To support research on the transmission of pathogens through the hands of healthcare personnel, a literature-based model was developed that describes how pathogens are transferred between patients. Five sequential steps are required for cross-transmission:
1. microorganisms are present on the patients skin or on the immediate patient surrounding;
2. the microorganisms are transferred to the hands of healthcare workers;
3. the microorganisms can survive on the skin of healthcare workers hands;
4. hand antisepsis of the healthcare workers is inadequate;
5. the contaminated hands touch another patient or an object that will come into contact with the patient.
Following this model, hand hygiene of healthcare worker is most important to prevent transmission. After contact with the skin of patients 100-1,000 colony forming units of bacteria can frequently be found on the hands of healthcare workers, emphasising the importance of adequate hand hygiene.