Antibiotic Resistance Flashcards
What is antimicrobial resistance (AMR)
when a microorganism such as bacterium, virus, fungus or parasite that can no longer be inhibited or killed by a drug that could previously treat an infection caused by that organism.
what can the microbes become resistant to that would warrant the term antimicrobial resistance
bacteria = antibiotics viruses = anti viral parasites = anti parasitic fungi = anti fungal
what is the importance of AMR
infections more difficult to treat
organisms can be multi drug resistant
some infections almost no remaining treatment options
worse health outcomes for patients
more costly
what are the two types of resistance
inherent
acquired
example of inherent resistance
gram negative bacteria outer membrane provides permeability barrier stopping sufficient antibiotic entering cell to exert action. lack transport system or target of the antibiotic
what is acquired resistance
when new antibiotic used most infections respond over time treatment fails as resistance is acquired not inevitable, some bactria have remained susceptible to specific antibiotics over a long period
how does acquired resistance result
changes in genome
which can either be by mutation and selection (vertical evolution)
or by exchange of genes between strains and species (horizontal evolution)
when does vertical evolution occur
absence of antibiotics as they act as selective pressure
what are the three ways bacteria can swap genes
conjugation cell-cell contact, DNA crosses a sex pilus
transduction genes transported by bacterial virus
transformation DNA acquired from environment
describe conjugation
conjugation cell-cell contact, DNA crosses a sex pilus
describe transduction
genes transported by bacterial virus
describe transformation
DNA acquired from environment
what are the 4 mechanisms of resistance
reduction in cellular permeability or concentration of antibiotic
conversion of active drug to inert product by an enzyme
changes in antibioitic target site resulting in resistance
altered metabolic pathway
describe reduction in cellular permeability or concentration of antibiotic
Doesn’t allow drug to get toxic levels in cell can be change in cell wall antagonism of antibiotic transport processes or generator of an efflux pump
what is a superbug
multi drug resistances
