Flashcards in Lecture 6 - Gastrointestinal Disease 2 Deck (26):
1
What can light microscopy show us when investigating GIT disease?
Cysts
'Pus' cells --> inflammation
Parasites
2
What can electron microscopy show us when investigating GIT disease?
Viruses
3
Describe the process of Latex agglutination / EIA / ELISA?
1. Known Ab place on bottom
2. Unbound sites blocked
3. Antigen added from sample
4. Known Ab with conjugated enzyme added
5. Substrate for enzyme added
6. Colour is read
4
What are routine media?
DCA
MAC
5
What are specialised media?
CAMP
BCSA
BP
CIN
6
What are enrichment media?
Selenite broth
7
How would we first identify significant isolates?
Biochemical tests
8
How would we confirm the pathogen?
Serological tests
9
How do we compare strains?
Phage typing
PFGE
10
How do we look for specific virulence determinants?
PCR
Gel electrophoresis
11
What are the features of Enterobacteriaceae?
GNR
Ox. Negative
Fermenters
12
What are the features of Vibrio (Vibrionaceae)?
GN (curved) R
Ox. positive
Fermenters
Motile
13
What are the features of Campylobacter (Vibrionaceae)?
GN (curved) R
Oc. positive
LNF
14
What does MAC allow to grow?
E. coli
Salmonella, Shigella
15
How do we differentiate between E. coli, Shigella and Salmonella on MAC?
Lactose fermenters --> pink (E. coli)
LNF --> Yellow / colourless (Salmonella, Shigella)
16
What does DCA allow to grow?
Similar to MAC
Salmonella: black dot
17
What do we do after culture on routine media?
Look for suspicious colonies:
LNF: Shigella, Salmonella, Yersinia
These are not normal flora of the gut
18
What does Selenite broth allow to grow?
Salmonella spp. --> brick red
19
What does BP select for?
Staphylococcus aureus --> black with zone of clearing
20
What does BCSA select for?
Bacillus cereus --> blue + white precipitate
21
What does CAMP select for?
Campylobacter
22
Describe how an agglutination reaction works
Bacteria + antibody --> visibly agglutinates
23
What is phage typing used for?
To determine the source: same phage types --> same source?
24
Describe the process of phage typing
1. Lawn culture of bacteria applied to plate
2. Panel of phages dotted onto a grid
3. Incubation of plate
4. Pattern of areas of lysis read
5. Phage type assigned
25
What bacteria is phage typing used for?
Salmonella
S. aureus
26