Therapy for Staph and Strep II

Question 1

What type of compound is vancomycin?

Answer 1

Glycopeptide

Question 2

Vancomycin mechanism of action?

Answer 2

Prevents cell wall synthesis, binds to d-ala-d-ala, prevents elongation and cross linking.

Question 3

Resistance to vancomycin?

Answer 3

D-Ala-D-Ala turned into D-Ala-D-Lactate, Vanco can’t bind. Also, thickened cell wall.

Question 4

What types of organisms does vancomycin affect?

Answer 4

Only gram positive organisms

Question 5

Is vancomycin bactericidal or bacteriostatic?

Answer 5

Slowly bactericidal, but bacteriostatic against enterococci

Question 6

What is vancomycin the drug of choice to treat?

Answer 6

MRSA and penicillin-resistent pneumococcus

Question 7

Why is the oral formulation used to treat C. diff?

Answer 7

Because it isn’t absorbed, so it doesn’t work systemically, only in gut lumen.

Question 8

Toxicity of vancomycin?

Answer 8

Nephrotoxicity, hypersensitivity (red man syndrome).

Question 9

Red Man syndrome

Answer 9

Histamine response to rapid vanco infusion. Huge widespread rash.

Question 10

What type of compound is daptomycin?

Answer 10

A cyclic lipopeptide

Question 11

What type of organisms does daptomycin treat?

Answer 11

Gram positive organisms (MRSA, MSSA, Enterococci, VRE). NO gram negative activity

Question 12

VRE

Answer 12

Vancomycin resistent enterococci.

Question 13

Does daptomycin have gram negative activity?

Answer 13

No!

Question 14

How does daptomycin work?

Answer 14

Binds to the cytoplasmic membrane using Ca and causes rapid depolarization, leading to intracellular ion release. Rapid bactericidal action, concentration dependent mechanism.

Question 15

What type of infections is daptomycin used for?

Answer 15

Skin and soft tissue infections. MSSA, MRSA, bloodstream infections. VRE.

Question 16

What isn’t daptomycin used for pneumonia?

Answer 16

It is inactivated by pulmonary surfactant.

Question 17

Adverse effects of daptomycin

Answer 17

Musculoskeletal pains, weakness, rhabdomyolysis

Question 18

Who is at increased risk for rhabdomyolysis when taking daptomycin? What to do to monitor?

Answer 18

Those on statins! Check CPK (creatine phosphokinase) levels and monitor muscle strength.

Question 19

Inhibitors of protein synthesis in gram positive cocci

Answer 19

Linezolid, doxycycline, clindamycin. These drugs are bacteriostatic.

Question 20

Inhibitors of protein synthesis

Answer 20

Linezolid, Doxycycline, Clindamycin. These drugs are bacteriostatic.

Question 21

What type of compound is doxycycline?

Answer 21

A tetracycline

Question 22

What organisms does doxycycline treat?

Answer 22

Gram positive and gram negative bacteria, also useful against INTRACELLULAR BACTERIA

Question 23

What is doxycycline used for?

Answer 23

Skin and soft tissue infections

Question 24

Where is doxycycline absorbed?

Answer 24

In the GI tract

Question 25

What is something tricky about taking doxycycline?

Answer 25

Avoid dairy, forms nonabsorbable chelates with Ca, Mg, Fe, Al

Question 26

Where does doxycycline concentrate?

Answer 26

In the liver, kidney, skin, and spleen. Large Vd.

Question 27

Adverse effects of doxycycline?

Answer 27

Binds to calcifying tissues like teeth and bones. GI discomfort, hepatoxicity, photosensitivity.

Question 28

Metabolism of Doxycycline

Answer 28

Hepatic metabolism, renal excretion

Question 29

What can clindamycin treat?

Answer 29

Potentially active against strep and staph. Anaerobic bacteria and non-enterococcal gram positive cocci. NO activity against enterococcus

Question 30

Does clindamycin reach therapeutic levels in CSF/urine?

Answer 30

No.

Question 31

Side effects of clindamycin?

Answer 31

Rash -- potentially C.Diff

Question 32

How to treat enterococcus?

Answer 32

Penicillin/ampicillin. Vancomycin (most is susceptible)

Question 33

How to treat vancomycin resistant enterococci?

Answer 33

Linezolid

Question 34

What is special about linezolid?

Answer 34

100% bioavailability, so oral is great.

Question 35

Problems with prolonged use of linezolid?

Answer 35

Thrombocytopenia and neuropenia, lactic acidosis, serotonin syndrome when taken with SSRIs.

Question 36

Serotonin syndrome

Answer 36

Cognitive: Mental status changes Autonomic: fever, hypertension, tachycardia Somatic: hyperreflexia, myoclonus, tremor

Question 37

Folic Acid antagonists

Answer 37

Trimethoprim-Sulfamethoxazole (TMP-SMZ, bactrim)

Question 38

Why is folate important?

Answer 38

Needed to synthesize DNA, RNA

Question 39

Is TMP-SMZ bactericidal or bacteriostatic?

Answer 39

Bacteriostatic

Question 40

What is TMP-SMZ used to treat?

Answer 40

MRSA/MSSA, but primarily UTIs, also treats listeria in the setting of beta lactam allergy.

Question 41

Where is TMP-SMZ absorbed?

Answer 41

Intestines, large Vd including CSF

Question 42

Why isn't TMP-SMZ given to neonates?

Answer 42

Causes kernicterus (bilirubin deposition, causes movement disorders and developmental delays).

Question 43

What is the drug of choice for MRSA?

Answer 43

Vancomycin

Question 44

What is rapidly bactericidal and can be used for strep and staph infections, but not pneumonia?

Answer 44

Daptomycin

Question 45

What is potentially active against strep and staph?

Answer 45

Clindamycin

Question 46

What should not be given to children or pregnant women?

Answer 46

Doxycycline

Question 47

What is associated with many side effects, so patients must be monitored closely?

Answer 47

Linezolid

Question 48

What drug does not have reliable streptococcal coverage?

Answer 48

TMP-SMZ