Antimicrobials: Background

Question 1

empiric antibiotics (meaning)

Answer 1

based on body part/suspected infection

Question 2

definitive antibiotics (meaning)

Answer 2

antibiotics based on culture/sensitivity results, which take about 2-3 days.

Question 3

deescalation of abx

Answer 3

as cultures start to come back, you can eliminate the empiric abx that are not applicable.

Question 4

penetration of antibiotics is hard in what 3 areas?

Answer 4

bone
lung
CNS

Question 5

minimum inhibitory concentration (MIC)

Answer 5

Lowest concentration of an antimicrobial that will inhibit the visible growth of an organism.

Question 6

the lower the MIC,

Answer 6

the more sensitive the drug is.

Question 7

post-antibiotic effect

Answer 7

after discontinuation, the abx continues to work.

Question 8

patient specific factors for abx

Answer 8

renal function
hepatic function
age

Question 9

drug specific factors of antibiotics include what 3 considerations?

Answer 9

IV vs PO
bacteriostatic vs bacteriocidal
cost per day

Question 10

bacteriostatic

Answer 10

growth inhibiting

Question 11

bacteriocidal

Answer 11

kills the organism

Question 12

Bacterial resistance mechanisms (4)

Answer 12

• inactivation by various beta-lactamase
• development of new binding proteins which have decreased affinity for the antibiotics
• decreased permeability of the bacterial cell wall
• modification of cell membrane constituents in certain organisms that prevent penetration

Question 13

cell wall/cell membrane in bacterial resistance (2)

Answer 13

• cell wall will prevent abx from getting into the cell wall b/c of decreased permeability.
• cell membrane is modified in certain organisms to prevent penetration (ie: proteins, efflux pumps).

Question 14

proteins: bacterial resistance

Answer 14

some binding proteins have decreased affinity for antibiotics, essentially putting a wall between themselves and the abx.

Question 15

beta lactamases: bacterial resistance

Answer 15

inactivation of the abx by various beta lactamase enzymes, mainly caused by indiscriminate use of abx.

Question 16

3 major gram positive organisms

2 minor

Answer 16

streptococcus
staphylococcal
enterococcal

corynebacterium
listeria

Question 17

gram negative organism examples (7)

Answer 17

escherichia (e coli)
klebsiella
proteus
influenza
psuedomonas 
legionella
M cat

Question 18

“easier” to treat

Answer 18

gram positive aerobes

Question 19

“harder” to treat

Answer 19

gram negative anarobes

Question 20

aerobic vs anaerobic in terms of treatment

Answer 20

aerobic is easier to treat than anarobic

Question 21

example of a spirochete

Answer 21

Lyme disease

Question 22

organism associated with tuberculosis

Answer 22

mycobacteria

Question 23

MAC

Answer 23

mycobacteria avium complex

seen in the immunosuppressed.

Question 24

cell wall active, beta lactam drug groups (4)

Answer 24

• penicillins
• cephalosporins
• thienamycins (“penems”)
• monobactams

Question 25

cell wall active, non beta lactam drug

Answer 25

vancomycin

Question 26

cell wall active vs protein synthesis active

Answer 26

cell wall active drugs destroy the cell wall while protein synthesis drugs starve the organism of nutrients.

Question 27

protein synthesis active drug groups (4)

Answer 27

ahminoglycosides
tetracyclines
macrolides
lincosamides

Question 28

which antimicrobial group works at the level of DNA gyrase?

Answer 28

fluoroquinolones

Question 29

which antimicrobial group works at the level of purine synthesis inhibition?

Answer 29

TMP-sulfa

Question 30

Bacteriostatic drugs

“ECSTaTiC” (6)

Answer 30

Erythromycin
Clindamycin
Sulfonamides
Tetracyclines
Trimethoprim
Chloramphenicol

Question 31

Bacteriocidal drugs (6)
Very Finely Proficient At Cell Murder

Answer 31

Vancomycin
Fluoroquinolones
PCNs
Aminoglycosides
Cephalosporins
Metronidazole