I work in hospital microbiology lab in the UK. We screen for ESBL's
by the antibiogram, noting a "notch" between the augmentin and ceftriaxone
disks on a routine sensitivity plate (we use stokes method). Then we
cornfirm ESBL's by using the Mast Diagnostics ESBL kit (compares zones sizes
of 3 third gen. cefalosporins discs to discs containing the same
cefalosporin + clavulanic acid). We have found that organsims other than
E.coli and Kleb spp. can be ESBL's.
Hope this is of help.