Test Questions on Micro lab final – Flashcards

Facultative Anaerobe

Does not require oxygen. Can grow with or without it. Able to detoxify toxic by products of oxygen.

Growth throughout the test tube. Due to ability to grow with or without oxygen

Microaerophile

Does not grow in atmospheric oxygen, but requires a small amount for growth. Able to detoxify toxic by products of oxygen.

Growth in the middle of tube. Due to not being able to grow in high oxygen, or no oxygen.

Anaerobe

Lacks the enzyme for using oxygen. Can’t live in oxygen. NOT able to detoxify toxic by products of oxygen.

Growth at bottom of tube. Due to not being able to grow in oxygen.

Anaerobic jar

A chemical pack and water is used, producing hydrogen and carbon dioxide. The hydrogen reacts with the free oxygen in the jar producing water, and an anaerobic condition. A methylene blue indicator is used to show the oxygen content. Blue = oxygen, white = NO oxygen. Mention in lab textbook. The indicator used in the lab turns red in the present of oxygen and white in the absence.

EMB

– E. Coli has a green metallic sheen on EMB. Due to being a vigorous lactose fermenter

Hektoen

– E. Coli has a pink to orange color (salmon) due to lactose fermentaion

EMB

- Enterobactor has a pink color due to lactose fermentation.

Hektoen

– Enterobactor has a pink to orange color (salmon) due to lactose fermentaion

EMB

- Proteus has NO color due to lactose NON-fermentation.

Hektoen

– Proteus has a BLACK precipitate due to H2S Production

Lactose

Non fermenter

Normal Flora

EMB

- Salmonella has NO color due to lactose NON-fermentation.

True Pathogen

Hektoen

– Salmonella has a BLACK precipitate due to H2S Production

EMB

- Shigella has NO color due to lactose NON-fermentation.

True Pathogen

Hektoen

– Shigella has a Blue-green color with NO Black precipitate due to NO H2S Production

Lactose

Non fermenter

Not

Normal Flora

NORMAL EMB

NORMAL HEKTOEN

Not normal Flora

Staphylococcus Aureus

Not

normal Flora

Staph Aureus

Causes a yellow color due to pH < 6.8 due to fermetination of manitol. Staph Aureus causes complete (Beta) hemolyses on blood agar. Manitol plate distinguishes between Staph A., and Staph E. Confirmation of Staph Aureus using an agglutination test.

Staphylococcus Aureus

Beta

Staphylococcus Epidermidis

Staph Epidermidis

Gamma

will distinguish between

Staph and Strep. Staph will cause bubbling with hydrogen peroxide. Strep will NOT bubble with hydrogen peroxide. GRAM Negative will NOT grow on manitol due to sodium chloride of 7.5%

Streptococcus Pyogenes

Streptococcus Pyogenes

Streptococcus pneumoniae

Normal flora (nose)

Streptococcus pneumoniae

causes partial (Alpha) hemolyses on blood agar, ? greenish color. Streptococcus pneumoniae is sensitive to Optichin (P disc).

Streptococcus pneumoniae

NO

bubbles with H2O2

ALPHA

Streptococcus pneumoniae

causes partial (Alpha) hemolyses on blood agar, ? greenish color. Streptococcus pneumoniae is sensitive to Optichin (P disc).

Plate

Bacteria

Results

EMB

E. Coli

Green sheen

Enterobactor

Pink color

Proteus

No color

Salmonella

No color

Shigella

No color

Gram positive does not grow here due to bile salts and dyes.

Hektoen

E. Coli

Salmon color

Enterobactor

Salmon color

Proteus

Black precipitate

Salmonella

Black precipitate

Shigella

Blue green,

No Black Precip.

Gram positive does not grow here due to bile salts and dyes.

Manitol

Staphylococcus Aureus

Yellow color

Staphylococcus Epidermidis

Pink color

Gram negative does not grow here due to 7.5% sodium Chloride

Blood

Staphylococcus Aureus

Beta hemolyses (complete)

Staphylococcus Epidermidis

Gamma hemolyses (none)

Streptococcus Pyogenes

Beta hemolyses (complete)

Streptococcus pneumoniae

Alpha hemolyses (partial)

Gram negative will cause alpha Hemolyses.