SUMMARYIn 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.

SUMMARYExperimental data suggest a role for the microflora in Systemic Lupus Erythematosus (SLE). Anti-ds-DNA antibodies may be pathogenic in SLE by forming immune complexes with DNA. Foreign bacteria in the intestines could constitute the stimulus for anti-ds-DNA antibody production in SLE. Colonization Resistance (CR) is the defence capacity of the indigenous microflora against colonization of the intestines by foreign bacteria. A low CR implies increase of translocation of bacteria and a higher chance of subsequent, possibly DNA-crossreacting antibacterial antibody production.We measured CR by a comprehensive biotyping technique in healthy individuals and patients with inactive and active SLE. CR tended to be lower in active SLE patients than in healthy individuals (P = 009, Wilcoxon one sided, with correction for ties). This could indicate that in SLE more and different bacteria translocate across the gut wall due to a lower CR. Some of these may serve as polyconal B cell activators or as antigens cross-reacting with DNA.

SUMMARYA 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.

Objective quantitation of serum antibody titres against Enterobacteriaceae using indirect immunofluorescence, read by videocamera and image processing system Apperloo-Renkema, H. (1991). Objective quantitation of serum antibody titres against Enterobacteriaceae using indirect immunofluorescence, read by videocamera and image processing system. Default journal. CopyrightOther than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Summary. 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.

SUMMARYThe 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 < 0f01). 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 < 3 and 741 for IgA, between < 3 and 8-7 for IgG and between < 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 lgM antibody mediated.