No abstract

Implant-related infections (IRIs) are a serious complication after orthopedic surgery, especially when a biofilm develops and establishes physical and chemical barriers protecting bacteria from antibiotics and the hosts local immune system. Effectively eliminating biofilms is essential but difficult, as it requires not only breaking the physical barrier but also changing the chemical barrier that induces an immunosuppressive microenvironment. Herein, tailored to a biofilm microenvironment (BME), we proposed a space-selective chemodynamic therapy (CDT) strategy to combat IRIs using metastable CuFe5O8 nanocubes (NCs) as smart Fenton-like reaction catalysts whose activity can be regulated by pH and H2O2 concentration. In the biofilm, extracellular DNA (eDNA) was cleaved by high levels of hydroxyl radicals (•OH) catalyzed by CuFe5O8 NCs, thereby disrupting the rigid biofilm. Outside the biofilm with relatively higher pH and lower H2O2 concentration, lower levels of generated •OH effectively reversed the immunosuppressive microenvironment by inducing pro-inflammatory macrophage polarization. Biofilm fragments and exposed bacteria were then persistently eliminated through the collaboration of pro-inflammatory immunity and •OH. The spatially selective activation of CDT and synergistic immunomodulation exerted excellent effects on the treatment of IRIs in vitro and in vivo. The anti-infection strategy is expected to provide a method to conquer IRIs.

Periprosthetic joint infection (PJI) is one of the formidable and recalcitrant complications after orthopedic surgery, and inhibiting biofilm formation on the implant surface is considered crucial to prophylaxis of PJI. However, it has recently been demonstrated that free-floating biofilm-like aggregates in the local body fluid and bacterial colonization on the implant and peri-implant tissues can coexist and are involved in the pathogenesis of PJI. An effective surface with both contact-killing and release-killing antimicrobial capabilities can potentially abate these concerns and minimize PJI caused by adherent/planktonic bacteria. Herein, Ag nanoparticles (NPs) are embedded in titania (TiO2) nanotubes by anodic oxidation and plasma immersion ion implantation (PIII) to form a contact-killing surface. Vancomycin is then incorporated into the nanotubes by vacuum extraction and lyophilization to produce the release-killing effect. A novel clinical PJI model system involving both in vitro and in vivo use of methicillin-resistant Staphylococcus aureus (MRSA) ST239 is established to systematically evaluate the antibacterial properties of the hybrid surface against planktonic and sessile bacteria. The vancomycin-loaded and Ag-implanted TiO2 nanotubular surface exhibits excellent antimicrobial and antibiofilm effects against planktonic/adherent bacteria without appreciable silver ion release. The fibroblasts/bacteria cocultures reveal that the surface can help fibroblasts to combat bacteria. We first utilize the nanoarchitecture of implant surface as a bridge between the inorganic bactericide (Ag NPs) and organic antibacterial agent (vancomycin) to achieve total victory in the battle of PJI. The combination of contact-killing and release-killing together with cell-assisting function also provides a novel and effective strategy to mitigate bacterial infection and biofilm formation on biomaterials and has large potential in orthopedic applications.

PURPOSE Current health care reforms in China have an overall goal of strengthening primary care through the establishment and expansion of primary care networks based on community health centers (CHCs). Implementation in urban areas has led to the emergence of different models of ownership and management. The objective of this study was to evaluate the primary care experiences of patients in the Pearl River Delta as measured by the Primary Care Assessment Tool (PCAT) and the relationships with ownership and management in the 3 different models we describe.METHODS This cross-sectional study was conducted on-site at CHCs in 3 cities within the Pearl River Delta, China, using a multistage cluster sampling method. A validated Mandarin Chinese version of the PCAT-Adult Edition (short version) was adopted to collect information from adult patients regarding their experiences with primary care sources. PCAT scores for individual primary care attributes and total primary care assessment scores were assessed with respect to sociodemographic characteristics, health characteristics, and health care service utilization across 3 primary care models. RESULTSOne thousand four hundred forty (1,440) primary care patients responded to the survey, for an overall response rate of 86.1%. Respondents gave government-owned and -managed CHCs the highest overall PCAT scores when compared with CHCs either managed by hospitals (95.18 vs 90.81; P = .005) or owned by private and social entities (95.18 vs 90.69; P = .007) as a result of better first-contact care (better first-contact utilization) and coordination of care (better service coordination and information system). Factors that were positively and significantly associated with higher overall assessment scores included the presence of a chronic condition (P <.001), having medical insurance (P = .006), and a self-reported good health status (P <.001).CONCLUSIONS This study suggests that government-owned and -managed CHCs may be able to provide better first-contact care in terms of utilization and coordination of care, and may be better at solving the problem of underutilization of the CHCs as the first-contact point of care, one key problem facing the reforms in China.