14 - Antimicrobial Resistance Flashcards
Antibiotics can attack the bacterial (3):
- DNA
- Cell wall
- Ribosomes
Give examples of Antibiotics that attack the bacterial DNA:
- fluoroquinolones
- novobiocin
- nitrofurans
- nitroimidazoles
Give examples of Antibiotics that attack the bacterial cell wall:
- Beta lactam antibiotics
- glycopeptides
- bacitracin
Give examples of Antibiotics that attack the bacterial ribosomes:
- tetracyclines
- aminoglycosides
- macrolides
- chloramphenicol
How do beta-lactams disrupt cell wall synthesis ?
Beta-lactams bind to transpeptidase active site blocking its activity and interrupting cross-linking and cell wall synthesis
Transpeptidase catalyzes the cross links between ________________ in the peptidoglycan, the result is covalent bonds between the peptide and sugar chains that create a rigid cell wall that protects the bacteria from osmotic forces that can result in cell rupture
glycan changes/ chains
Beta-lactam antibiotics, are similar to the ____________________ (D-Ala-D-ala) that are the ________ for the transpeptidases.
natural peptidoglycan subunits
substrate
All beta-lactam antibiotics contain the same core ___________________
4-member beta-lactam ring
The beta-lactam ring mimics the shape of the terminal D-Ala-D-Ala peptide sequence that is the substrate for the ____________
transpeptidase
T or F: Chemical modification of the structure of penicillins led to the development of synthetic beta-lactams – which have greater spectrums of activity, and greater resistance to _____________, as well as different pharmacokenetic properties
T
beta-lactamases
What are the 4 GENERAL resistance mechanisms to Beta-lactams?
1- Penetration: intracellular bacteria are resistant to beta-lactams if they are in a mammalian cell
2- Porins: gram negative bacteria are resistant to beta-lactams since the outer cell membrane protects the peptidoglycan, but porins can allow beta-lactams inside. However, some gram-negatives have smaller porins that excludes beta-lactams (general)
3- Pumps: gram negative bacteria can express ABC transporters to pump antibiotics out of the cell
4- Peptidoglycan is absent - some bacteria like mycobacteria lack a cell wall, and are thus not affected by beta-lactam antibiotics
What are the 2 SPECIFIC resistance mechanisms to Beta-lactams?
1- Penicillinases - some bacteria can make beta-lactamases that degrade beta-lactam antibiotics before they reach the cell
2- PBPs - some bacteria can express mutated transpeptidases that still has the enzymatic activity for cell wall synthesis, but does not bind to beta-lactam antibiotics
Antibiotic resistance is a _________ threat to humanity and has effects on: global health, food security, development/economics
multi-level
T or F: An antibiotic resistant infection can affect anyone, of any age, in any country regardless of immune status
T
Antibiotic resistance occurs _________, but overuse of antibiotics in humans and animals has ____________ the process
naturally
accelerated
By 2050, ________ people will die due to AMR annually
10 million
Antibiotics are widely used in : (3)
- human medicine
- agricultural production
- food processing
T or F: Reducing our meat consumption could reduce the risk of AMR
T
_______________ were marketed for routine use in agriculture by 1938
Sulphonamides
In the 1940’s _____________ was found to increase the rate at which poultry gained weight
aureomycin
Today, in North America, most chickens are fed ________ and ___________, and most beef cattle are fed ___________. Most dairy cattle are treated prophylactically with ________every lactation.
bacitracin, ionophores
ionophores
ceftiofur
AGPs improve pig growth rate by ___% and feed efficiency by ___%
- 2
2. 2
The WHO has a 5-pronged approach to combatting AMR:
- improve awareness and understanding of antimicrobial resistance
- to strengthen surveillance and research
- to reduce the incidence of infection
- to optimize the use of antimicrobial medicines
- to ensure sustainable investment in countering antimicrobial resistance
Canada’s 3-pronged response to combatting AMR:
- surveillance
- stewardship
- innovation
T or F: canada categorizes antibiotics based on their importance to human medicine
T
Category 1 antibiotic = _________ importance + give an example _________
very high
fluoroquinolones
Category 2 antibiotic = _________ importance + give an example _________
high
penicillins
Category 3 antibiotic = _________ importance + give an example _________
medium
bacitracins
Category 4 antibiotic = _________ importance + give an example _________
low
ionophores
T or F: category 4 antibiotics are currently used in human medicine?
F
Synercid is a semi-synthetic antibiotic that is approved to treat __________________ in humans
MRSA infections
________________ confer resistance to synercid
virginiamycin acyltransferases
__________confers resistance to colistin and bacitracin
MCR-1
What are some potential strategies to replace antibiotics?
- improved hygiene (vaccinations and new vaccinations)
- bacteriophages
- probiotics (new targeted probiotics)
- antibiotic derivatives
Antagonistic inner-bacterial interactions (novel solutions):
- anti-adherence/biofilm
- growth inhibition
- quorum-quenching
CIPARS stands for:
The Canadian Integrated Program for Antimicrobial Resistance Surveillance (CIPARS) monitors trends in antimicrobial use and antimicrobial resistance in selected bacterial organisms from human, animal and food sources across Canada.
