Antimicrobial resistance Flashcards
How does natural resistance in microbes occur
target not present (i.e. cell wall)
target not accessible
biofilms/spore
How do biofilms increase anti-microbial resistance
resistant to host defences
larger habitat range
what is a biofilm
multi-cellular structure
specialised
competition/co-ordination
contains environmental component
What are persistor cells
cells in transient state
non-dividing
found in biofilms
how do perisistor cells aid with antimicrobial resistance
not classically resistant
metabolically inert - Abx can’t target
can rebuild biofilms
How can drug resistance occur
mutation
gene transfer
selective advantage
What is cross-resistance
closely related antibiotics are resistant by the same bacterium
what are the 2 ways to determine antimicrobial resistance in the lab
minimum inhibitory concentration (MIC)
minimum bactericidal concentration (MBC)
How do entire populations develop resistance to drugs
horizontal gene transfer of plasmids
What are the types of HGT
Bacterial competence
bacterial transduction
bacterial conjugation
where does horizontal gene transfer must commonly occur
communities in GI tract
How does bacterial competence HGT occur
Antibiotic resistance gene released with other DNA from donor cell to recipient cell
How does variation through bacteriophage occur
phage infected donor cells
phage is released
injects resistance gene into recipient
How does bacterial conjugation HGT occur
Transposon in donor cell
donated to recipient via sex pili
What mechanisms acquired by HGT can microbes use to resist antibiotics
don’t take drug into cell
2nd membrane
eject drug from cell
