Differential Kinetics and Molecular Recognition Mechanisms Involved in Early Versus Late Growth PhaseStaphylococcus aureusCell Binding to Platelet Layers under Physiological Shear Conditions

Abstract

The results presented here demonstrate a differential mechanism and binding efficiency for the adhesion of early versus late growth phase S. aureus to immobilized platelets.

Platelet-Bacterial Interactions as Therapeutic Targets in Infective Endocarditis

“…All of the early S. aureus studies were carried out under static or non-physiological stirring conditions and therefore it is difficult to relate these studies to the disease processes. Studies using a cone and plate viscometer (a device that shears cells at a given flow rate) have demonstrated that protein A, ClfA, SdrC, SdrD and SdrE are important in thrombus formation (George et al, 2007;George et al, 2006;Pawar et al, 2004). However, extremely high shear rates were used in these rheological studies.…”

Platelet–bacterial interactions

“…Studies using a cone and plate viscometer have shown that protein A, ClfA, SdrC, SdrD and SdrE are important in thrombus formation [67][68][69]. However, extremely high shear rates were used in these rheological studies.…”

Staphylococcal Presence Alters Thrombus Formation Under Physiological Shear Conditions in Whole Blood Studies

“…58 Platelets therefore play an important role in the pathogenesis of endovascular infection by providing an adhesive surface for bacterial binding on blood vessel walls. 10 While a number of studies have focused on the molecular mechanisms responsible for platelet-staphylococcal binding, 18,19,45 the impact of bacterial presence on thrombus formation in whole blood is not well understood.…”

“…For example, previous studies in our laboratory and others have demonstrated staphylococcal adhesion to collagen, 32,33,36 fibrinogen, 23,34,35 von Willebrand factor, 24,34,35 and platelets. 18,19,33 Therefore the site of a growing thrombus provides a host of surfaces for S. aureus adhesion and subsequent integration. Fluid shear is an important parameter in these interactions and has been shown to influence the specific mechanisms of binding.…”

“…19,33,45 In particular, the S. aureus ClfA receptor has been shown to be critical for adhesion to fibrinogen and platelet-fibrin clots. 12,18,19,23,38,41,47,59 S. aureus has also been observed to activate platelets and promote bulk aggregation. 47,54,56 Taken together, these findings suggest that the influence of staphylococci on thrombus formation is likely complex.…”