title: Comparison of the bactericidal activity of various fluoroquinolones against Mycobacterium tuberculosis in an in vitro experimental model.
abstract: OBJECTIVE
  To compare the bactericidal activity of various fluoroquinolones against Mycobacterium tuberculosis in the latent and exponential growth phases.
  
  
  METHODS
  Ciprofloxacin, levofloxacin and moxifloxacin were tested against 16 M. tuberculosis clinical isolates (4 resistant and 12 susceptible to fluoroquinolones) from Elche, Spain, isolated between 1992 and 2009. To study bactericidal activity, an inoculum of approximately 10(5) cfu of each isolate was cultured in Middlebrook 7H9 broth. The broth was previously acidified to pH 4.6 to obtain the microorganism in the stationary phase. Cultures with different concentrations (0.1 to 50 mg/L) of antibiotic and antibiotic-free controls were incubated for 48 h then plated onto Middlebrook 7H11 to detect bacterial killing. In all stages of the process the M. tuberculosis strain ATCC 41323 was included as a quality control to ensure reproducible results.
  
  
  RESULTS
  Moxifloxacin and levofloxacin were found to exhibit bactericidal activity at lower concentrations and against more strains in both the latent and the exponential growth phases compared with ciprofloxacin. The bactericidal activity of moxifloxacin was greater than that of levofloxacin against microorganisms in the exponential growth phase, but the opposite was true in the latent phase.
  
  
  CONCLUSIONS
  Our data confirm the usefulness of moxifloxacin in the treatment of tuberculosis and suggest that levofloxacin may be used as an alternative drug in the treatment of latent tuberculosis when it is not possible to use isoniazid. Based on the results presented, ciprofloxacin appears to be a poor choice.
authors: Hospital General Universitario de Elche, Universidad Miguel Hernández, Elche, Alicante, Spain.
authors: Rosa
authors: R
authors: Cremades
authors: Juan Carlos
authors: JC
authors: Rodríguez
authors: Eduardo
authors: E
authors: García-Pachón
authors: Antonio
authors: A
authors: Galiana
authors: Montserrat
authors: M
authors: Ruiz-García
authors: Pilar
authors: P
authors: López
authors: Gloria
authors: G
authors: Royo
mesh_terms: D000995:Antitubercular Agents / Q000494:pharmacology*; D001372:Aza Compounds / Q000494:pharmacology; D002939:Ciprofloxacin / Q000494:pharmacology; D024881:Drug Resistance, Bacterial; D024841:Fluoroquinolones / Q000494:pharmacology*; D006801:Humans; D007538:Isoniazid / Q000494:pharmacology / Q000627:therapeutic use; D064704:Levofloxacin; D008826:Microbial Sensitivity Tests; D000077266:Moxifloxacin; D009169:Mycobacterium tuberculosis / Q000145:classification / Q000187:drug effects* / Q000254:growth & development / Q000302:isolation & purification; D015242:Ofloxacin / Q000494:pharmacology; D011804:Quinolines / Q000494:pharmacology; D013030:Spain; D014376:Tuberculosis / Q000382:microbiology
chemical_list: D000995:Antitubercular Agents; D001372:Aza Compounds; D024841:Fluoroquinolones; D011804:Quinolines; D002939:Ciprofloxacin; D064704:Levofloxacin; D015242:Ofloxacin; D000077266:Moxifloxacin; D007538:Isoniazid