Characterization of a polyvalent conjugate of Bacterroides fragilis by fluorescent antibody staining.

A polyvalent conjugate (fluorescein-isothiocyanate-labeled antibody reagent) prepared for Bacteroides fragilis contained conjugates prepared against three strains of B. fragilis. This conjugate stained 93% of the 111 B. fragilis test strains; the other 7% of B. fragilis stained at certain times but not others. The conjugate was specific for B. fragilis, 91 strains of anaerobes other than B. fragilis and aerobes failed to give a positive fluorescence. The advantage of this conjugate is that it provides a quicker and less expensive identification of B. fragilis than the use of pre-reduced biochemical media and gas chromatography.