Chapter 1 - A brief history of Microbiology

Antoni van Leeuwenhoek (1632-1723)

- began making and using simple microscopes

- examined water and visualized tiny animals, fungi, algae, and single-celled protozoa: "animalcules"

- organisms were called microorganisms, now they are called microbes

Carolus Linnaeus

developed a taxonomic system for naming plants and animals and grouping similar organisms together

what were the six categories that Leeuwenhoek's microorganisms are grouped?

1.) bacteria

2.) archaea

3.) fungi

4.) Protozoa

5.) Algae

5.) small multicellular animals

Bacteria and Archaea are both...

prokaryotic (lack nuclei)

- reproduce asexually

- found everywhere there is sufficient moisture

what do the cell walls of bacteria contain?

peptidoglycan

do the cell walls of archaea contain this?

no but they contain other polymers

Fungi

eukaryotic (membrane - bound nucleus)

what does fungi include?

molds - multicellular

yeasts - unicellular

Protozoa

- single-celled eukaryotes

- found in sufficient moisture

capable of locomotion by:

1.) Pseudopods - cytoplasmic extensions

2.) Cilia - numerous short protrusions

3.) Flagella - extensions of a cell that are fewer, longer, and more whiplike than flagella

algae

unicellular or multicellular and photosynthetic

apicomplexa

non-motile; (disease-causing) all medically relevant protozoa - e.g. malaria

column

thousands of bacterial cells

media (liquid or solid)

how bacteria is cultured

agar

solidifying agent of algae

gliding motility

many processes

the smooth gliding movement of mycobacteria

Parasites

worms

tape worms (microscopic to 23ft in length)

Virus

an infectious particle

- can be seen by electron microscopy

Vector

a mosquito (zeka, west nile, malaria)

- shuttles things from one place to another

What are the four questions that scientists are trying to find answers to?

- is spontaneous generation of microbial life possible

- what causes fernentation?

-What causes disease?

- How can we prevent infection and disease

Where did many philosophers and scientists believe living things arose:

1.) asexual reproduction

2.) sexual reproduction

3.) nonliving matter

who proposed spontaneous generation

aristotle

Redi's experiments

When decaying meat was kept isolated from flies, maggots never developed

Meat exposed to flies was soon infested

As a result, scientists began to doubt Aristotle's theory

Needham's Experiment

Boiled nutrient broth and then placed in a sealed flask which resulted in microbial growth

scientists didn't believe that animals could arise spontaneously, but microbes could

Spallanzani's experiments

Broth (gravy) is boiled in flask for an hour

One flask is left open

One flask is completely sealed

Flask did not become cloudy unless seal was broken

what did spallanzani conclude from needham

-needham failed to heat vials sufficiently to kill microbes

- microorganisms exist in air

- spontaneous generation of microorganisms does not happen

Pasteur's experiments

When the "swan-necked" flasks remained upright, no microbial growth appeared

When the flask was tilted, dust from the bend in the neck seeped back into the flask and made the infusion cloudy with microbes within a day

What threatened the wine industry in France?

spoiled wine

- some believed air caused fermentation

-others insisted living organisms causes fermentation

Pasteur's experiments led to the development of

pasteurization (process of heating liquids just enough to kill most bacteria)

what did pasteur also begin

industrial microbiology (intentional use of microbes for manufacturing products)

What did Pasteur develop?

-A germ theory of disease

-Germs became known as pathogens

What did Robert Koch study?

etiology (disease causation)

Anthrax

Examined colonies of microorganisms

Koch's postulates

1. Suspected causative agent must be found in every case of the disease and be absent for healthy hosts

2. Agent must be isolated and grow outside the host

3. When agent is introduced into a healthy, susceptible host, the host must get the disease

4. Same agent must be found in the diseased experimental host

Modern principles of hygiene not widely practiced in the mid 1800s

Healthcare associated infections (nosocomial)

What did Ignaz Semmelweis do

Required med students to wash their hands in chlorinated lime water

Resulted in higher patient survival rates

Joseph Lister advanced antisepsis...

In health care settings

How did he go about advancing antisepsis?

Spraying wounds, surgical incisions, and dressings with carbolic acid (phenol)

Nightingale introduced...

Cleanliness and antiseptic techniques into nursing

Advocated for hospital and public health policy reform

What did John Snow map?

Cholera epidemic in London

His work was the foundation for infection control and epidemiology

What did Edward Jenner develop

A vaccine against smallpox

Demonstrated validity of vaccination

Began field of immunology

Paul Ehrlich worked to identify

"Magic bullets" that would destroy pathogens but not harm humans

Discoveries began field of chemotherapy

What is the study of blood serum?

Serology

Where did von Behring and kitasato discover serology?

Presence in the blood of chemicals and cells that fight infection

Immunology

Study of body's defenses against specific pathogens

Chemotherapy

Fleming discovered pencilin