How Many Bacterial Species Are There in the Intestinal Tract?

Current research states that there are approximately 100 trillion bacterial species that make up the human intestinal tract. So how many bacterial species are there that make up the 100 trillion?

Most studies that rely on outdated information state 400-500 species - http://www.springerlink.com/content/3ndecf8hevnegjle/


This study cites 500-1000 bacterial species -
http://www.sciencemag.org/content/292/5519/1115.full


This study mentions 3,300-5,700 - http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.0060280


In this study, newer methods have identified ...upwards of 40,000 bäcterial species..." - http://www.ncbi.nlm.nih.gov/pubmed/18043225?dopt=Abstract&holding=f1000,f1000...


If we look at an earlier post on the effects of a 7-day course of antibiotics on the gut flora, we find that for 9 months after the use of antibiotics, only 1 species was present and it was antibiotic resistant - http://www.nature.com/ismej/journal/v1/n1/pdf/ismej20073a.pdf


It's easy to see how antibiotics can create devastating effects in anyone. Now with the field of epigenetics, we are learning that those effects may not be felt until decades later.
The intestinal tract is the gateway to health. Alter the health of the intestinal tract and you alter your health.
The effects have to be reversed.