International travel is well reported to be associated with acquisition of multidrug-resistant organisms, however, the impact of colonization of these multidrug-resistant organisms is currently uncertain. As colonization of multidrug-resistant organisms had been demonstrated to be associated with distinct intestinal microbiota composition and travellers constitute a generally healthy population with minimal antibiotics exposure; by evaluating serial stool samples before and after travel, the investigators can delineate a potential causal relationship between host intestinal microbiota and subsequent risk of acquisition of multidrug-resistant organisms.

Inclusion Criteria:

• Adults aged 18 years or above
• Chinese ethnicity
• Planning to visit any places outside of Hong Kong within the next three months
• Able to provide informed consent

Exclusion Criteria:

• Use of antibiotics within 4 weeks prior to the time of recruitment (Except for antimalarial prophylaxis)
• Hospitalization within 3 months
• Underlying gastrointestinal diseases, including gastrointestinal malignancy, inflammatory bowel disease, resection of small or large bowel
• Pregnancy

Adults planning for travel