how can you differentiate from staph. aureus or staph. epidermidis?
MSA PLATE. MANNITOL SUGAR FERMENTORS (AUREUS) turn the zones YELLOW.
MSA plate results?
Staph. Aureus colonies, yellow with yellow zones.
Staph. epidermidis, white with no change in zones.
EMB stands for?
eosin-methylene blue agar
what kind of medium is EMB?
selective & differential.
what do EMB plates select?
GRAM NEGATIVE RODS
How does EMB select?
dyes: eosin & methylene blue. selects G- only.
what is differentiating about EMB?
LACTOSE: lactose fermentors and non-lactose fermentors.
fermentors colonies appear PINK, RED, PURPLE, METALLIC GREEN
eosin-methylene blue agar. selects only GRAM NEGATIVE RODS. differentiates LACTOSE FERMENTORS WITH METALLIC GREEN, PINK OR RED COLONIES
which 2 colonies will grow on EMB with no coloration
shigella & salmonella. G- rods that DO NOT ferment lactose.
which bacteria will grown on EMB with green metallic sheen?
E COLI: FERMENTING LACTOSE
SSA stands for?
what type of medium is SSA?
selective & differential
what does SSA select?
only enteric, nonlactose, gram NEGATIVE.
SALMONELLA & SHIGELLA
what does SSA plates contain?
bile salts & sodium citrate
salmonella shigella agar. contains bile salts and sodium citrate. GROWS only SALMONELLA OR SHIGELLA white or clear. anything else that may grow will appear pink or red.
DIFFERENTIATES H2S production. SALMONELLA produces H2S, has BLACK CENTERS TO COLONY. Shigella, has no black colonies.
which microorganism will produce H2S as a byproduct, and what plate should be used to see it?
how do you differentiate between salmonella and shigella?
salmonella will have black centers due to H2S production
how do you test for staph or strept?
catalase test. staph produces catalase so will be positive.
what is the catalase test?
differentiates staph from strept. drop H2O2 peroxide onto slide. if bubbles, then it is positive for STAPH.
what could cause a false positive in a peroxide test?
if blood agar was scraped up with the colony it will be positive for CATALASE too.
which plates contain blood agar?
agar that tests for the presence of DNAase. The agar contains DNA and methyl green indicator. if the bacteria produces DNAase, the agar will turn clear as DNA is broken down.
what are some DNAse POSITIVE bacteria?
what test will differentiate between staph. aureus and staph. epidermidis?
drop plasma on slide, then mix with a loop of bacteria, if CLUMPS form it is POSITIVE FOR AUREUS
macConkey agar selects Gram NEGATIVE, enteric bacteria. differentiates for LACTOSE FERMENTORS. contains BILE SALTS and crystal violet which prohibits gram positive.
tests if bacteria can break down amino acid tryptophan and produce indole.
RED RING is positive for presence of INDOLE
what test is used to show the breakdown or tryptaphan?
INDOLE TEST using ERHLICHS REAGENT.
what reagent is used for indole test?
what is the result for a ECOLI indole test?
RED RING. positive for INDOLE, breaks down tryptaphan
methyl red test
tests for GLUCOSE breakdown.
what is the result for ECOLI methyl red test?
RED RING, positive for breakdown of GLUCOSE.
o'meara reagent. breakdown of glucose into acetoin. RED
what is the result of a ECOLI Voges-proskauer test?
RED. positive for breakdown of glucose into acetoin.
which two tests show breakdown of glucose?
voges-prokauer & Methyl Red
tests the ability to use citrate as source of carbon. pH indicator shows a basic pH change. positve test will turn blue.
check for the ability to break down urea into ammonia and CO2 with enzyme UREASE. RED IS POSITIVE FOR UREASE.
phenylalanine deaminase agar. ENZYME PHENYLALANINE DEAMINASE. add drops of FERRIC CHLORIDE, GREEN COLOR on surface is POSITIVE.
triple sugar iron. GLUCOSE, LACTOSE, SUCROSE. ACID production from glucose occurs at the butt. other fermentation occurs on top. YELLOW when acid is produced. POSITIVE for fermentation. RED is no fermentation.
TSI- red slant
TSI - yellow slant
TSI - YELLOW butt
TSI - black butt
sulfide, indole, MOTILITY.
MOTILITY= Growth spreads
INDOLE= add erhlichs reagent, RED +, breaks down TRYPTAPHAN.
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