Biofilm-associated methicillin-resistant staphylococcus aureus (MRSA) wound infections have an enhanced resistance to antimicrobial agents. As vacuum-assisted closure (VAC) therapy has been suggested as a tool to reduce wound bioburden, this study assessed the effect of VAC therapy on MRSA infected wounds.

This trial used MRSA strains obtained from chronic wounds of patients admitted to the Department of Vascular Surgery, Institute of Cardiovascular Diseases, in Belgrade, Serbia, from January of 2011 to December of 2014. Strains were identified using a number of genotyping methods and clustered into five clonal complexes. Prepared bacterial suspensions were treated with VAC therapy for three or six days to mimic once or twice weekly dressing changes. Biofilm formation was assessed quantitatively. Control bacterial suspensions were treated under equal conditions while at atmospheric pressure.

Biofilm production was reduced in all observed MRSA strains with VAC therapy. During three-day VAC therapy, biofilm formation was reduced in CC (P<0.01), SCCmec (P<0.01) and agr (P<0.05) types. Relative to the control condition, VAC therapy of MRSA strains diminished biofilm formation capacity after three-day (P<0.01) and six-day (P<0.05) intervals between dressing changes, with three days more effective than six (P<0.01)．

Results from this in-vitro study suggest that vacuum-assisted closure therapy, using twice weekly bandage changes, can produce additional benefit in the treatment of biofilm-associated methicillin-resistant staff aureus wound infections.