export_antibiotics

Question 1

Selective toxicity of antibiotics

Answer 1

Killing or inhibiting microorganism without harming host cells

Question 2

Bacteriostatic

Answer 2

Inhibit growth

Used when host defenses can be counted on

Question 3

Bactericidal

Answer 3

Killing bacteria

Used during invasive infection or with immunocompromised patient

Question 4

Antibiotic synergism

Answer 4

Combination of two antibiotics that enhance antibacterial activity when used together

Question 5

Antibiotic antagonism

Answer 5

Combo of antibiotics where one interferes with the other

Question 6

Broad-spectrum antibiotics

Answer 6

Effective against a large variety of bacteria

Question 7

Advantage of broad-spectrum antibiotics

Answer 7

Increase likelihood of effectiveness against bacterial infection of unknown etiology

Question 8

Disadvantage of broad-spectrum antibiotic

Answer 8

Increased likelihood in disrupting patient’s normal microbiota

Question 9

Narrow-spectrum antibiotics

Answer 9

Effective only against a small subset of bacteria

Question 10

Narrow-spectrum antibiotic advantage

Answer 10

Avoids disruption of normal microbiota

Question 11

Narrow-spectrum antibiotic disadvantage

Answer 11

Must know the specific bacteria and its resistances

Question 12

Do antibiotics cause resistance?

Answer 12

No - acquisition of genetic information may result in resistance

Question 13

What do antibiotics do, as far as selection against bacteria?

Answer 13

They select against sensitive bacteria, and select for resistance bacteria

Question 14

Antibiotic resistance categories

Answer 14

Sensitive (S)
Intermediate (I)

Resistant (R)

Question 15

(S) bacteria

Answer 15

Infection can be treated with recommended antimicrobial agent

Question 16

(I) bacteria

Answer 16

Infection can be treated where high dose is able to be used

Question 17

(R) bacteria

Answer 17

These isolates will not be inhibited by the usually achieved concentrations of the antimicrobial agents

Question 18

Empiric therapy

Answer 18

Used while waiting for lab results - generally broad-spectrum

Question 19

Targeted therapy

Answer 19

Refined treatment - narrow-spectrum

Question 20

Antibiotic prophylaxis

Answer 20

Prevent rather than treat disease

Used with immunocompromised patients, or exposure to high-risk pathogens

Question 21

Mechanisms of antibiotic resistance

Answer 21

Breakdown of antibiotic (hydrolysis)
Chemical modification of an antibiotic

Alteration of the target

Altered permeability (decreased influx or increased efflux)

Lack of target

Question 22

Minimum inhibitory concentration (MIC)

Answer 22

Lowest concentration of antibiotic that inhibits growth

Question 23

Minimum bactericidal concentration (MBC)

Answer 23

Lowest concentration of antibiotic that kills 99.9% of bacteria

Question 24

Kirby-Bauer Test

Answer 24

Disk-diffusion assay

Disks of antibiotic on agar plate to see what antibiotic is most effective

Question 25

E-test

Answer 25

More recent development where you read the lines on a strip of antibiotic Can determine MIC easier than disk-diffusion test

Question 26

Broth culture

Answer 26

Overnight incubation Can determine MIC using optical density of test tubes Can determine MBC by measuring remaining bacteria on a plate

Question 27

Cell wall synthesis inhibitors are specific for?

Answer 27

Peptinoglycan

Question 28

Cell wall active antibiotics

Answer 28

Only disrupts actively dividing bacteria by disrupting peptinoglycan synthesis

Question 29

Membrane active antibiotics

Answer 29

Disrupts or interferes with membrane integrity/synthesis | Effective against resting and actively dividing bacteria

Question 30

Beta-lactams

Answer 30

Bactericidal Inhibition of cell wall synthesis Ex. penicillins, cephalosporins, etc.

Question 31

Beta-lactam mechanism - step one

Answer 31

Penicillin binding protein binds to pentapeptide chain of peptidoglycan

Question 32

Beta-lactam mechanism - step two

Answer 32

Reactive serine will cleave Ala (position 5 of pentapeptide chain)

Question 33

Beta-lactam mechanism - step three

Answer 33

Generation of pentaglycine chain to bind two peptidoglycan chains

Question 34

Beta-lactam mechanism - step four

Answer 34

Penicillin binds to penicillin binding protein and blocks its active serine

Question 35

Beta-lactam mechanism - step five

Answer 35

Penicillin binding protein is inactive, and peptidoglycan chains cannot be expanded

Question 36

Beta-lactam resistance

Answer 36

``` Altered transpeptidases (decreased affinity to antibiotic) Altered outer-membrane permeability (mutation in porins) ``` Presence of efflux pumps Chemical modification of antibiotic (beta-lactamase)

Question 37

Vancomycin

Answer 37

Binds to the two D-Ala residues on the end of the peptide chain which prevents cross-linking = cell death

Question 38

Vancomycin resistance

Answer 38

The last D-Ala has been replaced by a D-lactate, preventing vancomycin binding

Question 39

Bacitracin

Answer 39

Interferes with dephosphorylation in cycling of lipid carrier that transfers peptidoglycan subunits to growing cell wall

Question 40

Tetracyclines

Answer 40

Bacteriostatic Bind 30S subunit Broad-spectrum

Question 41

Aminoglycosides

Answer 41

Generally bactericidal Bind to 30S subunit Oxygen-dependent (only will kill aerobic bacteria)

Question 42

Macrolides

Answer 42

Bacteriostatic Bind 50S subunit Alternative for those with penicillin allergies

Question 43

Quinolones

Answer 43

Bactericidal Inhibits DNA replication, recombination, and repair Affects DNA topoisomerase type II or IV

Question 44

Rifampin, rifabutin

Answer 44

Bactericidal | Binds to DNA-dependent RNA polymerase, inhibiting initiation of RNA synthesis

Question 45

Metronidazole

Answer 45

Bactericidal | Toxic compounds that damage DNA

Question 46

Antimetabolites

Answer 46

Target folate metabolism Bacteriostatic Sulfonamides and trimethoprim often used together for this