Intro to Microbiology

Microbiology
for the Surgical Technologist
History
1665 - 1884
Robert Hooke
Marked the beginning of Cell Theory
Anton Van Leeuwenhoek
Rudolf Virchow
Proposed the theory of Biogenisis
Louis Pasteur
established the Germ Theory of Fermentation
And the process of Pasteurization
Edward Jenner
Ignaz Semmelweis
Joseph Lister
Established some of the first principles of Aseptic Technique
Robert Koch
Hans Gram
Chemotherapeutic Agents
Chemotherapy
is the treatment of disease with chemical substances
Antibiotics
are naturally produced by bacteria and are used against other microbes
Twentieth Century Advances
Paul Ehrilich - 1910
Discovered SALVARSAN
Rebecca Lancefield - 1933
Alexander Fleming – late 1930’s
Discovered PENICILLIN by accident
Interferon discovered – 1960
Avery, MacLeod, and McCarty - 1944
Lederberg and Tatum – 1946
Discovered CONJUGATION
Watson and Crick – 1953
Robert Gallo – Late 1970’s
AIDS discovered - 1981

Nomenclature
Binomial System
Genus then Species
Example: Homo sapien or Homo sapien
H. sapien
Means wise man
The Five-Kingdom System
Procaryotae
Protista
Fungi
Plantae
Animalia
Units of Measure
Meter – (m) 1 m =
Decimeter – (dm) 10 dm =
Centimeter – (cm) 100 cm =
Millimeter – (mm) 1000 mm =
Micrometer – (m) 0.000001 m =
Nanometer – (nm) 0.000000001 m =
Angstrom – (Å) 0.0000000001 m

Sizes of Microbes
Bacteria
From 3 m to as small as 0.2 m
Erythrocytes (red blood cells)
About 7 m
Viruses
From 10 to 300 nm
Large protozoa
Can be 2000 m, or 2 mm in length

Microscopes
Compound (bright-field) Microscope
Two lenses with a light source
Objective lens
Ocular lens
Magnifies from 40x to 1000x
Oil immersion objective
Condenser
Resolution


Dark Field Microscope
Uses a dark field condenser
Phase-Contrast Microscope
Used to visualize the internal structures of a microbe
Fluorescence Microscope
Flurochromes
Electron Microscope
Used to visualize viruses
Uses electrons instead of light

Transmission Electron Microscope (TEM)
Focused beam of electrons
Drawbacks
Limited penetration of electrons
Special preparation of specimen
Cannot view in 3D
Scanning electron Microscope (SEM)
3D surface view of specimen
Primary and secondary electrons
Staining Methods
Preparing for staining
Smear
Simple stain
Single stain used
Common stains used are
Methylene blue
Carbolfuchsin
Safranin
Crystal violet
Viewed with immersion oil
Differential Stains
Gram Stain
Gram-positive
Turns purple
Gram negative
Turns red
Acid-Fast
Identifies Mycobacterium


Special Stains
Negative staining for capsules
Capsule
Protects the cell
Determines Virulence
Soluble in water
Utilizes India Ink and a simple stain
Halo effect

Spore Staining
Spores are difficult to stain
Stained with malachite green, then safranin
Appears green within a red cell

Flagella Staining
Enlarges flagella so that it can be seen
Culture Mediums
Culture
Microbes that grow and multiply in or on a culture medium
Agar
Solid medium used in petri dishes
Enriched media
Added nutrients so that FASTIDIOUS organisms will grow
Blood agar and Chocolate agar
Selective Media
MacConkey agar
both a selective and differential medium
Gram-negative culturs
Salmonella
PEA agar (Phenylethyl alcohol)
Blood agar with inhibitors
Gram-positive cultures

Differential Media
distinguish specific colonies of bacteria from other colonies that are growing on the same dish.
Reducing media
Anaerobic cultures

Words of Wisdom
The future is whatever you want it to be.
Gerladine A. Ferraro