SHV-27, a novel cefotaxime-hydrolysing beta-lactamase, identified in Klebsiella pneumoniae isolates from a Brazilian hospital.

From a collection of cefotaxime-resistant Klebsiella pneumoniae isolated from neonatal blood culture specimens in a maternity hospital in Aracaju, Brazil, two isolates (strains KPBRZ-842 and -843, indistinguishable by pulsed-field gel electrophoresis) were found to produce beta-lactamases with isoelectric points (pI) of 5.4 and 8.2, respectively. Using a gel overlay method, cefotaxime hydrolysis was shown to be associated with the pI 8.2 protein. Nucleotide sequencing of the gene encoding the pI 8.2 beta-lactamase revealed a bla(SHV-ESBL)-type gene differing from the gene encoding SHV-1 by three silent point mutations, and a fourth that resulted in an amino acid substitution, aspartate for glycine, at position 156. This novel SHV-type extended-spectrum beta-lactamase is designated SHV-27.