Bacterial Diagnostics Flashcards
Why is diagnosis important?
increase knowledge, avoid economic loss, help public health
What are the phases of diagnosis?
Pre-analytical phase
Analytical phase
Post-analytical phase
What is the clinicians role in pre-analytic phase?
make diagnosis, collect samples and select tests, prepare forms, use appropriate transport
T/F: Time and temp positively affect samples
False negatively affect
Why is getting treatment history important in pre-analysis?
r/o pathogens, determine resistance or therapy failure, judge if pathogen load may be decreased
When do you collect samples?
acute or early disease stage and BEFORE ANY MEDICATIONS/THERAPIES
What is an transudate?
fluid build-up due to a vessel leak, usually bilateral, pale or clear colored
What is an exudate?
tissue leakage due to inflammation and local damage, usually turbid and opaque
What are the 2 diagnostic methods?
detection of agent or detection of host immune response
Describe detection of agent method
detect bacteria, isolate cultures, detect ag, or molecular DNA detection
Describe detection of immune response method
serology (humoral detection)
detect cell mediated immunity
What is BSL?
biosafety levels, combination of techniques used to minimize exposure to biohazard
How is BSL ranked?
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)
What is Mac Conkey Agar selective for? differential for?
gram - and lactose fermentation
Bacterial colony
visible mass of bacteria all from single mother cell
Which type of PCR is quantitative?
real-time PCR - determines how many pathogens
Methods of detecting humoral response
Serology
Ab titers: paired serum or IgM to IgG conversion
What are the advantages of serology
widely used, rapid, some useful for carrier or chronic cases
What are the disadvantages of serology
false negatives and false positives
What is a test for cellular response?
TB skin test
Describe the TB Skin Test
First perform caudal fold test, if Ab present - swelling occurs
If positive test for Comparative Cervical Test
What is the comparative cervical test?
Inject with bovine and avian PPD and compared areas, if bovine >4x avian thats a POSITIVE
T/F: a negative on microscopy rules out infection
False, does not rule out infection
T/F: A negative on serology does not discard infection
True
T/F: A positive PCR in a healthy animal means active infection and requires treatment
False, doesnt mean active infection
T/F: a positive on culture cannot be host microbiota
False it can be host microbiota
