Animal Microbial Resistance Flashcards
What antibiotics target the cell wall
Beta lactam, glycopeptides, bacitracin
What antibiotics target DNA
Fluoroquinolones, novobiocin, nitroimidazoles
What antibiotics target ribosomes
Tetracyclines, aminoglycosides, lincosamindes
How do beta-lactams work
They bind the active site in transpeptidases (penicillin binding proteins) and stop the crossing linking between peptide and sugar chains
This is because the antibiotics are similar to the natural peptidoglycan subunits (D-Ala-D-ala)
All beta-lactam antibiotics contain…
The same core 4-member beta-lactam ring (the shape that mimics the terminal D-ala-D-Ala that is the substrate for the transpeptidase)
4 general resistance mechanisms to beta-lactams
Penetration (intracellular bacteria)
Porins (gram negative)
Pumps (gram neg can have ABC transporters)
Peptidoglycan is absent (mycobacteria)
2 specific resistance mechanisms to beta-lactams
- penicillinases (beta-lactamases)
2. PBPs (does not bind beta-lactams)
What are 3 levels of threat that AMR has on humanity
Global health, food security and development/economics
By 2050, how many people will die annually due to AMR
10 million
When was penicillin discovered
1928
When were sulphonamides marketed for routine use in agriculture
1938
What drug was found to increase the rate at which poultry gained weight
Aureomycin
What was used to prevent coccidiosis in broilers
Sulfaquinoxaline
By 1998, how many S. aureus isolated were resistant to penicillin
95%
What are most chickens and cattle fed in North america
Chickens: bacitracin, ionophores
Cattle: ionophores
What are beef cattle fed prophylactically with
Ceftiofur (category 1)
What is the WHO five-step approach to fighting AMR
- Improve awareness and understanding
- Strengthen surveillance
- Reduce incidence of infection
- Optimize AM medicines
- ensure sustainable investment in countering antimicrobial resistance
What is canada’s 3 pronged approach to combatting AMR
Surveillance, stewardship (conserving effectiveness of existing treatments) and innovation
What is Canada’s approach stewardship
Antibiotics are categorized into 4 groups based on importance in human medicine (specific warnings for categories 1-3
Synercid
Semi-synthetic antibiotic that is approved to treat MRSA
Virginiamycin
Approved for feed in a broiler chickens and swine
What is the connection between synercid and virginiamycin
Virginiamycin acetyltransferases confer resistance to synercid
What is MCR-1
It confers resistance to colistin and bacitracin
What can be used to replace antibiotics
Improved hygiene, bacteriophages, probiotics, antibiotic derivatives
