Emergence of extended-spectrum β-lactamase (ESBL) CTX-M-8 in Germany.

(20 min) with the inactivator, using the same reporter substrate. Inactivation by clavulanic acid was observed only after preincubation competitive assays (indirect IC501⁄456 mM). On the other hand, 3-phenyl boronic acid showed enzymatic inactivation in both competitive and pre-incubation assays at high concentrations (direct IC501⁄4390 mM and indirect IC501⁄4151 mM). INQ-1 seems to be a cephalosporinase compatible with b-lactamases belonging to group 1 of the functional classification scheme. Although INQ-1 may not explain by itself all the observed resistance to b-lactams in the clinical isolate of I. limosus, it contributes to the overall increase in MICs for the INQ-1-producing E. coli clone, even if transcriptional and post-transcriptional impairments are due to the unusual start codon and high GC.