MSA (Mannitol Salt Agar)
7.5% NaCl
Selective for members of staphylococcus
Useful media for MRSA
MacConkey Agar (MAC)
Selective and differential
NO GRAM+
test enterobacteria (poop/fecal bacteria)
ferment lactose to acid will turn pink to red color
Eosin Methylene Blue Agar (EMB)
Selective and differential
NO GRAM+
E.Coli shows green
poop bacteria
Xylose Lysine Deoxycholate Agar (XLD)
A lot of carbs; lactose, sucrose, xylose
Can detect salmonella
Blood agar plate (BAP)
Enriched media; adds 5% sheep blood to TSA medium
See production of Hemolysins
Beta: bad; clearing
Alpha: average; gray/green
Gamma: good; simple growth
Phenylalanine Deaminase Test (PDT)
Green Cap
Reagent: FeCl3
Inoc. Method: needle + fishtail
Result:
+ green, black
-orange
Citrate Utilization Test (CUT)
White Cap
No Reagent
Inoc. method: needle + stab+ fishtail
Result:
+blue
-green
Triple Sugar Iron Agar(TSIA)
Blue Cap
No reagent
Inoc.Method: needs + stab + fishtail
Result:
-Co2 bubble
-yellow top/bottom
-red top/bottom
-black=sulfur
SIM Medium
S=sulfur I=indole M=motility
Red Cap
Reagent: indole/kovac’s
Inoc.method: needle + stab
result:
+sulfur= black
-sulfur= not black
+indole=Red
-indole= no change
motility: Bacteria coming from stabline+ cloudy top.
If your organism is Gram positive, which media would you use to streak your unknown?
MSA
What type of media contains indicators to expose differences between microorganisms?
Differential
What type of media encourages the growth of certain types of organisms while inhibiting the growth of others?
Selective
How is indole production identified when using SIM media?
Kovac’s reagent causes red color change
What can occur in the Triple Sugar Iron Agar tubes to indicate that gas is present?
Cracks or movement of media (gas bubbles)
How do you know if an organism is catalase positive?
The sample creates bubbles
When citrate media turns green after inoculation and incubation, what does this indicate?
Fermentation has occurred
When using Blood Agar media we are analyzing the various types of hemolysis to interpret the results. What type of hemolysis is characterized by clearing of the media?
Beta
If an environmental microbiologist were to find a high percentage of coliforms in a water sample, it means that the sample is likely contaminated with…
feces
