Medical MicrobiologyThe History

EQ: Who are the major contributors to the development of Microbiology?

What is Microbiology?

They study of microbes or microorganisms

Microbes, or microorganisms are minute living things that are usually unable to be viewed with the naked eye.

What are some of examples of microbes? Bacteria, fungi, protozoa, algae, viruses, and some are

parasites (helminths)

Some are pathogenic

What is Microbiology?

Microbres When you hear the word bacteria, what comes to your mind?

What is Microbiology?

Not all bacteria cause disease

Most bacterial species cannot cause disease

Figure 1. Gram stain of a species of Micrococcus, commonly isolated from the skin and nasal membranes of humans. Figures from: http://textbookofbacteriology.net/normalflora.html

Microbes

Many species play beneficial roles

Production of antibiotics and foodstuffs

Decompose organic waste

Produce industrial chemicals such as ethyl alcohol and acetone

Produce fermented foods such as vinegar, cheese, and bread

Can microorganisms be good for us, beneficial? Explain your answer

What is Microbiology?

Ancient Microbiological History

Ancient people recognized many factors involved in diseases.

Most ancient people documented that some diseases are communicable

Example: When Black Death struck Europe entire villages were abandoned in an effort to escape the highly infectious plague (1347 A.D)

No medical knowledge existed in Medieval England to cope with the disease.

Ancient Microbiological History

The Romans were a hygienic bunch and were concerned with health and cleanliness (waste and sewage).

The Romans invented the first underground sewage system

Ancient Microbiological History The Romans understood that sewage could cause disease therefore

decided to build an underground sewage system which is an idea we still use today.

A network of pipes brought clean water into the city of Rome and removed waste.

Waste flushed from the latrines flowed through a central channel into the main sewage system and thence into a nearby river or stream.

The public bath houses was the place where people went to socialize and do business as well as getting clean.

History of Microbiology?

Discovering organisms

First microbes were observed in 1673

Robert Hooke- In 1665 reported that living things were composed of little boxes or cells devised the compound microscope and illumination system

Antoni van Leeuwenhoek- (1673-1723)

He is considered the father of bacteriology Made simple microscopes and began observing with them (1674) Discovered bacteria (he called them animalcules)

Leeuwenhoek's microscope consisted simply of:

A) a screw for adjusting the height of the object being examined

B) a metal plate serving as the body

C) a skewer to impale the object and rotate it

D) the lens itself, which was spherical

History of Microbiology: The Theories

Spontaneous Generation

Many believed in spontaneous generation:

Aristotle synthesized the hypothesis which stated that some vital force contained in given organic matter can create living organisms from inanimate objects.

In basic terms spontaneous generation stated that living organisms arise from non living matter.

Spontaneous Generation Spontaneous generation was disproved in 1668 by Italian Scientist,

Francesco Redi.

What are the steps to the scientific method?

If your were Francesco Redi, what experimental design would you create to disprove spontaneous generation?

Redi’s Experiment:

Redi’s question: Where do maggots come from?

Hypothesized: Redi suspected that flies landing on the meat laid eggs that eventually grew into maggots

Experiment: Placed meat in three separate jars

History of Microbiology: The Theories

Disproving Spontaneous Generation: Redi’s Experiment

History of Microbiology: The Theories

Jar #1 Jar #2 Jar #3

• Left open • Maggots developed• Flies were observed

laying eggs on the meat in the open jar

• Covered with netting • Maggots appeared on

the netting• Flies were observed

laying eggs on the netting

• Sealed • No maggots

developed

John Needham- revived the theory of spontaneous generation in 1745

Needham theorized that if he took chicken broth and heated it, all living things in it would die.

After heating some broth, he let a flask cool and sit at a constant temperature. The development of a thick turbid solution of microorganisms in the flask was strong proof to Needham of the existence of spontaneous generation.

Spontaneous Generation

History of Microbiology: The Theories

The Question: What causes tiny living things to appear in decaying broth?

Lazzaro Spallanzani (1729-1799) In 1776 he demonstrated that microorganisms were already in

the solution, the container, or the air

He took solutions which he knew would "breed" organisms and boiled them for up to an hour. The flasks were hermetically sealed to keep out contaminated air.

Spontaneous GenerationThe Question: What causes tiny living things to appear in decaying broth?

History of Microbiology: The Theories

Biogenesis In 1858 German scientist, Rudolf Virchow challenged

spontaneous generation with his concept of biogenesis

Living organisms arise from pre-existing life

Virchow presented his idea to the scientific community, but could not back it up with a convincing experiment

History of Microbiology: The Theories

Settlement of Spontaneous Generation

In 1861, a French scientist by the name of Louis Pasteur demonstrated where microorganisms came from

Father of Medical Microbiology

Demonstrated the microorganisms exist in the air and could contaminate sterile solutions by passing air through cotton filters

The filter trapped tiny particles floating in the air

History of Microbiology: The Theories

http://www.microbiologytext.com/index.php?module=Book&func=displayarticle&art_id=27

Louis Pasteur’s Swan neck flask experiment

http://www.microbiologytext.com/index.php?module=Book&func=displayarticle&art_id=27

History of Microbiology: The Theories French chemist Louis Pasteur’s design of

this experiment settled the argument.

Louis Pasteur performed numerous experiments to discover why wine and dairy products became sour

He found that bacteria were to blame (lactic acid fermentation)

Pasteur called attention to the importance of microorganisms in everyday life and stirred scientists to think that if bacteria could make the wine “sick,” then perhaps they could cause human illness.

Louis Pasteur’s experiments

History of Microbiology: The Theories

Golden Age of Microbiology1857- 1914

Beginning with Pasteur’s work, discoveries included the relationship between microbes and disease, immunity and antimicrobial medicine

Germ Theory of Disease

Germ theory states that specific microscopic organisms are the cause of specific diseases.