Infection Control - Microbes

Question 1

What types of microbes are there?

Answer 1

Bacteria, Fungi, Protozoans, Helminths, Arthropods, Viruses, Prions

Question 2

What are bacteria?

Answer 2

• Prokaryotic, unicellular
• relatively simple
• no membrane bound organelles
• no cell nucleus
• have cell walls
• usually found in between cells (extracellular)
• easy to design antibiotics to treat as drugs don’t have to enter or target human cells
• can produce endospores which can survive in harsh conditions for long periods of time e.g. anthrax in soil

Question 3

What are fungi?

Answer 3

• Eukaryotes with a cell wall
• Yeast: Unicellular: 000
• Moulds: Multicellular: =+=+=
• Fungal infections are called mycoses and treated with anti-fungal drugs

Question 4

What are protozoans?

Answer 4

• Unicellular, eukaryotic

- Usually transmitted by ingesting contaminated food or water

Question 5

What are Helminths?

Answer 5

• Multicellular, eukaryotic
• Parasitic worms
• Microscopic in at least one stage of their life cycle but some adult tapeworms can get up to a metre long
• Hydatid cysts are sacs full of tapeworms and can become problematic if untreated

Question 6

What are arthropods?

Answer 6

• Some are microscopic and cause infections themselves e.g. scabies
• Some transmit microbes e.g. ticks and mosquitoes

Question 7

What are viruses?

Answer 7

• Non-cellular
• Genetic material (RNA or DNA) surrounded by a protein coat
• Cannot replicate themselves. Use host cell machinery to replicate
• are obligate intracellular pathogens (hiding inside cells most of the time)
• some kill hosts to be released, others bud out of hosts
• most transmission is via close contact

Question 8

What are prions?

Answer 8

• Non-cellular infectious particles
• Miss-folded protein
• Rare and cause neuro-degeneration and currently no cure