Intro to Antibiotics I

Question 1

overprescription of antimicrobials

Answer 1

facilitate resistance

Question 2

prophylactic therapy

Answer 2

prevent infection or prevent dangerous disease in those already infected

ex/ HIV infection to prevent opportunistic or post-exposure prophylaxis in those in contact with meningococcal meningitis

Question 3

preemptive therapy

Answer 3

provide early, targeted therapy in high risk pts asymptomatic but who are infected

ex/ CMV tx if CMV + after solid organ transplant

Question 4

empiric therapy

Answer 4

infecting organism not known, antibiotics streamlined based on susceptibility and duration

ex/ staph aureus bacteremia treated empirically with vancomycin

Question 5

post-treatment suppressive therapy

Answer 5

cover patient with antimicrobial therapy at lower dose when infection has not been completely eradicated and immunological or anatomical defect still resent which lead to original infection

ex/ ortho implant that has become infected

Question 6

gold standard for ID of bacteria

Answer 6

gram stain

Question 7

minimum inhibitor concentration

Answer 7

lower concentration of drug that inhibits growth

Question 8

dilution test

Answer 8

serially diluted antibiotics tested with organism

MIC determined

Question 9

disk diffusion

Answer 9

antibiotic on disk
-measure size of clear zone

determine susceptible or resistant

NO MIC

Question 10

optical diffusion

Answer 10

test strip with varying antibiotic concentrations on agar

determine MIC

Question 11

narrow spectrum

Answer 11

single or limited group of microorganisms

Question 12

extended spectrum

Answer 12

gram positive and significant number of gram negatives

Question 13

broad-spectrum

Answer 13

wide variety of bacterial species

-gram positive and negatives

Question 14

bacteriostatic

Answer 14

arrest growth and replication of bacteria

protein synthesis inhibitors

Question 15

bacteriocidal

Answer 15

kill bacteria

Question 16

concentration dependent

Answer 16

extent of killing increases with concentration

aminoglycoside
fluoroquinolones

Question 17

time dependent

Answer 17

serum concentration above minimum kills bacteria

beta-lactam
vancomycin

Question 18

tetramycin

Answer 18

concentration dependent

Question 19

ticarillin

Answer 19

time dependent

Question 20

resistance mechanisms

Answer 20

reduced entry into pathogen

enhanced export

enzymes that destroy antibiotic

proteins transform prodrugs

alteration of target proteins

alternate pathways to those inhibited by antibiotics

Question 21

penicillins

Answer 21

thiazolidine ring connected to beta lactam ring

-attached to side chain

Question 22

mechanism of penicillins

Answer 22

inhibit transpeptidation rxn - last step in peptidoglycan synthesis

beta-lactams are analogs of D-Ala-D-Ala
-bind PBPs - stops cross-linking of the D-Ala

covalent binding
-cell autolysis

Question 23

bacterial resistance to beta-lactams

Answer 23

beta-lactamases

-drug destruction and inactivation

Question 24

natural PCNs

Answer 24

PCN G and V

gram positive cocci

streptococcus pneumoniae

Question 25

pregnant with syphilis

Answer 25

PCN V no alternative - if allergic need to be desensitized

Question 26

anti-staphylococcal PCN

Answer 26

PCNase resistant -staph aureus and staph epidermidis not MRSA oxacillin, dicloxacillin, nafcillin

Question 27

aminopenicillins

Answer 27

extended spectrum often given with beta-lactamase inhibitor extends beyond gram + and - haem influenza, E. coli, proteus, listeria ampicillin, amoxicillin

Question 28

upper resp tract infection with s. pyogenes, s. pneumoniae, h. influenza

Answer 28

ampicillin (and sulbactam) ``` or amoxicillin ( and clavulinic acid) ```

Question 29

anti-pseudomonal PCNs

Answer 29

pseudomonas, enterobacter, proteus piperacillin - extends to klebsiella and anaerobes piperacillin and ticarillin

Question 30

hospital acquired pneumonia

Answer 30

anti-pseudomonal PCNs ticarcillin or piperacillin

Question 31

cephalosporins MOA

Answer 31

beta-lactam | -same as PCNs

Question 32

cephalosporins

Answer 32

classified in generations

Question 33

no cephalosprin

Answer 33

active against MRSA, listeria, enterococci

Question 34

first gen cephalosporin

Answer 34

gram positive moderate gram neg orally active anaerobes cefazolin, cephalexin

Question 35

surgical prophylaxis

Answer 35

first gen cephalosporins cefazolin cefalexin

Question 36

second gen cephalosporin

Answer 36

increased gram negative activity cefoxitin, cefuroxime

Question 37

bacteriodes fragilis

Answer 37

cefoxitin

Question 38

third gen cephalosporin

Answer 38

less active gram positive and more active enterobacter ceftriaxone ceftazidime

Question 39

DOC for serious gram negative infections

Answer 39

klebsiella, proteus, providencia, serratia, haemophilus third gen cephalosporin

Question 40

gonorrhea and severe lymes

Answer 40

ceftriaxone

Question 41

covers pseudomonas

Answer 41

ceftazidime

Question 42

fourth gen cephalosporins

Answer 42

serious infection in hospitalized pts cefepime - active against pseudomonas

Question 43

empirical tx for hospital infections

Answer 43

cefepime 4th gen cephalosporin

Question 44

cross reactive with PCN

Answer 44

1% risk in cephalosporin use

Question 45

intolerance to alcohol

Answer 45

cephalosporin adverse effect disulram like rxn due to MTT group of cefotetan