A primary role of the large intestine is the absorption of about one liter of water per day. The large intestine also provides an environment for microbial fermentation of soluble fiber, starch and undigested carbohydrates. Anaerobic colonic fermentation results in production of short chain fatty acids, the main energy source for colonic epithelial cells. It is largely these SCFAs, in combination with amines derived from protein degradation, that provide buffering and create the slightly acidic pH of fecal matter.
Because the oxygen content of the colon is low, the vast majority of bacteria are anaerobes. There are, however, hundreds of varieties of anaerobic flora in vastly different concentrations, all growing very slowly. The significance of most of these flora remains largely unknown. Most researchers, therefore, utilize the aerobic flora as an indication of bacterial health.
Three frequently identified organisms, Lactobacilli, Bifidobacteria, and Escherichia coli, can be employed as indicators of eubiosis or healthy overall flora. Lactobacilli and Bifidobacteria are well established as offering intrinsic benefit and aiding digestion while helping to prevent overgrowth of abnormal flora.
Bacterial cultures also identify and show potential pathogens. The term “potential pathogen” because individuals may harbor traditional pathogens and appear healthy, while others harbor weak or questionable pathogens and have gastrointestinal complaints.
While they are sometimes found linked to GI tract disturbances, some intestinal bacteria may also be involved in the etiology of various chronic or systemic problems seemingly unrelated to GI function. These include Klebsiella, Proteus, Pseudomonas, and Citrobacter. These organisms may be involved, through molecular mimicry, in various autoimmune diseases. This has been reported in diabetes mellitus, meningitis, thyroid disease, ulcerative colitis, arthritis, ankylosing spondylitis and systemic lupus.
Some potential pathogens may cause clinical and subclinical malabsorption of nutrients and increase bowel permeability to large macromolecules. A number of clinicians speculate that this is directly related to the etiology of food and chemical sensitivity and intolerance.
Examples of laboratories offering such services include Meridian Valley Labs and Great Smokies Diagnostic Labs and more information along with their home pages can be found
here.
CDSA 2.0 (Comprehensive Digestive Stool Analysis), offered by Great Smokies is the most comprehensive GI analysis test available. It tests for parasites also.