title: Importance of the efflux pump systems in the resistance of Mycobacterium tuberculosis to fluoroquinolones and linezolid.
abstract: OBJECTIVE
  Our aim was to study the influence of efflux pump systems in the resistance of Mycobacterium tuberculosis to fluoroquinolones and linezolid.
  
  
  METHODS
  We studied the mutations in gyrA and gyrB genes and the influence of efflux pump systems with 2 inhibitors (reserpine and MC 207.110).
  
  
  RESULTS
  The effect of the active efflux system on the decrease in sensitivity to ciprofloxacin, moxifloxacin, levofloxacin, ofloxacin, gatifloxacin and linezolid was studied by investigating the variation in the in vitro activity of these compounds when assayed in association with reserpine and MC 207.110. These inhibitors exhibit activity both in strains that are resistant and in strains that are susceptible to these antibiotics. However, they are seen to be most active in resistant strains, since the minimum inhibitory concentration of the antibiotics studied in these strains was reduced between 2- and 6-fold.
  
  
  CONCLUSIONS
  Therefore, these mechanisms are involved in the resistance to both compounds. It would be of interest to carry out further studies to determine to what extent these active efflux systems influence resistance to the different groups of drugs used in the treatment of tuberculosis, with a view to the possibility of using the inhibitors of these systems in future therapeutic applications.
authors.affiliation: Section of Microbiology, Hospital General Universitario de Elche, Universidad Miguel Hernández, Elche, Spain.
authors.forename: I
authors.initials: I
authors.lastname: Escribano
authors.forename: J C
authors.initials: JC
authors.lastname: Rodríguez
authors.forename: B
authors.initials: B
authors.lastname: Llorca
authors.forename: E
authors.initials: E
authors.lastname: García-Pachon
authors.forename: M
authors.initials: M
authors.lastname: Ruiz
authors.forename: G
authors.initials: G
authors.lastname: Royo
mesh_terms: D000081:Acetamides / Q000494:pharmacology*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D027081:DNA Gyrase / Q000235:genetics; D024901:Drug Resistance, Multiple, Bacterial / Q000502:physiology*; D024841:Fluoroquinolones / Q000494:pharmacology*; D006801:Humans; D016623:Ion Pumps / Q000502:physiology*; D000069349:Linezolid; D008826:Microbial Sensitivity Tests; D009154:Mutation / Q000235:genetics; D009169:Mycobacterium tuberculosis / Q000187:drug effects*; D023303:Oxazolidinones / Q000494:pharmacology*; D014376:Tuberculosis / Q000188:drug therapy / Q000382:microbiology
chemical_list: D000081:Acetamides; D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones; D016623:Ion Pumps; D023303:Oxazolidinones; D027081:DNA Gyrase; D000069349:Linezolid