Selective enumeration of Bacteroides vulgatus and B. distasonis organisms in the predominant human fecal flora by using monoclonal antibodies

Abstract

The genus Bacteroides represents about one-third of the isolates from human fecal samples. The proportions of the different species are difficult to estimate because there is no method for rapid identification of mixtures of anaerobes. Monoclonal antibodies against Bacteroides vulgatus and B. distasonis were prepared. They did not react with the other Bacteroides species of the B. fragilis group. These reagents allowed direct enumeration of B. vulgatus and B. distasonis organisms in human fecal samples. Anaerobic bacteria resistant to 1-h contact with air were enumerated in fecal human samples, a filter was layered on the colonies, and then B. vulgatus colonies were identified by an immunoassay performed with the prepared monoclonal antibodies. Healthy human adult volunteers were tested. Most of them harbored B. vulgatus at high levels, while the B. distasonis levels were always lower. Kinetic studies suggested that time variations for each volunteer were small. The simplified quantification of Bacteroides strains at the species level described here will prove useful in complementing our knowledge of the factors which may influence the predominant human fecal flora.

Pattern extraction of structural responses of gut microbiota to rotavirus infection via multivariate statistical analysis of clone library data

“…It has been found that B. vulgatus was more abundant than the other members in the B. fragilis group in the fecal samples of healthy volunteers using a culture-dependent method (Meijer-Severs & van Santen, 1986). Corthier et al (1996), using monoclonal antibodies, detected B. vulgatus in the fecal samples of 50 healthy adults, and B. vulgatus was found to exist at high levels in most healthy human intestines. Furthermore, they also showed that the population level of B. vulgatus was not influenced by minor environmental variations.…”

Culture-independent characterisation of human faecal flora using rRNA-targeted hybridisation probes

“…For the enumeration of total Bacteroides, dilutions of human faecal samples were plated using brain-heart infusion and exposed to air for 1 h to preselect for non-extremely oxygen-sensitive microorganisms, prior to incubation under strict anaerobic conditions at 37 °C for 48 h (Corthier et al, 1996). Colonies were transferred onto Nytran-Plus membranes (Schleicher and Schuell, Ecquevilly, France) following the manufacturer's recommendations.…”

Transfer of the shuttle vector pRRI207 between Escherichia coli and Bacteroides spp. in vitro and in vivo in the digestive tract of axenic mice and in gnotoxenic mice inoculated with a human microflora

“…Faecal samples were collected, diluted and plated into appropriate agar plates. They were exposed to air for 1 h to preselect for microorganisms that were not extremely oxygen sensitive [20], prior to incubation at 37³C for 3 days under anaerobic conditions in a Freter anaerobic glove box [21]. Antibiotics (Coger and Sigma) were added as required at ¢nal concentrations of 10 Wg ml 3I tetracycline (Tc), 100 Wg ml 3I rifampicin (Rif), 10 Wg ml 3I clindamycin (Cc), 100 Wg ml 3I erythromycin (Em), 140 Wg ml 3I neomycin (Neo), 50 Wg ml 3I Nal, 100 Wg ml 3I streptomycin (Sm), 50 Wg ml 3I kanamycin (Kn) and 25 Wg ml 3I ampicillin (Ap).…”