26. Antibiotic Resistance Flashcards
What are the methods of antibiotic resistance?
Inactivation of enzymes Impair permeability Drug efflux Target modification Metabolic bypass
Name 2 examples of enzyme inactivation
B-lactamases
Aminoglycoside-modifying enzymes
Carbapenemase
What organisms produce b-lactamase?
Staph
Enterobacterales
EBSL
How can gram negative bacteria have antibiotic resistance by impairing permeability?
Change outer membrane porins or cell membrane transport proteins
Makes it more difficult for antibiotics to enter
Give an example of impaired permeability resistance?
Gentamicin and pseudomonas
What is drug efflux?
Bacteria makes new proteins which pump the drug out of the bacteria so it can’t reach its target
Give an example of drug efflux resistance
Tetracycline and quinolone resistance in gram -
What is target modification?
Binding site for the antimicrobial is altered
Give 2 examples of target modification
MRSA alters PBP2
Change in 30s ribosome prevents streptomycin binding
What is metabolic bypass?
Bacteria can activate different metabolic pathways
Give an example of metabolic bypass
Sulphonamids and trimethoprime usually inhibit folate synthesis
What are the methods of beta lactam resistance in gram + bacteria?
Target modification
Inactivation of enzymes
What are the methods of beta lactam resistance in gram - bacteria?
Target modification
Inactivation of enzymes
Permeability changes
What are the methods of resistance to aminoglycosides?
Aminoglycoside modifying agents
Methylation of 16s ribsomal RNA
What are the methods of resistance to quinolones?
Mutations in DNA gyrase (target modification)
Efflux pumps