Microbiology

Question 1

Eukaryote vs prokaryote ribosomes?

Answer 1

80S vs 70S

Question 2

Prokaryote equivalent to the nucleus?

Answer 2

Nuceloid

Question 3

Gram -ve summary?

Answer 3

• Stains pink
• Single-layered peptidoglycan wall
• Outer membrane
• High number of lipids, lipoproteins and lipopolysaccharides
• Produces endotoxins

Question 4

Gram +ve summary?

Answer 4

• Stains purple
• Multi-layered peptidoglycan wall
• No outer cell wall
• Low/no lipids, lipoproteins and lipopolysaccharides
• Produces exotoxins

Question 5

4 phases of bacterial growth?

Answer 5

Lag + exponential + stationary + death/decline

Question 6

What is the peptidoglycan wall made of?

Answer 6

Sugars and amino acids

Question 7

2 gram -ve cocci?

Answer 7

Neisseria meningitidis and gonorrhoeae

Question 8

2 gram -ve coccibacilli?

Answer 8

H. influenza and B. pertussis

Question 9

3 gram -ve bacilli?

Answer 9

Legionella, Klebsiella, Pseudomonas

Question 10

Gram +ve bacilli?

Answer 10

Clostridium e.g. C. diff

Question 11

Gram +ve cocci and test summary?

Answer 11

• Staph (+ve) and strep (-ve) via catalase test
• S. aureus (+ve) and s. epidermidis (-ve) via coagulase test
• Haemolysis for group A strep
• Alpha (green) = partial haemolysis via strep p. and viridans
• Beta (yellow) = full haemolysis via strep pyogenes
• Gamma (none) = staph

Question 12

Gram +ve cocci cluster?

Answer 12

Staphylococcus

Question 13

Gram +ve cocci chains?

Answer 13

Streptococcus

Question 14

Selective media function + example?

Answer 14

Allows organisms to be isolated e.g. mannitol salt agar isolates staph

Question 15

Differencial media function?

Answer 15

Chemicals produce visible changes in colonies via promoting differenciation

Question 16

Bacteriostatic vs baceriocidal action?

Answer 16

Target protein/DNA synthesis which resume after removal vs target cell wall and cause cell death

Question 17

Can you combine bacteriostatic/cidal abx?

Answer 17

No

Question 18

Beta lactam abx?

Answer 18

Penicillins and cephalasporins

Question 19

What is a beta lactam?

Answer 19

Chemical group that allows targeting of the bacterial cell wall

Question 20

Abx that target cell wall?

Answer 20

Penicillins + cephalasporins + glycopeptides

Question 21

Beta lactam resistant cillin?

Answer 21

Temocillin

Question 22

Beta lactamase targeted cillin and how this is overcome?

Answer 22

Amoxicillin and combined with clavaunic acid to make co-amoxiclav (beta lactam resistant)

Question 23

Penicillin action?

Answer 23

Targets PBPs on bacteria which cross links wall peptidoglycan chains causing cell death

Question 24

Glycopeptides gram cover?

Answer 24

Only gram +ve

Question 25

Glycopeptides?

Answer 25

Vancomycin and teicoplanin

Question 26

Abx that target protein/DNA synthesis?

Answer 26

Tetracyclines + aminoglycosides + macrolides

Question 27

Aminoglycoside?

Answer 27

Gentamicin

Question 28

Macrolides?

Answer 28

Erythromycin, clarithromycin and azithromycin

Question 29

What one out of TAM is bacteriostatic instead or cidal?

Answer 29

Aminoglycosides (gentamicin)

Question 30

Abx affecting nucleic acids?

Answer 30

Metronidazole + fluoro/quinolones

Question 31

Abx inhibiting folic acid synthesis?

Answer 31

Trimethoprim + sulphonamides

Question 32

5 bacterial adaptations to overcome abx?

Answer 32

- Forming biofilms - Persistor cells killing cidal abx - Mutation of PBP that created MRSA which is penicillin resistant - Increased efflux of abx via channels - Horizontal gene transfer

Question 33

4 factors causing abx resistance?

Answer 33

- Prior abx exposure - Over-under prescribing - Prescribing incorrectly - Prescribing when not needed

Question 34

Feature of mycoplasma pneumonia that makes it hard to treat?

Answer 34

Lacks a cell wall so is bacteriocidal resisitant

Question 35

4 antibiotics commonly used for empirical treatment for gram +ves?

Answer 35

Penicillins, vancomycin, teicoplanin and gentamicin

Question 36

Treatment for MRSA and C. Diff?

Answer 36

Vancomycin/teicoplanin/gentamicin

Question 37

Treatment for pseudomonas (s sound)?

Answer 37

Ciprofloxacin + cephalosporin

Question 38

Treatment for mycoplasma?

Answer 38

Tetracycline + macrolide

Question 39

2 streptococci that cause alpha haemolysis?

Answer 39

Pneumoniae and viridans

Question 40

Treatment for legionella?

Answer 40

Quinolone + macrolide

Question 41

Is mycobacterium tuberculosis gram +ve or -ve?

Answer 41

Gram +ve

Question 42

Antibiotic for coliform of gram -ve aerobe + anaerobes?

Answer 42

Gentamicin + metronidazole

Question 43

Antibiotic thats is unsafe during pregnancy and is excreted rapidly via the urine?

Answer 43

Gentamicin

Question 44

Is flucloxacillin narrow or wide spectrum?

Answer 44

Narrow gram +ve cover

Question 45

Name of the E. Coli 0157 toxin?

Answer 45

Veratoxin (VTEC)

Question 46

2 strict aerobes + strict anaerobe?

Answer 46

Pseudomonas and legionella + clostridium

Question 47

4 C antibiotics that cause C. diff?

Answer 47

Ciprofloxacin, Co-amoixclav, Clindamycin and Cephalasporins