title: Eradication of Staphylococcus aureus Catheter-Related Biofilm Infections Using ML:8 and Citrox.
abstract: Staphylococci are a leading cause of catheter-related infections (CRIs) due to biofilm formation. CRIs are typically managed by either device removal or systemic antibiotics, often in combination with catheter lock solutions (CLSs). CLSs provide high concentrations of the antimicrobial agent at the site of infection. However, the most effective CLSs against staphylococcal biofilm-associated infections have yet to be determined. The purpose of this study was to evaluate the efficacy and suitability of two newly described antimicrobial agents, ML:8 and Citrox, as CLSs against Staphylococcus aureus biofilms. ML:8 (1% [vol/vol]) and Citrox (1% [vol/vol]), containing caprylic acid and flavonoids, respectively, were used to treat S. aureus biofilms grown in vitro using newly described static and flow biofilm assays. Both agents reduced biofilm viability >97% after 24 h of treatment. Using a rat model of CRI, ML:8 was shown to inactivate early-stage S. aureus biofilms in vivo, while Citrox inactivated established, mature in vivo biofilms. Cytotoxicity and hemolytic activity of ML:8 and Citrox were equivalent to those of other commercially available CLSs. Neither ML:8 nor Citrox induced a cytokine response in human whole blood, and exposure of S. aureus to either agent for 90 days was not associated with any increase in resistance. Taken together, these data reveal the therapeutic potential of these agents for the treatment of S. aureus catheter-related biofilm infections.
authors.affiliation: Department of Clinical Microbiology, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin, Ireland.
authors.forename: S
authors.initials: S
authors.lastname: Hogan
authors.affiliation: Department of Clinical Microbiology, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin, Ireland.
authors.forename: M
authors.initials: M
authors.lastname: Zapotoczna
authors.affiliation: Department of Clinical Microbiology, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin, Ireland.
authors.forename: N T
authors.initials: NT
authors.lastname: Stevens
authors.affiliation: Department of Clinical Microbiology, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin, Ireland Department of Microbiology, Beaumont Hospital, Dublin, Ireland.
authors.forename: H
authors.initials: H
authors.lastname: Humphreys
authors.affiliation: Microbiology, School of Natural Sciences, National University of Ireland, Galway, Ireland.
authors.forename: J P
authors.initials: JP
authors.lastname: O'Gara
authors.affiliation: Department of Clinical Microbiology, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin, Ireland Department of Microbiology, Connolly Hospital, Dublin, Ireland eoneill@rcsi.ie.
authors.forename: E
authors.initials: E
authors.lastname: O'Neill
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects; D002210:Caprylates / Q000494:pharmacology*; D055499:Catheter-Related Infections / Q000188:drug therapy*; D004353:Drug Evaluation, Preclinical / Q000379:methods; D005419:Flavonoids / Q000494:pharmacology*; D006801:Humans; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects / Q000472:pathogenicity; D017207:Rats, Sprague-Dawley; D013203:Staphylococcal Infections / Q000188:drug therapy*; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000472:pathogenicity
chemical_list: D000900:Anti-Bacterial Agents; D002210:Caprylates; D005419:Flavonoids; C031492:octanoic acid