Surface appendages, hemagglutination, and adherence to human epithelial cells of Bacteroides intermedius

Four types of morphologically distinct surface appendages were found on oral strains of Bacteroides intermedius. These appendages, designated as A, B, C, and D, were different in size, with diameters of 1-2 nm, 12 nm, 8 nm, and 5 nm, respectively. Twenty different strains were examined by electron microscopy and 5 strains, 5, 17, 27, 113, and 25611, were selected to be representative of the different appendages encountered. Type A appendages were thin filaments peritrichously arranged on the cell surface and were associated mainly with Strains 5, 113, and ATCC 25611. Type B appendages were present on all 5 strains but these structures were scarce (i.e., less than or equal to 3 per organism). Type C appendages were associated exclusively with Strain 17. Type D appendages were present mainly on Strain 27. Hemagglutination activity of these organisms and their ability to adhere to human buccal epithelial cells were also tested. Strain 17, which possessed Type C appendage (uncommon to the other strains), agglutinated strongly with 5 different species of erythrocytes and adhered avidly to human buccal epithelial cells. The other strains, possessing different types of appendages, showed considerable variation in hemagglutination activity and adherence properties. Correlation between these surface appendages and adherent functions was speculated.