Adherence inhibition of Cronobacter sakazakii to intestinal epithelial cells by prebiotic oligosaccharides.
ABSTRACT Cronobacter sakazakii is an opportunistic pathogen that has been implicated in meningitis, NEC, and sepsis in neonates. Colonization and subsequent infection and invasion of C. sakazakii require that the organism adheres to host cell surfaces. Agents that inhibit or block attachment of the pathogen to epithelial cells could be useful in reducing infections. The goal of this research was to assess the ability of prebiotic galactooligosaccharides (GOS) and polydextrose (PDX) to inhibit adherence of C. sakazakii 4603 to a HEp-2 human cell line. Adherence experiments were performed in the presence or absence of prebiotics using HEp-2 cells grown to confluency on glass coverslips. Prebiotics and bacteria were added and incubated for 3 h. Coverslips were washed, and adherence was determined by cultural and microscopic methods. When measured microscopically or by cultural methods, significant reductions in adherence (56 and 71%, respectively) of C. sakazakii were observed in the presence of GOS (16 mg/ml). Adherence inhibition also occurred (48%) when a GOS-PDX blend (8 mg/ml each) was tested, although PDX by itself had less effect. Similar results were also observed for Caco-2 cells and also for another strain of C. sakazakii (29004). These results suggest that GOS and PDX, alone and in combination, may have an anti-adhesive effect on C. sakazakii and directly inhibit the adherence to gastrointestinal epithelial cells.
- SourceAvailable from: Itzhak Ofek[show abstract] [hide abstract]
ABSTRACT: The majority of infectious diseases are initiated by adhesion of pathogenic organisms to the tissues of the host. In many cases, this adhesion is mediated by lectins present on the surface of the infectious organism that bind to complementary carbohydrates on the surface of the host tissues. Lectin-deficient mutants often lack ability to initiate infection. Soluble carbohydrates recognized by the bacterial lectins block the adhesion of the bacteria to animal cells in vitro. Moreover, they have also been shown to protect against experimental infection by lectin-carrying bacteria in different organs of mammals such as mice, rabbits, calves and monkeys.In a phase II clinical trial, a pentasaccharide shown to have anti-adhesive activity against Streptococcus pneumoniae and Hemophilus influenzae in vitro failed to protect young children from nasopharyngeal colonization with these organisms and from developing otitis media. This could be because insufficient drug was delivered via nasal spray, because bacteria express multiple specificities, the inhibition of which may require a cocktail of oligosaccharides, or because children have different carbohydrate receptors from those of adults. The results of a clinical trial in which N-acetylneuraminyl(2-3)lactose was administered orally to Helicobacter pylori positive patients in an effort to reduce or eradicate bacterial colonization, are awaited with interest.Although the high cost of production of the required oligosaccharides is falling with the recent introduction of enzymatic methods of synthesis, new technologies, in particular the use of engineered bacteria, promise to lower it even further. Attachment of the oligosaccharides to soluble polymeric carriers will increase greatly their effectiveness as anti-adhesion agents. There is no doubt that anti-adhesive oligosaccharides will in the near future join the arsenal of drugs for the therapy of bacterial diseases.Glycoconjugate Journal 06/2000; 17(7):659-664. · 1.88 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: The present study was designed to evaluate the effect of 2 different combinations of prebiotic ingredients, polydextrose (PDX), galactooligosaccharides (GOS), and lactulose (LOS), at 2 different intake levels on the overall growth and tolerance in healthy term infants up to 120 days of age. Healthy, formula-fed, term infants (n = 226) were randomly assigned to 1 of 3 study formula groups: control group (n = 76), PG4 group (control formula supplemented with 4 g/L of a prebiotic blend, n = 74), or PGL8 group (control formula supplemented with 8 g/L of a prebiotic blend, n = 76). Anthropometric measurements were taken at 14, 30, 60, 90, and 120 days of age, and 24-hour dietary recall and 24-hour tolerance recall were recorded at 30, 60, 90, and 120 days of age. Adverse events were recorded throughout the study. There were no statistically significant differences among the 3 formula groups for weight growth rate or length growth rate at any time point. Significant differences in stool consistency were detected among the 3 formula groups at 30, 60, and 90 days of age (P < 0.001, P = 0.025, P = 0.004, respectively), with the supplemented formula groups having looser stools than the control group. The PGL8 group had significantly higher stool frequency compared with the control and PG4 groups at 30 days of age (P = 0.021 and P = 0.017, respectively), but all of the groups were similar at 60, 90, and 120 days of age. A statistical difference was detected among the formula groups in 3 categories of adverse events: diarrhea (control vs PG4, 4% vs 18%, P = 0.008), eczema (PG4 vs control, 18% vs 7%, P = 0.046; PG4 vs PGL8, 18% vs 4%, P = 0.008), and irritability (control vs PGL8, 4% vs 16%, P = 0.027). Infants fed formula supplemented with a prebiotic mixture achieved normal growth and stool characteristics more similar to those of breast-fed infants in comparison with infants fed an unsupplemented formula. A pediatrician needs to consider the risk of possible intolerance against the benefits of prebiotics.Journal of pediatric gastroenterology and nutrition 03/2007; 44(3):359-64. · 2.18 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: Research on human milk oligosaccharides (HMOs) has received much attention in recent years. However, it started about a century ago with the observation that oligosaccharides might be growth factors for a so-called bifidus flora in breast-fed infants and extends to the recent finding of cell adhesion molecules in human milk. The latter are involved in inflammatory events recognizing carbohydrate sequences that also can be found in human milk. The similarities between epithelial cell surface carbohydrates and oligosaccharides in human milk strengthen the idea that specific interactions of those oligosaccharides with pathogenic microorganisms do occur preventing the attachment of microbes to epithelial cells. HMOs may act as soluble receptors for different pathogens, thus increasing the resistance of breast-fed infants. However, we need to know more about the metabolism of oligosaccharides in the gastrointestinal tract. How far are oligosaccharides degraded by intestinal enzymes and does oligosaccharide processing (e.g. degradation, synthesis, and elongation of core structures) occur in intestinal epithelial cells? Further research on HMOs is certainly needed to increase our knowledge of infant nutrition as it is affected by complex oligosaccharides.Annual Review of Nutrition 02/2000; 20:699-722. · 9.16 Impact Factor