Micro Final Exam Media and biochemicals

BAP

* Primary Media
* Differential (hemolysis)

CHOC

* Primary media
* Enriched media

Columbia Naladixic Acid (CNA)

Selects for

* Gram positive organisms
* Differential (hemolysis)
* Enriched media

Phenylethyl alcohol agar (PEA)

Selects for Gram positive organisms

Bile Esculin Agar (BEA)

* Blackening (Enterococcus sp)
* No blackening of the media

Buffered Charcoal Yeast Extract (BCYE)

Legionella species

Bordet – Gengou (Pearls)

* Used to isolate Bordetella

Regan – Lowe (Mercury droplets)

* Used to isolate Bordetella

Salmonella-Shigella Agar (SS)

* Used for isolating Salmonella & Shigella.
* Salmonella = colorless w/black center
* Shigella = colorless

Hektoen enteric agar (HE)

* Isolate and differentiate Enteric Pathogens
* Orange = Lactose/Sucrose fermenter
* Black colonies = Salmonella
* Green colonies = Shigella

Xylose lysine deoxycholate (XLD) agar

* Isolate and differentiate Enteric Pathogens
* Yellow = Fermenters
* Red = Shigella
* Red with black centers = Salmonella
* Selective and Differential media

MacConkey (MAC)

* Selects for Gram Negatives and Differential (Lactose)

CAMPY Agar

* Used for isolating Campylobacter sp.

Skirrow agar

* Used for isolating Campylobacter sp.

Cefsulodin-Irgasan-Novobiocin (CIN)

* Selects for Yersinia (Bull’s eye)
* Selective & Differential media

Thiosulfate Citrate Bile Salts Sucrose (TCBS)

* Used for isolating Vibrio species = Selective & Differential media
* Yellow colonies = V. cholerae, V. alginolyticus
* Green/blue centers = V. vulnificus, V. parahaemolyticus

Eosin methylene blue  (EMB) (Can be used in the place of MAC)

* LF= blue/black colonies
* NLF = colorless
* E. coli = green metallic sheen
* Selective & Differential media

MAC – Sorbitol

* Used for the isolation of E. coli O157:H7 (sorbitol negative = COLORLESS)

Cystine agar

* Needed for isolating Francisella

Mannitol salt Agar (MSA)

* Identifying Staphylococci
* Staph aureus = YELLOW, ferments mannitol
* RED colonies = not Staph. Aureus (CoNS)

Thayer Martin (TM) agar

* Used for the isolation of N. gonorrhoeae and N. Meningitidis
* Screened for growth for 72hrs
* Enriched and Selective

Loffler Medium

* Stimulates the production of metachromatic granules for C. diphtheriae

Tinsdale Agar

* Differentiates Corynebacterium spp with potassium tellurite that is in the medium (BROWN-BLACK colonies)

Cystine-tellurite blood

* Isolation of C. diphtheriae

Coagulase

* Slide Coagulase – detects bound coagulase
* Tube Coagulase- detects free coagulase
* ==Clot/Clumping = Positive==
* No clot/Clumping = Negative

Novobiocin

* Resistant = S. Saprophyticus
* Susceptible = Other CoNS

Microdase (tetramethyl-p-phenylenediamine)

* ==Positive = BLUE-PURPLE==
* Negative = no color change

Bacitracin (A) disk

* Used for S. pyogenes identification (S)

PYR test (L-pyrrolidonyl-b-naphthylamide)

* ==Positive = PINK==
* Negative = no color change

Motility

* ==Positive = HAZE/movement out of the stab line==
* Negative =  NO movement from the stab line

ONPG (Ortho-Nitrophenyl-beta-D-Galactopyranoside)

* Test for slow lactose fermenters (have beta galactosidase not beta galactosidase permease)
* ==Positive = YELLOW (O-nitrophenol)==
* Negative = Clear

Methyl Red (Mixed acid pathway)

* ==RED = Positive==

Voges – Proskauer (VP)

* Used to determine the presence of acetylmethylcarbinol (acetoin) from glucose fermentation. Reagents added are alpha-naphthol and potassium hydroxide
* ==RED = positive==

Hippurate hydrolysis

* ==Positive = PURPLE==
* Negative = no color change
* ==\*\*S. agalactiae = positive\*\*==

Optochin (P) disk (ethylhydrocupreine hydrochloride)

* ==Positive = zone of inhibition==
* Negative = no zone
* ==\*\*S. pneumonia = ZOI (Positive)\*\*==

Bile solubility test (10% sodium desoxycholate)

* ==Positive – colonies dissolve==
* Negative – colonies not affected
* ==\*\*S. pneumoniae colonies dissolve (Positive)\*\*==

ELEK test

* Toxin testing for C. diphtheriae

Urea test (urease)

* ==Positive = PINK==
* Negative – No color change

Nitrate test

* sulfanilic acid and *N,N*-dimethyl-alpha-napthylamine are added to a nitrate broth, look for ==RED color change = Positive==
* If there is no color change, add zinc dust. If ==no color change (Positive)== but if RED = negative

MUG (4-methylumbelliferyl-b-D-glucuronide) Tests for b-glucuronidase

* EHEC does not have enzyme = COLORLESS
* Non-EHEC = BLUE

Citrate

* ==Positive = BLUE==
* Negative = GREEN

Indole - Kovac’s method

* Testing for the production of indole by tryptophanase
* p-dimethylaminobenzaldehyde, isobutyl or isoamyl alcohol, hydrochloric acid added to tryptophan broth
* ==RED = positive==

Indole - spot indole

* Testing for the production of indole by tryptophanase
* p-dimethylaminocinnamaldehyde is the reagent
* ==BLUE = positive==

Phenylalanine deaminase (PAD)

* Deamination of phenylalanine produces phenylpyruvic acid
* Add 10% ferric chloride
* ==GREEN = positive==
* ==\*\*Used in differentiation of Proteus, Morganella & Providencia==

Decarboxylase

* Reaction occurs in acidic environment; looking for an alkaline end product!
* ==Positive = PURPLE==
* Negative = YELLOW

Catalase

* Hydrogen peroxide
* ==Positive = Bubbles==
* Negative = No bubbles

Oxidase

* Determines presence of cytochrome oxidase system
* tetramethyl-p-phenylenediamine
* Dihydrochloride more specific
* p-Aminodimethylaniline oxalate
* ==Positive = PURPLE==
* Negative = YELLOW

ALA test

* ==Positive = RED==

Cystine trypticase agar

* Carbohydrate utilization
* ==Positive = YELLOW==

NET test

* Blue – Beta galactosidase = N. lactamica
* Pink – Hydroxyprolylaminopeptidase = N. gonorrhoehae
* Yellow- gamma-gutamylaminopeptidase = N. meningitides