Inhibition ofStaphylococcus aureusAdherence to Collagen under Dynamic Conditions

Abstract

Staphylococcus aureus is the most common etiological agent of bacterial arthritis and acute osteomyelitis and has been shown to bind to type II collagen under static and dynamic conditions. We have previously reported the effect of shear on the adhesion ofS. aureus Phillips to collagen and found that this process is shear dependent (Z. Li, M. Höök, J. M. Patti, and J. M. Ross, Ann. Biomed. Eng. 24[Suppl. 1]:S–55). In this study, we used recombinant collagen adhesin fragments as well as polyclonal antibodies generated against adhesin fragments in attempts to inhibit bacterial adhesion. A parallel-plate flow chamber was used in a dynamic adhesion assay, and quantification of adhesion was accomplished by phase contrast video microscopy coupled with digital image processing. We report that both recombinant fragments studied, M19 and M55, and both polyclonal antibodies studied, α-M17 and α-M55, inhibit adhesion to varying degrees and that these processes are shear dependent. The M55 peptide and α-M55 cause much higher levels of inhibition than M19 and α-M17, respectively, at all wall shear rates studied. Our results demonstrate the importance of using a dynamic system in the assessment of inhibitory strategies and suggest the possible use of M55 and α-M55 in clinical applications to prevent infections caused by S. aureus adhesion to collagen.

Fluid shear contributions to bacteria cell detachment initiated by a monoclonal antibody

“…One study reported that fluid shear-induced detachment of S. aureus from fibrinogen (range 1000-7000 s −1 ) did not change significantly with increasing shear force (Dickinson and Cooper, 1995). However, in our laboratory, we previously demonstrated that shear force alone did not cause S. aureus detachment from collagen (Mohamed et al, 1999). Based on these combined findings, we hypothesized that shear force would act synergistically with a destabilizing antibody to increase detachment.…”

“…The CNA (S. aureus collagen receptor) mouse monoclonal antibody (mAb) 9G7 isotype IgG 1 was used as the destabilizing mAb and was a gift from Dr. Joseph Patti, Inhibitex, Atlanta, GA and Dr. Pietro Speziale, Universita di Pavia, Pavia, Italy. Previous reports have demonstrated that only specialized antibodies to the collagen receptor promote destabilization in a static or fluid shear system (Mohamed et al, 1999;Visai et al, 2000). Monoclonal antibody 9G7 has been shown to block collagen binding to S. aureus Cowan-1, displace previously bound collagen from Cowan-1 in solution, and displace Cowan-1 initially bound to a collagen substrate in static assays (Visai et al, 2000).…”

“…The details of the parallel plate flow chamber, collagen coating procedure, and video microscopy system used have been previously described (Mohamed et al, 1999). Briefly, an inverted stage phase contrast microscope, a CCD camera, and NIH Image program (download available at http:// rsb.info.nih.gov/nih-image/download.html) were used to visualize and capture images of attached cells.…”

“…The adhesion receptors of Staphylococcus aureus have been extensively studied because of the organism's emerging antibiotic resistance and the seriousness of the infections it causes. Monoclonal antibodies specific for S. aureus receptors have demonstrated the ability to prevent adhesion in vivo and in vitro, and thus may have potential as a preventative strategy against staphylococcal infections (Mohamed et al, 1999;Nilsson, 1998). More recently, a monoclonal antibody specific for the S. aureus collagen receptor (CNA) was reported to destabilize cells bound to collagen in a static assay (Visai et al, 2000).…”

Influence of batch or fed-batch growth on Staphylococcus epidermidis biofilm formation

“…These findings indicate that attention must be taken in choosing the growth method used to measure biofilm production by S. epidermidis in order to make meaningful comparisons among different investigations. Biofilm formation by medically relevant S. epidermidis is used in many studies, including those looking for molecular and cellular correlates of biofilm formation (Heilmann et al 1996;Cramton et al 1999;Galbart et al 2000), in studies concerning prevention of biofilm formation by antimicrobial agents (Rupp and Hamer 1998) or to evaluate some host immune factors (Mohamed et al 1999). As many of these studies attempt to evaluate the role of PNAG in the pathogenesis of infection and in biofilm formation properties, the use of static-batch systems may not be suitable.…”