Mediation of attachment of Burkholderia pseudomallei to human pharyngeal epithelial cells by the asialoganglioside GM1-GM2 receptor complex

Abstract

Melioidosis is the term given to any infection caused by Burkholderia pseudomallei. This bacteria is one of the important causative agents of life-threatening pulmonary infections in the tropical and subtropical areas. The initiation of respiratory infections is attachment of this bacteria to pharyngeal cells. The precise mechanism of attachment of B. pseudomallei is not known. In this study, we found that asialoganglioside GM1 at concentrations of 25, 12.5, and 5 microg/ml significantly decreased the attachment of B. pseudomallei strain Sp-186 in a dose-dependent manner. On the other hand, asialoganglioside GM2 decreased the attachment of B. pseudomallei, but only at a concentration of 25 microg/ml. At a concentration of 1 mg/ml, glucose, N-acetyl-galactosamine, and galactose caused a significant decrease in attachment. However, at concentrations of 250 microg/ml, no decrease in attachment was observed in B. pseudomallei treated with these carbohydrates. Mannose and fucose at concentrations of 1 mg/ml had no effects on the inhibition of attachment of B. pseudomallei. Four other isolates of B. pseudomallei showed a significant decrease in attachment after treatment with asialoganglioside GM1. We conclude that asialogangliosides GM1 and GM2 are part of the receptor complex for B. pseudomallei on human pharyngeal epithelial cells.