title: High-level quinolone resistance is associated with the overexpression of smeVWX in Stenotrophomonas maltophilia clinical isolates.
abstract: Stenotrophomonas maltophilia is the only known bacterium in which quinolone-resistant isolates do not present mutations in the genes encoding bacterial topoisomerases. The expression of the intrinsic quinolone resistance elements smeDEF, smeVWX and Smqnr was analysed in 31 clinical S. maltophilia isolates presenting a minimum inhibitory concentration (MIC) range to ciprofloxacin between 0.5 and > 32 μg/mL; 11 (35.5%) overexpressed smeDEF, 2 (6.5%) presenting the highest quinolone MICs overexpressed smeVWX and 1 (3.2%) overexpressed Smqnr. Both strains overexpressing smeVWX presented changes at the Gly266 position of SmeRv, the repressor of smeVWX. Changes at the same position were previously observed in in vitro selected S. maltophilia quinolone-resistant mutants, indicating this amino acid is highly relevant for the activity of SmeRv in repressing smeVWX expression. For the first time SmeVWX overexpression is associated with quinolone resistance of S. maltophilia clinical isolates.
authors.affiliation: Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Cantoblanco, Madrid, Spain.
authors.forename: G
authors.initials: G
authors.lastname: García-León
authors.affiliation: Service of Microbiology, Hospital Universitario Marqués de Valdecilla-IDIVAL, Avda. Valdecilla s/n, Santander, Spain.
authors.forename: C
authors.initials: C
authors.lastname: Ruiz de Alegría Puig
authors.affiliation: Service of Microbiology, Hospital Universitario Marqués de Valdecilla-IDIVAL, Avda. Valdecilla s/n, Santander, Spain.
authors.forename: C
authors.initials: C
authors.lastname: García de la Fuente
authors.affiliation: Service of Microbiology, Hospital Universitario Marqués de Valdecilla-IDIVAL, Avda. Valdecilla s/n, Santander, Spain; Department of Molecular Biology, University of Cantabria, Cardenal Herrera Oria, s/n, Santander, Spain.
authors.forename: L
authors.initials: L
authors.lastname: Martínez-Martínez
authors.affiliation: Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Cantoblanco, Madrid, Spain. Electronic address: jlmtnez@cnb.csic.es.
authors.forename: J L
authors.initials: JL
authors.lastname: Martínez
authors.affiliation: Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Cantoblanco, Madrid, Spain. Electronic address: bsanchez@cnb.csic.es.
authors.forename: M B
authors.initials: MB
authors.lastname: Sánchez
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000235:genetics; D024881:Drug Resistance, Bacterial; D015870:Gene Expression; D020869:Gene Expression Profiling; D006801:Humans; D008826:Microbial Sensitivity Tests; D050505:Mutant Proteins / Q000235:genetics; D020125:Mutation, Missense; D015363:Quinolones / Q000494:pharmacology*; D012097:Repressor Proteins / Q000235:genetics; D020615:Stenotrophomonas maltophilia / Q000187:drug effects* / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D050505:Mutant Proteins; D015363:Quinolones; D012097:Repressor Proteins
keywords: Multidrug efflux pump; S. maltophilia; SmeDEF; SmeVWX; quinolone resistance