Gut health predictive indices linking gut microbiota dysbiosis with healthy state, mild gut discomfort, and inflammatory bowel disease phenotypes using gut microbiome profiling.

Despite the complexity of the gut microbiome, several scores that use taxonomic characteristics exist that attempt to identify a healthy gut or gastrointestinal disease. Two systems in use are the metagenomic aerotolerant predominance index (MAPI) and keystone scores. The aim of this analysis was to compare different gut microbiome scores, specifically MAPI and a keystone species score, on two cross-sectional data sets and to investigate correlations of these scores with self-reported gut discomfort and gastrointestinal disease. The first data set is a commercial data set (Sun Genomics data set) with whole-genome shotgun sequencing samples from 5,372 customers. The second data set is curated from publicly available data (public data set) with 2,415 samples from participants in human studies with gut-related taxonomic profiles. MAPI scores and keystone species scores were calculated using standard methodology. The MAPI score was significantly lower in men for the public data set. There was a graded response for both the MAPI and keystone scores between healthy subjects, subjects with mild gastrointestinal discomfort, and patients with gastrointestinal disease: the MAPI score was higher, and the keystone score was lower in subjects with gastrointestinal discomfort or with inflammatory bowel disease patients. The keystone and MAPI scores have the potential to help identify factors associated with gut microbial dysbiosis and gastrointestinal discomfort or disease. Furthermore, given the functional link of the MAPI score to oxidative stress in the microbiome, the scores can help to identify conditions where oxidative stress is one of the hallmarks of dysbiosis.IMPORTANCEGut bacteria play a role in both mild gastrointestinal discomfort, which includes bloating and constipation, and inflammatory bowel disease. There are many different types of bacteria in the gut, and gut microbiome composition differs greatly between different people. Therefore, it is difficult to predict who has a gut microbiome associated with a healthy gut and who might develop disease or experience gut discomfort. Several scoring systems have been developed to categorize gut health states. This analysis compared two different scoring systems using data from two different sources to see how well they could identify people with gastrointestinal disease, gastrointestinal complaints, or a healthy gut. The scoring systems showed similar trends according to gut health status: groups of people with gut bacteria imbalance or gut disease had a different score than groups of people with healthy gut bacteria.