wee, little beasties," there was continued discussion about how life arises, both microscopic life and larger forms of life, and up until the 1800s, the idea of spontaneous generation was widely accepted and became a theory.
This theory states that life can arise spontaneously from non-living matter, such as maggots appearing spontaneously on rotting meat.
This theory was challenged by several scientists, including Francesco Redi in the 1600s. He demonstrated that if meat was placed in a sealed container, no maggots would appear. But if meat was left open to the air, then flies would come and lay eggs on the meat, and then maggots would appear.
But despite this compelling evidence, the theory of spontaneous generation wasn't completely disproved until 1859 by Louis Pasteur, who we will definitely be talking about more in this video.
After that, the theory of biogenesis became accepted, which is the principle that all living cells arise from preexisting cells, and not from non-living things.
Another person you need to be familiar with is Edward Jenner, who lived from 1749 to 1823. He was instrumental in laying the foundation for vaccination.
So he observed that milkmaids who developed cowpox were immune to smallpox, which was a common and deadly disease at the time.
So he took a sample from one of the cowpox lesions on a milkmaid and injected that into a healthy young boy. The boy developed a mild infection from the cowpox, but when he was later infected with a sample from a smallpox lesion, he did not develop smallpox. And of note, the term vacca in vaccination means cow in Latin.
Now let's talk about Louis Pasteur, who lived from 1822 to 1895. He had many contributions to the field of microbiology, so let's go through some of those key contributions that you definitely have to know.
So first of all, as I mentioned before, he disproved spontaneous generation and provided evidence for the theory of biogenesis. He did this through a set of experiments using swan neck flasks and boiled broth.
So to be clear, there were definitely other scientists who did experiments using boiled broth, but it was Pasteur who ultimately disproved spontaneous generation.
Pasteur also discovered that microorganisms cause fermentation, which is the conversion of sugar into alcohol in the absence of oxygen.
And then through his work to try and figure out how to prevent beer and wine from spoiling and tasting sour, he discovered that heating the beer or wine for a few minutes killed the microbes that were responsible for spoiling the beverages.
This process became known as pasteurization, named after Louis Pasteur, and is still used today in a number of products such as milk and juice.
Finally, Pasteur was instrumental in the development of vaccines for a number of diseases, including cholera, rabies, and anthrax, and his work supported the germ theory of disease, which states that diseases are caused by microorganisms.
Next, let's talk about Joseph Lister, who lived from 1827 to 1912. He applied the germ theory of disease to surgery.
So back in the 1800s, surgeons did not bother to wash their hands prior to surgery, and about 50% of surgical patients would die following their operation due to infections.
So Joseph Lister insisted on handwashing prior to surgery, and he treated surgical wounds with phenol, which is a chemical disinfectant. This dramatically decreased post op infections, and he became known as the father of antiseptic surgery. Of note, the mouthwash brand Listerine is named after Joseph Lister.
Let's now talk about Robert Koch, who lived from 1843 to 1910. Koch discovered the causative agents for several deadly diseases, including the bacteria that causes anthrax, and his work provided further evidence for the germ theory of disease.
Koch also developed a technique for obtaining pure cultures, which is the growth of a single species of microorganism on a medium. He also developed a systematic approach to determine if a particular microorganism is responsible for a particular disease.
This is known as Koch's postulates, which is something you should definitely be familiar with, so let's go through those postulates now.
The first postulate states that the suspected pathogen must be present in all diseased people or animals but absent in healthy individuals.
In postulate 2, the suspected pathogen must be isolated and grown in a pure culture.
In postulate 3, if a healthy individual is infected with a suspected pathogen, they must develop the same signs and symptoms as seen in the original diseased people or animals.
And then in postulate 4, the pathogen must be re-isolated from the new host and be identical to the pathogen that was isolated in postulate 2.
The last key contributor in the history of microbiology that we're going to talk about is Alexander Fleming, who lived from 1881 to 1955.
Fleming had some plates of bacteria out in his lab when he left for holiday. When he came back, he noticed that mold growth on one of the plates was inhibiting the growth of bacteria on that plate.
So that mold was a strain of the penicillium species, and this led to the discovery of penicillin, which was the first natural antibiotic.
All right. It's quiz time, and in this particular quiz, I'm going to describe a famous person in the history of microbiology, and I want you to name the person I'm talking about. Are you guys ready? Let's go.
Number one.
This person discovered that heating wine or beer for a few minutes was effective in killing the microbes responsible for spoiling the beverages.
The answer is...Louis Pasteur.
Number two.
This person treated surgical wounds with phenol and is considered the father of antiseptic surgery.
The answer is...Joseph Lister.
Number three.
This person was the first to observe live microorganisms through a microscope and is considered to be the father of microbiology.
The answer is...Antonie van Leeuwenhoek.
Number four.
This person discovered penicillin, which was the first natural antibiotic.
The answer is...Alexander Fleming.
And number five.
This person developed a technique for obtaining a pure culture, and a systematic approach to determine if a particular microorganism is the cause of a particular disease.
The answer is...Robert Koch.
All right. I hope you did great with that quiz, and I hope you found this video to be helpful. Take care and good luck with studying.
[BLOOPERS]
So let's go through a few of those few. They must develop the same-- in postulate 3, the-- two, the suspected-- sorry.
