CYCLOHEXENOESCULETIN-BETA-D-GLUCOSIDE - A NEW SUBSTRATE FOR THE DETECTION OF BACTERIAL BETA-D-GLUCOSIDASE

A new substrate for the detection of bacterial beta-D-glucosidase was evaluated as an alternative to aesculin. This substrate, 3,4-cyclohexe noesculetin-7-beta-D-glucoside was compared with aesculin for the dete ction of beta-D-glucosidase in 150 enterococci, 40 streptococci, 12 Li steria in sp. and 250 strains of Enterobacteriaceae. In the Gram-posit ive strains tested, aesculin hydrolysis correlated with hydrolysis of 3,4-cyclohexenoesculetin-7-beta-D-glucoside. In the Gram-negative stra ins the new substrate was hydrolysed by all aesculin-positive strains and also by four strains (10%) of Escherichia coli which gave a negati ve aesculin reaction. 3,4-Cyclohexenoes culetin-7-beta-D-glucoside was shown to be a reliable alternative to aesculin and was shown to have significant advantages over aesculin when incorporated into solid medi a. This was due to the non-diffusible end product produced by hydrolys is of 3,4-cpclohexenoesculetin-7-beta-D-glucoside in the presence of i ron.