Characterization of a new TEM-type beta-lactamase resistant to clavulanate, sulbactam, and tazobactam in a clinical isolate of Escherichia coli.

摘要: A clinical Escherichia coli strain highly resistant to the combinations of amoxicillin-clavulanate, ampicillin-sulbactam, and piperacillin-tazobactam was isolated from a patient with community-acquired urinary tract infection who previously treated amoxicillin-clavulanate. These resistances were carried by 45-kb conjugative plasmid encoding for single beta-lactamase pI 5.4. Cloning sequencing new beta-lactamase, IRT-3, revealed identity blaT1 gene TEM-1 except replacement methionine residue at position 67 isoleucine 180 threonine. Both mutations segregated construction hybrid genes, only mutation related resistance suicide inhibitors. The inhibitory effects clavulanate, sulbactam, tazobactam on enzyme substantially decreased in comparison those as indicated 50% concentrations.