5.1 Lab

Question 1

Basic requirements of an ideal diagnostic procedure

Answer 1

-Speed
-Simplicity
-Sensitivity: represents the likelihood that an animal with a disease will have a positive test result
-Specificity: represents the likelihood that an animal without a disease will have a negative test result
-Low cost

Question 2

requirements for sending specimen to the lab

Answer 2

-label
-appropriate size sample
-sterile container

> > sample submission form: provide clinical history and a list of differentials, with details

Question 3

what is better, swab sample or tissue sample?

Answer 3

lab with prefer tissue sample

Question 4

what approaches to detection of bacteria can we use for feces, exudate, excretion, secretion, tissue, blood, and hair?

Answer 4

-isolation
-direct detection > antigen or nucleic acid

Question 5

what approaches to bacterial detection can we use for blood (serum)?

Answer 5

indirect detection > antibodies (serological tests)

Question 6

main types of agar used for bacterial isolation and what bacteria they are good for

Answer 6

blood agar - almost all types of bacteria
McConkey agar - gram negative only

Question 7

what is the coagulase test and why is it important? how does it work? what bacteria is it good for?

Answer 7

coagulase + prothrombin > staphylothrombin
>activates protease
>proteolysis, fibrinogen, fibrin clot

in summary, Coagulase is an enzyme which causes the clotting of blood plasma.

-tells us about pathogenicity > positive test means pathogenic, negative is often not pathogenic but might be
>commonly used to detect staph areus

Question 8

besides identification, why is isolation of bacteria important in certain cases?

Answer 8

-test for antibiotic resistance/ susceptibility pattern
-need pure, isolated colonies to run tests, else results will be mixed up

Question 9

how can we identify the genus/ species of bacteria?

Answer 9

-biochemical tests (old school)
-MADLI-TOF Mass Spectrometry