Antibiotic resistance 1 Flashcards
Why has development of new antibiotics slowed?
Expenses, no new targets, short term use, safety profiles
Two categories of antibiotic resistance?
Intrinsic and acquired
What is intrinsic antibiotic resistance?
Resistance that is not acquired from any mutation and was there from the start
What is acquired antibiotic resistance?
Bacteria has seen antibiotic and bacteria has developed resistance over time
Innate part of intrinsic and acquired resistance?
Pumps can pump the antibiotic out of the bacteria to stop it from having its effects
Impermeable barrier part of intrinsic resistance?
Gram -ve bacteria have impermeable outer membrane that covers the peptidoglycan targets
Vertical gene transfer part of intrinsic resistance?
Gene transfer from parent to offspring
Gene amplification part of acquired resistance?
Increase in the copy number of genes
Gene mutation part of acquired resistance?
Mutation in genes that can occur to result in diff protein products–> microbes can use them
Horizontal gene transfer part of acquired resistance?
Genes can be passed from bacterial cell to bacterial cell (that arent parent and offspring)
Tranduction part of HGT?
Phages can infect bacteria and insert their genetic material into the bacteria’s genome
Transformation part of HGT?
one bacteria dies and its DNA is taken up by a nearby cell
Conjugation part of HGT?
Two bacteria near to each other create a bridge and genetic material is transferred
Intrinsic antibiotic resistance?
Efflux pumps, inactivating enzymes, decreased uptake, target alterations
Acquired antibiotic resistance?
Transduction, conjugation, transformation
Mechanisms of antibiotic resistance?
Change the drug, degrade the drug, alter the target, export (efflux)
How can bacteria change the drug?
Produce enzymes that modify the drug–> add side groups, phosphorylate
How can bacteria degrade the drug?
ENzymes can break down the drug
e.g. becat lactamases degreade beta lactam ring
How can bacteria change the target?
Can add groups to the target via enzymes, or the genes for the target can mutate its DNA sequence
Different wys to pump antibiotic out?
Can either be broad or specific depending on the bacteria, the pump and the antibiotic
Types of spontaneous mutation that would have an effect?
Frameshift, point
Example of a point mutation in bacteria?
GyrA region of DNA gyrase has a quinolone resistance determinant region–> if a certain chain of AAs is present in it that bacteria is resistant to quinolones
How are point mutations passed on?
Vertically, not via HGT
Example of an acquisition of alternative genes or pathways?
D-Ala-D-Ala in the peptidoglycan is converted to D-Ala-D-Lac via mutations in multiple genes to prevent
