Antibiotic resistance Flashcards
(20 cards)
CRE meaning
Carbapenem resistance enterboacterieae
What are the mechanism of antimicrobial resistance (PETAM)
Perneability changes
Efflux
Target alteration/absence of target
Antibiotic inactivation
Metabolic bypass
Endogenous resistance is via what
Mutation
Exogenous resistance is via what
HGT
How does penicillin resitance come about
Beta-lactamases break bond in beta-lactam ring
How can aminoglycosides be modififed to reduce concentration of active antibiotic
Phosphorylation, acetylation, adenylation
Permeability changes can occur through what
Porins or MDR system
Which membrane are porins in
Outer membrane
Describe how P. aeruginosa are resistant to imipenem (porin)
There is reduced OprD porin
protein with hyperproduction of chromosomal cephalosporinase, show low level imipenem
resistance.
Are membrane associated pumps intrinsic or acquired
Either
Efflux mechanism in Gram+ve bacteria
ABC-type transporter mechanism
Efflux mechanism in Gram-negative bacteria
AcrAB-TolC
Do RND-type transporters have a broad substrate range
Yes (especially triclosan)
Resistance can occur due to overproduction of what WT enzyme, where there is a single change in promotor region genes
Alanine racemase
How does vancomycin resistance Enterococcus spp. undergo metabolic bypass
Substitute D-Ala-D-Ala terminus D-Ala-D-Lac/Ser
VRSA meaning
vancomycin resistance staphyloccus aureus
VSSA meaning
vancomycin susceptible staphyloccocus aureus
MRSA is associated with what mobile genetic element containing what
mecA, encoding new PBP2a with lower affinity for methicilin
is mrsa sensitive to vancomycin
yes
Why is VRSA resistant to vancomycin
Thicker cell wall, lower rate of vancomycin diffusion
