Dr. Zhanel - Other Abs Flashcards
Fluoroquinolones are ____ drugs
synthetic
Give a few examples of Fluoroquinolones
Norfloxacin
Ciprofloxacin
Levofloxacin
Moxifloxacin
Are fluoroquinolones bactericidal or bacteriostatic?
bactericidal
Describe the MOA of fluoroquinolones
- They inhibit bacterial DNA gyrase and/or topoisomerase IV, by binding to the complex of DNA/DNA gyrase
- DNA gyrase is an enzyme that introduces negative twists in DNA and helps separate its strands
- Results in inhibition of DNA replication, DNA repair, transcription, bacterial chromosome separation during division
How to bacteria become fluoroquinolone resistant?
- single step mutations involving DNA gyrase (GyrA mutations in Gram-negative bacilli and ParC mutations in Gram-positive cocci)
- The mutations cause reduced uptake and efflux
What is silver sulfadiazine commonly used topically for?
to control infections in burn patients
Is Sulfa trim bactericidal or bacteriostatic?
bacteriostatic
What is the most widely used oral and parenteral sulfonamide?
Sulfa trim
Why use a combo of sulfamethoxazole and trimethoprim?
-combo provides synergy, has a broad spectrum of action and reduces the emergence of resistant organisms
Describe the MOA of sulfa trim
- Inhibits synthesis of DNA
- Structurally similar to para-aminobenzoic acid (PABA), a factor required by bacteria for folic acid synthesis
- sulfonamides inhibit bacterial folic acid synthesis which results in a decrease in bacterial purines with subsequent inhibition of bacterial growth
*Humans do not synthesize folic acid but require it in their diet, and therefore human purine synthesis is not affected
List 3 mechanisms of antimicrobial resistance
- Reduced accumulation (reduced uptake, efflux)
- Drug modification/inactivation
- Target site modification
