MicroBio

Question 1

What is special about prion proteins and what disease process are they associated with?

Answer 1

No DNA/RNA

Mad cow disease

Question 2

Elements of bacterial cell structure used for:

a. movement
b. adhesion

Answer 2

a. Flagellum

b. Fimbriae/Pilli

Question 3

Name the main shapes of bacteria (3)

Answer 3

1. Coccus (round)
2. Bacillus (rod)
3. Spirochaetes

Question 4

What are the different types of atmospheres bacteria can exist in (5)

Answer 4

AEROBIC: presence of air
\+OBLIGATE: require O2
ANAEROBIC: absence of air 
\+OBLIGATE: killed by O2
FACULTATIVE: exist in both

Question 5

Differentiate between the terms pathogenicity and virulence.

Answer 5

Ability of microorganism –> disease vs. degree of pathogenicity of organism

Question 6

Name one type of organism resistant to sterilisation procedures

Answer 6

Prion proteins

Question 7

Gram + organisms stain…

Answer 7

Purple - thick peptidoglycan wall

Question 8

Gram - organisms stain…

Answer 8

Pink - thin peptidoglycan wall (N)

Question 9

Endotoxin is produced by…

Answer 9

Gram - organisms (N) - part of cell wall

Question 10

Exotoxin is produced by…

Answer 10

Gram + organisms - exported from cell wall

Question 11

Classify spores in terms of gram stain

Answer 11

Gram + bacilli (LATENCY)

Question 12

Gram + coccus in chains are?

Answer 12

Streptococci

Question 13

Gram + coccus in clusters are?

Answer 13

Staphlococcus

Question 14

The test to classify different streptococci?

Answer 14

Haemolysis:
Alpha (partial) - GREEN - Strep. pneumoniae + viridans Beta (complete) - YELLOW - Group A (pyogenes) and B Strep.
Gamma (none) - Enterococcus sp.

Question 15

Examples of: Alpha-haemolytic Streptococci?

Answer 15

Strep. pneumoniae + “viridans” group

Question 16

Examples of: Beta-haemolytic Streptococci?

Answer 16

Group A Strep. (Strep. pyogenes), Group B Strep.

Question 17

Examples of: Non-haemolytic Streptococci?

Answer 17

Enterococcus sp.

Question 18

The test to distinguish Staphylococcus aureus from other Staph. spp.?

Answer 18

Coagulase test +ve = Staph. aureus -ve = other Staph. spp. (common skin commensals)

Question 19

Treatment of choice for Staph. aureus infection?

Answer 19

Flucloxacillin

Question 20

Treatment of choice for anaerobic infections

Answer 20

Metronidazole

Question 21

Example of mycobacterium (and key buzzwords!)

Answer 21

TB - ZN STAIN, CASEOUS NECROSIS, GRANULOMAS

Question 22

Some examples of Gram- bacilli (5)

Answer 22

Bordetella 
H. influenzae 
Coliforms 
Pseudomonas 
Campylobacter

Question 23

Features of haemophillus influenzus

Answer 23

Coccobacillus

‘Chocolate agar’

Question 24

Examples of coliforms that are gut commensals (3)

Answer 24

E. coli Klebsiella sp. Proteus sp.

Question 25

Examples of coliforms that are gut pathogens (3)

Answer 25

Salmonella sp. Shigella sp. E. coli 0157

Question 26

The name of the toxin produced by E. coli 0157 is...

Answer 26

Verotoxin (VTEC)

Question 27

Treatment of choice for coliform infections?

Answer 27

Gentamicin

Question 28

Examples of gram- cocci in pairs (diplococci)

Answer 28

Neisseria meningitidis and Neisseria gonorrhoeae

Question 29

Examples of strict aerobes (2)

Answer 29

Pseudomonas sp. (Gram- bacilli) Legionella sp. (Gram- bacilli)

Question 30

Examples of strict anaerobes (2)

Answer 30

Clostridium spp. (Gram+ bacilli) Bacteroides spp. (Gram- bacilli)

Question 31

Examples of spirochaetes (2)

Answer 31

Syphillus | Lyme disease

Question 32

Genetic variation in bacteria is dangerous because...

Answer 32

Resistance to antibiotics may develop

Question 33

Gene transfer: Transformation

Answer 33

DNA from dead bacteria is taken up by living bacteria and incorporated into plasmids/bacterial chromosome.

Question 34

Gene transfer: Conjugation

Answer 34

Sex pilus forms between bacteria to allow transfer of plasmid DNA.

Question 35

Gene transfer: Transduction

Answer 35

Viruses can transfer bacterial DNA between cells they infect.

Question 36

The 5 methods of spread of infection are...

Answer 36

Inhalation, Ingestion, Inoculation, mother to Infant, Intercourse

Question 37

Viruses contain RNA or DNA, never both. True/False?

Answer 37

True Size of their capsid (protein coat) limits space

Question 38

Bactericidal antibiotics inhibit cell growth. True/False?

Answer 38

False Kill bacteria directly - bacteriostatic inhibits cell growth

Question 39

Viruses that remain persistant within the cell.

Answer 39

Reactivation (HSV, VZ) | Remain active for years (HIV, Hep C)

Question 40

What is the term given to an antibiotic that kills the bacteria without harming the host?

Answer 40

Selectively toxic

Question 41

Reason for prescribing more than one abx (3)

Answer 41

Covers broad range of microorganisms Prevents resistance Synergistic effect

Question 42

Why cant antibiotics be used to treat fungi?

Answer 42

No cell wall and have a different structure from bacterial ribosome + have a single circular chromosome

Question 43

Antibiotics that act on the bacterial cell wall (3)

Answer 43

Penicillins Cephalosporins Glycopeptides

Question 44

Vancomycin is part of which family of antibiotics?

Answer 44

Glycopeptides

Question 45

Penicillins are bactericidal/bacteriostatic, safe/not safe in pregnancy, excreted via kidneys/urine/liver

Answer 45

Bactericidal, safe in pregnancy, kidneys

Question 46

Benzylpenicillin is given IV and is AKA penicillin V. True/False?

Answer 46

False Penicillin G; phenoxymethyl-penicillin is AKA penicillin V

Question 47

Flucloxacillin is a ___ spectrum antibiotic. Which organisms is it effective against?

Answer 47

Narrow Staph and Strep only (1st line for Staph aureus)

Question 48

Beta lactamase destroys which antibiotic?

Answer 48

Amoxicillin

Question 49

Co-amoxiclav is probs the best antibiotic to have on a desert island - why?

Answer 49

Treats everything apart from Pseudomonas and MRSA Can be taken orally or IV

Question 50

Cephalosporins are bactericidal/bacteriostatic, safe/not safe in pregnancy, excreted via kidneys/urine/liver

Answer 50

Bactericidal, safe in pregnancy, kidneys + urine

Question 51

Glycopeptides are only active against Gram _ cell walls

Answer 51

+

Question 52

Name the antibiotics that inhibit protein synthesis (3)

Answer 52

Macrolides Tetracyclines Aminoglycosides

Question 53

Gentamicin [aminoglycoside] is bactericidal/bacteriostatic, safe/not safe in pregnancy, excreted via kidneys/urine/liver

Answer 53

Both bacteriostatic + bactericidal, not safe in pregnancy, urine

Question 54

Macrolides are bactericidal/bacteriostatic, safe/not safe in pregnancy, excreted via kidneys/urine/liver

Answer 54

Bacteriostatic, erythromycin safe in pregnancy, liver

Question 55

Can you name the 3 macrolides?

Answer 55

Erythromycin, clarythromycin, azythromycin

Question 56

Gentamicin belongs to which class of antibiotics?

Answer 56

Aminoglycosides

Question 57

In what way is gentamicin toxic?

Answer 57

Damages kidneys and XIIIth CN

Question 58

Name the antibiotics that act on bacterial DNA

Answer 58

Metronidazole, trimethoprim +/- sulphanimide, fluoroquinolones

Question 59

Metronidazole is bactericidal/bacteriostatic, safe/not safe in pregnancy, treats aerobes/anaerobes

Answer 59

Bactericidal, safe in pregnancy, anaerobes (Clostridium and Bacteroides)

Question 60

Trimethoprim +/- sulphonamide is bactericidal/bacteriostatic, can be combined with sulphonamide to form _____

Answer 60

Bacteriostatic, co-trimoxazole

Question 61

Give examples of fluoroquinalones (2)

Answer 61

Ciprofloxacin, levofloxacin

Question 62

What is PVL?

Answer 62

Severe strain of MRSA causing skin infections such as necrotizing fascitis

Question 63

The 4 antibiotics that most commonly cause C diff infection are...

Answer 63

Ciprofloxacin Co-amoxiclav Clindamycin Cephalosporins (ceftriaxone)