Combination of antibiotics with N-acetylcisteine and sub-MIC concentration of erythromycin was evaluated in two collection and 16 clinical strains of staphylococci isolated from PJI. The results were strain-dependent, so it evidences the necessity of perform individual studies of biofilm susceptibility. Staphylococci are the most common cause of prosthetic joint infections (PJI) (1), making the treatment of this disease difficult due to the increased resistance to antibiotics of biofilms. Combination between antibiotics and other compounds could be a good alternative. The aim of this study was to evaluate the effect of the combination of two compounds with nine antibiotics in biofilms formed by staphylococcal strains isolated from PJI.Summary Statement
Objectives
A study to evaluate biofilm development on different coatings of UHMWPE was performed. We observed a species-specific effect, with Prosthetic joint infection is intimately related to bacterial biofilms on implant biomaterials. Recently, diamond-like carbon (DLC) coating has been suggested to improve the antibacterial performance of medical grade GUR1050 ultra high molecular weight polyethylene (UHMWPE) supplied by Orthoplastics bacup, UK versus collection and clinical staphylococcal strains. The aim of this study was to make an approximation towards the actual impact of such coatings in biofilm formation.Summary Statement
Introduction
Prosthetic joint related-infections (PJRI) are severe complications in orthopaedic surgery. 35 staphylococcal strains INTRODUCTION
MATERIAL AND METHODS
Biofilm development is a major factor in the pathogenesis of implant-related infections. However, there are only a low number of studies that analyses the ability of clinical isolates of bacteria to develop biofilm in vitro. Here we study biofilm development in several strains of Staphylococcus aureus and Coagulase-negative Staphylococcus (CNS) consecutively isolated from retrieved orthopaedic implants from patients diagnosed of implant-related infections. We have evaluated in vitro biofilm development using the crystal violet technique in microtiter plates. Biofilm development was confirmed by visual microscopy and Confocal Laser Scanning Microscopy. Staphylococcal strains were isolated from implant-related infections by sonication of retrieved prosthesis as previously published by our group, and identified using conventional methods. Twenty-seven strains (15 S. aureus, nine S. epidermidis, and one each of S. hominis, S. lugdunensis and S. warneri) were included in the study. Four strains of S. aureus (26.7 %) and one strain of S. epidermidis (8.3 %) did not develop biofilm in the test, showing OD lectures almost identical to the negative control. No statistical differences were detected between the two groups. The microscopic examination confirms this finding. Among the biofilm-producing strains, an important difference of the amount of biofilm produced was detected. One strain (S. aureus) produced biofilm in greater amount than all other strains, detectable even by visual examination of the plate. In conclusion, not all staphylococcal strains isolated from implant-related infections are able to develop biofilm in vitro. There must be other pathogenic factors that are important in the pathogenesis of implant-related infections and need to be studied in order to develop a better strategy for treat these infections.
