Methicillin sensitive/resistant = Oxacillin sensitive/resistant

[MudPhud20XX]

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I was reviewing antibiotics from Kaplan and it says

"Methicillin sensitive or resistant means oxacillin sensitive or resistant."

I think I am missing the point here. Can anyone explain it to me? I mean both belong to very narrow spectrum penicillin, but they ain't the same right?

So when we say MRSAs, this also means they are also oxacillin resistant?

Many thanks in advance.

 

[Apoplexy__]

Methicillin is part of a group of penicillins notable for a bulky R group that confers B-lactamase immunity. This group of penicillin also includes oxacillin, nafcillin, dicloxacillin, etc. Therefore, MRSA is resistant to any penicillin within this class; its altered PBP confers resistance to all of these B-lactamase-immune penicillins.

Kaplan's phrasing of this point is admittedly strange. The concept is exactly the same as the fact that bacteria resistant to Neomycin are also going to be resistant to Gentamicin, Tobramycin, etc.

 

[thehundredthone]

I was reviewing antibiotics from Kaplan and it says

"Methicillin sensitive or resistant means oxacillin sensitive or resistant."

I think I am missing the point here. Can anyone explain it to me? I mean both belong to very narrow spectrum penicillin, but they ain't the same right?

So when we say MRSAs, this also means they are also oxacillin resistant?

Many thanks in advance.

The point is that though we call them methicillin sensitive/resistant, no one in their right mind would actually use methicillin for an MSSA infection. Hence the equivalence of oxacillin/cloxacillin/dicloxacillin becomes worthy of mention, because they are all in the same class as methicillin and they are the drugs used or not used in place of methicillin.