Microbiology

Question 1

Name the five key stages of clinical bacterial investigation.

Answer 1

1. microscopy
2. culture
3. identification
4. bacterial antibiotic sensitivity
5. report

Question 2

Dysuria

Answer 2

pain on passing urine (inflammation)

Question 3

Mid stream urines (MSU)

Answer 3

mid part of sample, avoids epithelial cell and skin organism contamination

Question 4

Catheter specimen urines (CSU)

Answer 4

obtained from bladder by catheter tube and collected in a bag

Question 5

Significant urine culture results

Answer 5

~ pure growth
~ high bacterial count
~ =/>100 colonies on the plate

Question 6

Significant urine microscope results

Answer 6

++ or +++ of WBCs

high bacterial count with NO WBCs

Question 7

No significance in culture

Answer 7

~ no growth
~ no significant growth
~ enteric/mixed growth
~ moderate/heavy skin organism growth

Question 8

When is chromorientation agar used?

Answer 8

urine sample culture
rose red = E.coli
brown = Proteus spp.
blue = Klebsiella/Enterobacter

Question 9

Ways of overcoming sample processing problems.

Answer 9

~ process ASAP
~ store in fridge
~ add boric acid to stop growth but not kill sample

Question 10

Which bacteria are all samples enteric ally screened for?

Answer 10

~ Salmonella spp
~ Shigella spp
~ Campylobacter spp
~ E. coli
~ parasites endemic to UK
~ norovirus/adenovirus

Question 11

XLD media is used to detect…

Answer 11

~ Salmonella (pink colonies with black centres)

~ Shigella

Question 12

Campylobacter media is used to detect…

Answer 12

campylobacter spp (silver/mercury coloured squashed colonies)

Question 13

Chrom 0157 media is used to detect…

Answer 13

E. coli 0157 (pink colonies)

Question 14

Selenite media is used to detect…

Answer 14

salmonella

Question 15

How do you confirm a salmonella diagnosis?

Answer 15

~ use serological testing to test somatic (surface) and H (fimbriae) antigens
~ serology used to divide into diff species

Question 16

How do you confirm a campylobacter diagnosis?

Answer 16

~ oxidase positive

~ gram film = seagull/curved shaped GNR

Question 17

How do you confirm an E. coli diagnosis?

Answer 17

studying serology + look for specific O somatic antigen

Question 18

What are sputum samples tested for?

Answer 18

respiratory infections

Question 19

What are blood culture samples tested for?

Answer 19

bacteraemia

Question 20

CSF

Answer 20

meningitis

sub arachnoid bleeds

Question 21

Which organisms are reported to the infection control team?

Answer 21

~ MRSA
~ C. difficile toxin A&B positive
~ any containment level III organism