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dc.contributor.authorFerrandiz-Avellano, Maria-Jose 
dc.contributor.authorde la Campa, Adela G
dc.identifier.citationAntimicrob Agents Chemother. 2014;58(1):247-57. doi: 10.1128/AAC.01706-13. Epub 2013 Oct 21.es_ES
dc.description.abstractWe studied the transcriptomic response of Streptococcus pneumoniae to levofloxacin (LVX) under conditions inhibiting topoisomerase IV but not gyrase. Although a complex transcriptomic response was observed, the most outstanding result was the upregulation of the genes of the fatDCEB operon, involved in iron (Fe(2+) and Fe(3+)) uptake, which were the only genes varying under every condition tested. Although the inhibition of topoisomerase IV by levofloxacin did not have a detectable effect in the level of global supercoiling, increases in general supercoiling and fatD transcription were observed after topoisomerase I inhibition, while the opposite was observed after gyrase inhibition with novobiocin. Since fatDCEB is located in a topological chromosomal domain downregulated by DNA relaxation, we studied the transcription of a copy of the 422-bp (including the Pfat promoter) region located upstream of fatDCEB fused to the cat reporter inserted into the chromosome 106 kb away from its native position: PfatfatD was upregulated in the presence of LVX in its native location, whereas no change was observed in the Pfatcat construction. Results suggest that topological changes are indeed involved in PfatfatDCE transcription. Upregulation of fatDCEB would lead to an increase of intracellular iron and, in turn, to the activation of the Fenton reaction and the increase of reactive oxygen species. In accordance, we observed an attenuation of levofloxacin lethality in iron-deficient media and in a strain lacking the gene coding for SpxB, the main source of hydrogen peroxide. In addition, we observed an increase of reactive oxygen species that contributed to levofloxacin lethality.es_ES
dc.description.sponsorshipThis study was supported by grants BIO2011-25343 from Plan Nacional de I+D+i of the Ministerio de Ciencia e Innovación. CIBER de Enfermedades Respiratorias (CIBERES) is an initiative from Instituto de Salud Carlos III.es_ES
dc.publisherAmerican Society for Microbiologyes_ES
dc.subject.meshAnti-Bacterial Agents es_ES
dc.subject.meshBacterial Proteins es_ES
dc.subject.meshFluoroquinolones es_ES
dc.subject.meshGene Expression Regulation, Bacterial es_ES
dc.subject.meshIron es_ES
dc.subject.meshLevofloxacin es_ES
dc.subject.meshMicrobial Sensitivity Tests es_ES
dc.subject.meshStreptococcus pneumoniae es_ES
dc.subject.meshTranscriptional Activation es_ES
dc.titleThe fluoroquinolone levofloxacin triggers the transcriptional activation of iron transport genes that contribute to cell death in Streptococcus pneumoniaees_ES
dc.rights.licenseAtribución-NoComercial-CompartirIgual 4.0 Internacional*
dc.contributor.funderMinisterio de Ciencia e Innovación (España)es_ES
dc.contributor.funderInstituto de Salud Carlos III - ISCIIIes_ES
dc.identifier.journalAntimicrobial agents and chemotherapyes_ES
dc.repisalud.centroISCIII::Centro Nacional de Microbiologíaes_ES

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