STAPHYLOCOCCUS-AUREUS BINDING TO HUMAN NASAL MUCIN

Colonization of human nasal mucosa with Staphylococcus aureus sets the stage for subsequent systemic infection. This study characterizes S. aureus adhesion to nasal mucosa in vitro and investigates tile interac tion of S. aureus with human nasal mucin. S. aureus binding to cell-as sociated and cell-free mucus was greater than to nonmucin-coated epith elial cells. Scanning electron microscopy of S. aureus incubated with human nasal mucosal tissue showed minimal binding to ciliated respirat ory epithelium. In a solid phase assay, S. aureus bound to purified hu man nasal mucin-coated wells significantly more than to bovine serum a lbumin-coated microtiter wells. Binding to mucin was saturable in a do se- and time-dependent fashion. Staphylococcal adherence to human nasa l mucin was inhibited by bovine submaxillary mucin but not by fibrinog en, Pretreatment of mucin with periodate but not with pronase reduced adherence. Trypsin treatment of the bacteria significantly reduced adh erence to mucin. I-125-labelled nasal mucin bound to two surface prote ins (138 and 127 kDa) of lysostaphin-solubilized S. aureus. Binding to human nasal mucin occurs in Dart via specific adhesin-receptor intera ctions involving bacterial proteins and the carbohydrate moiety in muc in, These experiments suggest that S. aureus binding to mucin may be c ritical for colonization of the nasopharyngeal mucosa.