Week 2 MicroLab

Question 1

Catalase test

Answer 1

does hydrogen peroxide get degraded?

positive is bubbly
staphylococci are positive
streptococci are negative

Question 2

coagulase test

Answer 2

is there clumps or is it white and milky?

positive is clumps and is staphylococcus aureus
negative is other staphylococci

Question 3

Oxidase test

Answer 3

presence of cytochrome oxidase which oxidizes the artificial electron donor and leads to purple color

Positive is purple and is neiserria, MORAXELLA CATARRHALIS
and psuedomonas, and aeromonas

Enterobacteriaceae is always negative

Question 4

P disc test with Optochin

Answer 4

Streptococci pneumoniae is sensitive and will see 15 mm ring of no growht
other alpha hemolytic streptococci are resistant and will grow up to the p disc

Question 5

Bacitracin sensitivity A disc

Answer 5

group A lancefield streptococci are sensitive and will see an area of inhibition, this includes streptococcus pyogenes

other Beta hemolytic non group a Streptococci are resistant and will grow up next to the A disc

Question 6

Bile Esculin Test

Answer 6

staphylococcus epidermididis is negative

enterococcus faecalis is positive

Question 7

Beta Hemolytic examples

Answer 7

Staphylococcus aureus
Streptococcus Pyogenes
Non group a beta hemolytic Streptococci

Question 8

Alpha Hemolytic examples

Answer 8

streptococcus pneumoniae

Streptococcus vindans

Question 9

gamma hemolytic examples

Answer 9

staphylococcus epidermidis
enterrococus faecalis
moraxella catarrhalis