The combination of MBP, neomycin and synbiotics reduces the prevalence of faecal Enterobacteriaceae and bacterial translocation; however, this was not associated with a reduction in inflammatory response or septic morbidity in this study. Larger trials are needed before a change in practice can be recommended.

The flagellum protein flagellin of Listeria monocytogenes is encoded by the flaA gene. Immediately downstream of flaA, two genes, cheY and cheA, encoding products with homology to chemotaxis proteins of other bacteria, are located. In this study we constructed deletion mutants with mutations in flaA, cheY, and cheA to elucidate their role in the biology of infection with L. monocytogenes. The ⌬cheY, ⌬cheA, and double-mutant ⌬cheYA mutants, but not ⌬flaA mutant, were motile in liquid media. However, the ⌬cheA mutant had impaired swarming and the ⌬cheY and ⌬cheYA mutants were unable to swarm on soft agar plates, suggesting that cheY and cheA genes encode proteins involved in chemotaxis. The ⌬flaA, ⌬cheY, ⌬cheA, and ⌬cheYA mutants (grown at 24°C) showed reduced association with and invasion of Caco-2 cells compared to the wild-type strain. However, spleens from intragastrically infected BALB/c and C57BL/6 mice showed larger and similar numbers of the ⌬flaA and ⌬cheYA mutants, respectively, compared to the wild-type controls. Such a discrepancy could be explained by the fact that tumor necrosis factor receptor p55 deficient mice showed dramatically exacerbated susceptibility to the wild-type but unchanged or only slightly increased levels of the ⌬flaA or ⌬cheYA mutant. In summary, we show that listerial flaA, cheY, and cheA gene products facilitate the initial contact with epithelial cells and contribute to effective invasion but that flaA could also be involved in the triggering of immune responses.

The two probiotics, L. rhamnosus 19070-2 and L. reuteri DSM 12246, ameliorated acute diarrhea in hospitalized children and reduced the period of rotavirus excretion. Oral bacteriotherapy was associated with a reduced length of hospital stay. The beneficial effects were most prominent in children treated early in the diarrheal phase.

Objective: This study was performed to investigate the dose-response effects of supplementation with Bifidobacterium animalis subsp lactis (BB-12) and Lactobacillus paracasei subsp paracasei (CRL-431) on blood lipids, recovery from feces and bowel habits. Changes of the fecal microflora was analyzed in the 10 10 CFU/day probiotic and placebo group. Design: The study was designed as a randomized, placebo-controlled, double-blinded, parallel dose-response study. Subjects: Healthy young adults (18-40 years) were recruited by advertising in local newspapers. Of the 75 persons enrolled, 71 (46 women, 25 men, mean age 25.6 years (range 18-40 years)) completed the study. Intervention: The volunteers were randomly assigned into five groups receiving either placebo or a mixture of the two probiotics in the concentration of 10 8 , 10 9 , 10 10 or 10 11 CFU/day in 2 weeks run-in period, 3 weeks intervention and 2 weeks wash-out. Diary reporting bowel habits and well being (abdominal bloating, flatulence and headache) was kept for all 7 weeks and blood lipids, fecal recovery of BB-12 and CRL-431, as well as fecal microflora was tested before, immediately and 2 weeks after intervention. Results: The fecal recovery of BB-12 increased significantly (Po0.001) with increasing dose. In the group receiving 10 11 CFU/ day BB-12 was recovered from 13 out of 15 volunteers. CRL-431 was not recovered in any of the fecal samples. Supplementation with probiotics did not change the fecal bacterial composition. A significant linear increase in fecal consistency (looser stool) with increasing probiotic dose (P ¼ 0.018) was observed. No overall dose-response effect was found on the blood lipids. High doses of probiotics were well tolerated. Conclusion: A dose-related recovery of BB-12 from feces was observed. Sponsorship: The study was sponsored by Chr. Hansen A/S, Hoersholm, Denmark. Keywords: dose-response study; probiotics; cholesterol; recovery from feces; constipation European Journal of Clinical Nutrition IntroductionIt is generally accepted that the composition of the intestinal microflora influences the health and well being of humans. With the many publications showing beneficial effects of probiotic bacteria, there has been an increasing interest in the mechanism behind. Most clinical studies have tested only one dose of probiotics, ranging from 4 Â 10 8 CFU/day for determination of gastrointestinal colonization and immune modulation (Valeur et al., 2004) Contributors: DCE, CNL and KFM wrote the protocol. DCE performed the study. CNL did the microbiological analysis of fecal samples and study product. EB performed the fluorescent whole cell hybridization of BB-12 like colonies. MB performed the PFGE of CRL-431 like colonies. PK performed the statistical analysis. CNL and SN wrote the first draft of the paper and all contributors participated in the revision and final approval of the paper.

The impact of controlled administration of Bifidobacterium animalis subsp. lactis BB-12 (BB-12) on the risk of acute infectious diseases was studied in healthy newborn infants. In this double-blind, placebo-controlled study, 109 newborn 1-month-old infants were assigned randomly to a probiotic group receiving a BB-12-containing tablet (n 55) or to a control group receiving a control tablet (n 54). Test tablets were administered to the infants twice a day (daily dose of BB-12 10 billion colony-forming units) from the age of 1 -2 months to 8 months with a novel slow-release pacifier or a spoon. Breastfeeding habits, pacifier use, dietary habits, medications and all signs and symptoms of acute infections were registered. At the age of 8 months, faecal samples were collected for BB-12 determination (quantitative PCR method). The baseline characteristics of the two groups were similar, as was the duration of exclusive breastfeeding. BB-12 was recovered (detection limit log 5) in the faeces of 62 % of the infants receiving the BB-12 tablet. The daily duration of pacifier sucking was not associated with the occurrence of acute otitis media. No significant differences between the groups were observed in reported gastrointestinal symptoms, otitis media or use of antibiotics. However, the infants receiving BB-12 were reported to have experienced fewer respiratory infections (65 v. 94 %; risk ratio 0·69; 95 % CI 0·53, 0·89; P¼ 0·014) than the control infants. Controlled administration of BB-12 in early childhood may reduce respiratory infections.

In children from day-care centers with mild gastroenteritis, the combination of L. rhamnosus 19070-2 and L. reuteri DSM 12246 was effective in reducing the duration of diarrhea.

Certain probiotic microorganisms have been found beneficial in the treatment of immune-related diseases and may also affect immune function in healthy people. Intervention studies of probiotics in healthy humans are urgently required. Here, the immunomodulating potential of Bifidobacterium animalis ssp. lactis (BB-12) and Lactobacillus paracasei ssp. paracasei (CRL-431) was studied in a double-blind placebo-controlled parallel dose-response trial (n=71) based on five randomly assigned groups of young healthy adults supplemented for 3 weeks with 0, 10(8), 10(9), 10(10) and 10(11) CFU day(-1), respectively, of a mixture of BB-12 and CRL-431. No statistically significant dose-dependent effect was found for phagocytic activity in blood leukocytes, fecal immunoglobulin A (IgA) concentrations or production of interferon-gamma and interleukin-10 in blood cells. When evaluating data according to the amount of viable BB-12 recovered from faeces, the interferon-gamma production in blood cells was significantly reduced. In conclusion, no solid effect on the immune function of young healthy adults supplemented with even high doses of B. animalis ssp. lactis BB-12 and L. paracasei ssp. paracasei CRL-431 was demonstrated in this study.

The virulence of different pulsed-field gel electrophoresis (PFGE) types of Listeria monocytogenes was examined by monitoring their ability to invade Caco-2 cells. Strains belonging to seven different PFGE types originating from both foods and humans were included. No significant differences in invasiveness were detected between strains isolated from humans and those isolated from food. Strains belonging to PFGE type 1 expressed a significantly lower ability to invade cells compared to strains belonging to other PFGE types. Although strains of PFGE type 2 also seemed to invade at a low level, this was not significant in the present study. PFGE types 1 and 2 as well as type 14 are more frequently found in food than the four other PFGE types examined and moreover have a relatively low prevalence in humans compared to their prevalence in food. Thus, the hypothesis that some PFGE types are less virulent than others is supported by this study showing that certain PFGE types of L. monocytogenes commonly found in food are less invasive than others to Caco-2 cells. In contrast to the differences in invasion, identical intracellular growth rates between the different PFGE types were observed. In vivo studies of the actual ability of the strains to invade the liver and spleen of cimetidinetreated rats following an oral dose of 10 9 L. monocytogenes cells were performed for isolates of PFGE types 1, 2, 5, and 15. After 2 days, equal amounts of bacteria were observed in the liver and spleen of the rats for any of the PFGE types tested.Listeria monocytogenes is an intracellular pathogen of humans and animals that expresses differences in virulence within individual strains (7, 27). Among the 13 serotypes known for this species, most isolates from human cases of listeriosis seem to belong to only three serotypes (1/2a, 1/2b, and 4b). While serotyping has limited application in epidemiological studies, more discriminatory molecular typing methods, such as multilocus enzyme electrophoresis (12, 16), pulsed-field gel electrophoresis (PFGE) (18,20), random amplification of polymorphic DNA (3, 4), ribotyping (23), and phage typing (14), have successfully been used to differentiate among isolates of L. monocytogenes.PFGE has been shown to be highly discriminative for strains of L. monocytogenes (10, 11, 15), either alone or in combination with other methods. PFGE typing of 123 isolates of L. monocytogenes from ready-to-eat foods and 39 isolates from human clinical cases of infection showed a significant difference in the distribution of PFGE types among food isolates compared to human isolates (18), with some types having a higher prevalence among food isolates and vice versa.Individual isolates of L. monocytogenes are known to vary in virulence (7,9). Most earlier studies that have described the association between various subtypes and the virulence of the strains have focused on multiplication inside the host rather than invasion into the intestinal mucosa. The results are not clear, however. By this approach, Nørrung and Anderse...