2014 Volume No 28 – pages 39-50
|
Title: Influence of physico-chemical material characteristics on staphylococcal biofilm formation – A qualitative and quantitative in vitro analysis of five different calcium phosphate bone grafts |
Author: M Clauss, U Furustrand Tafin, B Betrisey, N van Garderen, A Trampuz, T Ilchmann, M Bohner |
|
Address: Kantonsspital Baselland Liestal, Clinic for Orthopaedics and Trauma Surgery, Rheinstrasse 26, CH-4410 Liestal, Switzerland |
|
E-mail: martin.clauss at ksbl.ch |
|
Key Words: Biofilm, calcium phosphate, β-TCP, S. aureus ATCC 29213, S. epidermidis RP62A ATCC 35984, microcalorimetry, sonication, bone graft. |
|
Publication date: July 18th 2014 |
|
Abstract: Various compositions of synthetic calcium phosphates (CaP) have been proposed and their use has considerably increased over the past decades. Besides differences in physico-chemical properties, resorption and osseointegration, artificial CaP bone graft might differ in their resistance against biofilm formation. We investigated standardised cylinders of 5 different CaP bone grafts (cyclOS, chronOS (both β-TCP (tricalcium phosphate)), dicalcium phosphate (DCP), calcium-deficient hydroxyapatite (CDHA) and α-TCP). Various physico-chemical characterisations e.g., geometrical density, porosity, and specific surface area were investigated. Biofilm formation was carried out in tryptic soy broth (TSB) and human serum (SE) using Staphylococcus aureus (ATCC 29213) and S. epidermidis RP62A (ATCC 35984). The amount of biofilm was analysed by an established protocol using sonication and microcalorimetry. Physico-chemical characterisation showed marked differences concerning macro- and micropore size, specific surface area and porosity accessible to bacteria between the 5 scaffolds. Biofilm formation was found on all scaffolds and was comparable for α-TCP, chronOS, CDHA and DCP at corresponding time points when the scaffolds were incubated with the same germ and/or growth media, but much lower for cyclOS. This is peculiar because cyclOS had an intermediate porosity, mean pore size, specific surface area, and porosity accessible to bacteria. Our results suggest that biofilm formation is not influenced by a single physico-chemical parameter alone but is a multi-step process influenced by several factors in parallel. Transfer from in vitro data to clinical situations is difficult; thus, advocating the use of cyclOS scaffolds over the four other CaP bone grafts in clinical situations with a high risk of infection cannot be clearly supported based on our data. |
|
Article download: Pages
39-50 (PDF file) |
|