L16, 7.1 - pathogenesis Flashcards
types of microbes in humans
commensals - good
opportunistic - can be pathogenic depending on location and situations
obligate - always pathogenic
how can opportunistic MOs can become pathogenic
accquire extra DNA encoding VFs
how can commensals be pathogenic
if they enter deep tissues by trauma
what are the koch ostukates about a pathogen
- need to be present in the disease causes
- need to be isolated and grown
- can be reproduced and put into another host
- the pathogen can be recovered from that infected host
why are MOs envoling
mutations c uasing new variants and speicied
what body surfaces contain bacterila flora
mouth, nose, crevice, bowel, skin
why is it beneficial to have flora on boys sryfaces
protect against infeciton by preventing colonisation
what does anitbiotics do to the flora
removes the flora - causing infection and colinsaiton
what does the pathogen need to be successful
infect the hos t
repilicate and survive
transmit ot new host
disease is a combo of what factors
pathogen and host factor s
what molecule secreted from the bacteria can cause bacterial infection
exotoxins - VF
11 steps in successful bacterial infection
sex sense swim stick scavenge survive stealth strike back subvert spread scatter
what is the steo sex
acquiring Vf genes
how to acquire VF genes
- take up naked DNA
-phages carrying DNA
conjugation
what is the step of sense
sensing changes inthe environment
what is the step of switch
chnaging DNA seq
- regulating transcriptional (activatirs and repressors )and post translational (stability of protein)
what is the step fo swim
being motile - flagellum , twitching and swarming
what is the step of stick
- adhesions - #+ve and -ve
slime and capsules
what is the steo fo scavenge
- iron from binding porteins for replication, regualtinf VFs
what is the step of survive
face acid stress in stomach, heat shock and oxidiative stress
what is the step of stealth
destroy immune factors
resist complemtn and opsonisation
-hide by mimicing self AG
whar is the step of strike back
releaing toxins like Botulinum toxin
- to destroy host defences
what si the step of subvert
maniulate host cells for themselves
what is the step od spread in the host
spread via blood, pymph, tissues and immune cells
how can the bacteria scatter for transmission
areosols, sexual, faecal, enviromental
feautures of neisseria
- ve gram
- cause sexual infecftion
- heavily pilated
how does nerisseria cause infection
adhere to epithelial cells
- suppress T cell prolif
- prevent adative IS by having variation of outer membrane prteins
