Novel genetic structure associated with an extended-spectrum beta-lactamase blaVEB gene in a Providencia stuartii clinical isolate from Algeria

Abstract

A ceftazidime-resistant Providencia stuartii isolate from Algeria harbored a ca. 160-kb conjugative plasmid that contained a truncated bla(VEB-1b) gene flanked by three 135-bp repeated elements. This work gives further evidence of the worldwide spread of bla(VEB) genes that are associated with genetic structures other than class 1 integrons.

FIG. 1.

Double-disk synergy test with bla_VEB-1-positive P. stuartii strain BI on MH agar plates with clavulanate (A) or imipenem and cefoxitin (B) as inhibitors. The disks tested contained ticarcillin plus clavulanate (TCC), imipenem (IMP), cefoxitin (FOX), cefepime (FEP), and aztreonam (AZT).

FIG. 2.

Schematic representations of the genetic environment of the bla_VEB-1a gene in P. aeruginosa 10.2 (A) and of the bla_VEB-1b in P. stuartii BI (B) (2). The breakpoints and the Re in the bla_VEB-1-like gene environment are designated by broken lines and black triangles, respectively. The coding regions are shown as boxes, with an arrow indicating the orientation of transcription and white circles indicating the 59-bp element (59-be). Restriction sites that were used for cloning are indicated. Dashed lines in boldface indicate regions that were identified using PCR (the sequences of primers used are available upon request). The −10 and −35 promoter sequences of Re1 as well as the transcriptional initiation site (+1) are indicated by shaded boxes (2).