Infections 1 Flashcards
what is an infection
invasion and multiplication of a pathogenic organism in a host organism
what is infectious disease medicine
branch of medicine focusing on infections and pathogens
what are the 6 stages of infectious disease
acquisition
colonisation
penetration
spread
damage
resolution
name 2 catagories of the way our innate immunity can be broken down
physical and chemical barriers
what are the two forms of infection
endogenous
exogenous
what does endogenous mean
organisms present in or on the body
what does exogenous
microbes that are not part of our typical body flora
what is the 1st line of body defence
intact skin and mucous membranes
gives some examples of what body defence is in the 1st line of contact
sweat mucous antibacterial secretions stomach acid lysozymes
what is the 2nd line of body defence
phagocytosis and inflammation
what is phagocytosis
phagocytic cells in blood tissues and lung engulf and destroy microorganisms
what is the 3rd line of immunity
adaptive immunity
what are 3 examples of adaptive immunity
lymphocytes
antibodies
macrophages
what is exogenous infection usually termed
transmission
what are 5 forms of transmission
direct contact e.g. STIs
inahlation / droplet infection e.g. gastroenteritis
ingestion / faecal oral route
trauma / inoculation
transplacenta
what is colonisation
when an organism has established in a site whether it be internal or external but may not necessarily go on to invade and damage host tissue.
what is a biofilm
biofilm comprises any syntrophic consortium of microorganisms
in which cells stick to each other and often also to a surface.
These adherent cells become embedded within a slimy extracellular matrix
that is composed of extracellular polymeric substances.
what sort of cells form a bio film
bacteria seldom lone cells
why do biofilms add treatment difficulties
they hve co-operation between organisms creating a slimey outer layer making in more difficult to treat in a culture.
what are the 4 forms of damage a pathogen can cause
mechanical damage from bulk effects
toxins
altered cell function
host response e.g. swelling pus scarring etc
what are the two forms of toxins a pathogen can cause
exotoxin which is produced inside g+ve and diffuse out
endotoxin are LPS protein complexes mainly in cell wall G-ve bacteria
what are 4 stages of resolution in infection
recovery
latent infection
clinical latency
chronic infection
what is recovery mean
organism cleared from body no lasting effects
what is latent infection
initial symptoms resolve but infection not cleared and can re occur often occurs with viruses
what is clinical latency
can have a period of no symptoms but the infection course is continuing
what is chronic infection
some infection may never clear can take a very long time to clear. some may even have long term ramifications
what is a pathogen
an organism capable of causing disease
what is virulence
degree of pathogenicity of an organism
what is attenuation
a reduction in the virulence of a pathogen
what is exaltation
an increase in virulence
what is chemotherapy
use of synthetic chemicals to destroy infective agents
what are chemoterapeutic agents
chemicals intended to be toxic for the pathogenic organisms but safe for the host
what is a microbe
general term used to describe bacteria, fungi and viruses
what is a parasite
general term used to describe protozoa and helminths
what are the 3 molecular basis of chemotherapy
class 1
class 2
class 3 (best targets)
