3: Systemic Bacteriology II Flashcards
What is virulence?
The capacity of a microbe to do harm to a host
What is an endogenous microbe?
A microbe normally found within the body e.g commensal flora
What is an exogenous microbe?
A microbe normally not found within the body
What is a pathogen?
A harmful organism which causes pathology
What is a commensal organism?
An organism which exists as normal human flora
What is an opportunistic pathogen?
An organism which causes infection when the opportunity arises (e.g immunocompromise)
What are some examples of infectious protozoa?
Amoeba
Plasmodium (MALARIA)
Toxoplasma
What are some strains of fungi which cause disease?
Aspergillus spp.
Candida spp. (yeast infections)
What is a major disease associated with protozoa infection?
Malaria
What are some examples of Gram negative bacteria?
Neisseria spp.
Escherichia spp.
What are some examples of Gram positive bacteria?
Streptococcus spp.
Staphylococcus spp.
Enterococcus spp.
Clostridium spp.
What are two common Neisseria species which cause disease?
Which diseases?
Neisseria meningitidis - bacterial meningitidis
Neisseria gonorrhoeae - gonorrhoea
Neisseria spp. are examples of Gram ___ cocci.
negative
What is a coliform?
Gram negative bacilli which look like E. coli
What is the first line antibiotic used to treat infections caused by coliforms (Gram negative bacilli)?
Gentamicin
Why do people with coliform sepsis become very unwell very quickly?
When Gram negative bacteria die, the lipopolysaccharide released from their cell walls is an endotoxin
Which molecule, found on Gram negative cell walls, is an endotoxin?
Lipopolysaccharide
Give an example of an endotoxin released by dying Gram negative bacteria.
Lipopolysaccharide
Which immune cell is activated by endotoxins released by dying bacteria?
Macrophages
Which immune component is released by activated macrophages?
Pro-inflammatory cytokines
What condition is caused by endotoxin activation of macrophages, leading to widespread inflammation?
SYSTEMIC INFLAMMATORY RESPONSE SYNDROME
(SIRS)
Outline the process by which endotoxins cause fever.
Endotoxins activate macrophages
Macrophages release pro-inflammatory cytokines
Cytokines activate anterior hypothalamus
Anterior hypothalamus releases Prostaglandin E
Prostaglandin E triggers fever
What is the benefit of fever in a person fighting infection?
Fever (38-40ºC) slows bacterial growth
come back and study sepsis
particular gram -ve and +ve pathogens, look at on 2nd run thru
