3.6 - Disruption of plasma membrane, Antimicrobial Resistance, & Antimycobacterial Drugs Flashcards
How do polymyxins work?
What bacteria do they treat?
Adverse effects?
Gram-
–> Act like detergents to disrupt phospholipid membranes
–> Used only topically (or injected into infected body cavity due to nephrotoxicity
What is the main factor causing antibiotic resistance?
Overuse
What are the three main mechanisms used by bacteria to become resistant to antibiotics?
- Reduction of bacterial permeability
- Enzymatic Degradation of antibiotics
- Modification of the action site
What is an antibiogram?
A summary of the cumulative susceptibility of bacteria isolates to antibiotics during a specified period at a specific site. It Represents the proportion of each bacterium that is susceptible to a given antibiotic
What distinguishes mycobacteria from other bacteria?
A cell wall containing a large amount of waxy lipids, especially mycolic acid
What bacteria causes tuberculosis?
Mycobacterium tuberculosis
What kind of treatment is needed for Mycobacterium Tuberculosis?
Very prolonged treatment
–> 6-12 months with combination of drugs
What drug:
Is used to treat tuberculosis and is a powerful cytochrome P450 inducer and is almost used in combination with other drugs?
Rifampin
What are some adverse effects of rifampin?
–> Discoloration of body fluids
–> Epigastric pain
–> Flue like syndrome
What drugs are used to treat tuberculosis?
Rifampin, Isoniazid, ethambutol
What are the adverse effects of isoniazid?
–> Peripheral neuropathy that can be reduced with vitamin B6 (pyridoxine)
What is pyridoxine?
Vitamin b6
What are the adverse effects of ethambutol?
Optic Neuritis
–> Reduced vision caused by inflammation of optic nerve, often starts as red-green color blindness
What is an important components of fungus cell membranes that is often targeted by antifungal medication?
Ergosterol
What are the polyenes? How do they work?
Antifungal drugs: Amphotericin B, nystatin
–> Binds to ergosterol and forms holes in the membrane
