Antibiotics Flashcards
What is the issue with antibiotic resistance
The biggest current threat to medical science
What is antibiotics mode of action
Antibiotics can either be:
Bactericidial - killing bacteria
Acteriostatic - inhibit bacterial pathogens
Where do bacteria attack
Genome
Cell wall
Cell membrane
Ribosomes
How many different classes of antibiotic are there
Over 15
They are classed to similar strucutre etc
What are b-lactam antibiotics defined by
B-lactam ring
What are the examples of b-lactam antibodies
Penicillin, ampicillin
What is the mode of action of b-lactam antibodies
Inhibition of cell wall synthesis
What do b-lactam antibiotics aim to do to penicillin-idling proteins
Aim not to bind penicillin
These PBP proteins in peptidoglycan cross-linking transpeptidases and carboxypeptidases are key
What happens wen penicillin interacts with penicillin binding proteins
Little cross linking
Weaken cell walls
Osmotic pressure
Induction of autolysis pathway
What are examples of tetracyclines
Oxytetracycline, doxycycline
What are tetracyclines defined by
4 ring struute
What is the mod of action of etracyclines
Inhibitionn of protein synthesis
How do tetracyclines inhibit protein synthesis
Target16s rna n the 30s subunit - increases retinoids acid signalling
What are the side effects of tetracyclines
Anti-inflammatory - does more than one thing excellent
Examples of quinolones
Nlidixic acid
What are quinolones defned by
Central 2 ring strucutre
What is the mode of action of quinolones
Interference with DNA gyrase which is critical in DNA replication
Prevents supercoiling of dna
What are b lactams used to treat
Strangles
Streptococooola and colostridial infections
Mastitis
What do quinolones treat
Erfloxacin for poultry
E,coli, oampylobacteria
How does antibiotic resistance develop
- natural resistance in bacterial populations mutation occurring due to low treatment level
Acquired by plasmids from other bacteria/species
What causes B-lactam resistance
Increase production of PBP antibodies
Express decoy PBP
Mutations in PBP proteins - stop penicillin from binding but allows it to function
Stop cross linking within peptidoglycan wall
What are b-lactamases
Proteins encoded on bacterial plasmids or hormones
What examples of gam positive bacteria are b-lactamases on
S,aureus
How do we get aorund b-lactamses resistance
Create b-lactam inhibitors - allows antibiotic t function as they target the protective mechanism
What causes tetracycline antibiotic resistance
Send as gowhtpromoters until 2017 - we dont need it anymore as nutrition fattens animals
Causes resistant mechanisms- found by gene testing
Protective proteins bloc action against ribosome meaning drug can no longer reach the ribosome
