need help with your account or subscription? click here to email us (or see the contact page)
join telegramNEW! discord
jump to exam page:
search for anything ⋅ score predictor (โ€œpredict me!โ€)
NBME 18 Answers

nbme18/Block 2/Question#32 (reveal difficulty score)
Investigator studying vancomycin-resistant ...
Plasmid loss ๐Ÿ” / ๐Ÿ“บ / ๐ŸŒณ / ๐Ÿ“–

 Login (or register) to see more

 +19  upvote downvote
submitted by โˆ—match95(56)

Transposition of the vanA gene from vancomycin-resistant Enterococcus is how it transfers resistance. They use transposons which are located on plasmids. If you have plasmid loss, you won't have transposons, and resistance will decrease.

 Login (or register) to see more
azibird  Why can't this be a point mutation? +6
freenbme23  I don't think that this implies that it can't be point mutation, but rather plasmid loss is more likely. Also, the point mutation Would have to ultimately lead to the plasmid loss. +
thrawn  FA says transposition is responsible for antibiotic resistance and plasmids are for transferring the genes of toxins (though UW says also antibiotic resistance). Make up your minds sheeple +2
mariame  The most common Vancomicin resistant genes, vanA and vanB are found in a transposon. These have been transferred from Enterococcus to a multidrug resistance plasmid in Staph aureus. the super multidrug resistance plasmid now contains resistance genes against lactams, vancomycin, aminoglycosides, trimethoprim, and some desinfectants. +2
an1  @thrawn I recall that too, but I think it said transposition was antibiotic resistance and UW said transposons was for multi drug resistance +
uasid  The plasmid is lost during bacteria replication โ€“ when DNA is being replicated, the plasmid is not always replicated and passed on to subsequent generations, especially if there are several generations of replication. +1

Must-See Comments from nbme18

feliperamirez on He is medically qualified to drive
anechakfspb on Tubular atrophy
aneurysmclip on Endothelial nitric oxide synthase production
azibird on 24,25-Dihydroxycholecalciferol
famylife on Increased transcription of HMG-CoA reductase
match95 on Plasmid loss
apurva on Antineoplastic
cbreland on Basement Membranes
match95 on Proximal tubule: isotonic; Macula densa: ...
sugaplum on Abnormal migration of endoderm from the ...
amirmullick3 on Myelofibrosis
merpaperple on Primary spermatocyte
wishmewell on Alpha-synuclein
namira on Greening reaction on blood agar

search for anything NEW!