[A comparison of culture and immunofluorescence technics in the study of Bacteroides with black pigmentation]

The aim of that study was to compare culture and immunofluorescence (IF) methods to determine whether B. gingivalis and other B.P.B. can be detected in subgingival plaque of children. Samples were collected from the lingual sulcus of mandibular incisors, dispersed and diluted from 1 to 10(-5); 15 microliters of each dilution were plated on Trypticase soja agar and Todd-Hewitt agar supplemented with blood, Vit K 1 and hemin. The same dilutions were smeared on glass slides for indirect IF using an species-specific polyclonal rabbit whole cell antiserum to B. gingivalis ATCC 33 277. Representative colonies producing brown-to-black pigment were isolated, purified and further characterized. Using culture, BPB were detected in 46% of children (19/41). B. gingivalis was cultured from 6 children. Using immunofluorescence test (Fluotec*), 90% of 309 children 3 years old and more harbour detectable B.P.B., but B. gingivalis don't react with that test. B. gingivalis were detected by immunofluorescence in 72% of children (30/41) in the incisor plaque.