Here are a few recent and good articles on the microbiome.

The first is a good summary of recent science and a very readable article:

www.medscape.com/viewarticle/841748_1

It's interesting to read the comments on this topic posted by the various doctors, researchers, and health care professionals who use this site.

This is a more specific, very recent article about MS and the microbiome:

www.ncbi.nlm.nih.gov/pubmed/25843302?dopt=Abstract