antibiotic resistance Flashcards
what is natural resistance
the microorganism is not susceptible to the mode of action. either the target isn’t present or not accessible or metabolism effects the uptake and action of drug
what is a biofilm
most infections aren’t just one organism, they exist in communities to aid survival. it also increases the habitat range of an individual bacteria
factors surrounding biofilms
they’re a multicellular structure, co-operation, co-ordination and competition occurs
what are persistor cells
they are part of the biofilm, undergo horizontal transfer. they have a tolerance which isn’t the same as resistance, they’re metabolically inert (very slow growth, dormant or non-dividing)
persistor cells have a particularly high what
sporulation count
how does antimicrobial drug resistance occur
can arise by mutation or by gene transfer. can result from single or multiple steps
what can resistance provide to an organism
provides a selective advantage
what is cross resistance
a single mechanism, organisms are resistant to lots of closely related drugs
what is multiple resistance
includes multiple mechanisms, organisms resistant to multiple unrelated antibiotics
what are the 3 steps of development of resistance
variation>selection>evolution
horizontal gene transfer
mistakes in one gene = variation = can lead to resistance. which spreads rapidly through HGT
what are resistance mechanisms
Changes that were not present naturally but have been acquired directly or by HGT. for example secretion of beta lactamase
what are 2 resistance mechanisms
altered permeability, inactivation, altered target site
what is involved in the altered permeability mechanism
altered influx = changes to outer membrane. active efflux = energy dependant pump
what molecule is involved in inactivation mechanism
beta - lactamase
