EnterotoxigenicBacteroides fragilis–Associated Diarrhea in Children 0–2 Years of Age in Rural Bangladesh

Abstract

The burden of enterotoxigenic Bacteroides fragilis (ETBF)-related diarrhea was determined in a birth cohort of 252 children in rural Bangladesh. Isolation rates of ETBF in stool and risk factors for acquisition of ETBF and disease were established. Of 382 B. fragilis-positive specimens, 14.4% of the strains found in them produced enterotoxin, as determined by a tissue-culture assay. The overall isolation rate of ETBF was 2.3% (40/1750) from diarrheal specimens and 0.3% (15/5679) from nondiarrheal specimens collected throughout the 2 years of the study (P < .001). ETBF was isolated from 20.3% (40/197) of the B. fragilis-positive diarrheal specimens and from 8.1% (15/185) of the B. fragilis-positive nondiarrheal specimens (P < .001) and was significantly associated with acute diarrheal disease in children > or = 1 year of age (P = .0001). The diarrheal illness was mild in nature. In conditional multivariate analyses that examined environmental and host risk factors, the presence of livestock in the household area was linked to the acquisition of ETBF (chickens, P < .05; cows, P = .06). ETBF was found to be a small but significant contributor to diarrheal disease in this rural community. Improved management of livestock may be useful for the prevention of ETBF infection.

Enterotoxigenic Bacteroides fragilis: A potential instigator of colitis

“…In contrast, in studies conducted to date, children under the age of 1 are colonized apparently asymptomatically with ETBF. [11][12][13]16 Together, these results suggest a critical shift in the mucosal response to ETBF associated with age and likely other factors including diet or other environmental exposures.…”

“…ETBF are associated with diarrheal illnesses in animals, children, and adults. [11][12][13] In considerably more limited data, ETBF have been linked to IBD where these bacteria have been identified in mucosal washings of IBD patients and associated with clinically active IBD. 14,15 However, in all human studies evaluating ETBF colonization to date, a sizeable number of individuals (≈4%-30%) appear to be colonized, apparently asymptomatically, with ETBF.…”

Distribution, detection of enterotoxigenic strains and antimicrobial drug susceptibility patterns of Bacteroides fragilis group in diarrheic and non-diarrheic feces from Brazilian infants

“…Enterotoxigenic strains were identified in 4.6% of the fecal samples. It is accepted that this number may vary from 6 to 12% of children in the USA, approximately 10% in Europe and around 2 to 15% in Asia (9,11,25,29,34,35). In Brazil, there is a lack of scientific data on the incidence of ETBF in the population; however, data show the incidence of these microorganisms in HIV-positive children (3.1%) (8) The use of chloramphenicol has been declining in many countries due to the toxicity of the drug, which causes intestinal disorders, depression and anemia.…”

A Novel Selective Medium for Isolation of Bacteroides fragilis from Clinical Specimens

“…Several antibiotics (gentamicin, kanamycin, and novobiocin) were chosen based on their stability in prepared medium and antibacterial activities for common aerobes and facultative anaerobes that may hydrolyze esculin (19,24). Concentrations of the antibiotics were chosen empirically after reviewing those that were previously used in various selective media (18,19,24). The final formulation of the new medium consisted of (per liter) 15 g of bacteriological agar (Oxoid agar no.…”

“…While Bacteroides bile-esculin (BBE) agar supplemented with gentamicin has been developed for such a purpose, the selectivity of the medium is limited by increasing gentamicin resistance among enterococci and by the medium's inability to inhibit some lactobacilli (14)(15)(16)(17). Furthermore, BBE agar may not produce large colonies for some B. fragilis strains, and culture media based on brain heart infusion have been found to be superior to BBE agar for recovery of B. fragilis (18,19). Previous studies further reported that B. fragilis produced yellow colonies in the presence of glucose or glucuronic acid as a fermentable carbon source, and this may be a useful marker for enhancing recognition of the organism in mixed growth (18,20).…”