Microbiology

Question 1

Haemolysis test

Answer 1

1. Alpha haemolysis (green/brown)
   - Strep pneumoniae (optochin resistant)
   - Strep viridans (not optochin resistant)
2. B haemolysis
   (clear/colourless)
   - Staph aureus - Creamy yellow on blood agar + +ve coagulase test
   - Strep pyogenes
   - lancefield grouping
3. Gamma haemolysis
   - no haemolysis
   - Strep Bovis

Question 2

MacConkey agar

Answer 2

1. Only gram -ve bacilli
2. Lactose fermenting - pink/red
   - E. coli
3. Non-lactose fermenting
   (white/colourless)
   - Salmonella / shigella

Question 3

Viral envelope

Answer 3

1. Surround outer protein coat

2. Contain viral proteins and lipids

Question 4

Protozoa

Answer 4

Single celled eukaryotic organisms w definitive nucleus

Question 5

Mycobacterium

Answer 5

1. Acid fast bacilli
2. Escape phagolysosome
3. Live in cytoplasm

Question 6

Acquired resistance

Answer 6

1. Spontaneous gene mutation
2. Horizontal gene transfer
   - Conjugation (share plasmids)
   - Transduction (bacteriophages)
   - Transformation (pick up naked DNA)

Question 7

Catalase test

Answer 7

1. Staphylococci = +ve (bubble)
2. Streptococci = -ve
   3 Gram -ve = +vex

Question 8

Gram staining

Answer 8

1. Gram Negative = piNk

2. Gram +ve = purple

Question 9

Coagulase test

Answer 9

1. Staph aureus = +ve
   (clumping)
2. Other stap = -ve
   (no clumping)

Question 10

Lancefield grouping

Answer 10

Group A
- Strep pyogenes
Group B
- Strep agalactiae

Question 11

TB - culture plate

Answer 11

Lowenstein-Jensen culture

Question 12

Urinary Tract Infection - Pharmacology

Answer 12

1. Oral ciprofloxacin / co-amoxiclav
2. Severe = IV gentamicin / IV co-amoxiclav
3. Trimethoprim / cefalexin (not preg)