CTX-M-190, a novel {beta}-lactamase resistant to tazobactam and sulbactam identified in an Escherichia coli clinical isolate [PublishAheadOfPrint]

A novel β-lactamase CTX-M-190, derived from CTX-M-55 by a single substitution Ser133Thr, was identified in a natural Escherichia coli clinical isolate. CTX-M-190 exhibited potent hydrolytic activity against cefotaxime with kcat/Km 14.5 μM^-1 s^-1 and was resistant to inhibition by β-lactamase inhibitors tazobactam and sulbactam with the 50% inhibitory concentrations 77- and 55-fold higher than those of CTX-M-55, respectively. bla_CTX-M-190 was located within the genetic platform, ISEcp1-bla_CTX-M-orf477, which was harbored by a 70kb IncI1 plasmid.

http://ift.tt/2fzLf2Y