Bacillus is a genus of rod-shaped bacteria.

Gram-positive organism.

(looks like funky coral)

Spirillum in microbiology refers to a bacterium with a cell body that twists like a spiral.

Spirillum is a genus of gram-negative bacteria.

(Neon sign, black background with glowing bacteria.)

Staphylococcus is a genus of Gram-positive bacteria. Under the microscope they appear round (cocci), and form in grape-like clusters.

(Blue, looks like color-blind test.)

Streptococcus is a genus of spherical Gram-positive bacteria. They grow in chains or pairs, hence the name — from Greek στρεπτος streptos, meaning easily bent or twisted, like a chain (twisted chain). Contrast this with staphylococci, which divide along multiple axes and generate grape-like clusters of cells.

(Blue.)

Clostridium tetani is a Gram positive rod-shaped bacterium.

Endospore

(Easter Grass, Swollen Ends)

Amphitrichous bacteria have a single flagellum on each of two opposite ends (only one flagellum operates at a time, allowing the bacteria to reverse course rapidly by switching which flagellum is active).

(Brown snakes)

Peritrichous bacteria have flagella projecting in all directions.

(Brown furry)

Mycobacterium Tuberculosis

M. tuberculosis is characterized by caseating granulomas containing Langhans giant cells, which have a "horseshoe" pattern of nuclei. Organisms are identified by their red color on acid-fast staining.

(Acid-fast stain - red/purple)
(Non-acid stain - blue)

Blood red

Capsule Stain

Stain background - Red

Capsule - Unstained

Germ Theory of Disease - theory that microorganisms cause disease.

Tryptic Soy Agar - (TSA) - Solid medium, food for bacteria.

Fomite - any inanimate object or substance capable of carrying infectious organisms (such as germs or parasites) and hence transferring them from one individual to another.

Every colony has a specific set of characteristics:

Shape - circular, irregular, ounctiform (tiny)

Margin - entire(smooth), undulate/wavy, lobate, filamentous, rhizoid (branched)

Elevations - flat, raised, convex, pulvinate (very convex), umbonate (raised in the center)

Texture - moist, mucoid, dry

Pigment - opaque, translucent, shiny, dull

Common stains - Methylene Blue, Crystal Violet, Safranin

Heat fixing has two important purposes: kills bacteria and coagulates cell proteins so they are more visible.

Cells are transparent and dyes make them visible.  We can then see cell morphology and arrangement.

Counterstain - safranin is applied and gram negative cells turn the color of this dye which is pink/red.

Gram - have more lipid content in cell wall.  Alcohol forms holes in wall releasing CV in decolorization.

Decolorization of gram + does not make them porous so stain remains in cell.

Decolorization is most imp process of the gram stain.

Acid fast prganisms have mycolic acid in cell wall.

Mycolic acid is a waxy substance that prevents true decolorization of primary stain.

Two methods employed for acid fast bacteria - Ziehl-Neelsen and Kinyoun methods.
ZN uses heat as part of the process. K does not.

Capsules are composed of mucoid polysaccharides that repel most stains.
Capsule staining colors the background of the slide and leaves a "halo" around bacteria.

This area is hard to stain, so we stain everything else.

Congo red or nigrosin are commonly used to stain.

Scaheffer-Fulton Method - primary stain is Malachite green which is forced into spore by heating.

Counterstain is safranin.

Spores loacted according to the following: terminal, central, subterminal

Ryu stain is used to see flagella on bacteria.  It allows you to see the various arrangements of the flagella.

Montrichous

Amphitrichous - both ends

Lophotrichous - tufts at both ends

Peritrichous - flagella all over

9-Gently blot dry in biulous paper.

Observe under oil immersion.