The SOS response promotes qnrB quinolone-resistance determinant expression.
The qnr genes are plasmid-borne fluoroquinolone-resistance determinants widespread in Enterobacteriaceae. Three families of qnr determinants (qnrA, B and S) have been described, but little is known about their expression and regulation. Two new determinants, qnrC and qnrD, have been found recently. Here, we describe the characterization of the qnrB2 promoter and the identification of a LexA-binding site in the promoter region of all qnrB alleles. LexA is the central regulator of the SOS response to DNA damage. We show that qnrB2 expression is regulated through the SOS response in a LexA/RecA-dependent manner, and that it can be induced by the quinolone ciprofloxacin, a known inducer of the SOS system. This is the first description of direct SOS-dependent regulation of an antibiotic-resistance mechanism in response to the antibiotic itself.
Da Re
Sandra
S
INSERM, Equipe Avenir, Université de Limoges, Faculté de Médecine, EA3175, Limoges, France.
Garnier
Fabien
F
Guérin
Emilie
E
Campoy
Susana
S
Denis
François
F
Ploy
Marie-Cécile
MC
D000890:Anti-Infective Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics* / Q000502:physiology*; D002939:Ciprofloxacin / Q000494:pharmacology; D024881:Drug Resistance, Bacterial / Q000235:genetics / Q000502:physiology; D024202:Electrophoretic Mobility Shift Assay; D004755:Enterobacteriaceae / Q000187:drug effects / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects / Q000235:genetics; D008954:Models, Biological; D011401:Promoter Regions, Genetic / Q000235:genetics; D012697:Serine Endopeptidases / Q000235:genetics / Q000502:physiology; D000099160:LexA Repressor Protein
D000890:Anti-Infective Agents; D001426:Bacterial Proteins; D002939:Ciprofloxacin; D012697:Serine Endopeptidases; D000099160:LexA Repressor Protein