Please enable JavaScript.
Coggle requires JavaScript to display documents.
Antimicrobial and Antimicrobial Resistance - Coggle Diagram
Antimicrobial and Antimicrobial Resistance
History
Alexander Fleming
Discovered penicillin
Showed to be effective in killing many bacterial species
Unable to purify penicllin, ended up abandoning research
Erst Chain and Howard Florey
Purified tested compounds on police officer with life-threatening staphylococcus
Patient improved dramatically within 24 hours
Supply of purified penicillin ran out and he later died
Penicillin was so precious it was recycled from urine
Selman Waksman
Purified streptomycin from soil bacterium streptomycin griseus
Today, pharmaceutical companies examine soil samples from around the world
Sources of bacteria
Bacteria: streptomycin and bacillus sp.
Fungi: penicillium and cephalosporium
Commercial production
Careful selection of strain, grown in large vat using broth medium
When Mac antibiotic concentration is reached, drug purified from media
Classification
Classifications of antimicrobial drugs
Antibiotics - kill or inhibit growth of bacteria
Antifungals: kill or inhibit the growth of fungi
Kill or inhibit the growth of pathogenic eukaryotes
Antivirals: inhibit the replication or entry of viruses
Toxicity
Lowest dose toxic to patient/ dose used for therapy
High TI: less toxic (target process non-existent in humans
Relative and expressed as therapeutic index (TI)
Low TI: patient blood monitored for toxicity
Antimicrobial action
"Static" - inhibit microbial growth
"Cidal" - kills microbes
Spectrum of activity
Broad-spectrum antimicrobials
Narrow-spectrum antimicrbials
Antibiotic Resistance
Types of resistance
Intrinsic
Acquired
Acquisition
Spontaneous
Gene transfer
Basic Mechanisms
Stop or slow growth
Destroy antimicrobial drug
Change target of antimicrbial drug
Keep antimicrobial drug away from target
Beta-Lactam Drugs
Penicillins
Natural from penicillium chrysogenum
Penicillinase
Broad spectrum
Extended-spectrum
Penicillins + beta-lactamase
Cephalosporins
Carbapenems
Only effective against growing cells
Bind enzymes that link wall peptides - PBPs