Gram negative- Adam

Question 1

List clinically significant Gram neg bacteria

Answer 1

Salmonella spp.
Salmonella typhi
Pseudomonas spp.
Escherichia coli
Anaerobes
Campylobacter spp.
Helicobacter pylori
Haemophilus influenza

SSPEACHH

Question 2

What is escherichia coli

Answer 2

Ferments lactose
Bloody diarrhoea
Important cause of UTI

Question 3

What is salmonella spp

Answer 3

• Doesn’t ferment lactose
• Self-limiting enterocolitis with/without bloody diarrhoea
• Second most common cause of bacterial diarrhoea in UK
• Can be invasive (enter bloodstream)

Question 4

What is campylobacter spp

Answer 4

Causes foul smelling diarrhoea
Most common cause of bacterial diarrhoea in UK

Question 5

What is helicobacter pylori

Answer 5

• Curved rods
• Habitat is human stomach
• Damages mucosa and causes ulcers
• Risk factor for gastric adenocarcinoma

Question 6

What is Haemophilus influenza

Answer 6

• Mixed appearance
• Causes respiratory tract infection

Question 7

What is pseudomonas spp.

Answer 7

• May contaminate medical equipment
• Hospital acquired cause of sepsis
  o UTI, bacteraemia, pneumonia (rare)
• Multi-drug resistance mechanisms

Question 8

List clinically significant bacteria which are not readily identified by Gram staining and outline how they are identified or distinguished

Answer 8

Mycobacterium spp.
- Visualised by special stains e.g. ZN or auramine
o Resistant to decolorisation by acid and alcohol (AAFB)
- Leprosy
- TB
Mycobacterium tuberculosis
- High HIV prevalence in TB cases
- 9 million new cases/year
Spirochaetes
- Long, spiral shaped
- Diseases:
o Syphilis
o Lyme disease
o Leptospirosis