Microbiome alterations during and after international travel

BACKGROUND: The intestinal microbiome influences health through communication with the brain, the immune system and gut. Travel exposes people to a different microbes and enteric pathogens that can affect health of the traveller and family that continue beyond the journey. METHODS: PubMed was searched for microbiome changes, travellers' diarrhoea, acquisition of Enterobacteriaceae and multi-drug-resistant (MDR) microbiota during international travel. RESULTS: When days are shortened during long-haul travel east and diet composition and timing are changed the gut microbiome experiences its first challenge. Then if travel leads people into developing regions of Latin America, Africa and Southern- and Southeastern-Asia the composition of their microbiome undergoes further changes from a different diet, stress of a chaotic schedule, change in baseline exercise and exposure to proinflammatory or frankly pathogenic microbes. Reduction in diversity of the community of species (β-diversity), results in dysbiosis and colonization by pro-inflammatory Enterobacteriaceae (Esherichia coli or Klebsiella). Development of traveller's diarrhoea is a major event leading a reduced diversity of the intestinal microbiota (dysbiosis) and carriage of multiple drug resistance (MDR) enteric bacteria that can persist and spread to family and community upon returning home. A list of preventive measures travellers should be encouraged to follow during travel to high-risk regions of the world to help maintain a strong microbiome and to prevent diarrhoea and carriage of proinflammatory and resistant bacteria that damage microbiome health is provided. CONCLUSIONS: Future travellers should be forewarned about the hazards of international travel to their gut health, have an appreciation for safe and unsafe foods and have a plan for therapy should they develop diarrhoea. Additionally, international travel in the past year should be part of the medical history for patients developing an endogenous infection (e.g. urinary tract infection, sepsis of uncertain origin or a post-operative infection) as it may influence therapy.