SHV-14, a novel β-lactamase variant in Klebsiella pneumoniae isolates from Nijmegen, The Netherlands

Four ceftazidime-resistant isolates of a Klebsiella pneumoniae strain were collected from intensive care unit patients in Nijmegen. The Netherlands. These isolates had TEM-29 and SHV-14 beta -lactamases. SHV-14 is a novel variant, with two substitutions compared with the sequence of SIN-1: Ile8Phe and Arg43Ser. Its gene also had a silent C-->T mutation at nucleotide 481. The SHV-14 enzyme had slightly higher V-max rates than SHV-1 for oxyimino-aminothiazolyl cephalosporins, but this activity was insufficient for the enzyme to count as an extended-spectrum beta -lactamase.