FIG 3.

Schematic representation of regions surrounding the genes for CDD-1 and CDD-2 β-lactamases. The open reading frames are shown as arrows and intergenic regions as black lines. In strain ATCC 43255 (top), the gene for the CDD-1 β-lactamase (cdd1) is flanked by an ATP-dependent helicase (hlc) upstream and by an ABC transporter-coupled two-component system ATP-binding protein (abp) downstream. In strain 630 (bottom), two additional open reading frames are present between the gene for the CDD-2 β-lactamase (cdd2) and the hlc gene (an excinuclease ABC subunit A paralog of unknown function [ecn] and a putative membrane protein [pmp]). As a result, the intergenic region between the cdd gene and the upstream gene changed from 540 bp for cdd1 to 27 bp for cdd2.