How microbes cause disease

Question 1

what do microbes need to do to survive

Answer 1

adherance/colonisation
resist/avoid defence
persist and grow
exit&transmit to new host

Question 2

what is the period with vague symptoms before illness called

Answer 2

prodromal

Question 3

where do pathogens want to reach and how do they get there

Answer 3

sterile body sites, breach barriers eg BBB, skin, mucosal membrane

Question 4

who competes with pathogens

Answer 4

natural flora

Question 5

what chemicals do tears, saliva and mucus have in them which is antibacterial

Answer 5

lysozymes

Question 6

what other ways do we get rid of toxins/pathogens

Answer 6

cilia/urinary flushing/antimicrobial FAs in skin, mucus and phagocytes in lungs

Question 7

bacteria use more than one adherance mechanisms to stick to the host. give some examples

Answer 7

pili/fimbriae
outer membrane proteins eg adhesin&invasin

Question 8

where does e coli keep its adhesin

Answer 8

tip of the pili

Question 9

what are biofilms made of, what are they, give an example of a biofilm in action

Answer 9

slime layer, (Extracellular polymeric substances) polymer EPS, pseudonomas in CF - opportunistic infection

Question 10

how else that pili and fimbriae can pathogens adhere to host cell

Answer 10

via host ECM
Internalins Listeria monocytogenes bind E-Cadherin and C-met
- M proteins Strep. pyogenes bind to receptor on respiratory mucosa

Question 11

what are the two main problems with biofilms

Answer 11

avoiding host immunity
resistance to antibiotics

Question 12

what do bacteria use to form lesions

Answer 12

degradative enxymes

Question 13

what do degradativeenzymes do and not do

Answer 13

mess up tissue - hyaluronase and collagenase
do not kill cells

Question 14

what are the two types of invasion into host cells

Answer 14

trigger zipper

Question 15

who uses trigger and who uses zipper

Answer 15

T:salmonella, shigella
Z: listeria

Question 16

what is the complement

Answer 16

part of innate immune system 30 circulatory proteins

Question 17

what are the 3 things the complement does

Answer 17

opsonisation - tag path with IGG - cleared by pahogcytes
membrane attack complex - hole in bacterial membrane - lysis
enhancing inflammation - mast calls attract phagocytes to the area

Question 18

what is in lysosomes

Answer 18

NO, H2O2

Question 19

which cells have Fc receptors

Answer 19

almost all leukocytes

Question 20

how does a bacterail capsule lead to evasion of phagocytosis

Answer 20

prevents opsonisation

Question 21

how does Staph aureus avoid phagocytosis

Answer 21

binds to Fc region of antibody so the antibody can’t bind to phagocyte

Question 22

what’s the test for Staph aureus

Answer 22

catalase test - bubbles when you put H2O2 on it bc catalase turns it into H20 and O2

Question 23

what is the name of the pathogens that steal iron form the host

Answer 23

siderophores

Question 24

what is the commensal and how does it normally live

Answer 24

one organism benefits from the other and teh other is unaffected. Normal flora of the gut

Question 25

what is virulence

Answer 25

quantatitive ability of a pathogen to cause disease

Question 26

what are protozoae; give examples of parasitic protozoic diseases

Answer 26

unicellular EUKARYOTES eg malaria, leishmanaisis, Chagas, trypanosomiasis, cryptosporidiosis

Question 27

what are the shapes of different bacteria

Answer 27

cocci - spherical vibrio - spiral tail bacillues - rodlike

Question 28

what stain is used to identify bacteria? What colour do they go

Answer 28

Gram stain gram-ve pink gram+ purple

Question 29

describe gram -ve and +ve bacteria

Answer 29

+ve thick peptoglycan outer wall, no extra membrane -ve thin peptoglycan wall, extra membrane

Question 30

how would you identify bacteria

Answer 30

microscope - size, shape, colour, gram stain

Question 31

what is the bacteria responsible for syphilis and how do you identify it

Answer 31

spirochaetes and darkfield microscopy

Question 32

which stain is needed to identify TB bacteria and what bacteria is it

Answer 32

mycobacteria, Ziehl-Nielsen stain

Question 33

how do staphylococci and streptococci look different under a microscope?

Answer 33

strepp: chains of spheres staph: clusters of spheres

Question 34

which two common bacteria are gram +ve

Answer 34

staphylococci and streptococci

Question 35

how do you differentiate between staph and strep?

Answer 35

catalase test. chuck bleach on it. Stapg is catalase +ve, bubbles form

Question 36

what is staphylococcus aureus

Answer 36

bad bacteria, causes abcesses, wound infections, really gross, can go to bones

Question 37

how does staph aureus cause TSS

Answer 37

superantigen causing cytokine cascade

Question 38

what do you get in the first stage of syphilsi

Answer 38

a gross swelling called a chancre at the site of where the spirochaetes enter the body

Question 39

when do fungi cause a problem

Answer 39

in immunocompromised people

Question 40

what is aspergillosis

Answer 40

fungal pneumonia only in immunosuppressed

Question 41

what is aspergillosis

Answer 41

fungal pneumonia only in immunosuppressed

Question 42

what are some things you need to mention to the lab about a patient

Answer 42

travel, symptoms, contact, food, drugs, animals

Question 43

what is a MALD-TOF machine

Answer 43

desktop maspec. provides fingerpirnt of all bacteria in the database

Question 44

what is the 1,2,3 of teh complement

Answer 44

1)opsonisation - microbes are coated with IGG as a tag for phagocytosis C3B 2)membrane attack complex C5B - hole in bacterial membrane - lysis 3)inflammation enhancement - mast cell attract phagocytes to the area