title: Comparative in vitro efficacies of ethanol-, EDTA- and levofloxacin-based catheter lock solutions on eradication of Stenotrophomonas maltophilia biofilms.
abstract: The aim of this study was to compare the in vitro activity of ethanol, EDTA and levofloxacin (Levo), alone or in combination, on biofilms of Stenotrophomonas maltophilia recovered from patients with catheter-related bloodstream infections (CRBSIs) at a university hospital in Argentina. First, 24 and 48 h biofilms were formed in microtitre plates and challenged with 25 or 40 % ethanol for 1 h. Biofilms, of the 14 local isolates and from the reference strain K279a, were eradicated after both treatments as shown by plate counts and the regrowth technique. Second, 24 h biofilms of all isolates were established in silicone catheter segments and challenged with 25 or 40 % ethanol, Levo (2.5 mg ml(-1)), EDTA (30 mg ml(-1)), 25 % ethanol-EDTA or Levo-EDTA for 1, 3 and 24 h. Viable counts of biofilms treated for 1 h with 25 or 40 % ethanol or 25 % ethanol-EDTA were under the limit of detection. Killing of biofilms by Levo or Levo-EDTA was gradual and it was only after 24 h of treatment that no differences could be seen between the effects of these catheter lock solutions (CLSs) and those of ethanol (P>0.05). Levo-EDTA, in combination, did not act synergistically against biofilms. After 24 h of exposure, EDTA did not eradicate biofilms but reduced biofilm survival rates to 1-5 %. The effect of the different CLSs on biomass reduction, estimated by crystal violet staining, was highly dependent on the isolate, and the most effective agents were 25 and 40 % ethanol. Our results suggest that when used as a CLS for short periods, ethanol at low concentrations, alone or in combination with a chelator, can decontaminate the line from S. maltophilia in cases of CRBSI and help, in conjunction with systemic antibiotics, in the retention of precious vascular catheters.
authors.affiliation: Cátedra de Microbiología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, 1113 Buenos Aires, Argentina.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Passerini de Rossi
authors.affiliation: Cátedra de Microbiología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, 1113 Buenos Aires, Argentina.
authors.forename: Laureana
authors.initials: L
authors.lastname: Feldman
authors.affiliation: Cátedra de Microbiología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, 1113 Buenos Aires, Argentina.
authors.forename: María Saliba
authors.initials: MS
authors.lastname: Pineda
authors.affiliation: Laboratorio de Bacteriología Clínica, Departamento de Bioquímica Clínica, Hospital de Clínicas José de San Martín, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Av. Córdoba 2351, 1120 Buenos Aires, Argentina.
authors.forename: Carlos
authors.initials: C
authors.lastname: Vay
authors.affiliation: Cátedra de Microbiología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, 1113 Buenos Aires, Argentina.
authors.forename: Mirta
authors.initials: M
authors.lastname: Franco
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001118:Argentina; D016470:Bacteremia / Q000382:microbiology; D018441:Biofilms / Q000187:drug effects*; D055499:Catheter-Related Infections / Q000382:microbiology; D002408:Catheters, Indwelling / Q000382:microbiology*; D002614:Chelating Agents / Q000494:pharmacology; D015169:Colony Count, Microbial; D004492:Edetic Acid / Q000494:pharmacology*; D000431:Ethanol / Q000494:pharmacology*; D006785:Hospitals, University; D006801:Humans; D064704:Levofloxacin; D008826:Microbial Sensitivity Tests; D015242:Ofloxacin / Q000494:pharmacology*; D012996:Solutions / Q000494:pharmacology; D020615:Stenotrophomonas maltophilia / Q000187:drug effects* / Q000254:growth & development / Q000302:isolation & purification
chemical_list: D000900:Anti-Bacterial Agents; D002614:Chelating Agents; D012996:Solutions; D000431:Ethanol; D064704:Levofloxacin; D004492:Edetic Acid; D015242:Ofloxacin