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

Abstract

A technically simple method—the MAST double disc (MDD) test—for the detection of extended-spectrum β-lactamase (ESBL) production by bacteria is described. A wide range of ESBL, non-ESBL and Class 1 β-lactamase-producing isolates was examined. The MDD test, which uses discs containing ceftazidime and a complementary disc containing ceftazidime and clavulanate and a second 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 an inexpensive alternative to current methods for the detection of ESBL production.