Piperacillin/tazobactam resistance in a clinical isolate of Escherichia coli due to IS26-mediated amplification of bla TEM-1B

Abstract

An E. coli and K. pneumoniae phenotype resistant to piperacillin/tazobactam has recently emerged. Here, the authors show that hyperproduction of the β-lactamase driving this resistance occurs due to excision and reinsertion of a translocatable unit containing bla TEM-1B, creating a tandem array.