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Flashcards in Medical microbiology Deck (11):
1

What are categories of microorganism that cause infection?

- Bacteria
- Viruses
- Fungi
- Parasites
- Prions

2

What are the two main sites of specimen collection?

Sterile and non-sterile sites

3

What are examples of sterile sites?

Bloods
CSF
Lung
Bladder

4

What are examples of non-sterile sites?

Skin
Nasopharynx
Urethra
Gut

5

Give examples of infections and how you would sample them

UTI - Mid-stream urine
Chest infection - sputum
Tonsilitis/pharyngitis - throat swab
Wound or site infection - swab or pus
Diarrhoea - faeces
Bacteraemia - blood culture
Meningitis - cerebro-spinal fluid

6

What is the role of microscopy in diagnosis of bacterial infection?

Useful technique for sterile samples where you want to get a quick result.

Gives in initial idea of the type of bacteria

7

What is the role of Gram stain in diagnosis of bacterial infection?

Relatively quick test that lacks sensitivity

Can't usually identify particular species

8

What is the role of bacterial culture in diagnosis of bacterial infection?

Sensitive
Can identify different bacterium and stave off others depending on what conditions you're interested in
Slow, can take a couple of days or up to a week for TB

9

Conditions you can alter for bacterial culture

Type of media, non-selective (blood, chocolate) or selective (MacConkey)
Atmosphere
Temperature
Duration of incubation

10

How do you detect viruses?

- Molecular methods, real time PCR
- Antigen detection
- Serology
- Rarely used methods, electron microscopy or cell or tissue culture

11

How do you diagnose parasites?

- Microscopy: parasites, cysts, ova in faces or blood films for malaria
- Sometimes serology to see past exposure