Bouheraoua, Nacim Poirel, Laurent Bourreau, Baptiste Bonnin, Rémy Laroche, Laurent Naas, Thierry Nordmann, Patrice 2018-02-26 Integrons are genetic elements that can acquire and rearrange gene cassettes. The blaBEL-1 gene encodes an extended-spectrum β-lactamase, BEL-1, that is present at second position of the variable region of class 1 integrons identified in Pseudomonas aeruginosa. The mobility of the bel-1 gene cassette was analyzed in physiological conditions and with the integrase gene being overexpressed. Cassette mobility in Escherichia coli was detected by excision/integration into the recipient integron In3 on the conjugative plasmid R388, with the over-produced integrase. Despite several antibiotic pressures, the bel-1 cassette remained at the second position in the integron, highlighting its stability in P. aeruginosa. Overexpression of the integrase gene in E. coli induced the bel-1 cassette recombination. However, cassettes containing two genes (blaBEL-1/smr2 or blaBEL-1/aacA4) were excised suggesting that the bel-1 cassette attC site was defective. We showed that bel-1 is a stable gene cassette under physiological growth conditions irrespective of the selective antibiotic pressure, that may be mobilized upon over-overexpression of the integrase gene. application/pdf https://folia.unifr.ch/global/documents/306597 https://folia.unifr.ch/documents/306597/files/nor_imr.pdf eng info:eu-repo/semantics/altIdentifier/doi/10.1128/AAC.00030-18 info:eu-repo/semantics/openAccess License undefined Antimicrobial Agents and Chemotherapy. - 2018, p. AAC.00030-18 info:eu-repo/classification/udc/57 Integrase-mediated recombination of the bel-1 gene cassette encoding the extended-spectrum β-lactamase BEL-1 http://purl.org/coar/resource_type/c_6501