title: In vitro efficacy of daptomycin and teicoplanin combined with ethanol, clarithromycin or gentamicin as catheter lock solutions.
abstract: BACKGROUND
  Despite widespread use, optimum choice of antimicrobial agents, concentrations, combinations and exposure times have not been determined for antibiotic lock technique (ALT). Our objective was to evaluate the efficacy of different antibiotic combinations using an in vitro model of catheter-related infection. Daptomycin (DAP) 5 mg/mL, teicoplanin (TEC) 5 mg/mL, both alone and combined with gentamicin (GM) 2.5 mg/mL, clarythromycin (CLA) 5 mg/mL or ethanol 35 % were evaluated against four clinical strains of methicillin resistant coagulase negative staphylococci. Lock solutions were renewed every 24 h.
  
  
  RESULTS
  After 72 h catheters were reincubated with culture media to investigate bacterial regrowth. All antibiotic combinations resulted in significant reductions (p < 0.05) of Log(10) cfu/mL at 72 h for both organisms compared with controls. DAP resulted in significant reductions of Log(10) for all organism versus TEC (p = 0.001). Only DAP reached the limit of detection at 72 h, however did not prevent regrowth after 24 h of ALT removal. DAP + Ethanol and TEC + ethanol eradicated biofilm at 72 h, but only DAP + ethanol (against all strains) and DAP + CLA (against two strains) prevented regrowth at 24 h after ALT removal.
  
  
  CONCLUSIONS
  Based on these data, ALT with DAP + ethanol and DAP + CLA should be explored in clinical trials.
authors.affiliation: Laboratorio de Investigación Antimicrobiana, Hospital Universitario San Cecilio. Instituto de Investigación Biosanitaria de Granada, 18012, Granada, Spain. dprruiz@yahoo.es.
authors.forename: Diego
authors.initials: D
authors.lastname: Parra
authors.affiliation: Servicio de Microbiología, Hospital Universitario San Cecilio, 18012, Granada, Spain. dralexpexa@yahoo.es.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Peña-Monje
authors.affiliation: Laboratorio de Investigación Antimicrobiana, Hospital Universitario San Cecilio. Instituto de Investigación Biosanitaria de Granada, 18012, Granada, Spain. nievescoronado@gmail.com.
authors.forename: Nieves María
authors.initials: NM
authors.lastname: Coronado-Álvarez
authors.affiliation: Laboratorio de Investigación Antimicrobiana, Hospital Universitario San Cecilio. Instituto de Investigación Biosanitaria de Granada, 18012, Granada, Spain. jhquero@ugr.es.|Servicio de Enfermedades Infecciosas, Hospital Universitario San Cecilio. Instituto de Investigación Biosanitaria de Granada, Avda Dr. Olóriz 16, 18012, Granada, Spain. jhquero@ugr.es.
authors.forename: José
authors.initials: J
authors.lastname: Hernández-Quero
authors.affiliation: Laboratorio de Investigación Antimicrobiana, Hospital Universitario San Cecilio. Instituto de Investigación Biosanitaria de Granada, 18012, Granada, Spain. arrapj@gmail.com.|Servicio de Enfermedades Infecciosas, Hospital Universitario San Cecilio. Instituto de Investigación Biosanitaria de Granada, Avda Dr. Olóriz 16, 18012, Granada, Spain. arrapj@gmail.com.
authors.forename: Jorge
authors.initials: J
authors.lastname: Parra-Ruiz
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology* / Q000627:therapeutic use; D018441:Biofilms / Q000187:drug effects; D057785:Catheters / Q000382:microbiology; D017291:Clarithromycin / Q000494:pharmacology; D017576:Daptomycin / Q000494:pharmacology; D004359:Drug Therapy, Combination / Q000379:methods*; D000431:Ethanol / Q000494:pharmacology; D005839:Gentamicins / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D007552:Isotonic Solutions / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D016106:Methicillin Resistance / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D013212:Staphylococcus epidermidis / Q000187:drug effects* / Q000254:growth & development; D017334:Teicoplanin / Q000494:pharmacology; D014640:Vancomycin / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D005839:Gentamicins; D007552:Isotonic Solutions; C010380:Locke's solution; D000431:Ethanol; C030880:gentamicin A; D017334:Teicoplanin; D014640:Vancomycin; D017291:Clarithromycin; D017576:Daptomycin