Microbiology

Question 1

How do we name bacteria using genus and species?

Answer 1

-Genus:
>Start with capital letter, in italics
-Species:
> No capital letter , in italics

Question 2

Why do we use Rapid urine analysis?

Answer 2

-Differentiate which urine samples ARE from urinary tract infections
- Sample contains 1x10(5) cfg/ml of bacteria = we perform microscopy/ further culture
-Less we chuck away

Question 3

What is the common bacterial cause for:
1. Soft tissue infections
2. Urinary tract infections

Answer 3

1. *Staphylococcus.aureus
   -Group A streptococci
   -Pseudomonas aeruginosa

2.
*Uropathogenic Escherichia Coli
-Proteus mirabilis
-Klebsiella pneumoniae
-Enterococcus faecalis
-Staphylococcus saprophyticus

Question 4

Why do we use gram staining?
-How is the test done?

Answer 4

-First test we get back, helps us choose what antimicrobial to use/change for patient.

Question 5

Why do we use selective and differential media?

Answer 5

-Selective: Prevent certain organisms growing in the first place
-Differential: Colour changes in colonies to tell us about organisms biology

Question 6

Why we use nutrient agar to culture bacteria?

Answer 6

Question 7

Why do we use CLED to culture bacteria?

Answer 7

Question 8

Why do we use Mannitol-salt agar to culture bacteria?

Answer 8

Question 9

Analyse what these medium results mean?

Answer 9

Question 10

Why do we use motility testing?
-How do we use it to differentiate between E.coli + Klebsiella

Answer 10

-E.coli is motile
-Klebsiella is non-motile

Question 11

Why do we use oxidase test?

Answer 11

• All Enterobacterales are
  (ox -)
  -E.coli
  -Klebsiella
  -Proteus

Question 12

Why do we use Catalase test?

Answer 12

Question 13

Patient 1 : 36 Yr old male

Answer 13

• Cellulitis
  -Take aspirate sample
  -Staphylococcus aureus
  -Flucloxacillin

Question 14

Patient 2 : 17 Yr old female

Answer 14

-Uncomplicated, community acquired, lower tract urinary infection
-Mid-stream urine sample
-Uropathogenic Escherichia Coli
-Drink water, Oral trimethoprim x3 day course

Question 15

Patient 3: 22 yr old female

Answer 15

• Urine and blood sample sent to Microbiology
• Pyelonephritis
• Not staphylococcus aureus , maybe saprophyticus
  -Send to E.D

Question 16

Patient 4: 69 yr old man

Answer 16

-Health care acquired complicated upper renal urinary tract infection
-Remove catheter , take sample from first lot of urine from new catheter
-Uropathogenic Escherichia Coli - Staphylococcus aureus?
-Prescribe gentomicin

Question 17

What is MRSA?

Answer 17

-a type of bacteria that’s resistant to several widely used antibiotics > harder to treat

Question 18

What bacteria would be found on a sample of healthy skin?

Answer 18

-CONS (Gram positive)
-Enterobacterales

Question 19

Test yourself with this table

Answer 19

Question 20

Why do we use blood agar?

Answer 20

-Differentiate bacteria based on their hemolytic properties
-Beta-hemolysin breaks down the red blood cells and hemoglobin completely. This leaves a clear zone around the bacterial growth.
-Alpha-hemolysin partially breaks down the red blood cells and leaves a greenish color behind.