title: [Role of double strand DNA break repair for quinolone sensitivity in Escherichia coli: therapeutic implications].
abstract: BACKGROUND
  Quinolones are one of the types of antibiotics with higher resistance rates in the last years. At molecular level, quinolones block type II topoisomerases producing double strand breaks (DSBs). These DSBs could play a double role, as inductors of the quinolone bactericidal effects but also as mediators of the resistance and tolerance mechanisms.
  
  
  METHODS
  In this work we have studied the molecular pathways responsible for DSBs repair in the quinolone susceptibility: the stalled replication fork reversal (recombination-dependent) (RFR), the SOS response induction, the translesional DNA synthesis (TLS) and the nucleotide excision repair mechanisms (NER). For this reason, at the European University in Madrid, we analysed the minimal inhibitory concentration (MIC) to three different quinolones in Escherichia coli mutant strains coming from different type culture collections.
  
  
  RESULTS
  recA, recBC, priA and lexA mutants showed a significant reduction on the MIC values for all quinolones tested. No significant changes were observed on mutant strains for TLS and NER.
  
  
  CONCLUSIONS
  These data indicate that in the presence of quinolones, RFR mechanisms and the SOS response could be involved in the quinolone susceptibility.
authors.affiliation: Rocío González-Soltero, Departamento de Ciencias Biomédicas Básicas. Universidad Europea de Madrid. C/Tajo s/n. 28670. Villaviciosa de Odón (Madrid), Spain. mariadelrocio.gonzalez@uem.es.
authors.forename: Rocio
authors.initials: R
authors.lastname: González-Soltero
authors.forename: Ana
authors.initials: A
authors.lastname: García-Cañas
authors.forename: Rosa B
authors.initials: RB
authors.lastname: Mohedano
authors.forename: Belén
authors.initials: B
authors.lastname: Mendoza-Chamizo
authors.forename: Emilia
authors.initials: E
authors.lastname: Botello
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology; D002939:Ciprofloxacin / Q000494:pharmacology; D053903:DNA Breaks, Double-Stranded; D004265:DNA Helicases / Q000235:genetics / Q000502:physiology; D004260:DNA Repair; D004261:DNA Replication; D004269:DNA, Bacterial / Q000235:genetics / Q000378:metabolism*; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D004927:Escherichia coli Infections / Q000188:drug therapy / Q000382:microbiology; D029968:Escherichia coli Proteins / Q000235:genetics / Q000502:physiology; D043211:Exodeoxyribonuclease V / Q000235:genetics / Q000502:physiology; D005798:Genes, Bacterial; D006801:Humans; D008826:Microbial Sensitivity Tests; D058990:Molecular Targeted Therapy; D009268:Nalidixic Acid / Q000494:pharmacology; D009643:Norfloxacin / Q000494:pharmacology; D015363:Quinolones / Q000494:pharmacology*; D011938:Rec A Recombinases / Q000235:genetics / Q000502:physiology; D059767:Recombinational DNA Repair; D013014:SOS Response, Genetics; D012697:Serine Endopeptidases / Q000235:genetics / Q000502:physiology; D000099160:LexA Repressor Protein
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D002939:Ciprofloxacin; D004265:DNA Helicases; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D043211:Exodeoxyribonuclease V; D009268:Nalidixic Acid; D009643:Norfloxacin; D015363:Quinolones; D011938:Rec A Recombinases; D012697:Serine Endopeptidases; D000099160:LexA Repressor Protein; C468322:exodeoxyribonuclease V, E coli; C506743:priA protein, E coli