arbutin and Diarrhea

The present study characterised 73 Hafnia alvei isolates and five Escherichia isolates (originally identified as H. alvei) isolated from cases of diarrhoeal disease by the International Centre for Diarrhoeal Disease Research Branch (ICDDRB) in Bangladesh. Based upon the hydrolysis of arbutin and aesculin and the fermentation of salicin and D-arabinose, four distinct biotypes could be recognised among the 73 H. alvei isolates tested; biotype 1 (D-(-)-arabinose-positive only) accounted for 75% of all isolates analysed. Hydrolysis of aglycone compounds such as arbutin, salicin and aesculin appeared to be associated with expression of beta-glucosidase activity. ICDDRB isolates, when compared with type or reference strains of H. alvei, were shown not to belong to the genus Hafnia based upon resistance to Hafnia-specific bacteriophage 1672, possession of the phoE gene, expression of glutamate decarboxylase activity and significant 16S rDNA sequence divergence (approximately 8%) from the type strain, ATCC 13337T. True H. alvei strains, implicated in outbreaks of diarrhoeal disease in Canada, lacked the eaeA gene in contrast to ICDDRB isolates. Twenty-two H. alvei isolates were selected for further study. Based upon partial 16S rDNA sequencing, these 22 isolates fell into two genomic groups (genomospecies), identical to DNA groups previously established by DNA hybridisation studies. Markers such as motility, biotype, or enzymic or carbohydrate fermentation patterns did not correlate totally with DNA grouping, although malonate utilisation appeared to be the single best discriminatory phenotype. The results indicate that the genus Hafnia is heterogeneous and there do not appear to be any laboratory data available specifically linking these organisms to gastro-enteritis.

Topics: Adhesins, Bacterial; Animals; Arabinose; Arbutin; Bacterial Typing Techniques; Bangladesh; Benzyl Alcohols; beta-Glucosidase; Carrier Proteins; Diarrhea; Electrophoresis, Gel, Pulsed-Field; Escherichia coli; Escherichia coli Proteins; Esculin; Fermentation; Genes, Bacterial; Genotype; Glucosides; Hafnia alvei; Humans; Hydrolysis; Phenotype; RNA, Ribosomal, 16S

The effect of microorganisms isolated from the upper gastrointestinal tract of malnourished children on intestinal sugar absorption was studied in rats in vivo. Pure cultures of organisms were grown overnight in a nutrient broth and the resultant supernatant fluid which contained microorganisms in similar numbers to those found in the patients was used as the basic solution for jejunal perfusions which were done in anesthetized adult Wistar rats. The substrate used was arbutin (p-hydroxphenyl-beta-glucoside), a recognized marker of intestinal active sugar transport. Of the gram-positive cocci studied, only the saprophyte, Staphylococcus saprophyticus, did not adversely affect the intestinal absorption of arbutin. The only gram-positive rod studied, a lactobacillus, also significantly inhibited arbutin absorption. Of the Enterobacteriaciae studied, Salmonella paratyphi B, a Shigella and Proteus sp. did not affect arbutin absorption. All the species of Escherichia coli studied, including a nonpathogenic variety, inhibited absorption. Klebsiella sp. and Pseudomonas sp. were also effective. Of the Candida sp., C. albicans and C. parapsilosis were inhibitory while C. tropicalis was not. These results suggest that microorganisms not generally considered enteropathogenic may adversely affect intestinal function when present in the lumen of the gut in excessive numbers and contribute to the production of diarrhea in children with malnutrition.

Topics: Animals; Arbutin; Candida; Child, Preschool; Diarrhea; Digestive System; Escherichia coli; Female; Humans; Infant; Intestinal Absorption; Klebsiella; Lactobacillus; Male; Nutrition Disorders; Plants, Medicinal; Pseudomonas; Rats; Species Specificity; Staphylococcus; Streptococcus