IS SMALL-BOWEL BACTERIAL OVERGROWTH OF PATHOGENIC SIGNIFICANCE IN PERSISTENT DIARRHEA

Bacterial overgrowth in the upper small intestine is postulated to cause persistent diarrhea. We compared the fecal and upper intestinal flora in 82 patients with persistent diarrhea aged less-than-or-equal-to 36 months and weight-for-length less-than-or-equal-to 90% of National Center for Health Statistics standards (NCHS) and 39 non-diarrheal children with age less-than-or-equal-to 36 months, nutritionally matched with the patients and residing in the same environment. In the age groups less-than-or-equal-to 12 months and > 12 months the duodenal fluid bacterial counts greater-than-or-equal-to 10(5)/ml were found with similar frequency in patients and controls for aerobic (p = 0.33; p = 0.1) and anaerobic (p = 1.0; p = 1.0) bacteria. However, the duodenal isolation rates of any aerobic bacteria (p < 0.05) without regard to counts and Enterobacteriaceae (p = 0.06) were higher in patients than in controls. Colonization with Enterobacteriaceae was directly correlated with increased stool weight over a 7-day observation period (p < 0.05; p < 0.01). One or more pathogens were isolated in the feces of 58% of the patients and 43.8% of the controls. Enteroadherent E. coli of the localized [EAEC-L] (p < 0.01) and aggregative [EAggEC] (p = 0.22) phenotypes were isolated more commonly from the feces of patients. The duodenal fluid detection rates for Klebsiella were significantly greater (p < 0.01) in patients, while Giardia lamblia was detected more commonly in the duodenal fluid of controls (p < 0.01). The presence of specific pathogens in the feces did not seem to be related to the extent of small bowel colonization. Thus small bowel overgrowth with aerobes or anaerobes is common in malnourished children with or without diarrhea. However, specific pathogens such as EAEC-L, EAggEC and Klebsiella may be associated with persistent diarrhea.