Commercial mouthwashes are ineffective against oral MRSA biofilms.

OBJECTIVE

The aim of this study was to evaluate and compare the activity of oral mouthwashes against biofilm forms of MRSA isolated from the oral cavity and the bloodstream.

STUDY

DESIGN

The time-kill kinetics efficacy of 7 over-the-counter mouthwashes were tested against 28 clinical MRSA biofilm isolates for 0.5, 1 and 2 min.

RESULTS

Treatments of MRSA biofilms formed by oral and bloodstream isolates were not significantly different, with mouthwashes displaying a rapid and modest anti-biofilm effect. None of the biofilm isolates were completely eradicated by the compounds tested, with a maximal killing of only approximately 70% shown by Corsodyl and Peroxyl. Maximum activity of all compounds tested was observed after 0.5 min. Fluorigard showed the poorest overall activity (57% reduction).

CONCLUSIONS

MRSA colonize the oral cavity, and are more prevalent in institutionalized persons and the elderly. Over-the-counter mouthwashes are ineffective at killing MRSA biofilms, which has infection control implications.