Impact of International Travel on the Emergence and Spread of Antimicrobial Resistance in The Netherlands

Rationale: Antimicrobial resistance (AMR) among Enterobacteriaceae constitutes an increasingly important human health hazard worldwide. Also in the Netherlands AMR rates have been on the rise in recent years. A limited number of previous studies have suggested high acquisition rates of AMR E. coli during international travel, but information on travel-associated risk factors, duration of colonization and local transmission of imported AMR are largely, if not entirely, lacking.

Objectives: Prospectively study the influence of foreign travel and associated risk factors on the acquisition of AMR in the endogenous microbiota of healthy individuals and the subsequent persistence of AMR carriage and transmission to household members of these carriers. Examine whether carriers of resistant Enterobacteriaceae have a higher risk of bacterial infections in the year after travel (compared to non-carriers). Explore the full width of AMR genes and transferable genetic elements acquired during international travel.

Study design: multicenter longitudinal cohort study.

Study population: healthy, adult (> 18 years) volunteers travelling abroad for 1 week - 3 months. Non travelling household members of these traveling volunteers.

Methods: Travelers and non-traveling household members will be recruited at outpatient travel clinics throughout The Netherlands. Faecal samples and questionnaires will be taken before (t=0) travel, immediately after travel (t=1) and 1 month upon return (t = 2). For volunteers that acquire AMR Enterobacteriaceae, repeated questionnaires and faecal samples will be taken after 3, 6 and 12 months.