2. Patient to result

Question 1

What is the diagnostic pathway?

Answer 1

1. request
2. sample collection
3. transport of samples
4. reception
5. safety issues -risks?
6. non culture techniques
7. culture of clinical samples
8. identification and sensitivity
9. result

Question 2

What are sterile sites?

Answer 2

• Blood/bone marrow aspirate
• CSF
• Tissue (meningitis)
• Lower respiratory tract (BAL)
• Bladder

Question 3

What are non-sterile sites?

Answer 3

• Upper respiratory tract (commensal bacteria)
• Skin
• GI tract
• Vagina
• Urethra (skin commensals and faecal flora)

Question 4

What are examples of specimens received?

Answer 4

• MSU (main stream urine)
• Blood culture (sepsis)
• Urethral swab (STI)
• Faeces (C.diff)
• Toe nail clippings (fungal infections)
• Sputum (cystic fibrosis)

Question 5

What are the rules for sample collection?

Answer 5

• take appropriate specimen
• collect before antibiotics are given
• avoid contamination
• label specimens correctly
• complete request form completely
• transport should be asap

Question 6

What is the bacterial transport media?

Answer 6

STM - Stuarts transport media
- contains charcoal to inactivate any toxic bacterial bi-products
- used for swabs: not fluids

Question 7

What is the virus transport media?

Answer 7

VTM - viral transport media
- buffered salt solution containing serum
- contains antimicrobials to control overgrowth of contaminating bacteria and fungi

Question 8

Why should samples be refrigerated at 4 degrees?

Answer 8

to slow down any microbial growth

Question 9

What is the role of the clinical microbiology reception?

Answer 9

• check specimen/ form
• allocation of unique laboratory number
• macroscopic appearance- discard unsuitable samples

Question 10

What is the ACDP?

Answer 10

Advisory Committee on Dangerous Pathogens
- has different categories for pathogens: 1,2,3 etc

Question 11

What is category 1?

Answer 11

A biological agent unlikely to cause human disease

Question 12

What is category 2?

Answer 12

A biological agent that can cause human disease; hazardous to employees; unlikely to spread in community

Question 13

What is category 3?

Answer 13

A biological agent that can cause severe human disease; serious hazard; risk of spread in community; prophylaxis

Question 14

What is category 4?

Answer 14

A biological agent that can cause severe human disease; serious hazard to employees; likely spread in community; no effective treatment

Question 15

What are non culture techniques?

Answer 15

• direct microscopy
• antigen detection
• PCR
• Serological response

Question 16

What are culture techniques?

Answer 16

• solid agar

Question 17

When is direct microscopy used?

Answer 17

• for a clinical sample
• widely use light microscopy
• can use wet preparation; parasite ova and cysts
• can use stained preparations; gram stain for bacteria and yeast

Question 18

What is antigen detection?

Answer 18

• use antigen detection kits
• contain latex beads coated with specific antibodies for antigen
• if in direct contact with bacteria, then agglutination occurs

Question 19

What are different types of solid agar?

Answer 19

• basic; nutrient agar
• enriched agar
• selective agar
• differential agar

Question 20

What is enriched media?

Answer 20

general purpose medium
- horse blood agar
useful for demonstrating haemolysis
- chocolate agar
useful for growing fastidious organisms

Question 21

What is selective media?

Answer 21

• medium where a selective compound has been added
• inhibit growth of commensals. allow growth of bacteria
• eg.. CCFA - grey colonies

Question 22

What is differential media?

Answer 22

medium it which an indicator (dye has been added
- CLED
Bromothymol blue ( yellow in acid pH)