Adhesion of Stenotrophomonas maltophilia to mouse tracheal mucus is mediated through flagella

Abstract

Adhesion of Stenotrophomonas maltophilia, an opportunistic pathogen, to different surfaces has been reported in the literature. However, its ability to adhere to mucus and the involvement of different bacterial appendages in this process has not been elucidated. In this study, bacterial adhesion to mouse tracheal mucus as well as the role of flagella in the adhesion process were investigated using clinical isolates of S. maltophilia. All the clinical isolates adhered to mouse tracheal mucus to varying degrees, showing isolate-to-isolate variation. Isolate Sm2 was selected to study the kinetics of bacterial adhesion to mouse tracheal mucus. The process of bacterial adhesion started after 30 min of incubation, and significant adhesion was detected after 1 h. Bacteria pre-treated with S. maltophilia anti-flagellin antibody were used to determine the role of flagellin in bacterial adhesion. The attachment of S. maltophilia flagellin preparation to mucus was assessed by enzyme immunoassay. Pre-treatment of the bacteria with anti-flagellin antibody resulted in a significant decrease in adhesion to mucus and this decrease was antibody concentration dependent. A similar observation was made when pure flagellin was allowed to interact with mucus. Pre-treatment of mouse tracheal mucus with flagellin led to a significant decrease in bacterial adhesion at concentrations of 40 and 80 µg ml⁻¹ (P<0.05). The ability of S. maltophilia to adhere to mucus was also reduced when mechanically deflagellated bacteria were checked for this property (P<0.005). It was concluded that S. maltophilia has the ability to adhere to mouse tracheal mucus and that flagella play an important role in this process. However, further studies using genetically defined mutants lacking flagella are needed to support this observation.