Resistance mechanisms of mucoid-grownStaphylococcus aureusto the antibacterial action of some disinfectants and antiseptics

The effects of commercial preparations of some disinfectants and antiseptics on mucoid-grown Staphylococcus aureus were investigated. Substantial reductions in their killing efficiencies were observed in the presence of mucoid-grown staphylococci but not with non-mucoid organisms. The reductions in antibacterial efficacies were comparable to the inhibitory effects of hard water, killed yeast, asparagine, blood plasma, thioglycollate and Tween-80. These reductions could be eliminated by washing mucoid organisms in saline broth or sub-culturing in BHI broth. This indicated that protection by the extracellular slime covering is an effective resistance mechanism of mucoid-grown staphylococci.