Micro Lab 7 ‐ Acid Fast Staining And Endospore Staining

Front 1

Simple stain

Back 1

Uses a single, basic (positively‐charged) dye to add color to microbial cells so that
they can be easily seen. As a result, all cells are stained the same color.

Front 2

Differential stain

Back 2

Uses two basic (positively‐charged) dyes to distinguish between two different
microbial groups or structures by color reaction. As a result, these groups are stained in two
contrasting colors.

Front 3

Since few microorganisms are acid‐fast, this
stain is useful when it is suspected that a disease
caused by a known *acid‐fast pathogen.

Back 3

Why is the acid‐fast stain useful in medicine?

Front 4

The cell walls of acid‐fast bacteria contain a *thick
and *waxy layer of mycolic acid, which is responsible
for a high degree of resistance to chemicals and
dyes. Steam heat drives the *primary stain, *carbol fuchsin, into the acid‐fast cell walls.

Back 4

Why is heat needed for the first step of the *acid‐fast staining method?

Front 5

Spores are surrounded by thick cell wells / spore coats, which make them resistant to harsh
conditions. Steam heat drives the *primary stain, *malachite green, through these spore coats.

Back 5

Why is steam heat used with the *malachite green
in this endospore stain?

Front 6

*Pink (acid‐fast) and *blue (non‐acid‐fast)

Back 6

During the acid‐fast stain procedure, what color
do acid‐fast and non‐acid‐fast bacteria stain?

Front 7

Mycobacterium and Nocardia.

Back 7

Name two genera of *acid‐fast bacteria.

Front 8

Tuberculosis, also *leprosy and *nocardosis

Back 8

Name one disease caused by Mycobacterium.

Front 9

Spores form under harsh condition, such as
during nutrient depletion. As a result, an older
culture is more likely to produce *spores.

Back 9

Why is an *older culture (5‐day) of bacillus needed
for the endospore stain?

Front 10

*Green (spores) and *pink/red (vegetative cells)

Back 10

During the endospore stain procedure, what color
do the *spores and *vegetative cells stain?

Front 11

Bacillus and Clostridium

Back 11

Name two genera of bacteria that *produce endospores.

Front 12

Anthrax, also *tetanus and *botulism

Back 12

Name one disease caused by *endospore‐forming bacteria.

Front 13

Acid Fast Staining and Endospore Staining

Back 13

Micro Lab 7 ‐ is