Answer:
Erythromycin is often first choice against strep throat.
There are however certain strains that are "immune"

Vancomycine can be a choice if Erythromycine does not work.
This list not extensive and is not made to suggest that a doctor should not have the final say.
Contributor: Morten
First answer by Morten Brendefur. Last edit by Morten Brendefur. Contributor trust: 81 [recommend contributor recommended]. Question popularity: 1 [recommend question].