Bacterial Infections of the Lung - Mechs. of Resitance

Question 1

Macrolides

MOR?

Answer 1

(MYCINS)
• Ribosomal Methylation and Mutation of 23S rRNA
• Active Efflux

Question 2

Tetracyclines

MOR?

Answer 2

(CYCLINEs)
• Decreased entry
• Increased Efflux
• Target Insensitivity

Question 3

Fluroquinolones

MOR?

Answer 3

(FLOXACINs)
• Mutation of DNA gyrase
• Active Efflux

Question 4

Penicillins

MOR?

Answer 4

(CILLINs)
• Drug inactivation (ß-lactamase)
• Altered PBPs (target insensitivity)

Question 5

Cephalosporins

MOR?

Answer 5

(CEFs or CEPHs)
• Decreased permeability or gram - outer membrane (altered porins)
• Active Efflux

Question 6

Aminoglycosides

MOR?

Answer 6

• Drug Inactivation (aminoglycoside modifying enzyme)
• Decreased permeability of gram - outer membrane
• Active efflux
• Ribosomal methylation

Question 7

Vancomycin

MOR?

Answer 7

Replacement of D-ala by D-lactate

Question 8

A patient is treated with an antibiotic that elicited a hypersensitivity reaction. It is noted on the patients chart that they are allergic to penicillin. What would be the best alternate drug options for this patient, assuming you want a drug with the same MOA?

Answer 8

ß-lactamase alternates less likely to trigger hypersensivity:
• Cephalosporins (cefazolin, cefepime, ceftazidime, ceftriaxone)
• Meropenem
• Piperacillin

DO NOT USE drugs like Amoxicillin or Ampicillin

Question 9

What cephalosporin can you give to someone who is typically allergic to cephalosporins?

Answer 9

NONE - there is COMPLETE cross-reactivity across cephalosporins

Question 10

A patient is started on an antibiotic and begins to develop a yellow hue to their sclera. Name 2 drugs that this could be.

Answer 10

Macrolides
• Azithromycin
• Erythromycin

Question 11

What antibiotic may stunt bone growth?

• what other effects might you see?

Answer 11

• Doxycycline - chelates Ca2+

Other Side effects:
• Teeth Discoloration
• Photosensitivity

Question 12

What antibiotic is known to cause neuromusclar paralysis?

• what other effects might you see?

Answer 12

• Gentamicin

Other Side Effects:
• Nephrotoxicity
• Ototoxicity

Question 13

What is the most notable adverse effect of Levofloxacin?

Answer 13

Levofloxacin (fluroquinolone)

• Tendon Rupture
• Cartilage Damage in childer

Question 14

Soon after getting put on an antibiotic for septic shock a man begins to develop siezures. Name two drugs that could do this?

Answer 14

Carbapenems:
• Imipenem (most likely - for adverse effects)
• Meropenem

Question 15

Other than gentamicin name another antibiotic that causes Nephro- and ototoxicity.
• what other side effects does this drug have?

Answer 15

Vancomycin

Other Side Effects:
• Red Man Syndrome

Question 16

What antibiotic should not be given with any type of ß2-agonist?
• why?
• Name another adverse effect of this drug.

Answer 16

• Linezolid - its a non-specific MAOI (monoamine oxidase inhibitor)

Other Side Effects:
• BONE MARROW SUPPRESSION - could see a pancytopenia

Question 17

What antibiotic should never be given to someone with a pre-existing coagulopathy?

Answer 17

• Piperacillin

Question 18

What drugs may prolong the QT interval?

• which of these also is a major CYP3A4 inhibitor?

Answer 18

Macrolides:
• Azithromycin
• Erthromycin - also inhibits CYP and Pgp

(notice clarithromycin is not included)

Question 19

Which antibiotics should generally be avoided when breastfeeding?

Answer 19

• Clarithromycin (note: other macrolides are safe)
• Linezolid
• Metronidazole
• Piperacillin

Question 20

Candidiasis and rash develops in a breastfeeding infant whose mother had a recent bout of pneumonia. What drug was the most likely cause?

Answer 20

Piperacillin

Question 21

What drug may cause hepatotoxicity in pregnancy?

Answer 21

Erythromycin

Question 22

What drug may cause damage to the 8th cranial nerve in a developing fetus?

Answer 22

Gentimycin - may damage the vestibulocochlear nerve

Question 23

What is the function of Cilastin?

• what antibiotic is it most likey to be administered with?

Answer 23

Cilastin:
• Reversible, competitive inhibitor of renal dehyropeptidiase-1 (DHP-1) and enzyme that breaks down impipenem to NEPHROTOXIC metabolites

Question 24

A patient develops pneumonia following infection with strep. pneumonae (gram +) and is administered Daptomycin. He dies 3 days later after succumbing to the infection. Why?

Answer 24

Daptomycin is DENATURED by lung surfactant so it is useless in the treatment of pulmonary infection