Microbiology Review Flashcards
What color are gram (+) bacteria’s when a gram stain is done?
Crystal violet
What color are gram (-) bacteria’s when a gram stain is done?
Red
Which bacteria (+ or -) has a rigid/thick outer layer? What is the layer called?
Gram positive; peptidoglycan
Which bacteria (+ or -) is not easily stained? Why?
Gram (-); a lipopolysaccharide layer does not allow the dye to adhere to peptidoglycan
How many layers does a gram (+) bacteria have?
Two
How many layers does a gram (-) bacteria have?
Three
How many groups of bacteria are divided by gram stains?
Three (Red, Crystal violet, and bacteria that do not stain)
How are bacteria named?
With a genus (first name) and species (last name)
(T/F) - Nomenclature for bacteria have to be italicized
TRUE
(T/F) - Bacteria cannot be grouped under a non-species name
FALSE - they can in some cases; for example: Enterobacteriaceae
What common morphology (forms) are Gram (+)?
Cocci
(T/F) - Bacilli can occur in gram (+)
True; uncommon though
What genus bacteria(s) forms cocci clusters? Is it gram (+ or -)?
Staphylococcus; Gram (+)
What genus bacteria(s) form cocci chains? Is it gram (+ or -)?
Streptococci (also Enterococci); Gram (+)
What test helps differentiate staphylococcus and streptococcus/enterococcus?
Rapid catalase test
If the catalase test comes out positive, what genus is it?
Staphylococcus
If the catalase test comes out negative, what genus is it?
Streptococcus or Enterococcus
Which test is helpful to differentiate Staphylococcus aureus with Staphylococcus epidermidis?
Coagulase test
Which staphylococcus is virulent (deadly), S. epidermidis or S. aureus?
Staphylococcus aureus
If a coagulase test is positive, what staph species would that indicate? How would it look like in test tube?
Staphylococcus aureus; coagulated
If a coagulase test is negative, what staph species would that indicate? How would it look in a test tube?
Staphylococcus epidermidis; no coagulation
Which staph species contaminates the blood more?
Staph. epidermidis
What test helps differentiate streptococci species?
Hemolysis
How many hemolysis tests are there? Name them
3
- Beta
- Alpha
- Non-hemolytic (gamma)