Bactericidal activity of denture-cleaning formulations against planktonic health care–associated and community-associated methicillin-resistant Staphylococcus aureus

The aim of this study was to examine the survival dynamics of several epidemic health care–associated (HA) and community-associated (CA) methicillin-resistant Staphylococcus aureus (MRSA) in planktonic state in widely employed denture-cleaning solutions. The bacteriocidal activity of five widely employed denture-cleaning formulations were examined against five phage-types of HA-MRSA (EMRSA 15, EMRSA 16, Irish 1, Irish 2, unique type), as well as a CA-MRSA strain, in this study. Viable MRSA cells (circa 105 cfu/mL) were coincubated with optimum recommended working concentrations of denture-cleaning solutions for up to 17 hours (overnight). Recovery experiments were unable to isolate any of the inoculated MRSA organisms 10 minutes post inoculation. The significance and impact of this short study indicates that HA-MRSA and CA-MRSA are not able to remain culturable for 10 minutes in planktonic form, in commonly used denture-cleaning formulations widely available on the UK High Street, suggesting that these formulations may be useful in lowering the numbers of MRSA. Further work is however required to examine the more complex survival dynamics of MRSA in naturally derived denture biofilm, associated with dental plaque and the use of such cleaning formulations.