Generalities of Gram Staining

All cocci are gram (+) except _

NVM

• Neisseria

• Veilonella

• Moraxella

All bacilli are gram (-) except

BLACC MEN

• Bacillus,

• Lacobacillus,

• Listeria,

• Actinomyces,

• Clostridium,

• Corynebacterium

• Mycobacterium

• Erysipelothrix

• Nocardia

(and Proprionbacterium)

Spiral shaped organisms are gram _

Gram (-)

TRUE OR FALSE: Bacteria with no cell walls aren’t generally gram stained

TRUE

(Mycoplasma, Ureaplasma, Treponema, Chlamydia, Rickettsia)

This is a lipid rich material that makes Mycobacteria acid-fast

Mycolic acid

Sputum smear size for AFS

2×3cm

How many OIF needed to read before reporting as negative

300 OIF

This is used in a loop to remove excess sputum from loop; done before flame sterilization

Alcohol sand mixture

Most crucial step in staining

Decolorizer

Purpose of the Mordant

Enhances primary stain

Give the answer to the following for Gram Staining:

• Primary stain

• Mordant

• Decolorizer

• Secondary stain

Primary Stain

• Crystal Violet

Mordant

• Gram’s Iodine

Decolorizer

• Acetone-alcohol

• 95% ethanol

• Acetone (rapid)

Secondary Stain

• Safranin

• Carbol Fuchsin

These faintly staining Gram (-) organism (must be Basic Fuchsin instead of Safranin)

LB VC

• Legionella

• Brucella

• Vibrio

• Campylobacter

What to check in a Gram Stain smear to see if its properly decolorized

WBCs (Gram negative); Red

This is a more sensitive fluorescent stain for AFS

Auramine O / Auramine Rhodamine method

How long does Auramine O take?

10 min

This is a staining technique for color blind MTs

Spengler’s

Three AFS method associated with Leprosy

• Baumgarten

• Fite-Farraco

• Wade Fite