Co-Evolution of Antimicrobial Resistance Flashcards
(26 cards)
How many deaths are associated with AMR globally each year
5.3 million deaths from bacterial infections
14 millions directly attributable to AMR
What regions are most affected by AMR
Sub-Saharan Africa followed by South Asia
Which infection types are most impacted by AMR
Lower Respiratory Infections (LRIs) > Bloodstream Infections (BSIs)
Name the top 3 AMR bacterial pathogens
- E. coli
- Staphylococcus aureus
- Klebsiella pneumoniae
What is the major challenge in tracking AMR in LMICs
Lack of reliable data and surveillance systems
What is ‘collateral damage’ in AMR
Unintended selection for multiple resistance mechanisms when using one antibiotic (e.g. Drug A selects for resistance to B, C, D due to gene clustering)
What happens when you switch antibiotics in presence of collateral resistance
Bacteria often remain resistant which can lead to clinical failure
Why can bacteria rapidly acquire resistance to multiple drug
Genes are physically clustered on plasmids
Spread via horizontal gene transfer (HGT)
Facilitated by homologous recombination
What can worsen AMR in a setting such as Dessie, Ethiopia
Healthcare inaccessibility, economic inflation, and limited drug availability
What leads to AMR in Dessie, Ethiopia
Shared use of meropenem
Sub-lethal doses create selection pressure
Leads to NDM-producing CRE (Carbapenem-Resistant Enterobacterales)
How does poor WASH contribute to AMR in Sierra Leone
Environmental reservoirs from human waste
Hospital-acquired infections (HAIs) due to lack of sanitation
e.g. ESBL-E. coli and K. pneumoniae
How does heavy metal pollution contribute to AMR
Resistance genes linked to metal-resistance genes, increasing selection even without antibiotics
What are plasmids and their role in AMR
Circular DNA that carry AMR genes
Transferred between bacteria by conjugation
What are transposons
Jumping genes that move within and between chromosomes/plasmids
What are IS (insertion sequences) elements
Short DNA that rearrange genomes, facilitating resistance
What are ICEs (Integrative & Conjugative Elements)
Large gene cassettes that carry multiple resistance genes and transfer between bacteria
What maintains IS and ICEs in populations
Toxin-antitoxin (T/AT) systems stabilise plasmids
Balance between fitness cost and survival benefit
How is AMR linked to livestock farming
AMR genes spread via food, water, and contact
Antibiotics used in animal feed select for resistance
What lab methods are used to track AMR spread
Conjugation assays – track plasmid transfer
PCR-based plasmid typing – identify genes
Whole-genome sequencing (WGS) – map transmission
What is NMD-5 resistance
New Delhi Metallo-beta-lactamase-5 - confers carbapenem resistance, found in clinical, environmental, and animal samples
What causes resistance to Tigecycline
TetX3–8 genes
Dangerous as Tigecycline is a last-resort drug
What is colistin resistance and how does it work
MCR genes (MCR-1, MCR-3.1, MCR-3.2)
Modify lipid channels in bacterial membranes
How do G+ and G- bacteria share resistance genes
HGT bridges previously distinct resistance mechanisms
How does environmental degradation impact AMR
Increases plasmid transfer rates, linking pollution with AMR
