CONTROLLING MICROBIAL GROWTH: IN VIVO Flashcards
These are substances obtained & purified from other microbial organisms
Antibiotics
Antimicrobia1 agents that are chemically synthesized
Chemotherapeutic agents
Principles of antimicrobial action:
This means that the agent must be inactive form, take account which the route the patient receiving the agent, orally or intravenously
Pharmacodynamic design
Principles of antimicrobial action:
The ability to achieve adequate levels depends on this property and to know the anatomic place which the bacteria is present
Pharmokinetic properties
What are the direct interactions between the antibacterial agent and the bacterial cell (Basic steps for antimicrobial activity)
- Surface binding
- Uptake
- Target binding
- Growth inhibition or lysis and death
Inhibit the growth of an organism
Bacteriostatic
The agent that kills the microorganism
Bacteriocidal
The processes or structures most frequently targeted are:
- Cell wall (peptidoglycan) synthesis
- Cell membrane
- protein synthesis
- DNA and RNA synthesis
- Metabolis pathways → folic Acid metabolism
Mode of action of inhibition of CM synthesis
Disrupts the phospholipid bilayer
Cyclic lipopeptide agents that disrupts the cellular membranes
Polymyxin B and colistin
Examples of polymyxins
Polymyxin B and colistin
Effectiveness varies with the molecular makeup of the bacterial call membrane, these are not equally effective against all bacteria.
Polymyxins
Most effective against gram-negative bacteria, whereas activity against gram-positive bacteria tends to be poor.
Polymyxins
Pose toxicity to humans (neurotoxicity and nephrotoxicity)
Polymyxin’S
Agents of last resort when gram-negative bacilli that are resistant to all other available agents are encountered
Polymyxin’S
Example of bacteria’s thatare resistant to all agents encountered
Pseudomonas aeruginosa
Acinetobacter spp.
Deoxyribonycheic Acid inhibitors:
Fluoroquinolones
Examples of fluoroquinolones
Ciprofloxacin
Levofloxacin
Ofloxacin
Norfloxacin
Moxifloxacin
MOA: agents bind to and interfere with DNA gyrase enzymes involved in the regulation of bacterial DNA supercoiling
Fluoroquinolones
Potential bactericidal agents and have a broad spectrum of activity that includes gram-negative and gram-positive organisms
Fluoroquinolones
Targets DNA gyrase in gram-negative and topoisomerase IV in gram-positive organisms
Fluo. roquinolones
Fluoroquinolones targets _____ in gram-negative bacteria
DNA gyrase
Fluoroquinolones targets _____ in gram- positive bacteria
Topoisomerase IV
MOA : presence of nitro group is reduced by a nitroceductase in the bacterial cytoplasm generating cytotoxic compounds free and radicals that disrupt the host DNA
Metronidazole
Ribonucheic avid inhibitors:
Rifamycin
Example of Rifamycin
Rifampin (also known as ritampicin)
MOA: The agents bind to the RNA and inhibits the synthesis of the RNA
Ribonucleic Acid inhibitor: rifampin
MOA: inhibit the conversion of PABA (Para amino benzoic acid) to folate
Folic Acid metabolism
Example of folic acids
Sulfonamide
Trimethoprim
Essential to synthesis of adenine & thymine
Folic Acid
MOA: bind to ribosomal subunits
CHON synthesis
Examples of 50S ribosomal unit:
Macrolide- lincosamide- streprogramins Group
Kerolides
Oxazolidinones
Chloramphenicol
Macrolide- lincosamide- streprogramins Group
Erythromycin
Azithromycin
Clarithromycin
Clindamycin
Examples of 30S ribosomal subunit
Tetracycline
Streptomycin
Gentamycin
Aminoglycosides
Glycylglycines
Agents that kill both gram-positive and gram-negative bacteria’s
Broad spectrum antibiotics
MOA: interfere the transpeptidation of the peptidoglycan layer:
Inhibition of cell wall
Binds to transpeptidase and binds to d-alanyl-carboxypeptidase
Inhibition of all wall
The __________ stimulates the release of autolysins that are capable of digesting the existing all wall
antibiotic penicillin binding CHON complex
Example of drug that inhibit the cell wall
B-lactams
Drug class comprises the largest group of antibacterial agents, and dozens of derivatives are available for clinical use
B-lactams
Example of alteration of PBPs through transformation
Penicillin -resistant S. Pneumoniae
Release b-lactamase in the extracellular environment
Gram positive
Retains b-lactamase enzymes within the periplasmic space providing increased protection from beta-lactam antimicrobialo
Gram negative
