Microbial Diagnostic Tests

Question 1

How does gram staining work?

Answer 1

Fixation, crystal violet, iodine treatment, discolouration and counter stain (safranin)

Question 2

What are the 3 main cell shapes?

Answer 2

Cocci (sound), bacilli (rods) and spiral

Question 3

How would you conduct a PCR test?

Answer 3

Separate strands
Add primers
DNA polymerase to add complementary strand
New strand is template
More primers
More DNA polymerase
New strand is sequenced
Final product is dsDNA

Question 4

What is the ELISA test?

Answer 4

Antigens stuck to well
Add patient serum
If antibodies present=bind
Non bound antibodies removed
Animal antibody against human antibody added and bound with enzyme
Clear liquid added=coloured if enzyme bound to antibody
Colour indicates antibody present
Opp for antigens