Presentation

Question 1

SediMax principle

Answer 1

Automated urine analyser
Transfer sample to Sedivettes
Uncap tube, load onto track and start analysis
Sample is mixed, 0.2ml is transferred to a cuvette, cuvette is centrifuged at 2000 RPM for 10 seconds
A camera takes bright-field and phase-contrast pictures of 10 points across specimen
Image evaluation software then detects and classifies formed elements of urine

Question 2

EntericBIO Gastric Panel 2 Principle

Answer 2

Campylobacter, Salmonella, Shigella, VTEC, Cryptosporidium, Giardia
Sample preparation:
‘tea-coloured solution’
Denaturing
Enteric Bio Workstation
Need to be careful not to overload PCR
Use Swab to take up a small amount of sample, just enough to make a tea-coloured solution
SPF tubes used
Heating step to separate double stranded DNA into single strands suitable for amplification
Further sample preparation done by EntericBio workstation

Question 3

ROCHE light cycler 480 principle

Answer 3

Multiplex PCR amplification and hybridisation of target genes
Analysis of the amplified nucleic acid by melting curve analysis

Question 4

GeneXpert principle

Answer 4

Norovirus and C.Diff
Simply have to just add sample to cartridge -> very very little sample needed
○ Swab a tiny amount of sample and add to buffer
○ Snap off swab tip in buffer and vortex together
Add mixture to norovirus GeneXpert cartridge
Sample preparation, amplification and detection are all done on board
Detection of target sequence through real-time PCR

Question 5

Isolation of urines

Answer 5

Only urines with a white cell count >20 are cultured
If patient is immunocompromised then a raised wcc is not required
Raised rbcs, epithelial cells or presence of bacteria are not cultured without the presence of high wbcs
Positive urines are cultured on Orientation Chromagar
A non-selective chromagar for the qualitative direct detection, differentiation and presumptive ID of uropathogens
Incubated aerobically for 16-24 hours

Question 6

XLD

Answer 6

Xylose lysine deoxycholate agar
Shigella = red
Salmonella = black

Question 7

DCA

Answer 7

Deoxycholate citrate agar
Shigella = colourless
Salmonella = black

Question 8

CCDA

Answer 8

Charcoal Cefoperozone Deoxycholate agar for Campylobacter

Incubated microaerophilically @ 42 degrees

Question 9

VTEC

Answer 9

Verotoxin producing E. Coli

Sorbitol MacConkey

Question 10

Sorbitol MacConkey

Answer 10

VTEC = non sorbitol fermenter = colourless
E coli = sorbitol fermenter = pink

Question 11

Urinary pathogens

Answer 11

E. Coli
Yeast - immunocompromised or catheterised
S. sapro = young sexually active women
S. aureus = commensal
GNBS (Kleb, Enterobacter, Seratia) = potentially infectious
Proteus = catheterised patients
Pseudomonas = catheterised patients
Enterococci = contaminants
Lactobacillus = commensal of women

Question 12

C. diff genes

Answer 12

Toxin A and Toxin B

Question 13

Campylobacter gene

Answer 13

Tuf

Question 14

Salmonella gene

Answer 14

SpaO gene

Question 15

Shigella gene

Answer 15

IpaH gene

Question 16

VTEC serotype

Answer 16

E. Coli o157H&

Question 17

Enteric virus

Answer 17

Norovirus

Question 18

Norovirus genes

Answer 18

G1 and G2

Question 19

Common parasites

Answer 19

Cryptosporidium
Giardia