module 11 pt 2 Flashcards
pathogen
microbial parasites that cause disease or tissue damage in a host
pathogenicity
ability of a parasite to inflict damage on a host
virulence
the relative ability of a pathogen to cause disease
opportunistic pathogen
causes disease only in absence of normal host resistance
infection
microorganism is established and growing in a host, whether or not the host is harmed
disease
damage or injury to the host that impairs host function
what is an ID
the minimum number of organisms required to cause an infection in the host
what are the pathogens various stargetegies to establish virulence
adherence
invasion
multiplication
how effective is adherence ?
it is necessary, but not sufficient to start disease
what do bacteria and viruses normally adhere to?
epithelial cells
what can biofilm growth be
adhesion factor
what do fimbriae do
promote adherence
what helps microbial adherence to host tissues
capsules and fimbriae
whats an example of a bacteria that uses capsules to prevent phagocytosis
S. pneumonia
what are adhesions
glycoprotein or lipoproteins found on the pathogens surface that enable it to bind to host cells
how does N gonorrhoea adhere
mucosal epithelial cells
opa protein and pili
how do pathogens adhere to host
specific receptor molecules on the cells surface
why does neisseria gonorrhoea adhere only to mucosal epithelial cells in the genital tract, eye, rectum, and throat
Opa surface proteins bind to CD66 host protein found on the surface of urogenital epithelial cells
what is colonization
the growth of microorganisms after they’ve gained access to host tissues
when does biofilm formation happen (stages?)
in colonization
what are the 2 key microorganisms that contribute to dental caries
lactic acid bacteria S. sobrinus and S. mutans
how do S. sobrinus attach
it has a capsule adhesion that is specific for host salivary glycoproteins
how do S. mutans attach
produces dextran to adhere to teeth
what allows for the production of the capsule and dextran
sugar
is the infection ion process considered disease
no because it is growing but might not cause disease (disease is when the growing in host causes damage and injury that impairs host function)
what do most pathogens depend on
nutrients availability
what is bacteremia
the presence of bacteria in the bloodstream
what is septicemia
blood borne systemic infection
what can septicemia lead to
massive inflammation
septic shock and death
what is invasion
the ability of a pathogen to spread and cause disease (growth in host tissue at densities that inhibit host function)
what are the enzymes that enhance virulence by breaking down or altering host tissue to provide access to nutrients (5)
hyaluronidase
collagenase
protease
nuclease
lipase
what protects the pathogen by interfering with normal host defence mechanisms such as clotting
coagulase - produced by S. aureus
what are salmonella pathogenicity islands
distinct genomic regions that contain clusters of genes responsible for virulence
where are salmonella pathogenicity islands located
usually on bacterial chromosomes
how are SPIs typically queried
horizontal gene transfer
what do SP1 do
invade host cells and change its function to promote bacterial entry
what do SP2s do
involved in survival and replication in host cells such as macrophages
attenuation
the decrease or loss of virulence
what is attenuation used for
virulence in vaccine production
how does attenuation work
when pathogens are kept in laboratory culture their virulence decreases
