Staphylocci Identification
What type of Agar plate do we use to select for Gram-Positive?
CNA plate (Colistin and nalidixic acid)
Which hemolysis pattern can be described as complete destruction of the red blood cells
Beta-hemolysis
Positive for Bile Esculin
What Ph indicator is used for the Macconkey agar?
Neutral red
What does KIA stand for and what does it test for?
Kligler's Iron agar
It tests for metabolism of glucose and lactose and the production of hydrogen sulfide
( this is more sensitive than SIM)
In a catalase test, we know a positive result is a result of bubbling what is the gas being produced?
Oxygen or O2
Which species of streptococci belongs to group A beta hemolytic streptococci (GABHS)?
Strepococcus pyogenes
What does purple indicate for the Sodium Hippurate test?
Positive for Sodium Hippurate
What inhibits the growth of Gram-positive bacteria?
Bile salts and crystal violet
What is SIM?
It is Sulfide agar and it tests for hydrogen sulfide, indole, and motility.
Why do we do a Coagulase test?
A coagulase test is used to indicate the pathogenicity and virulence and distinguish Staphylococcus aureus from other species
The bacteria, S. pyogenes, is known to produce specific streptolysins what are they and how do we test for them?
O streptolysin( oxygen labile) and streptolysin S (oxygen stable). to be able to test for O streptolysin you have to stab deep into the agar where there is no oxygen.
What alpha-hemolytic Streptococci is positive for Bile Esculin?
Enteroccocus faecalis
In the Indole test what enzyme is produced and what reagent do you add?
enzyme = tryptophanase
reagent= Kovac's
What is the name of the pH indicator added to the KIA media?
Phenol red
What infection is S. saprophyticus responsible for and how can you test for it and is it resistant to Novobiocin?
It is responsible for urinary tract infections. You can use the Novobiocin test to distinguish it from opportunistic pathogens because it is resistant to it.
What hemolysis pattern does not produce hemolysins?
Gamma hemolysis
What bacteria is positive for Sodium Hippurate?
S. agalactiae
for the Mehtyl Red test what is the name of the Ph indicator and what color indicates fermentation.
The Ph indicator is Methyl Red and and when fermentation occurs the test tube turn red.
If a KIA test comes back and it is classed “A/A + G”, what would this tube look like?
This tube is classed “K/A + H2S”. How do we know that the base portion of the tube is acidic
yellow with breaks in the media
We know that it is acidic because of the yellow in the tube meaning that acid was produced
The catalase test is useful for identifying and separating Bacillus from Clostridium. Why might this be important?
This is important because it can differentiate between the two. Bacillus is catalase pos and Clostridium is catalase neg.
what hemolysis pattern is produced when the incomplete degradation of the hemoglobin is liberated from lysed erythrocytes. ( greenish surrounding the colonies)
Alpha hemolysis
In the Citrate test what is the Ph indicator and what do the different colors indicate?
Ph indicator= bromthymol blue
neutral = green
alkaline= prussian blue or pos result
In the VP test what intermediate is present?
Acetylmethylcarbinol(acetoin)
How do we recognize motility in the SIM tube?
When bacteria move throughout the whole tube and creates a cloudy appearance in the entire tube.