pathogens Flashcards
—— have been a major cause of mortality throughout history
infectious diseases
pathogen
microbial parasites that are able to cause infections
infection
situation in which a microorganism is established and growing in a host, causing damage
disease
damage or injury to the host that impairs host fxn
pathogenicity
the ability of a parasite to inflict damage to the host
virulence
measure of pathogenicity
opportunistic pathogen
cause disease only in the absence of normal host resistance. the normal microbiome contains opportunistic pathogens (e.g. if the microbiome of the got enters the urinary tact, it’ll cause disease)
different species have different —— properties
virulence
a pathogen is usually identified by the:
set of virulence genes that are carried and expressed
name and describe the two factors that determine virulence
1) invasiveness: the ability of a microorganisms to become established in the host to overcome the host defensives and to spread in the tissues
2) toxigenicity: the capacity of the microorganism to produce substances known as toxins that damage specific tissues of the host
name the different factors used by pathogens to become invasive
- adhesins
- capsule
- enzymes that destroy host tissues
- invasins
adhesins
promote specific attachment to the host cell surfaces
- one adresin type is usually able to attach to one r a few cell types, determine the site of colonization
——- form loose attachments (adhesins)
while ——- mediate close attachments (adhesins)
fimbriae, pilli,
afrimbial adhesins, surface proteins (not filaments)
(T/F)
capsules are produced by some bacterial pathogens
true
function of capsules
prevents the pathogen from being destroyed by hist cell immune system (phagocytes, complement, etc)
- also mediates attachment to host cells and to other bacteria
capsules are essential virulence factors for :
1) streptococcus pneumoniae
2) haemophilus influenzae
(T/F) the capsule is always a virulence factor
false
invasiveness is essential to get —- in the tissues and …
depper, consume nutrients
pathogens often use —- to enter
wounds
through —–, penetration would be easier. explain
mucosa. because there is a single layer of cells with mucous. so if the pathogen manages to destroy the cell they may be Abe to enter or they can enter the cels and grow there
loos connective tissue is also called
explain its function and location
extracellular matrix
this is underneath the cell layer. gue around cells made of collagen fibres, hyalouonic acid, fibronection –> structural components that makes it like gue
Extracellular enzymes
NOTES
invasins
surface proteins, or injected proteins that allow micro-organism to enter cells
- invasion of the host cells, including phagocytes, protect the bacteria; pathogens against the host immune system
- the bacterium grows inside the host ** good source of nutrients
—– are major virulence factors of intracellular pathogens
invasins
name some pathogens that rely on invasins
- salmonella
- listeria
- chlamydia
- mycobacterium
toxigenicity is often a result of —–
invasion
extracellular enzymes causing damage are —–
toxins
(T/F) toxin production is not always necessary for an organism to be highly virulent. often host’s immune response may result in damage
true
bacterial pathogens are associated with 2 distinct categories of diseases, explain them:
1) infectious diseases: result from the pathogen’s growth
2) intoxications: realist from the presence of a specific toxin
toxins are divided into 2 categories, explain them:
1) exotoxins: secreted into the surroundings as the bacterial pathogen grows
2) endotoxins: part of the bacterial pathogen
