S1 - Antibiotics Flashcards
Antibiotic
A naturally occurring compound that can kill a microbial organism (Usually bacteria or parasites)
Antimicrobial
Antibiotics as well as synthetic compounds
Multiple mechanisms of action including interfering with the building of cell wall and stopping nucleic acid synthesis
Pharmacotherapy
Basically drug treatment
Antibiotics are a different form of pharmacotherapy (Treatment) than drugs used to treat chronic diseases, in that they target bacterial receptors/proteins instead of patient’s proteins. This makes each patient’s treatment unique as organisms fight back, hide, etc.
Empiric therapy
Nonspecific treatment
When a bacterial infection is suspected but isn’t identified yet, a doctor can prescribe a general antibiotic until it is identified. This is called empiric therapy
Definitive therapy
Specific treatment
Once the bacteria is identified by laboratory tests, they are supposed to describe an antibiotic that is specifically tailored to that pathogen, which is called definitive therapy.
Doctors don’t always transition from empiric to definitive therapy the way they should, which can be a driver of antibiotic resistance.
Pharmacodynamics
How antibiotics interact with both the bacteria and the patient
Can impact a lot of how effective an antibiotic is going to be. Some antibiotics may inhibit bacterial growth (bacteriostatic), while others kill the organism (bacteriocidal). For example, if the antibiotic interferes with DNA replication it is likely bacteriostatic. If it causes cell lysis, it is bacteriocidal. Usually both are effective, but some infections (like meningitis) require bacteriocidal antibiotics.
MIC
The minimum amount of antibiotic for inhibiting bacterial growth (If it is bacteriostatic)
MBC
The minimum amount of antibiotic needed to kill a bacteria (if it is bacteriocidal)
Pharmacokinetics
Pharmacokinetics is how the patient impacts the concentration of the antibiotic in the body. When an antibiotic is administered, it goes through three stages: absorption, distribution (concentrated differently throughout the body), and metabolism/excretion (most excreted in same form).
How quickly the antibiotic goes through each stage depends on a variety of factors. For example, it matters whether an antibiotic is hydrophobic or hydrophilic, how large the antibiotic is, and how it is administered.
Who discovered/popularized penicillin
Alexander Fleming formally discovered in 1928
Mold Penicillum notatum on petri dish
Purified by Florey and Chain (British researchers) and disseminated during WWII
The process of absorption, distribution, metabolism/excretion of antibiotics, what impacts it and why it matters in conjunction with pharmacodynamics in determining dosage.
How quickly the antibiotic goes through each stage depends on a variety of factors. For example, it matters whether an antibiotic is hydrophobic or hydrophilic, how large the antibiotic is, and how it is administered.
Side effects of antibiotics
Antibiotics can alter microbiome composition and allow for opportunistic pathogen infection.
How do beta-lactams work?
Beta-lactams are a type of antibiotic (E.g. penicillin and cephalosporin) that have a double-ring structure and work by interfering with the enzyme that constructs bacteria cell walls.
They are effective against many types of bacteria, but not against certain atypical organisms such as MRSA.
How does tetracycline work?
Tetracyclines are 4 ring structures that work by physically preventing binding of tRNA to the ribosome, thus inhibiting translation and protein synthesis.
How do anti-metabolites work?
Anti-metabolites function by mimicking something that the bacteria needs to metabolize to survive and starving the bacteria by inhibiting its enzymes.
