Beta-Lactamase (+) organisms

[Silverish]

I've been working through Uworld and there is a discrepancy.
When you have a beta-lactamase (+) organism, is it susceptible to cephlasporins or not?

I understand cephlasporins are beta-lactams, but I've come across a question that said beta-lactamase organisms really only work against penicillins and not so much cephlasporins.

Now, I'm seeing a question that they do render them inactive.
Anyone have some insight on this specific subject?

---

Members don't see this ad.

 

[Entadus]

It depends on the type of beta-lactamase. For example Staph Aureus will typically express a beta-lactamase that confers resistance to penicillin,

Further examples are the AmpC beta-lactamases in Enterobacter. Also ESBL's (extended spectrum beta-lactamases). Both of these examples will have no problem chewing up your cephalosporins.

Then you have your carbapenemases. Klebsiella can pass that to E. Coli and other gram(-) rods, conferring resistance to imipenem. Think KPC (K. pneumo. carbapenemase) and NDM1 (New Delhi Metallo-beta-lactamase)