Intro Flashcards
What are the two major emerging infection threats
Healthcare associated infections: Staphylococcus aureus (including MRSA)
Enterococcus species (Including VRE)
Clostridium difficile
Nosocomial (hospital acquired) pneumonia
Wound infections
Implant / Device related infections
Antibiotic resistance
Gram-negative bacteria –
Enterobacteriaceae (e.g. Escherichia coli)
Describe the Koch’s postulates
A specific microorganism is always associated with a given disease.
The microorganism can be isolated from the diseased animal and grown in pure culture in the laboratory.
The cultured microbe will cause disease when transferred to a healthy animal.
The same type of microorganism can be isolated from the newly infected animal
Describe bacteria
Small, single celled, prokaryotic organisms, divide by binary fission, may be mobile (flagella).
‘classical’ bacteria – S. aureus, E. coli etc
Mycoplasma and Chlamydiae
Cell wall deficient bacteria causing pneumonia and urogenital infections
Describe viruses
Particles of nucleic acid DNA or RNA
in a protein coat
+ / - a lipid capsule
Not living cells – cant replicate unless
Infecting a living cell
Viruses infect all living cells including bacteria
Virus - cell interactions are usually very specific
Describe fungal pathogens
Candida species (e.g. albicans)
A yeast
unicellular
reproduce by budding
Aspergillus species (e.g. fumigatus)
A mould
multi-cellular
reproduce by spores
Describe protozoa
A huge family of single-celled eukaryotic parasites
Major tropical and zoonotic diseases
Describe helminths
A huge family of single-celled eukaryotic parasites
Major tropical and zoonotic diseases
What are the three key features of the immune system
The immune system has ‘memory’
This memory is antigen specific
The immune system is tolerant
Define tolerence
Tolerance = a state of immunological non-reactivity to an antigen
What are commensal organisms
‘Commensal’ organisms are organisms that inhabit our bodies without doing harm in normal situations
Why is tolerance important
This is important because many antigens that we exposed to are not harmful
Our own proteins (‘self antigens’)
Harmless environmental antigens (pollen, foods)
‘Commensal’ organisms (organisms that inhabit our bodies without doing harm in normal situations)
How can the immune system go wrong
Allergy
Autoimmunity
Acquired immunodeficiency
Genetic immunodeficiency
