Antinfectives

Question 1

Name bacteriostatic antibiotics

Answer 1

Tetracyclines, Macrolides, Sulfonamides, Trimethoprim, and Chlorapheniol

Question 2

Name bacteriosidal antibiotics

Answer 2

Penicillins, Aminoglycosides, Cephalosporins, Bacitracin, Fluoroquinolenes

Question 3

What is the most common nasocominal bacteria?

Answer 3

Gram + Steph aureus (MRSA)

Question 4

When should you suspect an ocular bacterial infection and hence prescribe antibiotics?

Answer 4

When you have:

1. mucopurulent discharge
2. diffuse conjunctival infection
3. corneal compromise (preventive bc compromised cornea is more susceptible to infections).

Question 5

True or False: Most acute red eyes do not involve a bacterial infection.

Answer 5

True.

Question 6

What type of toxins do Gram- bacteria release?

Answer 6

Endotoxins (LPS).

*upon lysis, gram- bacteria will release endotoxins (LPS) which are pyretic, heat stable and mildly antigenic.

Question 7

True or False: Staphylococcus bacteria account for 50% of all ocular infections.

Answer 7

True.
The most common type of Staphylococcus ocular pathogens are steph aureus and steph epidermidis. (both are penicillin resistant).

Question 8

Which bacteria is considered the 2nd most common nosocomial infection?

Answer 8

*Pseudomonas aeruginosa
A gram- enteric and prominent water-borne bacteria.
The #1 nosocominal bacteria is Steph aureus (gram+ cocci MRSA)

Question 9

Which bacteria is the most common infection leading to ocular blindness in the world?

Answer 9

Chlamydia (which is a Gram- host dependent bacteria)

Question 10

Name the two β-LACTAM ANTIBIOTICS (cell-wall inhibitors)

Answer 10

Penicillins and Cephalosporins.

Question 11

Name the two Stand-alone cell wall inhibitor antibiotics.

Answer 11

Bacitracin and Vancomycin.

Question 12

T or F: Penicillins are predominantly useful for treating Gram+ infections and anaerobic infections

Answer 12

True

Question 13

What are the adverse reactions of Penicillins?

Answer 13

1. Hypersensitivity
   I: Anaphylaxis*
   II: Hemolytic anemia*
   III: Serum sickness
   IV: Steven’s Johnson Syndrome
2. Cross reactive (15% risk) with cephalosporins, especially the 1st generation

Question 14

How do Cephalosporins differ from Penicillins?

Answer 14

• Although both Penicillins and Cephalosporins have B-lactam ring structures, Cephalosporins have 6 member rings vs. the 5 member rings in Penicillins.
• Cephalosporins are also less susceptible to PCNase compared to Penicillins.

Question 15

What are the adverse reactions of Cephalosporins?

Answer 15

1. Hypersensitivity (same type as Penicillins)
2. Vitamin K deficiency
3. Blood dyscrasia: cytopenia

*1st generation Cephalosporins are cross reactive with Penicillin allergy.

Question 16

What are contraindications of Cephalosporins?

Answer 16

Hemophilia

Question 17

Why are Bacitracin available only in topical ointment only?

Answer 17

Due to their profound nephrotoxicity (renal damage).

Question 18

How is Polysporin® Ointment different than Ak-tracin ointment?

Answer 18

*both are Bacitracin antibiotics. The main difference is that AK-tracin has only Gram+ coverage, Whereas Polysporn Ointment additionally contains Polymixin B to allow for additional Gram- coverage (including pseudomonas).

Question 19

What are the adverse reactions of Vancomycin?

Answer 19

1. RED MAN SYNDROME!!!! (IV induced mast cell degranulation)

2. Ototoxicity and nephrotoxicity

Question 20

What type of antibiotics are the drug of choice for MRSA and MRSE infections and bacterial endophthalmitis?

Answer 20

IV Vancomcin

Question 21

What are some characteristics of Vancomycin?

Answer 21

1. Poor oral absorbtion
2. IV Vancomycin is the drug of choice for MRSA and MRSE infections and bacterial endophthalmitis.
3. Gram+ coverage only.

Question 22

Name 2 cell membrane toxins that are used in combination products?

Answer 22

Polymixin B (surfactant) and Gramicidin

Question 23

Name the antibiotics that are protein synthesis inhibitors.

Answer 23

30s inhibitors: Aminoglycosides and Tetracyclines

50s inhibitors: Macrolides and Chloramephenicol (stand alone drug)

Question 24

What is the unique added benefit of Tetracyclines?

Answer 24

Anti-inflammatory benefits due to the inhibition of MMPs & bacterial lipases.

Question 25

Fanconi’s Syndrome is an adverse reaction of which antibiotics?

Answer 25

Tetracyclines

Question 26

What does the pnemonic “PAT an empty stomach” mean?

Answer 26

Penicillines, Aminoglycosides and Tetracyclines (with exception to Doxycycline) should be taken on an empty stomach.

Question 27

All Tetracyclines should be taken on an empty stomach except for Doxycycline. What unique adverse reaction of Doxycycline makes it crucial to take with food?

Answer 27

Risk of erosive esophagitis

Question 28

What is a distinct adverse reaction of Minocycline?

Answer 28

Vestibular toxicity within 2-3d of therapy in up to 70%

Question 29

Name the four tetracycline contraindications.

Answer 29

1. Pregnancy
2. Nursing mothers
3. Children under 8 yrs of age
4. Renal failure (except Doxycycline)

Question 30

What are the adverse reactions of macrolides?

Answer 30

Breast cancer and augment plasma levels of theophylline

Question 31

Name the contraindication of macrolides.

Answer 31

Pregnancy: avoid Clarithromycin (pregnancy Category C)

Question 32

T or F: Chloramphenicol is a 50s protein synthesis inhibitor.

Answer 32

True: both macrolides and chloramphenicols are 50s protein synthesis inhibitors.

Question 33

Which antibiotic causes Gray-baby syndrome?

Answer 33

Chloramphenicols