Travelling to tropical and subtropical countries is a known risk factor for becoming colonized with extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae. Especially travellers returning from the Indian subcontinent show high colonization rates of up to almost 90%.

While risk factors for becoming colonized have been identified in several studies, no preventive measure has been tested so far.

One of the factors associated with becoming colonized while travelling is suffering from travellers' diarrhoea. Earlier studies looking at diarrhoea in childhood as well as school and/or work absenteeism because of diarrhoeal diseases have shown protective effects through good hand hygiene. Furthermore, a recent retrospective study has shown lower rates of travellers' diarrhoea in people using hand gel sanitizers. Improving hand hygiene in travellers through increased hand washing and the use of hand gel sanitizers might therefore not only decrease the rate of travellers' diarrhoea but the carriage rate with ESBL-producing Enterobacteriaceae as well. However, there is no prospective data available to prove the usefulness of such an intervention, neither in the prevention of travellers' diarrhoea nor in the prevention of colonization.

In the current study, investigators plan to compare colonization rates with ESBL-producing Enterobacteriaceae in travellers receiving pre-travel advice on improved hand hygiene (including the use of hand gel sanitizers) with travelers receiving standard advice.

Inclusion Criteria:

• age > 18 years
• travelling to the Indian subcontinent (India, Bhutan and/or Nepal) for up to 4 weeks

Exclusion Criteria:

• age < 18 years
• travelling to other destinations than India, Bhutan and/or Nepal
• antibiotic treatment at the time of the first sampling