Functional and structural characterization of the genetic environment of an extended-spectrum beta-lactamase blaVEB gene from a Pseudomonas aeruginosa isolate obtained in India.
A Pseudomonas aeruginosa clinical strain isolated from a patient hospitalized in a New Delhi, India, hospital was resistant to expanded-spectrum cephalosporins, imipenem, and aztreonam. A bla(VEB-1)-like gene named bla(VEB-1a), which codes for the extended-spectrum beta-lactamase VEB-1a, was identified. The genetic environment of bla(VEB-1a) was peculiar: (i) no 5' conserved sequence (5'-CS) region was present upstream of the beta-lactamase gene, whereas bla(VEB-1)-like genes are usually associated with class 1 integrons; (ii) bla(VEB-1a) was inserted between two truncated 3'-CS regions in a direct repeat; and (iii) four 135-bp repeated DNA sequences (repeated elements) were located on each side of the bla(VEB-1a) gene. Expression of the bla(VEB-1a) gene was driven by a strong promoter located in one of these repeated sequences. In addition, cloning of the beta-lactamase content of this P. aeruginosa isolate followed by expression in Escherichia coli identified the naturally occurring AmpC beta-lactamase and a gene encoding an OXA-2-like beta-lactamase located in a class 1 integron, In78, in which an insertion sequence, ISpa7, was inserted within its 5'-CS region.
Service de Bactériologie-Virologie, Hôpital de Bicêtre, 78 rue du Général Leclerc, 94275 Le Kremlin-Bicêtre Cedex, France.
Daniel
D
Aubert
Delphine
D
Girlich
Thierry
T
Naas
Shanta
S
Nagarajan
Patrice
P
Nordmann
D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001483:Base Sequence; D003001:Cloning, Molecular; D003227:Conjugation, Genetic; D003470:Culture Media; D004269:DNA, Bacterial / Q000096:biosynthesis / Q000235:genetics; D024881:Drug Resistance, Bacterial / Q000235:genetics; D018274:Electroporation; D007194:India; D007525:Isoelectric Focusing; D007700:Kinetics; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D010957:Plasmids / Q000235:genetics; D011552:Pseudomonas Infections / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000201:enzymology / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism*; D047090:beta-Lactams / Q000494:pharmacology
D000900:Anti-Bacterial Agents; D003470:Culture Media; D004269:DNA, Bacterial; D047090:beta-Lactams; D001618:beta-Lactamases