Changes in microbiome during and after travellers' diarrhea: what we know and what we do not

The study of bacterial pathogens has advanced from culture on plates to basic biochemical studies; to sequencing reference genomes and attempting to ascribe those qualities to the whole species; to evaluating complete communities based on the universal marker of the 16S rRNA gene; to now sequencing all available nucleic acids in any sample to characterize the community as a whole. These types of scientific advances highlight that there are multiple layers of information within any sample, and to some extent we are only now beginning to be able to identify, categorize and understand the complex interactions of the host, pathogen and microbiome. In most cases, we can only now generate the data to examine these samples, but the detailed understanding of the significance of the data is lacking. We anticipate that in the future these microbiota and community data will be able to be modelled, understood and potentially used as either markers of disease, or diagnostics. This review provides a brief overview of the state of the use of microbiome studies using Travellers Diarrhea samples and what those studies have told us. More importantly these studies highlight what is remaining to be elucidated.