Antimicrobials

Question 2

At what 3 points should an antimicrobial agent be administered/evaluated?

Answer 2

1. empirical therapy choice based on patient assessment; 2. pathogen-specific therapy once pathogen is identified; 3. adjust for resistance once drug suscepitibilities known

Question 3

how is empirical therapy selected?

Answer 3

consider probably/possible pathogens associated with type of disease process in your patient, factoring in personal risk factors, and decide on a broad spectrum antimicrobial

Question 4

what are the 4 major factors that should be considered when choosing an empirical antimicrobial?

Answer 4

disease process, pathogen, host/patient, potential drugs

Question 5

what sites are difficult to treat?

Answer 5

CNS, eye, infected vegetation on heart, bone

Question 6

what type of antibiotic is most effective against diseases with toxin involvement?

Answer 6

antibiotics that inhibit protein synthesis (e.g. clindamycin)

Question 7

what two components of the history are especially important in determining the etiologic agent?

Answer 7

exposure hx (travel, foods, animals, ill contacts) & infectious disease hx (recent infections, colonization with resistant pathogens)

Question 8

what public health concerns are important to consider?

Answer 8

possible role of therapy to decrease duration of shedding or period of infectivity

Question 9

aspects of patient demographic that are especially important when selecting empirical therapy

Answer 9

1) AGE, 2) Co-morbidities, 3) drug allergies & interactions

Question 10

Don’t give _________ to someone with renal or liver dysfunction.

Answer 10

vancomycin, gentamicin

Question 11

Don’t give _________ to someone with GI disease/abnormalities.

Answer 11

oral medications

Question 12

Impact of the Antibiotic/Drug: What to Consider

Answer 12

side-effects, cost, administration, spectum of activity

Question 13

General features of amoxicillin

Answer 13

Beta-lactam penicillin (inhibits wall synthesis); oral only

Question 14

Amoxicillin is effective against?

Answer 14

many Streptococci, enterococcus, Gram negatives like haemophilus, E coli, Pasteurella

Question 15

Use amoxicillin for?

Answer 15

minor respiratory infections such as otitis media, sinusitis, mild pneumonia

Question 16

What are the best IV drugs for MSSA?

Answer 16

oxacillin/nafcillin

Question 17

General features of augmentin

Answer 17

beta-lactam penicillin (amox) + beta-lactamase inhibitor (clav acid); oral formation

Question 18

Augmentin is effective against?

Answer 18

same drugs as amoxicillin + anaerobes, MSSA

Question 19

Use augmentin for?

Answer 19

minor respiratory infections, also dog/cat bites, pathogens resistant to amox due to beta-lactamase production

Question 20

What is the IV equivalent for augmentin (oral)?

Answer 20

ampicillin/sulbactam (Unasyn)

Question 21

Piperacillin/tazobactam (Zosyn) should be used against?

Answer 21

more resistant Gram negative bacteria and anaerobes

Question 22

General features of ceftriaxone (Rocephin)

Answer 22

beta-lactam cephalosporin, 3rd generation; IV (or IM)

Question 23

Ceftriaxone is effective against?

Answer 23

Gram neg rods, streptococci, some Gram + (but not MRSA, pseudomonas)

Question 24

Use ceftriaxone for?

Answer 24

severe infections, including CNS infections (can add vanc if need more gram + coverage)

Question 25

Ceftazidime and cefepime work well against?

Answer 25

pseudomonas

Question 26

cephalexin (Keflex)

Answer 26

common oral 1st generation cephalosporin

Question 27

General features of azithromycin

Answer 27

macrolide (protein synthesis inhibitor); oral (also an IV form)

Question 28

Azithromycin is effective against?

Answer 28

mycoplasma, chlamydia, pertussis, "atypical" bacteria, respiratory bacteria (altho resistance problem)

Question 29

Use azithromycin for?

Answer 29

penicillin allergy, mycoplasma pneumoniae, chlamydia trachomatis, pertussis, etc.

Question 30

General features of clindamycin

Answer 30

lincosamide (protein synthesis inhibitor) that is given both orally and IV

Question 31

Clindamycin is effective against?

Answer 31

Lots of Gram+, many MRSA, anaerobes, NOT enterococcus

Question 32

Use clindamycin for?

Answer 32

Oral/dental infections, some Staph, toxin-producing bacteria

Question 33

Which drug is responsible for the majority of C. diff acquisition?

Answer 33

clindamycin!

Question 34

General features of vancomycin

Answer 34

glycopeptide (inhibits wall synthesis), IV (oral only for C diff)

Question 35

Vancomycin is effective against?

Answer 35

Most Gram+ bacteria, including MRSA and C. diff (except VRE)

Question 36

Use vancomycin for?

Answer 36

severe infections due to Gram + bacteria (add a cephalosporin for gram negative coverage)

Question 37

General features of metronidazole (Flagyl)

Answer 37

produces toxic nitrates in anaerobic bacteria; oral and IV

Question 38

Metronidazole is effective against?

Answer 38

Anaerobes

Question 39

Use metronidazole for?

Answer 39

Gut anaerobes, C. diff (if susceptible), combine to cover Gram neg gut

Question 40

General features of trimethoprim/sulfamethoxazole (Bactrim, Septra)

Answer 40

sulfonamide (inhibits folate synthesis), oral (also IV form)

Question 41

TMP-SMX is effective against?

Answer 41

variety of gram+ and gram-, some atyptical (pneumocystis-PCP)

Question 42

Use TMP-SMX for?

Answer 42

ear infections, UTI, staph skin infection, PCP prophylaxis

Question 43

General features of gentamicin

Answer 43

aminoglycoside (inhibits protein synthesis); IV only

Question 44

Gentamicin is effective against?

Answer 44

many gram-, some gram+ (synergistic with ampicillin)

Question 45

Use gentamicin for?

Answer 45

gram negative coverage; synergy against gram positives

Question 46

General features of levofloxacin

Answer 46

fluoroquinalone (impacts bacterial DNA synthesis), Oral & IV

Question 47

Levofloxacin is effective against?

Answer 47

Many Gram+ and Gram-

Question 48

Use levofloxacin (or ciprofloxacin) for?

Answer 48

adults with sinopulmonary infections, UTI, some skin infections

Question 49

Possible etiologic agents for lobar pneumonia

Answer 49

1. Strep pneumoniae, 2. staph aureus; others: strep pyogenes, oral anaerobes, atypical pneumonias

Question 50

What empirical antibiotic should be used for lobar pneumonia?

Answer 50

Ceftriaxone (penicillin-resistant pneumococcae) + vancomycin (resistant gram+)

Question 51

Possible etiologic agents post-appendix rupture

Answer 51

1. Gram negative enterics (E. Coli), 2. Anaerobes, 3. Enterococci

Question 52

What empirical therapy should be used for a ruptured appendix?

Answer 52

Amp+Gent+Metro or Zosyn

Question 53

Probable infectious etiologies for a bite wound

Answer 53

Pasteurella, Staph aureus, GAS, anaerobes

Question 54

Treat bite wound with?

Answer 54

augmentin unless found to be MRSA

Question 55

Empirical therapy for bacteremia, possible septic shock

Answer 55

vancomycin (gram +) + cefepime (for gram- rods)

Question 56

Probable infectious etiologies for pharyngitis

Answer 56

1. strep pyogenes, 2. adenovirus, 3. EBV, etc.

Question 57

Empirical therapy for a patient with pharyngitis

Answer 57

Throat Culture/Rapid Strep Test --> if positive for RST then treat with penecillin, amox, etc.

Question 58

Treat GC with?

Answer 58

ceftriaxone

Question 59

Treat chlamydia with?

Answer 59

azithromycin (short course, less likelihood of yeast infection)

Question 60

Empirical therapy for osteomyelitis

Answer 60

MRSA treatment -- vancomycin

Question 61

Possible etiologic agents in infant meningitis

Answer 61

E. Coli, GBS, listeria, HSV

Question 62

Empirical Rx for infant meningitis

Answer 62

Ampicillin + gentamicin or cefotaxime (ceftriaxone contraindicated in newborns)