Abnormal fecal flora in a patient with short bowel syndrome

Abstract

D-Lactic acidosis associated with encephalopathy is a clinical condition that occurs in patients with short bowel syndrome. We studied the fecal flora and the composition of fecal water of a child who developed this unusual disorder. Bacteriological studies showed that the patient's stool contained a marked predominance of gram-positive anaerobes. Two strains were identified, Lactobacillus plantarum and Lactobacillus salivarius, as the main bacteria isolated. Fecal water showed pH 4.8 and total lactic acid (sum of L- and D-lactic acids) was the principal organic anion found in the feces. We also incubated the patient's stool in a continuous culture with a view to determining the effect of the pH on the production of volatile fatty acids (VFA) and L- and D-lactic acids. The culture was maintained at pH 5.0, 5.5, 6.0, and 6.5 for four consecutive periods of four days each. We then studied the culture for a further four days at pH 5.0 once again. This study showed that with the progressive rise of the pH from 5.0 to 6.5 L- and D-lactic acids decreased and VFA production increased. D-Lactic acid formation was inhibited at pH 6.5, but when the culture was returned to pH 5.0, it increased to a high level again. These results suggest that the pH plays an important role in the ecological changes in the colonic bacteria that result in D-lactic acid production.

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“…A more acidic environment (lower pH) encourages the growth of acid-resistant bacteria (including Lactobacilli ) and increases lactic acid production 27 . Several D-la case studies have shown an overgrowth of Lactobacillus species in stool samples 27-29 . With no comparative control group, we could not determine whether ME/CFS patients in our sample had an overgrowth of Lactobacilli .…”

“…The pH level influences bacterial composition. A more acidic environment (lower pH) encourages the growth of acid-resistant bacteria (including Lactobacilli ) and increases lactic acid production 27 . Several D-la case studies have shown an overgrowth of Lactobacillus species in stool samples 27-29 .…”

Examining clinical similarities between myalgic encephalomyelitis/chronic fatigue syndrome and d-lactic acidosis: a systematic review

“…The dysbiosis is distinguished by an increased colonisation of lactic acid-producing bacteria, particularly bacteria that produce d -lactate (e.g., Lactobacillus fermenti, L acidophilus, and Streptococcus ; see review by Petersen [13]). An overgrowth of Lactobacilli has been identified in SBS patients with increased d -lactate levels [26, 28, 37, 47, 64, 68, 72, 74, 75, 103]. This dysbiosis has been proposed as a result of an impaired small intestine, either due to congenital causes, surgery for midgut volvulus, gangrene or inflammatory bowel disease [104]; functional SBS and carbohydrate malabsorption [32, 36]; or colonic stagnation [62].…”

“…Increased bacterial fermentation can further reduce bowel motility [31], alter colonic pH and change the level of bacterial metabolites. This can include a reduction in volatile fatty acids [26] and increased d -lactate production [shown in 26, 54, 64, 66, 75, 105]. …”

“…Selected Bifidobacterium ( Bifidobacterium adolescentis, Bifidobacterium breve ) and Lactobacillus ( L. plantarum, L. salivarius, L. casei subspecies rhamnosus, L. delbrueckii subsp. Lactis, L. acidophilus, L. fermentum, L. buchneri ) species have been identified as predominant in patients with d -la [26, 28, 29, 37, 47, 54, 64, 68, 74, 75, 145]. Similarity between species identified as overgrown in d -la patients and those used in probiotic studies could also generate skepticism about the relevance of d -lactate theory for ME/CFS.…”