Micro

Question 1

are cocci and bacilli mostly gram +ve or -ve?

Answer 1

cocci: +ve
bacilli: -ve

Question 2

process of gram staining

Answer 2

Come In And Stain

Crystal violet
Iodine
Acetate/ alcohol
Safranin counterstain

Question 3

gram +ve bacilli

Answer 3

c diff, listeria

Question 4

main gram -ve cocci

Answer 4

n meningitidis + n gonorrhoea (-ve diplococcus)

Question 5

what is blood agar made of?

Answer 5

sheep + horse blood

Question 6

what is chocolate agar?

Answer 6

BA cooked for 5 mins at 80 degrees to release some nutrients for organisms to grow eg fastidious organisms like H influenzae

Question 7

function of cled agar and MacConkey agar

Answer 7

differentiate lactose fermenting and non-lactose fermenting gram -ve bacilli

Question 8

3 main gram -ve bacteria

Answer 8

e coli, salmonella, shigella

Question 9

main gram -ve bacteria: lactose fermenting or not?

Answer 9

e coli is, salmonella and shigella aren’t

Question 10

how do main gram -ve appear on CLED agar?

Answer 10

e coli yellow, s/s blue

Question 11

how do main gram -ve appear on MacConkey agar?

Answer 11

e coli pink, s/s yellow/ colourless

Question 12

what is grown on gonococcus agar?

Answer 12

neisseria species

Question 13

function of XLD agar

Answer 13

differentiate salmonella and shigella

Question 14

appearance of salmonella and shigella on XLD agar

Answer 14

salmonella: red w black centres
shigella: red only

Question 15

function of Sabouraud agar

Answer 15

fungal culture

Question 16

culture medium for TB

Answer 16

Lowenstein-Jensen medium

Question 17

how do you differentiate gram +ves

Answer 17

catalase test

Question 18

results of catalase test for staph and strep

Answer 18

+ve staph
-ve strep

Question 19

appearance of staph and strep

Answer 19

staph clusters, bunch of grapes
strep chains

Question 20

how do you differentiate between diff types of staph

Answer 20

coagulase test

Question 21

results of coagulase test

Answer 21

+ve: s aureus
-ve: other staph

Question 22

how do you differentiate types of strep?

Answer 22

haemolysis on BA

Question 23

types of results of haemolysis on BA

Answer 23

gamma: no haemolysis
alpha: partial haemolysis
beta: full haemolysis

Question 24

what type of bacteria is enterococcus?

Answer 24

y-haemolytic strep

Question 25

how do you differentiate types of alpha haemolytic strep

Answer 25

optochin test

Question 26

results of the optochin test

Answer 26

optochin-sensitive: s pneumoniae optochin-resistant: s viridans

Question 27

key types of beta haemolytic strep

Answer 27

Group A, B, C, G antigenic groups (Lancefield groups)

Question 28

what is s pyogenes

Answer 28

Group A beta haemolytic strep

Question 29

what is s agalectiae

Answer 29

Group B beta haemolytic strep

Question 30

Where do Lancefield groups A, C and G beta haemolytic strep typically cause infection?

Answer 30

tonsils, pharynx, skin

Question 31

Where does Lancefield group B beta haemolytic strep typically cause infection?

Answer 31

neonatal sepsis and meningitis

Question 32

Why is it important to distinguish s aureus from other types of staph?

Answer 32

much more virulent, has coagulase (causes blood coagulation) and DNAase (can destroy DNA)

Question 33

2 ways to distinguish s aureus from other staph

Answer 33

coagulase test culture on blood agar

Question 34

how does s aureus appear on blood agar compared to other staph

Answer 34

GOLD (aureus = gold), others are colourless

Question 35

main subgroups of gram -ve bacteria

Answer 35

lactose-fermenting and non-lactose-fermenting

Question 36

how do you differentiate diff types of non-lactose-fermenting gram -ve bacteria?

Answer 36

oxidase test

Question 37

results of oxidase test for gram -ve bacteria

Answer 37

+ve: pseudomonas aeruginosa -ve: colliforms eg salmonella and shigella

Question 38

how do you differentiate types of colliforms?

Answer 38

sensitivities and API strip (analytical profile index)

Question 39

2 main ways to diagnose viral infection

Answer 39

viral detection serology testing

Question 40

what is serology testing

Answer 40

testing for the immune response looks for antibodies or complement eg ELISA, immunofluorescence, complement fixation test

Question 41

what is viral detection?

Answer 41

looks for the actual virus eg PCR, electron microscopy

Question 42

pros and cons of PCR

Answer 42

v fast + sensitive big risk of false +ve

Question 43

what does serology test for

Answer 43

detects Igs vs the virus

Question 44

types of diagnostic swabs

Answer 44

green viral swab black charcoal bacterial swab

Question 45

what virus causes shingles

Answer 45

varicella zoster virus (VZV)

Question 46

what virus causes infectious mononucleosis (glandular fever)

Answer 46

Epstein-Barr virus (EBV)

Question 47

differential to EBV

Answer 47

s pyogenes (do a black charcoal swab) present w white/ yellow purulent lining over tonsils (even tho viral usually non-purulent)

Question 48

how is EBV diagnosed?

Answer 48

FBC- atypical lymphocytes- basophilic cytoplasm + prominent nucleolus serology for EBV Igs w clotted sample- ELISA test, IgM +ve = acute EBV IgM EBV +ve: acute infection IgG EBV +ve: chronic/ past infection

Question 49

other EBV infectious mononucleosis sx except tonsillitis

Answer 49

cough, fever, splenomegaly

Question 50

atypical lymphocytes: think....

Answer 50

EBV

Question 51

s pyogenes ix

Answer 51

antistreptolysin titre (ASOT) antibody produced vs streptolysin toxin- marker for extent of infection latex agglutination test confirms result

Question 52

s pyogenes tx

Answer 52

supportive therapy- IV fluids, analgesia avoid contact sports for 6 weeks to prevent splenic rupture