Bacterial Diagnostics

Question 1

Why is diagnosis important?

Answer 1

increase knowledge, avoid economic loss, help public health

Question 2

What are the phases of diagnosis?

Answer 2

Pre-analytical phase
Analytical phase
Post-analytical phase

Question 3

What is the clinicians role in pre-analytic phase?

Answer 3

make diagnosis, collect samples and select tests, prepare forms, use appropriate transport

Question 4

T/F: Time and temp positively affect samples

Answer 4

False negatively affect

Question 5

Why is getting treatment history important in pre-analysis?

Answer 5

r/o pathogens, determine resistance or therapy failure, judge if pathogen load may be decreased

Question 6

When do you collect samples?

Answer 6

acute or early disease stage and BEFORE ANY MEDICATIONS/THERAPIES

Question 7

What is an transudate?

Answer 7

fluid build-up due to a vessel leak, usually bilateral, pale or clear colored

Question 8

What is an exudate?

Answer 8

tissue leakage due to inflammation and local damage, usually turbid and opaque

Question 9

What are the 2 diagnostic methods?

Answer 9

detection of agent or detection of host immune response

Question 10

Describe detection of agent method

Answer 10

detect bacteria, isolate cultures, detect ag, or molecular DNA detection

Question 11

Describe detection of immune response method

Answer 11

serology (humoral detection)
detect cell mediated immunity

Question 12

What is BSL?

Answer 12

biosafety levels, combination of techniques used to minimize exposure to biohazard

Question 13

How is BSL ranked?

Answer 13

1: not disease associated
2: rarely serious human disease (ringworm)
3: serious or lethal disease with possible tx (anthrax)
4: very serious and lethal disease with little to no tx (smallpox, ebola)

Question 14

What is Mac Conkey Agar selective for? differential for?

Answer 14

gram - and lactose fermentation

Question 15

Bacterial colony

Answer 15

visible mass of bacteria all from single mother cell

Question 16

Which type of PCR is quantitative?

Answer 16

real-time PCR - determines how many pathogens

Question 17

Methods of detecting humoral response

Answer 17

Serology
Ab titers: paired serum or IgM to IgG conversion

Question 18

What are the advantages of serology

Answer 18

widely used, rapid, some useful for carrier or chronic cases

Question 19

What are the disadvantages of serology

Answer 19

false negatives and false positives

Question 20

What is a test for cellular response?

Answer 20

TB skin test

Question 21

Describe the TB Skin Test

Answer 21

First perform caudal fold test, if Ab present - swelling occurs
If positive test for Comparative Cervical Test

Question 22

What is the comparative cervical test?

Answer 22

Inject with bovine and avian PPD and compared areas, if bovine >4x avian thats a POSITIVE

Question 23

T/F: a negative on microscopy rules out infection

Answer 23

False, does not rule out infection

Question 24

T/F: A negative on serology does not discard infection

Answer 24

True

Question 25

T/F: A positive PCR in a healthy animal means active infection and requires treatment

Answer 25

False, doesnt mean active infection

Question 26

T/F: a positive on culture cannot be host microbiota

Answer 26

False it can be host microbiota