B&B: Other antibiotics

Question 1

Quinolones

Answer 1

Ciprofloxacin
Levofloxacin
Moxifloxacin
Norfloxacin

Question 2

Quinolones

Answer 2

Inhibit enzymes for bacterial DNA synthesis

• DNA gyrase
• Topoisomerase IV

Question 3

All Quinolones have

Answer 3

a double ring structure

Question 4

Most Quinolones have

Answer 4

fluorine attached

Question 5

Bacterial Topoisomerase enzymes

Answer 5

DNA Gyrase and Topoisomerase IV

Question 6

DNA Gyrase

Answer 6

Introduces ds break

Repairs break

Question 7

Topoisomerase IV

Answer 7

Separates daughter chromosomes

Decantenation

Question 8

Inhibition of bacterial topoisomerase enzymes causes

Answer 8

DNA damage and cell death

Question 9

Quinolone resistance mechanisms

Answer 9

Alterations of DNA gyrase and topoisomerase IV
Alteration in cell permeability
Efflux of drug

Question 10

Quinolones

Answer 10

Many gram (+), gram (-), atypicals
Common clinical uses (adults only)
-UTI (E. coli, other enteric gram negatives)
-Pneumonia (S. pneumo, H. flu, atypicals)
-Abdominal infections (enteric gram negatives)

Question 11

Naladixic acid (not a fluoroquidinone), Norflaxin

Answer 11

One of first Quinolone drugs
Mostly gram (-) coverage
Limited/no gram (+) coverage

Question 12

Ciprofloxacin

Answer 12

Quinolone
Some gram (+) coverage
-Rarely used alone for gram (+) due to resistance
-Good gram (-) coverage
-Most reliable pseudomonas coverage
-Used in UTIs, GI infections
-Cipro ear drops for otitis externa

Question 13

Levofloxacin

Answer 13

Quinolone
More gram (+)/atypical coverage than Cipro
-Better strep pneumo coverage than Cipro
-Covers most methicillin resistant staph aureus
Less effective against pseudomonas than Cipro
Commonly used in pneumonia (strep, atypicals)

Question 14

Quinolones: Adverse Reactions

Answer 14

GI upset
-Anorexia, N/V, abdominal discomfort
Neuro
-HA, dizziness

Question 15

Quinolones: Adverse Reactions

Answer 15

Qt prolongation on EKG
Caused by blockage of K+ channels
Can lead to torsades de pointes

Question 16

Vancomycin

Answer 16

Inhibits peptidoglycan formation (cell wall)
Binds D-analyl-D-alanine peptides
Prevents crosslinking
When cell wall formation is greater than cell formation, cell dies

Question 17

Vancomycin has the same effect but via different mechanism in regards to what drug

Answer 17

beta lactams (inhibit transpeptidases)
Vancomycin blocks transpeptidase binding

Question 18

Vancomycin resistance

Answer 18

Terminal amino acids change
-D-alanyl-D-alanine changes to D-alanyl-D-lactate
VRSA emerges

Question 19

Vancomycin is only effective in

Answer 19

Gram (+)

Too large to pass outer membrane gram negatives

Question 20

Vancomycin Common uses

Answer 20

1. Methicillin Resistant Staph Aureus (MRSA)
2. Oral therapy for C. difficile pseudomembranous colitis
   Often given empirically when MRSA is a concern
   -Endocarditis
   -Severe pneumonia/sepsis

Question 21

Vancomycin adverse effects

Answer 21

Generally well tolerated
Nephrotoxicity
-Increased risk with concomitant aminoglycoside therapy
Ototoxicity (rare)
Red Man Syndrome: Direct activation of mast cells releases histamine. Pseudoallergic drug reaction. Slow infusion = no symptoms.

Question 22

Nitrofurantoin

Answer 22

Rarely used antibiotic
MOA not understood
Bactericidal drug
Only use for UTIs (concentrates urine)

Question 23

Can Nitrofurantoin be given during pregnancy.

Answer 23

Yes. Administer for UTIs during pregnancy. Avoid TMP-SMX, Quinolones.

Question 24

What can Nitrofurantoin trigger in G6PD patients?

Answer 24

hemolysis