We tested the bioactivity of a dalbavancin + heparin (DH) vs. dalbavancin (D) against biofilms of Staphylococcus aureus ATCC43300 (MRSA) and Staphylococcus epidermidis ATCC35984 (MRSE) comparing DH median value of cfu counts and metabolic activity with that obtained for D before and during storage under freezing up to 6 months. The addition of heparin to a dalbavancin lock solution did not affect its bioactivity against staphylococcal biofilms irrespective of its preservation time under freezing.

Based on previous studies of our group in which we demonstrated that dalbavancin loaded in bone cement had good elution capacity for the treatment of biofilm-related periprosthetic infections, we now assess the anti-biofilm activity of dalbavancin and compare it with that of vancomycin up to a 3-month period. We performed an in vitro model based on calculation of percentage reduction of log cfu/ml counts of sonicated steel discs contaminated with Staphylococci and further exposed to bone cement discs loaded with 2.5% or 5% vancomycin and dalbavancin at each study period (24 hours, 48 hours, 1 week, 2 weeks, 6 weeks, 3 months). In addition, we tested the anti-biofilm activity of eluted vancomycin and dalbavancin at each study period based on a 96-well plate model assessing percentage reduction of metabolic activity. Overall, dalbavancin showed a significant concentration decrease from 2 weeks of incubation and maintain its anti-biofilm activity up to 3 months, whereas, despite vancomycin showed a significant decrease at 1w and then it gradually increased, its anti-biofilm activity was significantly lower. Dalbavancin percentage reduction cfu/ml counts were higher than those of vancomycin, both at 2.5% and 5% concentrations. Reduction of log cfu/ml counts were higher for S. epidermidis than for S. aureus, being more notable for 5% dalbavancin at month 3. In addition, percentage reduction of metabolic activity also decreased at 3 months in 5% dalbavancin and 5% vancomycin, being more notable in the last.

Background/Objectives: The standard of care for acute bacterial skin and skin structure infections (ABSSSIs) requiring intravenous (IV) antibiotics includes vancomycin, administered over several days, in a hospital or outpatient setting resulting in significant costs. Dalbavancin, a long-acting single-dose lipoglycopeptide IV therapy may offer a cost-effective option for adult patients with ABSSSIs in Canada. Methods: A cost-utility analysis (CUA) was performed to evaluate the potential benefits of dalbavancin compared to other IV antibiotics for the treatment of adult patients with ABSSSIs who require IV antibiotics but whose hospitalization, if necessary, is anticipated to be £ 72 hours. Results: This analysis utilized a decision-analytic model showing that dalbavancin was dominant against all IV antibiotic comparators when considering the healthcare system or societal perspective and was associated with lower costs and improved patient adherence. For the sub-population analysis against PWID (people who inject drugs) and the homeless, dalbavancin generated even greater cost savings. Conclusions: We report that dalbavancin when used to treat ABSSSI requiring IV antibiotics may offer cost savings for Canadian healthcare providers through reduced hospitalization time, lower administration and labor costs, minimized risk of healthcare-acquired infections (HAIs), improved patient compliance and optimized resource allocation particularly in patients at risk of non-compliance (First Nations, the homeless and PWID).