Infection Flashcards
What are the 5 types of microorganisms?
Bacteria
Fungi
Prions
Protozoa
Viruses
What are prions and what happens when they fold and misshape?
They are proteins that occur naturally in brains of animals and people.
Normally are harmless, however when they fold and misshape they cause devastating illnesses.
Do human cells have cell walls?
No
What are bacteria?
Unicellular
Do not require living tissue to survive
Outer rigid cell wall - gram positive and gram negative
What are gram positive bacteria?
Can be aerobic and anaerobic
Thick layer of peptidoglycan
Picks up crystal violet stain
What are some examples of gram positive aerobic bacteria?
Staphylococcus
Streptococcus
Bacillus
Listeria
What are some examples of gram positive anaerobic bacteria?
Clostridium
Bifidobacterium
Eubacterium
Lactobacillus
Propionibacterium
What are gram negative bacterias?
Can also be aerobic and anaerobic
Has an outer membrane and so REPELS crystal violet
Thin peptidoglycan layer on inside
Picks up pink stain
More resistant to antibiotics due to cell wall
Why are cell walls important
Its a way “in” for antibiotics
What are some examples of gram negative aerobic bacterias?
Salmonella
E.coli
Legionella
What are some examples of anaerobic gram negative bacterias?
Bacteroides
Pervotella
Porphyromonas
What are some types of fungi?
Ringworm
Athletes foot
Thrush
What are fungi?
Fungal cell walls are rigid and multi-layered, made of polysaccharides.
Fungi can grow in low o2 environments and withstand temperature variations.
What are some examples of fungal chest infections
Pneumonia
Histoplasmosis
Aspergillosis
What is the problem with anti fungal meds?
Many anti fungal meds used to treat systemic infections are toxic to the host as fungal cell composition is similar to human cells
What are some common anti fungal meds?
Amphotericin
Ketoconazole
Fluconazole
What are viruses
Most common of all pathogens
Very very small
DNA/RNA is protected by a layer of protein called a capsid
Some viruses have an external membrane called an envelope
Not a living organism, think of them as machines.
What does the layer of protein called a capsized mean for a virus?
It means the outside of a virus is “sticky” so it can catch onto membrane bound proteins easily.
It then pusses into a cell and hijacks the cellular machinery in order to membrane.
It cannot independently replicate.
Result is often host cell destruction.
Cannot live long outside a host cell.
What happens when you get a cold?
Virus latches on to epithelial cells in oropharynx.
Pushes way into epithelial cells and hijacks cell machinery.
Replicates inside cell and cells explode.
Causes no epithelial covering in throat causing sore throat.
Self limiting as particular virus is fragile.
How small is the typical virus
50nm
Viruses are extremely small and hard to target.
E coli bacteria is 1000nm
Can bacteria be infected by a virus
Yes
How many viruses are there known
10 to the power of 31
How are viruses safe from the immune response?
They can “hide” inside cells whilst they replicate, therefore safe from immune response.
What are protozoa?
Basically a parasite (not worms)
They are unicellular eukaryotes.
Protozoa are microscopic, one-celled organisms that can be free-living or parasitic in nature. They are able to multiply in humans, which contributes to their survival and also permits serious infections to develop from just a single organism.
How is protozoa spread
Can be injected into host when bitten by insect, such as malaria and mosquitoes.
What are some common antiprotozoals?
Metronidazole
Tinidazole
Nifuratel
Early treatment is key for success.
