title: Abnormal fecal flora in a patient with short bowel syndrome. An in vitro study on effect of pH on D-lactic acid production.
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.
authors.affiliation: Departamento de Bioquímica Clínica. Facultad de Farmacia y Bioquímica, Buenos Aires, Argentina.
authors.forename: M I
authors.initials: MI
authors.lastname: Caldarini
authors.forename: S
authors.initials: S
authors.lastname: Pons
authors.forename: D
authors.initials: D
authors.lastname: D'Agostino
authors.forename: J A
authors.initials: JA
authors.lastname: DePaula
authors.forename: G
authors.initials: G
authors.lastname: Greco
authors.forename: G
authors.initials: G
authors.lastname: Negri
authors.forename: A
authors.initials: A
authors.lastname: Ascione
authors.forename: D
authors.initials: D
authors.lastname: Bustos
mesh_terms: D001421:Bacteria, Anaerobic / Q000302:isolation & purification; D001928:Brain Diseases, Metabolic / Q000209:etiology / Q000378:metabolism; D002648:Child; D005232:Fatty Acids, Volatile / Q000378:metabolism; D005243:Feces / Q000737:chemistry / Q000382:microbiology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007773:Lactates / Q000378:metabolism*; D019344:Lactic Acid; D007778:Lactobacillus / Q000302:isolation & purification; D008297:Male; D012778:Short Bowel Syndrome / Q000150:complications / Q000382:microbiology*
chemical_list: D005232:Fatty Acids, Volatile; D007773:Lactates; D019344:Lactic Acid