Study of colonization resistance for Enterobacteriaceae in man by experimental contamination and biotyping as well as the possible role of antibodies in the clearance of these bacteria from the intestines.

The colonization resistance (CR) of the digestive tract was determined in 10 healthy volunteers by oral contamination with a neomycin resistant Escherichia coli (NR-E. coli) strain and measurement of the faecal concentration of this strain during 14 days after the contamination. This 'gold standard' was compared with another parameter of CR; the determination of the mean number of different biotypes of Enterobacteriaceae isolated from four faecal samples per volunteer. Both measures are significantly correlated (P less than 0.01). The NR-E. coli strain could be cultured from faecal samples of 4/10 volunteers as long as 300 days after contamination. Serum antibody titres against endogenous E. coli strains and the NR-E. coli strain used for experimental oral contamination were measured by an indirect immunofluorescence (IIF) assay. The assay was read by a video camera connected to an image processing system. The 95% confidence limits of antibody titres (log2) against endogenous E. coli strains ranged between less than 3 and 7.1 for IgA, between less than 3 and 8.7 for IgG and between less than 3 and 7.4 for IgM. Antibody titres against the NR-E. coli4 strain were within this (normal) range. The serum antibody titres against the NR-E. coli strain increased slowly after oral contamination, especially IgG and IgM. Little increase in IgA titres could be observed. An increase of serum antibody titres did not correlate with the elimination of the oral contaminant from the intestines. Therefore, we conclude that the CR is not IgG nor IgM antibody mediated

Benefits of mycophenolate mofetil in non-transplant kidney diseases

Les glomérulopathies constituent une cause d'insuffisance rénale non négligeable. Les traitements cytotoxiques utilisés avec les corticostéroïdes pour induire la rémission de la protéinurie et stabiliser la fonction rénale, ainsi que pour prévenir la rechute, présentent des effets secondaires importants : infections, néoplasies secondaires, infertilité et alopécie, voire néphrotoxicité. Le mycophénolate mofétil (MMF), utilisé en prévention du rejet lors de la transplantation d'organes, présente des caractéristiques intéressantes dans ce contexte particulier. Son profil d'effets secondaires est aussi avantageux. La présente revue de la littérature montre que le MMF semble efficace dans la plupart des glomérulopathies, sous réserve de résultats encore assez limités qui demandent à être confirmés.Glomerular diseases remain frequent causes of end-stage renal failure. Immunosuppressive drugs in association with corticosteroids induce remission of proteinuria and stabilize renal function, as well as prevent relapses, but are responsible for severe portential side-effects: infections, secondary malignancies, sterility and alopecia, and even nephrotoxicity. Mycophenolate mofetil (MMF), a well-known drug in transplantation, presents interesting characteristics potentially useful in the teatment of glomerulopathies. Moreover, its side-effect profile is safer. The present review of literature suggests that MMF is efficient for the treatment of glomerular disease, even if the results of the different studies remain limited and require further confirmation

Circulating antibodies against faecal bacteria assessed by immunomorphometry: combining quantitative immunofluorescence and image analysis.

A new technique to study the prevalence of circulating antibodies directed against different morphological groups ('morphotypes') of bacteria in fresh faeces is presented. The technique combines quantitative indirect immunofluorescence with digital image analysis. Plasma antibody titres and patterns of IgA, IgG and IgM isotype against morphotypes of faecal bacteria were determined in ten healthy individuals

Determination of colonization resistance of the digestive tract by biotyping of Enterobacteriaceae.

In studies concerning the effect of antibiotics on faecal microflora, Colonization Resistance is an important parameter. Colonization Resistance correlates inversely with the number of different biotypes of Enterobacteriaceae isolated from faecal samples. Nine healthy volunteers were studied during 6 weeks, in order to determine the natural variation in the number of different biotypes of Enterobacteriaceae per faecal sample. The numbers of biotypes ranged from 1-15 per faecal sample, the mean number of biotypes varied between 2.6 and 7.3 different biotypes per faecal sample per healthy volunteer. Inter-individual variations of five biotypes in the mean number of biotypes per faecal sample are normal. We assessed the minimal number of faecal samples that should be taken for comprehensive biotyping so as to determine reliably the mean number of different biotypes representative for the Colonization Resistance of an individual. It was found that a minimum of four faecal samples was required

Objective quantitation of serum antibody titres against Enterobacteriaceae using indirect immunofluorescence, read by videocamera and image processing system

A new way of measuring indirect immunofluorescence (IIF) of microscopic bacterial slide preparations by videocamera and an image processing system is presented. This method is compared with the conventional method of reading the slides by eye. The advantages of this new approach are objective reading, greater accuracy and easier performance. We have applied the method to measure serum antibody titres against endogenous Enterobacteriaceae. The method offers the opportunity to combine IIF with automatic morphological analysis, thereby maximally exploiting the possibilities of the immunofluorescence technique.