gram positive bacteria

Question 1

what are the 2 major gram positive cocci

Answer 1

streptococci
and
staphylococci

Question 2

how do gram positive cocci grow

Answer 2

in clusters (staphylococcus)

in chains (streptococcus)

Question 3

how to treat staphylococcus aureus

Answer 3

flucloxallin 3 months

Question 4

what is coagulase

Answer 4

enzyme produced by bacteria that clots blood plasma.

Fibrin clot formation around bacteria may protect from phagocytosis.

Question 5

how many species of staphylococci

Answer 5

at least 40

Question 6

normal habitat of staphylococcci

Answer 6

nose and skin

Question 7

how is staphylococcus aureus spread

Answer 7

by aerosol and touch

• carriers and shedders

Question 8

virulence factors for staphylococcus aureus

Answer 8

• Pore-forming toxins (some
  strains)
  • a - haemolysin & Panton-Valentine Leucocidin
  – Proteases
  • Exfoliatin
  – Toxic Shock Syndrome toxin (stimulates cytokine release)
  – Protein A (surface protein which binds Ig’s in wrong orientation)

Question 9

what is MRSA resistant to

Answer 9

B lactams
gentamicin, erythromycin,
tetracycline

Question 10

2 types of coagulase negative staphylococci

Answer 10

S epidermidis

S saprophyticus

Question 11

describe S epidermis

Answer 11

Infections in debilitated, prostheses (opportunistic)
– Main virulence factor -
ability to form persistent biofilms

Question 12

describe S saprophyticus

Answer 12

Acute cystitis
haemagglutinin for adhesion
urease

Question 13

what do you look at after identifying whether bacteria is in chains or clusters

Answer 13

haemolysis on blood agar

Question 14

what is B haemolysis

Answer 14

complete clearing/lysis of blood agar around the bacteria

Question 15

what is A alpha

Answer 15

only a bit of clearing on blood agar around the bacteria (partial clearing)

there is a green tint to it

Question 16

what is sero grouping

Answer 16

only applies to B haemolysis

classifies them

based on the carbohydrate expressed on cell surface antigens

Question 17

2 types of B haemolytic sero grouping

Answer 17

group A - S pyogenes - important pathogen

group B - S agalactiae- neonatal infections

Question 18

virulence factors for S pyogenes

Answer 18

exported factors - enzymes and toxins

surface factors - capsule and M protein

Question 19

infections caused by S pyogenes

Answer 19

wound infections
tonsillitis and pharyngitis
otitis media
impetigo
scarlet fever

complicates - rheumatic fever & glomerulonephritis

Question 20

what is black on an chest x ray

Answer 20

air

Question 21

what is white on a chest x ray

Answer 21

gunk that shouldnt be there

Question 22

signs of streptococcus pneumonia

Answer 22

cough
severe pain in chest
rust coloured sputum

Question 23

causes of S pneumonieae

Answer 23

pneumonia
otitis media
sinusitis
meningitis

Question 24

predisposing factors for S pneumonia

Answer 24

impaired mucus trapping
hypogammaglbulinaemia
asplenia

Question 25

virulence factors for S pneumonia

Answer 25

capsule inflammatory wall constituent cytotoxin

Question 26

describe alpha haemolytic vidridans group streptococci

Answer 26

can cause dental caries and abscesses important in infective endocarditis case deep organ abscesses

Question 27

3 gram positive bacilli

Answer 27

listeria monocytogenes bacillus anthracite corynebacterium diptheriae

Question 28

3 types of clostridia (gram positive bacilli0

Answer 28

c tetani c botulinum c. difficile

Question 29

describe clostridia

Answer 29

spore forming survive in environment produce toxins

Question 30

how do gram positive stain

Answer 30

Gram positive bacteria retain the colour of the crystal violet stain in the gram stain (because they have a cell wall composed of a thick layer of peptidoglycan). They stain purple.

Question 31

3 classifications of streptococci

Answer 31

Haemolysis Lancefield typing Biochemical properties

Question 32

what is lancefield grouping

Answer 32

a method of grouping catalyse negative, coagulase negative bacteria based on bacterial carbohydrate cell surface antigens

Question 33

what arw the important gram positive bacteria

Answer 33

S.aureus, S.epidermis, S.pyogenes, S.pneumoniae, viridans streptococci, C.diphtheriae

Question 34

how are gram psoitive bacteria spread

Answer 34

aerosols, surface-to-surface contact, colonization of prostheses

Question 35

how to manage gram psoitive bacteria

Answer 35

antimicrobials and vaccination