Clinical failure of Cephalosporin and Monobactam therapy due to Extended Spectrum β-lactamases (ESBLs) is a growing problem in hospitals as they undetected by current isolation and susceptibility tests.
ESBLs often have low, or only marginally elevated minimum inhibitory concentrations (MICs) to third generation cephalosporins and monobactams which means that they appear sensitive in routine susceptibility testing.
Over the last 10 years, ESBL producing Enterobacteriaceae have dramatically increased such that in some studies, as many as 40% of Klebsiella spp isolated in ICU have been shown to produce ESBL.
The ESBL detection disc shows the presence of ESBLs and can be easily incorporated into routine screening methods.
The Cross includes a β-lactamase inhibitor, Clavulinic acid, next to the two third generation Cephalosporins that have been most widely recommended for ESBL demonstration ; Ceftazidime and Cefotaxime. The Clavulinic acid suppresses the production of ESBL and therefore the organism can be inhibited by the cephalosporin where they diffuse together in the medium.
The tips of the cross are optimally positioned to produce easy to read, reproducible results. Other ESBL detection protocols involve positioning individual discs or strips at carefully measured distances. The ESBL cross can be easily applied to the plate with minimal delay. This design conforms to the specification for the double disc Confirmatory Test of the National Standards Method QSOP 51i2.2 published by the Health Protection Agency.