MO Quinn, VE Miller and AR Dal Nogare
Pulmonary and Critical Care Division, University of Texas, Southwestern Medical Center, Dallas 75235-9034.

Exoglycosidases remove peripheral monosaccharides from oligosaccharides and hence are capable of altering respiratory epithelial cell surface carbohydrates. We obtained saliva and tracheal secretions from 34 critically ill patients and saliva from 23 healthy subjects. Compared with the normal subjects, the ill patients had large amounts of mannosidase, fucosidase, hexosaminidase, and sialidase activity. Sialidase increased adherence of several gram-negative bacteria to epithelial cell monolayers and pure glycoproteins. Pretreatment of glycoproteins with some of the patients' saliva samples also increased bacterial adherence to the glycoproteins. We conclude that respiratory tract exoglycosidase activity increases during critical illness. By altering normal cell surface carbohydrates, exoglycosidases may facilitate bacterial adherence and respiratory tract colonization.