Card Set Information
biol 251 lab 9
What are the sources of fecal contamination?
water source stars at mountain picks to revers that mixed with washes. All of these sources are exposed to human/animal fecal contamination and other pollutants.
All ferment lactose
All gram negative rods
All anaerobe facultatives
All produce gas
What does coliforms and non-coliforms of fecal contamination have in common?
They all cause GI tract infections
Why the media we used in lab 8 is selective media
Because it inhibit the growth of gram positive bacteria and
select the growth of gram negative
Why is the media we used in lab 8 is deferential media
It differentiate between
lactose fermenting coliforms
gram negative that do not ferment lactose
Water screening test
A quick test of coliforms in 100 mL of water.
The water will change color blue/green and participials will glow under 360 nm UV light if coliforms are present
Why is Eosin methylene blue (EMB) is a deferential media?
Lactose frequenters produce acid:
produce a lot of acid turn media color green shean
lactose fermenters produce less acid turn the media pink to red/purple
Why is Eosin methylene blue (EMB) is a selective media?
Because it selects gram negative growth only
Some dyes in this media
inhibit gram +
EHA Media (Hektoen Enteric agar)
: Contains bile salt that inhibits G+
turn agar color to pink, yellow or orange
: blue green
MCA (MacConkey agar)
: Bile salt & crystal violet inhibit G+
Lactose frementer turn media
Define and list characteristics of coliforms. Why is water tested for coliforms?
Because they can cause GI tract infections
Name three diseases spread through water.
Dysentery, diarrhea, and vomiting, cholera
(Methicillin resistance staphylococcus aureus)
: VRE (vancomycin resistance enterococcus)
Enzyme produced by Staphylococcus that break down oxygen radicals
Staphylococcus in general
normal residents of the body
opportunists can become pathogenic under certain conditions
Mannitol salt plate
Mannitol is used as sugar
: Because it will turn yellow if mannitol is fermented (S. saprophyticus & S. aureus)
: because it selects for only halotolorant bacteria
What are S aureus, S. saprophyticus and S. epidermis have in common?
What differentiate between them?
All are halotolorant
; cause (endocarditis inflammation of the heart lining),
Cannot ferment mannitol
cause UT infection,
: cause MRSA,
(BAP) Blood agar plate
: gamma hemolysis (non hemolysis)
: gamma hemolysis
: Beta hemolysis (complete hemolysis)