Detection of extended-spectrum beta-lactamases in members of the family Enterobacteriaceae: comparison of the MAST DD test, the double disc and the Etest ESBL

A technically simple method-the MAST double disc (MDD) test-for the detecti on of extended-spectrum beta-lactamase (ESBL) production by bacteria is des cribed. A wide range of ESBL, non-ESBL and Class 1 beta-lactamase-producing isolates was examined. The MDD test, which uses discs containing ceftazidi me and a complementary disc containing ceftazidime and clavulanate and a se cond pair containing cefotaxime and cefotaxime and clavulanate was compared with the standard double disc diffusion test and an Etest method, Both the Etest and the MDD correctly Identified 93% of ESBL producers, The MDD is a n inexpensive alternative to current methods for the detection of ESBL prod uction.