Antibiotics

Question 1

Penicillin/ Beta Lactam

Answer 1

MOA- binds to PBPs and inhibits transpeptidation of peptidoglycan thus inhibiting NAM cross-linking

GP: Everything but Staph
GN: only Niserria meningitis
Anaerobes: Clostridium for mouth infections

Clinical applications- dental infection

SE: Hypersensitivity- rash, anaphylaxis

*** Beta Lactamase Sensitive

Question 2

Ampicillin/ Amoxicillin

Answer 2

Everything the same as Penicillin, but also covers H. Flu

Also drug of choice for Listeria and Enterococcus

***Beta Lactamase Sensitive

Question 3

Piperacillin

Answer 3

Everything same as Ampicillin AND Pseudomonas, Enterobacteria, and acinetobacteria
Anaerobes: Yes, Clostridium, B fragilis

***Beta Lactamase Sensitive

Question 4

Nfacillin, Dicloxacillin

Answer 4

All gram + including Staph, but not MRSA

GN:

Question 5

1st Generation Cephalosporins- Beta Lactams

Answer 5

MOA- binds to PBPs and inhibits transpeptidation of peptidoglycan thus inhibiting NAM cross-linking

GP: Everything including Staph
GN: Neissiera, H flu, E. coli, Klebsiella

SE: Hypersensitivity- rash, anaphylaxis, DO NOT give to pts with a history of severe hypersensitivity. Cross reactivity with penicillins

Question 6

3rd Generation Cphalosporins- Beta Lactam

Answer 6

Ex: Ceftriaxone- great for pneumonia

GP: Everything, Ok for MSSA
GN: Everything

Clinical uses: pneumonia, Lyme disease

Question 7

4th generation Cephalosporins- Beta lactam

Answer 7

Ex: Cafepime

GP: Everything, Ok for MSSA
GN: Everything

Clinical uses: Crosses BBB- good for CNS infections

Question 8

Monobactam- Beta Lactam

Answer 8

Good coverage: Only gram negatives rods (GNRs)

SE: No hypersensitivity or cross-reactivity- good for pts with severe penicillin allergy

Question 9

Carbapenems- Beta Lactam

Answer 9

Good Coverage: Broad Spectrum, just about everything except for MRSA and enterococcum faceium.
Anaerobes: YES!

SE: hypersensitivity- rash and siezures in pts with renal failure

note: reserve for only most serious infections

Question 10

Glycopeptides

Answer 10

MOA: Inhibits peptidoglycan synthesis by blocking transpeptidation by binding to d-d alanine portion of peptidoglycan

Ex: Vanco

GP: Everything
GN: nothing
Anaerobes: yes!

Question 11

Daptomycin

Answer 11

MOA: binds to Ca channels resulting in depolarization and potassium efflux resulting in cell death

Good: GP including MRSA and VRE

Bad: GN, anaerobes

SE: reversible myopathy

Question 12

Ciprofloxacin- Fluoquinolones

Answer 12

MOA: Inhibits DNA Gyrase (Topoisomerase in bacteria)

Good: GN

Bad: GP

Clinical uses of Fluoroquinolones: Complex UTI, Intra-abdominal inections, pneumoniae (except cipro). Note: reserve fluoro abx for serious infections

SE: tendon/cartilage damage

Question 13

Levofloxacin- Fluoquinolones

Answer 13

GP- most everything except staph
GN- most everything except enterobactr
No anaerobes

Question 14

Moxifloxacin- Fluoroquinolones

Answer 14

Same coverage as Levo with better anaerobe coverage

Question 15

Rifampin

Answer 15

MOA: Inhibitor of bacterial RNA pol.

Clinical uses: TB, Staph prosthetic valve endocarditis

Note: induces P450 enzymes to accelerate metabolism of many drugs. Also use in conjunction with other classes to prevent resistance

Question 16

Metronidazole

Answer 16

MOA: Highly active radical that binds to DNA and destabilizes it

Good: Anaerobes, C diff, Protozoa, combination therapy for M tuberculosis

Question 17

Trimethoprim/Sulfamethoxzaole Sulfonamides

Answer 17

MOA: Inhibit Folate synthesis, we get folate from diet, but bacteria must make their own

Good: Staph, including MRSA, several GN agents including E. coli

Clinical applications: UTI, MRSA, Pneumocystis Pneumoniae, Staph infections, but not bacteremia

Question 18

Linezolid

Answer 18

MOA: binds to 50s subunit preventing formation of the ribosome fMet-tRNA complex

Good: VRE, MRSA, reserved for bacteria resistant to the usual antibiotics

SE: thrombocytopenia

Question 19

Aminoglycosides

Answer 19

MOA: bind to 30s subunit and block synthesis

Ex: gentamicin, tobramycin, Amikacin

GN: most everything except N meningitides
GP: nothing

SE: renal toxicitty, hearing loss, vertigo

Clinical: poor distribution to CSF and adipose (use Height/weight when dosing)

Question 20

Tetracycline

Answer 20

MOA: binds to 30s subunit and prevents attachment of aminoacyl tRNA to A site

GP: Strep, Staph including MRSA, spirochetes (lyme), Rikettsia, Chamydia

GN: GNRs- broad but not potent

SE: teeth staining, phototoxicity, intracranial pressure. Avoid in children under 7

Question 21

Macrolides

Answer 21

MOA: binds to 50s subunit and inhibits translocation step (move from P to A)

Ex: Erythromycin (rarely used due to GI effects), Azithromycin:
GP- just about everything
GN: N. meningitides, H flu

Good:H flu, CAP, Chlamydia

Question 22

Clindamycin

Answer 22

MOA: binds to 50s subunit and interferes with aminoacyl translocation

Good: Gram +, some staph/strep including MRSA

Bad: Gram -

SE: Diarrhea- increased risk of C difficile diarrhea

Question 23

What drugs do you use to treat MRSA?

Answer 23

Daptomycin, Linezolide, Clindamycin, Trimeth/Sulfa

Question 24

What drugs do you use for Anaerobes?

Answer 24

Penicillin (mouth), Piperacillin, Moxifloxacin, Metronadizole, Carbenapems, Vanco