Glucuronidase-negative Escherichia coli in the ECOR Reference Collection

Abstract

The ECOR collection, consisting of Escherichia coli isolates from many countries, includes β-D-glucuronidase-negative strains. Ten of 29, or 34% of human fecal isolates, were glucuronidase-negative after 24 h at 37°C in lauryl tryptose broth supplemented with 4-methylumbelliferyl-β-D-glucuronide (LT-MUGUR, Difco). Seven of 29, or 24% of human fecal isolates, were glucuronidase-negative when tested in Autoanalysis-Colilert “MMO-MUG” medium (Access Medical Systems). In contrast, none of the 11 urinary tract isolates were glucuronidase-negative on either medium. These data suggest that LT-MUGUR and Colilert media may be more appropriate for detecting urinary tract E. coli than they are for human fecal E. coli.