Bone cells, namely osteoblasts and osteoclasts work in concert and are responsible for bone extracellular matrix formation and resorption. This homeostasis is, in part, altered during infections by Staphylococcus aureus through the induction of various responses from the osteoblasts. This includes the over-production of chemokines, cytokines and growth factors, thus suggesting a role for these cells in both innate and adaptive immunity. Staphylococcus aureus decreases the activity and viability of osteoblasts, by induction of apoptosis-dependent and independent mechanisms. The tight relationship between osteoclasts and osteoblasts is also modulated by Staphylococcus aureus infection. The present review provides a survey of the relevant literature discussing the important aspects of Staphylococcus aureus and osteoblast interaction as well as the ability for antimicrobial peptides to kill intra-osteoblastic Staphylococcus aureus, hence emphasizing the necessity for new anti-infectious therapeutics.

The need for bone and joint prostheses is currently growing due to population aging, leading to an increase in prosthetic joint infection cases. Biofilms represent an adaptive and quite common bacterial response to several stress factors which confer an important protection to bacteria. Biofilm formation starts with bacterial adhesion on a surface, such as an orthopedic prosthesis, further reinforced by matrix synthesis. The biofilm formation and structure depend on the immediate environment of the bacteria. In the case of infection, the periprosthetic joint environment represents a particular interface between bacteria, host cells, and the implant, favoring biofilm initiation and maturation. Treating such an infection represents a huge challenge because of the biofilm-specific high tolerance to antibiotics and its ability to evade the immune system. It is crucial to understand these mechanisms in order to find new and adapted strategies to prevent and eradicate implant-associated infections. Therefore, adapted models mimicking the infectious site are of utmost importance to recreate a relevant environment in order to test potential antibiofilm molecules. In periprosthetic joint infections, Staphylococcus aureus is mainly involved because of its high adaptation to the human physiology. The current review deals with the mechanisms involved in the antibiotic resistance and tolerance of Staphylococcus aureus in the particular periprosthetic joint infection context, and exposes different strategies to manage these infections.

In the healthcare environment, microorganisms’ cross-transmission between inanimate surfaces and patients or healthcare workers can lead to healthcare-associated infections. A recent interest has grown to create antimicrobial copper touch surfaces, in order to counteract microbial spread in the healthcare environment. For the first time, five French long-term care facilities were at 50% fitted with copper alloys door handles and handrails. Related to the environmental bacterial contamination, 1400 samples were carried out on copper and control surfaces over three years after copper installation. In addition, some copper door handles were taken from the different facilities, and their specific activity against methicillin-resistant S. aureus (MRSA) was tested in vitro. In comparison to control surfaces, copper door handles and handrails revealed significantly lower contamination levels. This difference was observed in the five long-term care facilities and it persists through the three years of the study. High and extreme levels of bacterial contamination were less frequent on copper surfaces. Although, the antibacterial activity of copper surfaces against MRSA was lowered after three years of regular use, it was still significant as compared to inert control surfaces. Therefore, copper containing surfaces are promising actors in the non-spreading of environmental bacterial contamination in healthcare facilities.

Common spruce (Picea abies L.) is a fast-growing coniferous tree, widely used in several countries for the production of sawn wood, timber and pulp. During this industrial exploitation, large quantities of barks are generated as waste materials. The aim of this study was the bio-guided investigation and the effective recovery of methanol-soluble metabolites of common spruce bark for the development of new dermo-cosmetic agents. The active methanol extract was initially fractionated by Centrifugal Partition Chromatography (CPC) using a triphasic solvent system in a step-gradient elution mode. All resulting fractions were evaluated for their antibacterial activity, antioxidant activity and their capability to inhibit tyrosinase, elastase and collagenase activity. In parallel, the chemical composition of each fraction was established by combining a ¹³C-NMR dereplication approach and 2D-NMR analyses. As a result, fourteen secondary metabolites corresponding to stilbene, flavonoid and phenolic acid derivatives were directly identified in the CPC fractions. A high amount (0.93 g) of E-astringin was recovered from 3 g of crude extract in a single 125 min run. E-Astringin significantly induced the tyrosinase activity while E-piceid, taxifolin, and taxifolin-3′-O-glucopyranoside exhibited significant anti-tyrosinase activity. The above compounds showed important anti-collagenase and antimicrobial activities, thus providing new perspectives for potential applications as cosmetic ingredients.

Brunot-Gohin C, et al. J Periodontal Implant Sci. 2016 Dec;46(6):362-371. https://doi.org/10.5051/jpis.2016.46.6.362