S. aureus is a major component of the normal flora of the skin and nostrils, which probably explains its high prevalence as a contaminant, as it can easily be discharged by several human activities including sneezing, talking and contact with moist skin. It has also been associated with numerous infectious
disease conditions and nosocomial infections. It follows that since users constantly touch interfaces and often sneeze, there is every chance of introducing S. aureus on to the interface in use. Also, airborne organisms can be transported from users or passers-by (Oluduro et al. 2011)