Fig. 1

Appearance after over-night incubation for ESBL phenotyping of (a) an ESBL-positive strain and b an ESBL-negative strain. Plate a shows an example of what was taken as a positive ESBL test result. Plate b shows an example of a negative ESBL test result. In both cases, cefpodoxime was used only to screen and not in confirmation. Cefotaxime and ceftazidime were used in both screening and confirmation. CPD cefpodoxime 10 µg, CPD/CLV cefpodoxime 10 µg + clavulanate 10 µg, CTX cefotaxime 30 µg, CTX/CLV cefotaxime 30 µg + clavulanate 10 µg, CAZ ceftazidime 30 µg, CAZ/CLV ceftazidime 30 µg + clavulanate 10 µg