Hydrophobic and adherence properties of Clostridium difficile

Nine strains of Clostridium difficile isolated from symptomatic and asymptomatic patients and four other species of clostridia were tested for relative hydrophobicity by determining the degree of adherence to polystyrene. Under three different conditions of growth all strains of Clostridium difficile had high rates of adherence, whereas the other clostridial species showed no pronounced adherence. Isolates of Clostridium difficile were also tested for their ability to adhere to human embryonic intestinal cells and adult colon cells. All strains adhered to both cell lines, although the percentages of organisms adhering varied. Adherence was greatest at pH 5.5-6.0 but was not significantly altered at a pH of 7.0-7.8 (p = 0.15, p = 0.20); it decreased significantly upon washing with 1% Tween 80 but not with 0.1% Tween 80. This capacity for adherence may play a part in the organism's colonization of the human intestinal tract.