L18, 7.3 bacterial invasion

Question 1

what is invasin

Answer 1

injected VF to enbale cell invasion

Question 2

steps in infection from invasion to transmission

Answer 2

attachment/invasion
prolif in host 
evasaion of host defences
damage to the host
transmission

Question 3

sites of microbial infection

Answer 3

skin
urogenitatry tract
respiratory
gastrointestinal tract
mouth

Question 4

host barriers in the skin

Answer 4

commensal to prevent colinsation
FA
Antimicrobial producrs by sebum and commenusals

Question 5

how do pathgeons overcome skin barriers

Answer 5

PHYSICal damage - cuts and burns
UV damage
bites
insects

Question 6

host barriera in the respiratory tract

Answer 6

• particesl filtered by nasal hairs

- cililary action - has antimicrobial properties

Question 7

how do pathogens overcome barriers in the respiratory tract

Answer 7

adhesion

• ciliostatic substances
• muco-ciliary defect in the host

Question 8

host barriera int he urogenitary tract

Answer 8

urine sterile

• unitary tract flushed - prevents colonisation
• strong spincter muscle - preventing acess to the blladder

Question 9

host barriers inthe git

Answer 9

saliva -anti bacterial substances
stomach - acid
large intestine - mucus and commensal - mechanical barrier

Question 10

adhesin present in the bacteria

Answer 10

flagella
fimbriae
gram -ve outer membrane proteins ]
gram +ve cell wall proteins

Question 11

roles of flagella

Answer 11

motility through attachment sites and mucus layer

Question 12

structure of flagella

Answer 12

flagella - filament and hook

basal body

Question 13

what is fimbriae and function of it

Answer 13

smaller projection than flagella

-extends out to the host cell so the bacteria doesnt get engulfef

Question 14

function of G -ve outer memebrane proteins

Answer 14

closer attachment ot he hsot and promote invasio

Question 15

egs of host Rs

Answer 15

integtrins - in intestine, resp tract,
sialic acid
carbs

Question 16

what events can ahdesins can cause when binding to a host cell

Answer 16

• adhesion poke through the host and inject its stuff
• makes the host express the bacterial receptors on its surface
• bacteria produce its AG for that receptors to bind and invade

Question 17

what immune cells does salmonella invade and how

Answer 17

Mo cells

- by fimbriae and delivery systems of SPI-1 and SPI-2

Question 18

host defences in Mo cells

Answer 18

use H2O2 and NO to kill pathogens

-phagocytosis

Question 19

hoow does salmonella stop NO production in Mo ells

Answer 19

competes for arginine so Mo doesnt use it make NO