Biochemical Tests Part 2 Flashcards
Results for Lysine Iron Agar
Slant (Deamination) = Burgundy red (+); Purple (-)
Butt (Decarboxylation) = Purple (+); Yellow (-)
Purple: Deamination neg, Decarboxylation pos
*deAmination & deCarboxylation = A first sa alphabet meaning una makita from opening of tube (slant)
Result interpretation of LIA
K/K (Purple/Purple) : Decarboxylase (+)
R/A (Red-Burgundy/Yellow) : Deamination (+) w/ Glucose Fermentation
K/A (Purple/Yellow) : Decarb & Deam (-) w/ Glucose fermentation
What organisms presents as K/K, H2S(+) on LIA
Salmonella
What organism presents as K/A, H2S (-) on LIA
Shigella
What organism Presents as R/A, H2S (-) o LIA
Proteus, Providencia, Morganella (PPM)
Organisms reported as K/K on LIA
E. coli, Klebsiella, Enterobacter (EKE)
Serratia
Hafnia
Salmonella
Reported as K/A on LIA
Enterobacter cloacae
Yersinia spp
Shigella spp
Reported as R/A on LIA
Proteus, Providencia, Morganella (PPM)
Determines the ability of an organism to use citrate as sole carbon source and inorganic ammonium salts as sole nitrogen source
Citrate Utilization Test
Part of IMViC (indole, methyl red, Voges-Proskauer, and citrate), which is used to differentiate Enterobacteriaceae from other gram-negative rods
Media used for Citrate Utilization test
Simmon citrate
pH indicator of Citrate utilization
Bromthymol Blue
*SHOT tag gsm Blue (Simmon Citrate Agar, HEA, OF medium, Thiosufate Citrate Bile Sucrose Agar)
Positive result for Citrate Utilization Test
Growth in the medium w/ or w/out a change in the color of the indicator
Positive and Negative QC for Citrate utilization test
Positive QC: Serratia
Negative QC: E. coli
Enterobacter (+), Other gram neg rods (-)
Principle is based on the ability of some bacteria to hydrolyze urea into ammonia water and CO2, leading to alkalinity of the medium
Urease Test
Proteus spp. may be presumptively identified by the ability to rapidly hydrolyze urea
pH Indicator of Urease Test
Phenol Red
*TX MU C Aling Dionesia Pacqiuao (TSI, XLD, MSA, Urease, Acidimetric, Dermatophyte Test Medium: Phenol Red)
Medium used for Urea Test
Christensen Urea
Other name for Urease Method
Christensen’s Method
*Name from the medium used: Christensen Urea
Positive Result for Urea
Color change from Yellow to RED (Orange to Magenta)
Positive & Negative QC for Urease Test
Positive QC: Citrobacter
Negative QC: E. coli
What are the Rapid Urease positive Bacteria
Proteus, Providencia, Morganella (PPM)
*Other Urease (+) organism Mnemonic (PUNCH: Proteus, Providencia, Ureaplasma, Nocardia, Citrobacter, Helicobacter)
What are slow Urease positive organism
Citrobacter
Klebsiella
Enterobacter
Yersinia
Serratia
*Mnemonic C-KEYS (U have C-KEYS to my heart)
Measures and organism’s ability to decarboxylate/hydrolyze an amino acid to produce amine
Decarboxylase Test
*Differentiate decarboxylase-producing Enterobacteriaceae from other gram-negative rods
pH indicator of Decrboxylase test
Bromcrescol Purple
Positive result for Decarboxylase test
Color change from Yellow (acid) to Purple (Alkaline)
What are the amino acids used in Decarboxylase test and what are the products of their decarboxylation
Lysine > Cadaverine
Ornithine > Putrescine
Arginine > Citrulline
Positive QC for Decarboxylation test
Lysine = Klebsiella pneumoniae
Ornithine = Klebsiella obsytoca
Arginine = Klebsiella obsytoca
Determines the ability of anorganism to ferment a specific carbohydrate in a basal medium, w/ or w/out gas production
Fermentation Media
A fermentation medium consists of a basal medium containing a single carbohydrate (glucose, lactose, or sucrose) for fermentation and a color indicator of choice
What is used in Fermentation media that allows for differentiation of EBC’s (Enterobacterceae) from Coryneforms
Coryneforms = Corynebacterium
Peptone medium w/ Andrade’s acid fuchsin
Brain Heart infusion Broth w/ Bromcresol purple is used to distinguish enterococci from streptococci
What is used to detect gas formation in in fermentation media
Durham tube
Positive result for fermentation media
Indicator changes color to pink w/ or w/out Gas production
Negative result = no color change (Solution remains clear/ Pale Yellow/ Straw colored)
Organism that presents as Positive (Pink), with gas on Fermentation Media
E. coli
Organism that presents as Positive (Pink), without gas on fermentation media
Shigella
Organism that presents as Negative (Straw/Pale yellow/Clear) on fermentation media
Pseudomonas aeruginosa
Cannot ferment glucose
This test is used to identify organisms that produce the enzyme tryptophanase
Indole Test
Tryptophanase: Hydrolyzes: Tryptophan > indole + Pyruvic acid/Pyruvate + Ammonia
Test is part of IMViC
Reagent used for Enterobacteriaceae in Indole test
Kovac’s reagent
Contains para-dimethylaminobenzaldehyde (DMAB), and concentrated hydrochloric acid
Reagent used for other gram negative bacilli in Indole Test
Ehrlich’s Reagent
p-dimethylaminobenzaldehyde (DMAB) and Xylene