Adhesion of staphylococci to polymers with and without immobilized heparin in cerebrospinal fluid

• Published in: Journal of biomedical materials research 1997, Vol.38 (1), p.35-42
• Main Authors: Nomura, Sadahiro, Lundberg, Fredrik, Stollenwerk, Maria, Nakamura, Kazuyuki, Ljungh, Åsa
• Format: Article
• Language: English
• Subjects: Bacterial Adhesion; Biocompatible Materials - chemistry; Biological and medical sciences; cerebrospinal fluid; Cerebrospinal fluid. Spinal cord. Spinal roots. Spinal nerves; Heparin - cerebrospinal fluid; hydrophobic interaction; Medical sciences; Neurosurgery; perfusion model; Polymers; Polyvinyl Chloride - chemistry; shunt infection; Silicones - chemistry; Staphylococcus - cytology; Staphylococcus epidermidis; surface heparinization; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Thermodynamics
• ISSN: 0021-9304; 1097-4636
• DOI: 10.1002/(SICI)1097-4636(199721)38:1<35::AID-JBM5>3.0.CO;2-I

Infections of cerebrospinal fluid (CSF) shunts constitute a serious clinical problem. The role of adhesion by coagulase negative staphylococci, the most common etiological agent, was examined in vitro to polyvinyl chloride (PVC), silicone, and to PVC and silicone with end‐point attached (EPA) heparin. These are flexible materials commonly used in neurosurgical implants. Bacterial adhesion was quantitated by bioluminescence. The bacterial adhesion to biomaterial surfaces increased with increasing concentrations of bacterial cells. Scatchard plot analysis showed continuous negative (concave) slopes, indicating multiple interactions between biomaterial and bacteria. The thermodynamic studies showed a positive value of the standard entropy change at 37°C, which indicates that hydrophobic interactions are important in bacterial adhesion to polymers. Incubation with CSF for 1 h decreased bacterial adhesion in 75% of the samples compared to incubation in buffer. Thus, the contribution of CSF proteins, like fibronectin, for the initial bacterial adhesion might be small. Heparinization of silicone and PVC decreased the numbers of adhered bacteria by 23 to 54% and 0 to 43% compared to unheparinized surfaces. Among putative inhibitors tested, suramin, chondroitin sulfate, and fucoidan inhibited adhesion to 81 ± 19, 78 ± 22, and 64 ± 7%, respectively. These findings indicate that hydrophobic interactions play an important role, and heparinization rendering the biomaterial surface hydrophilic is therefore effective to reduce bacterial adhesion. Heparinized polymers incubated with putative inhibitors may be the optimal way to prevent shunt infections. © 1997 John Wiley & Sons, Inc. J Biomed Mater Res (Appl Biomater) 38: 35–42, 1997