Double B-lactam

Only for certain situations, such as Ampicillin/Sulbactam plus Meropenem for Acinetobacter, or double carbapenem (Meropenem plus Ertapenem) for Klebsiella.

Also, some in-vitro studies found that double beta lactams have better effect than single beta lactam. However you should be aware that these studies didn’t compare other antibiotics combinations with the double beta lactam, in most cases, it compare double beta lactam vs single beta lactam use