Stains, packet #4 Flashcards
When staining Gram + with Crystal Violet what color does it retain?
Purple.
At what stage in Gram - does the bacteria retain the pink dye?
the Safranin step.
What are the four steps in Gram staining?
- Crystal violet
- Gram’s iodine
- Acetone/ Alcohol
- Safranin
Which step is the decolorizing step in Gram staining?
Acetone/Alcohol
If you forgot to add the counterstain to the mixed culture sample at the end of the staining procedure, gram-negative cells would appear __________ and gram-positive cells would appear __________.
Colorless; Purple.
Are spore formers Gram negative or Gram positive?
Gram +
Clostridium & Bacillus
All cocci are Gram positive except for?
Neisseria and Moraxella
What is the Ziehl-Neelsen Stain used for?
Acid fast organisms
What does Acid fast mean?
Acid fast is a physical property of certain bacteria (and, less commonly, protozoa), specifically their resistance to decolorization by acids during staining procedures.
What reagents are used for Acid fast staining?
Carbol Fuchsin
Acid Alcohol
Methylene Blue
For acid fast what color does the organism retain with all reagents?
Red
For non acid fast what color does the organism retain with: Carbol Fuchsin?
Red
For non acid fast what color does the organism retain with: Acid Alcohol?
Colorless
When non acid fast retains a Blue color what reagent is being used?
Methylene Blue
Do bacteria have a nucleus?
No
What internal structures do Gram positive and Gram negative both have?
Nucleiod region
Plasmids
Mesosomes (though primarily Gram +)
Ribosomes
Granules
What internal structure is exclusive to Gram + bacteria?
Endospores
What in the function of endospores?
Resistance to heat, chemical and dehydration.
They are used for survival only!
What is bacteriocin production and where is it produced?
Bacteriocin- is how bacteria are harmful to one another.
It is produced in the plasmids
What chemical composition is in the nucleiod region?
DNA
RNA
Proteins
Which bacterial structure is involved in protein synthesis?
Ribosomes
What are granules made of and what is their function?
Made of glycogen, lipids, polyphosphate
They store food, and reduce osmotic pressure
What structure is involved in Cell division and secretion
Mesosomes
What are plasmids composed of?
DNA
How do bacteria grow?
By binary fission
During lag time is there an increase in number of bacterial cells?
NO
During what phase is there rapid exponential growth?
Log phase
What is the generation time?
The time it takes for one cell to divide into two.
When is generation time determined?
During log phase
When the nutrients are used up and toxic products like acids and alkalis begins to form, what phase is that?
The stationary phase
What is the death phase?
The excretory phase (1. used up all nutrients, 2. living in waste)
What is a selective medium?
A medium that selects for certain bacteria by inclusion of special nutrients and/or antibiotics.
What is a differential medium?
A medium in which different bacteria can be distinguished by differences in colonial morphology or color.
What mediums are used for Corynebacterium?
- Lofflers coagulated serum medium (s)
2. Tellurite agar (d)
Enteric bacteria is cultured in what two mediums?
- Eosin methylene blue (d)
2. Mac Conkey’s (d)
Hektoen enteric agar (d) is used for what organisms?
Intestinal pathogens
Legionella is cultured in what medium?
CYE (Charcoal-yeast extract agar) (s)
Lowenstein-Jensen medium (s) is used to culture what organism?
Mycobacterium
When is chocolate agar used for Neisseria?
from normally sterile sites
Chocolate agar is used for what 2 organisms?
Neisseria (from normally sterile sites)
Haemophilus
Neisseria form sites with normal flora is cultured in?
Thayer Martin selective medium (s)
What is the Thayer Martin medium supplemented with?
vancomysin, nystatin and colistin to inhibit normal flora
Vibrio cholera is cultured in?
Thiosulfate Citrate Bile Salts Sucrose (TCBS) (s)
Mycoplasma, Ureaplasma are cultured in?
Cholesterol, purines and pyrimidines
Francisella, Brucella, Legionella and Pasteurella grow in ?
Cysteine
Factors X ( protoporphyrin) and V (NAD) growth requirements are with?
Haemophilus ( influenza and aegypticus)
