KEGG Genome database, Cedecea neteri strain SSMD04 (http://www.genome.jp/kegg-bin/show_organism?org=cnt). †The molecular classification of β-lactamases is based on the primary amino acid sequence of these enzymes (also known as the Ambler classification scheme). For a review, see . NA, not applicable. ‡Sequence signature contains the core H-X-H-X-D motif characteristic of class B β-lactamases, but also contains additional residues reported in  that constitute an expanded motif specific to metallo-β-lactamases. §Only one conserved sequence element was identified in the deduced amino acid sequence of ORF JT31_03975. Motif S-X-X-K is characteristic of class A and D β-lactamases. The absence of the conserved zinc ion interaction domain (H-X-H-X-D) suggests that this ORF may encode a novel metallo-β-lactamase or a variant class A or D β-lactamase. ¶Proposed gene name for this C. neteri SSMD04 ORF based on sequence analysis (this study).