Introduction to Microbiology and Parasitology
Louie Oalin Domingo, MD Professor 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) (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
Phagocytosis
Gram
Gram staining
Escherich
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 (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: b. Halophiles:
produced methane as by product
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”)
Naming and Classifying Organism
Established by Carolus Linnaeus in 1735
Became the Linnaean System of Classification
Scientific names were Latin because it is traditionally used by scholars
Assigned 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 aureus Ascaris lumbricoides Streptococcus pyogenes Homo sapiens
