Soap dispensers transfer bacteria

GRAM-negative bacteria can be spread efficiently through contaminated liquid soap in refillable dispensers used in public settings, researchers have demonstrated.  

After infection outbreaks linked to bulk soap dispensers in healthcare settings, the US Centers for Disease Control and Prevention recommended nearly a decade ago against adding soap to a partially empty dispenser.

Now microbiologists have conducted the first study showing that washing hands with contaminated soap actually increases the amount of bacteria on the hands, and it can be transferred.

Lab tests of liquid soap contaminated with Serratia marcescens at a concentration of over 107 CFU (colony forming units)/ml showed more than 105 CFU/ml remained on each hand after washing. 

A palm print left on an agar surface by a contaminated hand transferred more than 102 CFU/ml of the bacteria.

A second study in a school with contaminated soap dispensers showed