lab final (medias) Flashcards
what is the purpose of a MAC plate?
differentiate lactose-fermenting and lactose non-fermenting gram-negative cells
what are the selective agents in a MAC plate and what do they do
crystal violet and bile salts
select for gram-negative and enteric bacteria
what are the differential agents in MAC plate and what do they do
lactose and neutral red
lactose is fermented which results in acidic pH and neutral red to turn a bright pink-red color
what is the pH indicator in a MAC plate
neutral red
what is the purpose of an MSA plate
to determine if the bacteria is halophilic (salt loving) and if the bacteria can ferment mannitol
what does halophilic mean
able to grow in high salt environment
what is the purpose of blood agar plate
identify hemolysis
blood agar plate has __ media
enriched
what is hemolysis
breakdown of red blood cells
what is the purpose of sabarouds dextrose agar
grow fungi
what is the selective agent in MSA plate and what does it select for
salt
gram + staphylococcos
what are the differential agents in MSA plate and what do they differentiate
mannitol - fermentation of acids
phenol red - ph indicator
what is the purpose of the simmons citrate test
identify the microbe’s ability to use citrate as an energy source
which test uses bromothymol blue
sodium citrate
what is the purpose of sim test
test ability of organism to reduce sulfur, produce indole, and motility
what is the selective ingredient in the indole test
kovac’s reagent
what does kovac’s reagent do in indole test test
identifies production of indole
reacts with indole to produce a red compound
what is the purpose of mrvp test
determine which fermentation pathway is used to utilize glucose
what are the products of mrvp test
mixed acids or alcohol
what is the pH indicator in mrvp test and what does it do
methyl red
indicates if pH is below 4.4 which indicates glucose fermentation and acid production
what is the purpose of mueller hinton agar
used in the kirby-bauer method to determine antibiotic resistance
which test is used in the kirby bauer method
muller hinton
what is the purpose of catalase test
determine presence of catalase
how do you interpret the results of catalase test
hydrogen peroxide is added
in a positive reaction, catalase breaks down hydrogen peroxide and causes bubbles
what is the broth dilutions test used for
determine MIC (minimum inhibitory concentration) and MBC (minimal bactericidal concentration) of an antimicrobial drug
what are negative and positive results for mrvp test
negative - yellow
positive - red
what are negative and positive results for citrate test
negative - green
positive - growth or blue
in the sim test, what is a positive and negative reaction for sulfur reduction
positive - black
negative - no color change
what does a positive and negative result on a MAC plate look like
positive - bright pink
negative - yellow
what does a positive and negative result look like on a MSA plate
positive - yellow
negative - pink
what do results look like for lactose broth test
positive - yellow
negative - pink
how do staph aureus and strep aureus react to catalase
staph: catalase positive
strep: catalase negative
s aureus and s pyogenes produce what type of hemolysis
Beta hemolysis
what is the selective ingredient in SDA and what does it do
antibiotics - grow fungi
what is a positive result for motility test
moved away from the stab line
what is a positive result for indole test
pink
what is added to the mrvp test to indicate glucose fermentation and alcohol production
koh+
what is the purpose of lactose broth
identify lactose fermentation and acid production
what is the ph indicator in lactose broth
phenol red
what is a positive result of lactose broth
yellow and gas bubble in durham tube
which test uses a durham tube for gas collection
lactose broth
s pyogenes is catalase positive or negative
catalase negative
