ABSTRACT
This chapter attempts to indicate the various possible approaches to the problem, advantages, and disadvantages of small bowel colonization. Bacterial culture of jejunal or gastric juice to detect overgrowth is time consuming and expensive. Consequently, although it is necessary to culture samples when searching for specific pathogens, there is a need for rapid and cheap methods of detecting the presence of bacteria and this can best be achieved by assaying the products of bacterial metabolism. Tryptophan is metabolized by the bacterial enzyme tryptophanase to indole, ammonia, and pyruvic acid. Bacterial metabolites have varying levels of specificity and so the choice of the metabolite may depend not only on the equipment available but also on the requirements of the clinician. The assay of bacterial metabolites as markers of bacterial overgrowth of the small bowel is extremely attractive since it offers the opportunity of diagnosis of the syndrome without intubation.
