MICRO - Lecture 1 Introduction to Microbiology and Parasitology (1)

Introduction to Microbiology and Parasitology

Louie Oalin Domingo, MDProfessor I

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)

Brief History

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, peppercorn

Brief History

Spontaneous Generation Theory (Abiogenesis) (1650- 1850)

- a theory proposed by some scientists that living things came from non-living 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 (1857-1914)

- many microbiologic advances were made

- spearheaded by Koch’s and Pasteur

Golden Age of MicrobiologyYear 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)AntibioticGenetic Engineering

Types of Microorganisms

Bacteria (sing. bacterium)- simple, unicellular organisms- prokaryotic - not enclosed in a nuclear

membrane- have several shapes (rod, bacilli,

cocci, spiral)- produced by binary fission- 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 MicroorganismParasites

- 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 “galis-aso”)

Naming and Classifying Organism

Established by Carolus Linnaeus in 1735Became the Linnaean System of

ClassificationScientific names were Latin because it is

traditionally used by scholarsAssigned organism with two names:

GENUS and SPECIES

Naming and Classifying Organism

GENUS- first letter is capitalized

• Species- all small letters

• Both Genus and Species are underlined OR italicized

Examples:Staphylococcus aureusAscaris lumbricoidesStreptococcus pyogenesHomo sapiens