Molecular mimicry appears to be the mechanism by which intesti- nal enterobacteria cause ankylosing spondylitis in genetically suscep- tible individuals.

Ebringer has successfully treated ankylosing spondylitis with a low starch diet similar to Gottschall's regimen for bowel disease. This diet lowers the concentration of Klebsiella in stool and decreases the titre of anti-Klebsiella IgA. He has also proposed that rheumatoid ar- thritis, which is associated with HLA-DR4, involves a similar molecu- lar mimicry between HLA-DR4 and Proteus mirabilis, as cross-reac- tive Proteus antibodies are higher in patients with rheumatoid arthritis than in controls. Abnormal immune responses to compo- nents of the normal gut flora represents a form of dysbiosis which suggests novel treatment for inflammatory diseases.

Treatment Approaches
Diet-Putrefaction dysbiosis is usually managed with a diet high in both soluble and insoluble fiber and low in saturated fat and animal protein. Dairy products have a variable effect. Fermented dairy foods like fresh yogurt are occasionally helpful. These dietary changes work to lower the concentrations of Bacteroides and increase concen- trations of lactic acid-producing bacteria (Bifidobacteria, Lactobacil- lus and lactic acid streptococci) in the colon(44,45). Supplementing the diet with defined sources of fiber can have variable effects on colo- nic dysbiosis. Insoluble fiber decreases bacterial concentration and microbial enzyme activity(46,47). Soluble fiber, on the other hand, tends to elevate bacterial concentration and enzyme activity at the same time that it raises the levels of beneficial short chain fatty acids. This disparity may explain the superior effect of insoluble fiber in the prevention of colon cancer(48-51). Fructose-containing oligosac- charides, found in vegetables like onion and asparagus, have been developed as a food supplement for raising stool levels of Bifidobac- teria and lower stool pH.(52)

In fermentation dysbiosis, by contrast, starch and soluble fiber may exacerbate the abnormal gut ecology(3,33). When the upper small bowel is involved, simple sugars are also contra-indicated. A diet free of cereal grains and added sugar is generally the most helpful. Fruit, fat and starchy vegetables are tolerated to variable degree in differ- ent cases. Oligosaccharides found in some vegetables, carrots in par- ticular, inhibit the binding of enterobacteria to the intestinal mucosa. Carrot juice and concentrated carrot oligosaccharides have been used in Europe for bacterial diarrhea for almost a century(53). BiotherapiesÑAdministration of bacteria indigenous to the healthy human colon can reverse relapsing Clostridium difficile infection(54). Lactobacillus administration has long been used in an attempt to im- prove gut microbial ecology. Regular ingestion of acidophilus milk lowers stool concentrations of urease-positive organisms and of bacte- rial enzymes which may contribute to carcinogenesis(55). Fermented dairy products and Iyophilized Lactobacillus preparations have been shown to be useful in treating and preventing salmonellosis, shig- ellosis, antibiotic-induced diarrhea and in inhibiting tumor growth (56). Problems with Lactobacilli include the failure of organisms to adhere to the intestinal mucosa or to survive damage from gastric acid and bile. The acidophilus sweepstakes has led to the search for newer and better strains for medical uses(57,58).