Micro-organisms
Bacteria, viruses, fungi and parasites: what sets them apart, Gram staining and bacterial shapes, colonisation and infection, multidrug-resistant bacteria and spores, and healthcare-associated infections.
- 33 cards
- 3 topics
- Free
The outline, topic by topic
Each topic is weighted the way the exam weighs it.
- Concepts
- Scenarios
- Understand
A few cards from the deck
Bacterium: what is it?
Show the answer
A single-celled organism without a nucleus (prokaryote), able to multiply on its own.
Antibiotics target its own structures.
A patient has Clostridioides difficile diarrhoea. How should hands be cleaned when leaving the room?
- Washing with soap and water, then an alcohol rub
- Alcohol rub alone
- No washing, gloves are enough
- Rinsing with water alone
Show the answer
Washing with soap and water, then an alcohol rub
Spores resist alcohol: only washing removes them mechanically.
Gram stain: what is it?
Show the answer
A stain that sorts bacteria by their wall: Gram-positive (purple) or Gram-negative (pink).
It guides the antibiotic choice before the full result.
Why do Gram-positive and Gram-negative bacteria take different colours?
- They have different nuclei
- Gram-negatives are viruses
- It is chance
- Their walls differ: the thick wall of Gram-positives holds the purple
Show the answer
Their walls differ: the thick wall of Gram-positives holds the purple
This wall difference also explains differences in antibiotic sensitivity.
Cocci and bacilli: what is it?
Show the answer
Bacterial shapes: cocci, round (staphylococci in clusters, streptococci in chains); bacilli, rod-shaped (Escherichia coli).
Shape and Gram together give a first name.
The lab reports Gram-positive cocci in clusters in a blood culture. Which bacterium is likely?
- A streptococcus
- A staphylococcus
- Escherichia coli
- A virus
Show the answer
A staphylococcus
Streptococci form chains, E. coli is a Gram-negative bacillus.