Microbiology and
Parasitology
Brief History of Microbiology
Robert Hooke (1665)
- described a thin slice of cork called “little
boxes” or “cells”
- started the Cell Theory
( all living things are composed of cells)
Anton van Leeuwoenhoek (1632-1723)
- Father of Microbiology/
Bacteriology/ Protozoology
- saw through his
single-lens microscope
“animalcules” (little animals)
- examined scrapings from his teeth, water
from ditches and ponds, stools, water soaked in
blood, sperm.
Spontaneous Generation
Theory (Abiogenesis) (16501850)
- a theory proposed by
some scientists that living
things came from nonliving things
Brief History
 Francisco Redi (1668)
- strong opponent of spontaneous generation
theory
- theorized that maggots did not arise from
decaying meat
- set-up six jars with decaying meat: three
jars sealed; three jars unsealed
- not all scientists convinced; they argued
that air is needed for life to thrive
- set up three jars with decaying meat
covered by fine nets
Brief History
John Needham (1745)
- favored spontaneous
generation theory
- found that even he
heated broth, before putting
it in a flask, cooled solutions were teaming with
organisms
- claimed that organism developed
spontaneously from fluids
Brief History
Lazaro Spallanzani (1755)
- opposed John
Needham’s theory
- he said that
microorganism from air
might have entered the flasks after they
were boiled
Brief History
Theory of BIOGENESIS (1858)
- states that all living things
arise from pre-existing living
things
- proposed by Rudolph Virchow
Brief History
 Louis Pasteur (1822-1895)
- strongly supported biogenesis theory
- said that microorganism are present in
air and can contaminate sterile solution
- placed a broth in the flask, boiled it and
bent the tube into S-shape
- put a fatal blow in theory of
spontaneous generation
Brief History
Golden Age of Microbiology (18571914)
- many microbiologic advances were
made
- spearheaded by Koch’s and Pasteur
Golden Age of Microbiology
Year
Scientist
Discoveries
1857-1864
Louis Pasteur
Fermentation, Pasteurization and
disproved spontaneous generation
theory
1867
Joseph Lister
Aseptic Surgery
1876
Robert Koch
Germ theory of disease
1879
Neisser
Neisseria gonorrhoeae
1881- 1883
Robert Koch
Pure cultures/ Mycobacterium
tuberculosis and Vibrio Cholera
1884
Metchnikoff
Gram
Escherich
Phagocytosis
Gram staining
Escherichia coli
Golden Age of Microbiology
Year
Scientists
Discoveries
1887
Petri
Petri Dish
1889
Kitasato
Clostridium tetani
1890
Von Bering
Diphtheria antitoxin
Ehrlich
Theory of Immunity
1898
Shiga
Shigella dysenteriae
1910
Chagas
Trypanosoma cruzi
Ehrlich
Treponema pallidum
Brief History
Louis Pasteur (1857)
- Fermentation was
discovered
- He was asked by
a group of merchant why
beer and wine soured (spoilage)
- He found out that yeasts convert sugar to alcohol
that makes it sour
- He boiled (55 C) the wine and beer enough to kill
bacteria (PASTEURIZATION)
Brief History
 Louis Pasteur
- discovered that some microorganism
require oxygen to live (aerobes) while others do
not (anaerobes)
- discovered the infectious agent that cause
silkworm disease and how to prevent it
- developed vaccines to fight cholera,
anthrax and swine erysipelas (skin disease)
Brief History
GERM THEORY OF DISEASE
- theory that microorganism have
similar relationship with plants and animals
- microorganism can cause disease
- strongly proved by Robert Koch
Brief History
Robert Koch (1843 – 1910)
- discovered Bacillus
anthracis, a bacteria that
causes anthrax (his basis
for Koch’s postulate)
-discovered Mycobacterium
tuberculosis (Pulmonary Tuberculosis) and
Vibrio cholera (cholera)
Brief History
 Koch’s Postulate (1884)
- strengthened Germ theory of disease
- Isolated Bacillus antrhacis from dead cattle
then cultured (cultivate/grow) it
- the cultured organism was injected to
healthy animal
- the healthy animal which becomes sick,
took sample of their blood and isolated the
organism
- he found out that the cultured organism
was same as the isolated organism
Brief History
 KOCH’S POSTULATE principles:
1. A particular microorganism must be found in all
cases of the disease and must not be present in healthy
animals or humans
2. The microorganism must be isolated from the
disease animal or human and grown in pure culture in
laboratory
3. The same disease must be produced when
microorganisms from pure culture are inoculated into
healthy susceptible laboratory animals
4. The same microorganism must be recovered from
the experimentally infected animals and grown again in
pure culture
What is Microbiology?
Study of very small living
organisms (microorganism) or
microbes (Burton’s)
“micro” =small;
“bio”= life;
“logos”=study
Why Study Microbiology?
 Indigenous Micro flora/ Normal Flora/
Mircrobiota
 Some organism causes diseases (Opportunistic
pathogen)
 Contribute to balance Eco-system (ecology)
 Important in various industries (food and
beverage)
 Antibiotic
 Genetic Engineering
Types of Microorganisms
Bacteria (sing. bacterium)
- simple, unicellular organisms
- prokaryotic
- not enclosed in a nuclear membrane
- have several shapes (bacilli, cocci,
spirillium)
- produced by binary fission or
conjugation
- e.g. Staphylococcus, Streptococcus
Types of Microorganism
Archaea
- prokaryotic
- not known to cause disease in humans
- divided into three groups:
a. Methanogens: produced methane as by product
b. Halophiles: lived in extremely salty environment
c. Thermopiles: lived in hot sulfurous environment
Type of Microorganism
Fungi (sing. Fungus)
- eukaryotic
- unicellular or multicellular
- have special cell walls called chitin
- most typical fungi are Molds
- e.g. Pityriasis versicolor (“an-an”)
Tinea pedis (athlete’s foot)
Type of Microorganism
Protozoa (sing. Protozoan)
- unicellular, eukaryotic
- move by pseudopods, cilia, flagella
- pleomorphic (assumes many sizes and shapes)
- free-living and/or parasitic
- e.g. Entamoeba histolytica- Amoeba
Types of Microorganism
Algae (sing. Alga)
- photosynthetic eukaryotes
- unicellular
- composed of cell wall called cellulose
- play a vital role in balance of nature
- produces oxygen and carbohydrates
used by other animals
Types of Microorganism
Viruses
- very small (cannot be seen by a
naked eye)
- acellular (not cellular)
- multiply once inside the host cell but
inactive when outside the host (INERT)
- e.g. Measles virus, Influenza A
(H1N1), HIV, Rotavirus, Human Papilloma
Virus
Types of Microorganism
Parasites
- multicellular
- strictly not microorganism but of
medical importance
- the host is usually harmed (disease)
- e.g. Ascaris lumbricoides (roundworm)
Enterobius vermicularis (pinworm or
seatworm)
Sarcoptes scabies (scabies or “galisaso”)