Chapter 10 Antimicrobial Agents Flashcards
Paul Ehrlich
Created magic bullets which were an arsenic compounds that killed microbes
Alexander Flemming
Develop the first fungi antifungal penicillium crysogenum released from penicilling
Gerhad Domagk
Discovered sulfanilamide
which was develop from bacterial antimicrobial and it was the antibiotic that was widely distributed
Selman Waksman
He discovered many antibiotics
Semi synthesis
Chemically altered antibiotics that are more eefective longer lansting or easier to adminiter than naturally occuring ones
Synthesis
Antmicrobials that are completely synthesized in a lab
Ex: Fungi
Penicillium chrysogenum the antimicrobial used is penicillin G
Ex:Bacteria
Bacillus lichenifomis the antibiotic used is bacitracin
Chemotherapy
Successful chemotherapy requires selective toxicity to the specific bacteria that is causing harm
Antiviral drugs are limited
They are limited because viruses are not living
Beta-lactams
Antibiotics that contain a Beta-lactam ring in their chemical structure like penicillin
Beta-lactams are more prominent in Gram-positive microorganisms because they have a ticker peptidoglycan than Gram negative they only have an outer layer
Inhibition of synthesis of fungal walls
Targets of polysaccharides is a selective toxic fungal
▪ Echinocandins inhibit the enzyme that
synthesizes glucan
Inhibition of Protein Synthesis
▪ Prokaryotic ribosomes are 70S (30S and 50S)
▪ Eukaryotic ribosomes are 80S (40S and 60S)
▪ Drugs can selectively target translation
▪ Mitochondria of animals and humans contain 70S
ribosomes
Polymyxin
Disrupts cytoplasmic membranes of Gram-
negative bacteria
▪ Toxic to human kidneys
– Some parasitic drugs act against cytoplasmic
membranes
Atovaque
Interferes with electron transport in proctozoa and fungi
Drugs that block activation of viruses
Amantadine, rimantadine, and weak organic
bases prevent viral uncoating.
Antimetabolic agents
Can be effective when pathogen and host metabolic processes interfere
Trimethoprim also interferes with nucleotide synthesis.
– Antiviral agents can target unique aspects of viral
metabolism.
Inhibition of Nucleic Acid Synthesis
– Several drugs block DNA replication or RNA
transcription
– Drugs often affect both eukaryotic and prokaryotic
cells
Attachment antagonists
Block viral attachment or
receptor proteins
– New area of antimicrobial drug development
– Pleconaril blocks viral attachment
– Arildone prevents viral uncoating
Ideal antimicrobial agents are
-Readily available
– Inexpensive
– Chemically stable
– Easily administered
– Nontoxic and nonallergenic
– Selectively toxic against wide range of pathogens
Narrow spectrum effective against few organisms
specific what the target is
Ex: it can only target like viruses
Broad-spectrum effective against many organisms
beneficial because they target a lot pathogens but allowed for secondary infections like giving you yeast infection
– May allow for secondary or superinfections
to develop
– Killing of normal flora reduces microbial
antagonism
Effectiveness of antimicrobial
▪ Diffusion susceptibility test
▪ Minimum inhibitory concentration test
▪ Minimum bactericidal concentration test
Zone of inhibition (clear inhibited) (is an area where bacteria cannot grow to due to the presence of antibiotics) meets bacterial growth is called suspetibility test
Routes of administration
Topical, Intravenous (administration delivers drug directly to bloodstream),
the intramuscular, oral route,
Toxicity
▪ Cause of many adverse reactions poorly
understood
▪ Drugs may be toxic to kidneys, liver, or nerves
▪ Consideration needed when prescribing drugs to
pregnant women
Ex: mild toxicity around the area of a vaccine site
Therapeutic index
Is the ratio of the dose of a
drug that can be tolerated to the drug’s effective
Dose (higher the therapeutic the agent the higher the dose)
Anaphylactic shock
– Disruption of normal microbiota
▪ May result in secondary infections
▪ Overgrowth of normal flora causing secondary
infections
