Biochemical Tests
What is the reagent for the catalase test?
3% Hydrogen peroxide
Bacitracin can be used to help identify which two organisms?
Micrococcus luteus and Streptococcus pyogenes
What is the reagent for the coagulase test?
rabbit plasma
What four organisms are included in TSI Group I organisms?
E. coli
Klebsiella spp.
Enterobacter spp.
Serratia spp.
What is the carbohydrate source in TCBS agar?
Sucrose
What are the two reagents for the nitrate test?
Sulfanilic acid and alpha naphthylamine
SXT is used to help identify which organisms?
Beta hemolytic strep
A and B resistant
All others sensitive
The following results were obtained from the growth of white, pinpoint colonies:
Catalase: positive
Coagulase: negative
Novobiocin: sensitive
Mannitol salt: growth positive, negative fermentation
What is the identity of the organism?
Staphylococcus epidermidis
What three organisms are PAD positive?
Proteus, Providencia, and Morganella
Lactose, sucrose, and salicin
What sugars are in TSI media?
glucose, lactose, sucrose
What disk is used to test for beta lactamase production?
Cefinase
What is the most likely identity of an organism with the following results?
Catalase: negative
PYR: negative
CAMP test: negative
Hippurate hydrolysis: negative
6.5% NACl: negative for growth
Bile esculin: positive for growth and esculin hydrolysis
Group D Strep
An gram-negative organism gave the following biochemical results:
TSI Group II
Oxidase: negative
MR: positive, VP: negative
Urease: negative
LIA: positive
Citrate: negative
Indole: positive
What is the identity of the organism?
Edwardsiella tarda
Name a gram-positive selective media.
CNA, SSA or PEA
What is the reagent for the PAD test?
10% ferric chloride
What two disks are used to determine the presence of the erm gene?
Erythromycin and Clindamycin
What is the reagent for the Hippurate hydrolysis test?
Ninhydrin
A gram-negative organism gave the following biochemical results:
TSI Group III
Oxidase: negative
Catalase: positive
Indole: positive
PAD: positive
MR: positive, VP: negative
Motility: positive
Citrate: positive
What is the identity of the organism?
Providencia spp.
What ingredients are included in anaerobic media that boosts growth?
Vitamin K and Hemin
What is the reagent for the oxidase test?
tetra-methyl- p-phenylenediamine dihydrochloride
The presence of the mecA gene is identified using what antimicrobial agent?
oxicillin
Growth of a gram-positive organism demonstrated a weakly positive catalase test, so the preliminary report identified the organism as a Staphylococcus species. The patient was administered vancomycin with no improvement. What is the most likely identification of the causative agent?
Vancomycin resistant Enterococcus
TSI Group V
Catalase: positive
Oxidase: negative
Citrate: positive
MR: negative, VP: negative
SIM: negative, negative, negative
OF: yellow in uncovered tube
Nitrate: negative
Growth at 42: positive
Acinetobacter baumannii
What are the selective agents included in Thayer Martin media?
Vancomycin and Colistin