Internal Medicine - Infectious Diseases - Antibiotics

Question 1

Penicillins cover Strep viridans, Strep pyogenes, oral anaerobes, syphilis, and Leptospira. On top of these, what other organisms are covered by ampicillin and amoxocillin?

Answer 1

E. coli
Lyme disease
Some gram-negative bacteria

Question 2

What are the five main organisms covered by amoxicillin?

Answer 2

HELPS:
H. influenza
E. coli
Listeria
Proteus 
Salmonella

Question 3

What 2 important, common infections are NOT covered by penicillins?

Answer 3

MRSA and Enterococcus

Question 4

Methicillin is never the right answer for any infection. Why?

Answer 4

It causes renal failure due to allergic interstitial nephritis.

Question 5

What are the best initial therapy-agents for hospital-acquired/ventilator-associated pneumonia?

Answer 5

Pipercillin, ticarcillin, azlocillin, and mezlocillin

+ beta-lactamase inhibitors (ex: tazobactam or clavulanic acid)

Question 6

What major bacteria/bacterial groups are covered by agents such as pipercillin, ticarcillin, azlocillin, and mezlocillin?

Answer 6

Gram-negative bacilli (ex: E. coli and Proteus)

Pseudomonas

Question 7

When a patient tells you they are allergic to penicillin, you should ask them if they have ever taken/reacted to what other class of antibiotics?

Answer 7

Cephalosporins

Question 8

If a question describes anaphylaxis, what antibiotic group should you NOT use?

Answer 8

Beta-lactam antibiotics

Question 9

What major bacteria is NOT covered by first generation cephalosporins (ex: cefazolin, cephalexin, cephradrine, cefadroxyl)?

Brand names: Ancef, Keflex, Velosef, Duricef

Answer 9

Pseudomonas

Question 10

What two agents are typically used to treat healthcare-associated pneumonia?

Answer 10

Vanc and Zosyn

vancomycin and pipercillin+tazobactam

Question 11

What are two important side effects of cefotetan and cefoxitin (second generation cephalosporins)?

Answer 11

Increased risk of bleeding (deplete prothrombin)

Disulfiram-like reaction with alcohol

Question 12

What two antibiotics are commonly used to treat community-acquired pneumonia?

What is the “best therapy” for community-acquired pneumonia?

Answer 12

Ceftriaxone and macrolide (azithromycin)

Fluoroquinolones (cipro, levo, etc.)

Question 13

What population should ceftriaxone be avoided in? Why?

Answer 13

Neonates
Impairs biliary metabolism: displaces bilirubin from albumin leading to increased risk of bilirubin encephalopathy, especially in hyperbilirubinemic neonates.

Question 14

What groups of bacteria do carbapenems cover?

Answer 14

Almost everything: gram-negative bacilli (including resistant organisms), anaerobes, streptococci, and staphylococci. They’re broad-spectrum big-guns.

Question 15

How does ertapenem differ from other carbapenems?

Answer 15

Does NOT cover Pseudomonas.

Question 16

What single drug belongs to the class of monobactams?

Answer 16

Aztreonam

Question 17

What bacteria/groups of bacteria does aztreonam cover?

Answer 17

Exclusively gram-negative bacilli, including Pseudomonas.

Question 18

What fluoroquinolone is commonly used to treat cystitis and pyelonephritis?

Answer 18

Ciprofloxacin

Question 19

Fluoroquinolones are commonly used to treat diverticulitis and GI infections. However, they must be administered with one other medication. What is the medication and why?

What fluoroquinolone is an exception to this rule?

Answer 19

Metronidazole to cover anaerobes; fluorequinolones do not cover anaerobes…

EXCEPT moxifloxacin: can be used as a single agent (without metronidazole) for diverticulitis.

Question 20

What are three major/most severe side effects of fluoroquinolones?

Answer 20

1. Bone growth abnormalities in children and pregnant women.
2. Tendonitis and Achilles tendon rupture
3. QT prolongation

Question 21

Aminoglycosides cannot be administered by themselves. What medication(s) must they be administered with and why?

Answer 21

Given with beta-lactam antibiotics; cannot penetrate cell wall on their own.

Question 22

What group of bacteria do aminoglycosides NOT cover?

Answer 22

Anaerobes; aminoglycosides need oxygen to work.

Question 23

What are the two main toxicities associated with aminoglycosides?

Answer 23

Nephrotoxicity

Ototoxicity

Question 24

What are the major adverse effects (4) of doxycycline/tetracyclines?

Answer 24

Tooth discoloration (children)
Fanconi syndrome (type II renal tubular acidosis)
Photosensitivity
Esophagitis/ulcer

Question 25

Trimethoprim/Sulfamethoxazole (Bactrim) is used in the setting of which type of pneumonia?

Answer 25

Treatment and prophylaxis of pneumocystis pneumonia (in HIV patients)

Question 26

What are the two major/most dangerous side effects of TMP/SMX?

Answer 26

Hemolysis in patients with G6PD deficiency

Bone marrow suppression due to folate antagonism

Question 27

What five antibiotics can be used to treat moderate to severe MRSA infections?

Answer 27

In order of escalation: 
Vancomycin
Linezolid
Daptomycin
Tigecycline
Ceftaroline

Question 28

What is the major side effect with use of linezolid?

Answer 28

Reversible bone marrow toxicity

Question 29

What is the major side effect with use of daptomycin?

Answer 29

Elevated CPK

Question 30

What four antibiotics can be used to treat minor MRSA infections?

Answer 30

TMP/SMX
Clindamycin
Doxycycline
Linezolid

Question 31

What major group(s) of antibiotics are used to treat infections with anaerobes above the diaphragm?

Answer 31

Clindamycin (preferred)

Penicillin (G, VK, amipicillin, or amoxicillin)

Question 32

What major group(s) of antibiotics are used to treat infections with anaerobes below the diaphragm?

Answer 32

Metronidazole + beta-lactam/lactamase combinations

Question 33

What is the one major indication for use of nitrofurantoin (Macrobid)?

Answer 33

Cystitis, especially in pregnant women.