Unknown Cultures Flashcards
physiological tests detect the…
products of enzymatic reactions
a “positive” test indicates that the
enzyme is made by the organism
Catalase Test
tested for:
positive test:
negative test:
- catalase enzyme
- bubbles when peroxide is added
- no change when peroxide is added
Oxidase Test
tested for:
positive test:
negative test:
- presence of cytochrome oxidase
- blue color when oxidase reagent is added
- no color change
what test has a time limit of 30 secs- 1 min?
the oxidase test
which medium contains sodium thioglycollate? why is this significant?
FTM
b/c it keeps O2 levels low
in an FTM tube where is oxygen absent?
at the bottom of the tube
what is used for carbohydrate fermentation?
4 tubes
- glucose
- lactose
- sucrose
- mannitol
carbohydrate fermentation produces
acid and/or gas
in carbohydrate fermentation the test tubes contain….
- a durham tube
- an indicator
what is the indicator found in the test tubes for carbohydrate fermentation? what color changes indicate acid and alkaline condition?
phenol red
- acid: yellow
- alkaline: pink
citrate slants contain
- citrate
- bromophenol blue indicator
Citrate Test
tested for:
positive test:
negative test:
- citrate
- bright blue
- green
blue at alkaline pH
green at neutral pH
Startch Hydrolysis
tested for:
positive test:
negative test:
- enzyme amylase
- zone of clearing after addition of grams iodine
- no zone of clearing
function of amylase
cleave strach into glucose
Hemolysis Test
tested for:
positive test:
negative test:
- hemolysin
- zone of clearing
- no zone of clearing
beta-hemolysis indicates
complete clearing of blood around colonies
alpha-hemolyisis indicates
partical clearing of blood around colonies
gamam-hemolysis indicates
no hemolysis at all
BAP is
TSA containing 5% sheeps blood
Urea Hydrolysis
tested for:
positive test:
negative test:
- urease
- hot pink
- yellow-orange
yellow-organge is the initial color so a negative result would be no color change
Nitrate Reduction Test
tested for:
positive test:
negative test:
- reduction of nitrate(NO3) to nitrite (NO2)
- dark pink-red
- no color change
confirming the nitrate reduction test
tested for:
positive test:
negative test:
- nitrate reduction
- no color change after zinc addition
- dark pink-red after zinc addition
why does the nitrate reduction test need to be confirmed?
b/c some cells convert nitrite into other molecules such as N2 and NH3
SIM stands for
sulfate, indole, motility
SIM medium allows for what 3 physiological tests
- formation os H2S from catabolism of sulfur containing amino acids
- typrophan hydrolysis
- motility
positive result for H2S production is
a black precipitate
positive result for tryptophan hydrolysis is
pink color w/ addition of Kovac’s reagent
positive result for molitity is when
the organism spreads from the line of innoculation
what are the extra tests that differentiate the staphlococcus species?
MSA plate
Coagulase Test
MSA test is selective for ____ and differentital for _________.
- halophiles
- mannitol fermentation (yellow)
Coagulase Test causes precipitation of fibrin around
Staphylococcus aureus
coagulase test indicates
the clotting of plasma
What is the addition test to distinguish Streptococcues agalactiae
CAMP test
In the CAMP test streptococcus agalactiae enchances the hemolysis of
Staphylococcus aureus
what is a positive result for the CAMP Test
enhanced hemolysis
what are the main medically important species of staphlococcus
S. aureus
S. epidermidis
S. saprophyticus
what are the main medically important species of streptococcus
- S. pyogenes
- S. pneumoniae
- S. agalactiae
which streptococcus species is significant due to its antibiotic resistance?
Enterococcus faecalis
staphylococcus and streptococcus are
gram positive cocci
define pyogenic
pus- forming
