Probiotics in diarrhea
Several reports exist on the benefits of probiotics in this common complication of the use of antibiotics. For example, in the prevention of antibiotic-associated diarrhea, 45 patients being treated with antibiotics were given, concurrently, one capsule of either Enterococcus SF68 or placebo for 7 days (10 centers) twice daily.
Enterococcus SF 68 was effective in reducing the incidence of antibiotic-associated diarrhea compared to placebo (8.7% compared to 27.2%, respectively) (96). Important here is the evidence that Enterococcus SF68 has been withdrawn because of the risk of antibiotic resistance transfer. Not all reports are similarly encouraging but the type of probiotics used may be important in achieving results.
Probiotics in acute diarrhea
Multiple studies in children have shown that Lactobacillus, administered orally, may have antidiarrheal properties. To determine the effect of Lactobacillus GG on the course of acute diarrhea in hospitalized children, a prospective, placebo-controlled, triple-blind clinical trial was carried out in Pakistan. Forty children (mean age, 13 months) received either oral Lactobacillus GG (n = 21) or placebo (n = 19) twice daily for 2 days, after rehydration in addition to the usual diet.
The clinical course of diarrhea was followed during the treatment period. The features for admission into the study groups were similar and were characterized by severe diarrhea, malnutrition and inappropriate management before presentation. Response was evident on day 2, when the frequency of both vomiting and diarrhea was less in the Lactobacillus group. In those patients with acute nonbloody diarrhea (n = 32), the percentage of children with persistent watery diarrhea at 48 hours was significantly lower in the Lactobacillus group (31 % versus 75%). No significant difference was observed after 48 hours in those with bloody diarrhea (97).
Van Niel et al. (98) conducted a meta-analysis of randomized, controlled studies to assess whether treatment with Lactobacillus improved clinical outcome in children with acute infectious diarrhea. They conducted a search in bibliographic databases of traditional biomedical as well as complementary and alternative medicine literature published between 1966 and 2000. The original search yielded 26 studies, nine of which met the criteria. A reduction of 0.7 days in diarrhea duration and a reduction of 1.6 stools for diarrhea frequency was attained on day 2 of treatment in the participants who received Lactobacillus compared to those who received placebo. A preplanned subanalysis suggested a dose-effect relationship. The results of this meta-analysis suggested that Lactobacillus is safe and effective as a treatment for children with acute infectious diarrhea.
Probiotics in rota virus diarrhea
Rotavirus was discovered in children with gastroenteritis by Bishop et al. in 1973 (99). This agent causes widespread morbidity and 870,000 deaths worldwide each year. As Bishop said, "after doing a lot of background reading, it became clear that there probably was an infectious agent but we could not get anything to grow in culture". Bishop et al. (99) participated in the development of vaccines against rotavirus, the first of which was licensed for use in the USA in 1998.
The effect of orally administered lactobacilli on acute rotavirus diarrhea was tested by Isolauri et al. (100) in 42 well-nourished children aged 5-28 months. After oral rehydration, the patients received human L. casei strain GG 1010 CFU twice daily for 5 days. The control group was not given lactobacilli. Lactobacillus GG was found in the feces of 83% of the group with L. casei strain GG. The diarrheal phase was shortened in that group. The dietary supplementation with lactobacilli significantly influenced the bacterial enzyme profile. Urease activity during diarrhea transiently increased in the control group but not in the group receiving L. casei strain GG. No intergroup differences were found in B-glucuronidase, B-glucosindase, and glycocholic acid hydrolase levels.
Therefore, Isolauri et al. suggested that rotavirus infection gives rise to biphasic diarrhea, the first phase being an osmotic diarrhea and the second associated with overgrowth of specifically ureaseproducing bacteria. Oral bacteriotherapy appears to be a promising means to counteract the disturbed microbial balance.
To evaluate the ingested strain's adherent properties and ability to inhibit murine rotavirus infection, Duffy et al. (101) administered human Bifidobacterium sp. strain bifidum to BALB/c lactating mice (n = 58) and their litters (n = 327 pups). ELISA and anaerobic bacteriologic techniques were used to measure murine rotavirus shedding and colonization of Bifidobacterium in the small intestine.
At 1316 days of gestation, pregnant dams (and their expected litters) were randomly assigned to one of four experimental groups as follows: normal controls; B. bifidum-treated only; murine rotavirus-infected only; and B. bifidum-treated plus murine rotavirus-infected dams and litters. During the acute phase of diarrhea, 80% of small-intestine cultures in B. bifidum-treated litters were positive for the ingested B. bifidum strain compared to 24% of fecal cultures.
The examination of tissue cross sections under electron microscopy revealed the ingested B. bifidum strain survived passage through the upper gastrointestinal tract and adhered to the small-intestine epithelium. After the administration of the high dose of virus, diarrhea developed in all pups, but onset was significantly delayed in B. bifidum-treated plus
Murine rotavirus-infected litters compared to litters infected with murine rotavirus only. B. bifidum-treated plus murine rotavirus-infected pups demonstrated a significant reduction in murine rotavirus shedding compared with litters challenged with murine rotavirus only at day 2-10 after inoculation. More direct studies are needed to assess the mechanisms by which this anaerobe may modify the course of murine rotavirus infection at the level of gut epithelium.
Qiao et al. (102) evaluated the potential synergistic effects of Bifidobacterium spp. (B. bifidum and B. infantis), with or without prebiotic compounds (arabi no-galactan, short-chain fructooligosaccharide, iso-maltodextrins), on modulating the course of rhesus rotavirus infection, as well as their ability to mediate the associated mucosal and humoral immune responses. Therefore, they fed these species orally to pups. Rotavirus-specific IgA and IgG in serum, rotavirus antigen, and specific IgA in feces were measured by ELISA. Mucosal total IgA and IgG levels were determined in Peyer's patches by flow cytometry.
Significantly delayed onset and early resolution of diarrhea were observed in bifidobacteria-treated, rhesus rota virus-infected mice compared with rhesus rotavirus-infected control mice. They saw that supplementation with prebiotic compounds did not shorten the clinical course of diarrhea more than that observed with bifidobacteria treatment alone. Rotavirus-specific IgA in feces was elevated 16-fold on day 5 postinfection in bifidObacteria-treated, rhesus rotavirus-infected mice compared with the rhesus rotavirus-infected only group. In addition, the level of rotavirus-specific IgA in serum was fourfold higher in bifidobacteria-treated, rhesus rota virus-infected litters versus mice challenged with rhesus rotavirus alone on 28 and 42 days postinfection.
They found no enhancement of the immune response in rhesus rotavirus-infected mice that were treated with both bifidobacteria and prebiotic compounds over those treated with bifidobacteria alone. These findings suggested that bifidobacteria may act as an adjuvant by modulating early mucosal and strong humoral rotavirus-specific immune responses, and mitigate the severity of rotavirus-induced diarrhea (102).