Using smartphone is increasing in hospital with various purpose and it has more extended surface than non-smart phone. Therefore investigators can consider the bacterial contamination rate of smartphone will be higher than that of non-smartphone.

Hospital-acquired infections(HAI) are causing grave concern in almost all the hospitals of the world and causing increased morbidity and mortalities.

The transmission of HAI occurs through hospital staff and inanimate hospital environment, equipment, and devices that the hospital staff use.Recently, cellphones (CP) were blamed to cause nosocomial infections.

The mobile phones are used routinely all day long but not cleaned properly, as health care workers' may do not wash their hands as often as they should. The aim of the present study was to evaluate the prevalence of bacterial contamination of mobile phones in ICU health care providers. and especially compare the contamination rate between smartphone and non-smartphone.

Using smartphone is increasing in hospital with various purpose and it has more extended surface than non-smart phone. therefore we can consider the bacterial contamination rate of smartphone will be higher than that of non-smartphone.

Inclusion Criteria:

• healthcare providers of MICU who have cellular phones

Exclusion Criteria:

• healthcare providers of MICU who have not cellular phones

healthcare providers of MICU in Seoul national university hospital and Seoul national university Bundang hospital who have cellular phones