Is an oritavancin catheter lock solution active against biofilms of staphylococci and enterococci?

Background: Oritavancin (ORT) is a new single-dose lipoglycopeptide showing activity against staphylococci and vancomycin-resistant enterococci. However, there is no data regarding its potential use as a catheter lock solution are scarce. We constructed an model to analyze the efficacy and stability of an ORT lock solution against the biofilm of staphylococci and enterococci over 7 days at 37 °C.

Methods: We used , , and vancomycin-susceptible ATCC strains. We performed a metabolic activity assay using a 2-mg/ml solution of ORT over a 7-day incubation period at 37 °C. The solution was tested against 24-h biofilms of each strain at day 0 and 7. Metabolic activity was measured using the XTT assay, and median absorbance obtained at 490 nm in the spectrophotometer was compared between day 0 and day 7.

Results: The percentage reduction in metabolic activity was 95.3 % between biofilms treated with ORT solution incubated for 7 days and biofilms treated with ORT solution before incubation.

Conclusion: Ours is a proof-of-concept study that shows ORT to be a potential treatment as a catheter lock solution for eradication of staphylococcal and . biofilms. It is needed to further test ORT against more clinical strains and to compare its activity with other antimicrobials in a biofilm model.