Lecture 2: Early MICROBIO

Robert Hooke (1665)

Used a compound microscope to describe mold and coined the term 'cells'.

What are microbes?

Microscopic organisms too small to be seen with the naked eye

Antony van Leeuwenhoek

First to describe microbial organisms in detail, calling them 'wee animalcules' in pond water and dental plaque.

Spontaneous Generation

The discredited belief that simple life forms could spontaneously arise from non-living matter

What idea supports that mice could be created with a recipe?

Spontaneous generation

Louis Pasteur

Disproved spontaneous generation, showed microbes are present in dust/air, and developed pasteurization.

What experiment showed the microbes are in air and dust particles?

Pasteur's broth experiment

How did the broth experiment show microbes are in the air?

The swan neck flask allowed air to get into the tube while trapping dust particles in the swoop and kept the broth sterile. When dirty air was let in, the broth was contaminated.

Pasteurization

Heating food to a high temp/pressure to kill most harmful bacteria to keep food from spoiling

Who developed the smallpox vaccine?

Edward Jenner

How did Jenner make the vaccine?

He injected a healthy boy with cow-pox infected liquid, then small pox liquid, and the boy survived

What is variolation?

Injecting patients with low doses of small pox so they don't get small pox

Germ Theory of Disease

[Infectious] diseases are caused by microorganisms

Contagions of disease are

Organic and living

What are Koch's postulates?

Methods for pure culture and aseptic technique

What is the purpose of the postulates?

To show that a particular single organism causes a disease

Koch's First Postulate

The microbe must be present in every case of the disease.

Koch's Second Postulate

The microbe must be isolated from the diseased host and grown in pure culture.

What is the importance of an isolated disease being grown in a pure culture?

To make sure it is the only organism being tested

Koch's Third Postulate

The specific disease must be reproduced when a pure culture is injected into a healthy host.

What should happen to the healthy host after the 3rd postulate?

The host should die

Koch's Fourth Postulate

The microbe must be recoverable so when a sample is taken from the host, the microbe is found.

Limitations of Koch's Postulates

Some microbes cannot be grown in pure culture, there are no animal models for some microorganisms, and not all hosts react the same to every infectious agent.

Ignaz Semmelweis

Introduced hand washing and antiseptic practices to medicine to stop childbed fever.

What did Ignaz Semmelweis believe caused childbed fever?

Unwashed hands

Lister and Nightingale

Lister popularized antiseptics in surgery; Nightingale introduced antiseptic techniques to nursing.

Fanny Hesse

Wife of Koch who added agar into lab plates to grow bacteria better

Julius Petri

Invented the Petri dish to better agar culture techniques for purifying bacterial colonies.

Petri dish and purpose

Dish with a lid to be able to see cultures without contaminating anything

What was used before petri dishes?

A bell cover for a plate, that when removed would contaminate the specimen.

Alexander Fleming

Discovered penicillin in 1928 by observing bacteria-free clearings around mold on a contaminated plate.

What did Flemming discover and how did he find it?

Penicillin which was the mold/fungi that prevented bacterial growth