Aim. metagenomic
Aim. Surgical management of PJI remains challenging with patients failing treatment despite the best efforts. An important question is whether these later failures reflect reinfection or the persistence of infection. Proponents of reinfection believe hosts are vulnerable to developing infection and new organisms emerge. The alternative hypothesis is that later failure is a result of an organism that was present in the joint but was not picked up by initial culture or was not a pathogen initially but became so under antibiotic pressure. This multicenter study explores the above dilemma. Utilizing
Aim. The clinical relevance of microbial DNA detected via
Despite recent advances in the diagnosis of periprosthetic joint infection(PJI), identifying the infecting organism continues to be a challenge, with up to a third of PJIs reported to have negative cultures. Current molecular techniques have thus far been unable to replace culture as the gold standard for isolation of the infecting pathogen. Next- generation sequencing(NGS) is a well-established technique for comprehensively sequencing the entire pathogen DNA in a given sample and has recently gained much attention in many fields of medicine. Our aim was to evaluate the ability of NGS in identifying the causative organism(s) in patients with PJI. After obtaining Institutional Review Board approval and informed consent for all study participants, samples were prospectively collected from 148 revision total joint arthroplasty procedures (83 knees, 65 hips). Synovial fluid, deep tissue and swabs were obtained at the time of surgery and shipped to the laboratory for NGS analysis (MicroGenDx). Deep tissue specimens were also sent to the institutional laboratory(Thomas Jefferson University Hospital) for culture. PJI was diagnosed using the Musculoskeletal Infection Society(MSIS) definition of PJI. Statistical analysis was performed using SPSS software.Introduction
Methods
Recent reports demonstrate that Next Generation Sequencing (NGS) facilitates pathogen identification in the context of culture-negative PJI; however the clinical relevance of the polymicrobial genomic signal often generated remains unknown. This study was conceived to explore: (1) the ability of NGS to identify pathogens in culture-negative PJI; and (2) determine whether organisms detected by NGS, as part of a prospective observational study, had any role in later failure of patients undergoing surgical treatment for PJI. In this prospective study samples were collected in 238 consecutive patients undergoing revision total hip and knee arthroplasties. Of these 83 patients (34.9%) had PJI, as determined using the Musculoskeletal Infection Society (MSIS) criteria, and of these 20 were culture-negative (CN-PJI). Synovial fluid, deep tissue and swabs were obtained at the time of surgery and sent for NGS and culture/MALDI-TOF. Patients undergoing reimplantation were excluded. Treatment failure was assessed using the previously described Delphi criteria. In cases of re-operation, organisms present were confirmed by culture and MALDI-TOF. Concordance of the infecting pathogen(s) at failure with the NGS analysis at the initial stage CN- PJI procedure was determined.Background
Methods
Periprosthetic joint infection is an increasing reason for revision surgery. Tissue cultures are a standard (std.) diagnostic procedure but may be hindered by bacteria that are difficult to cultivate. The use of dithiothreitol (DTT) to detach the formed biofilm has been proposed to improve the diagnostic security. The aim was to compare the diagnosis results using the microDTTect device with the routine PJI diagnostics and next generation sequencing (NGS) from DTT treated explants. 66 patients with revision surgeries were included in this study (38 aseptic; 28 septic). We compared std. microbiology tissue cultures with the microDTTect cultures of the DTT treated explants and NGS of bacterial DNA isolated from DTT solution.Aim
Method
Osteoarthritis is a global problem and the treatment of early disease is a clear area of unmet clinical need. Treatment strategies include cell therapies utilising chondrocytes e.g. autologous chondrocyte implantation and mesenchymal stem/stromal cells (MSCs) e.g. microfracture. The result of repair is often considered suboptimal as the goal of treatment is a more accurate regeneration of the tissue, hyaline cartilage, which requires a more detailed understanding of relevant biological signalling pathways. In this study, we describe a modulator of regulatory pathways common to both chondrocytes and MSCs. The chondrocytes thought to be cartilage progenitors are reported to reside in the superficial zone of articular cartilage and are considered to have the same developmental origin as MSCs present in the synovium. They are relevant to cartilage homeostasis and, like MSCs, are increasingly identified as candidates for joint repair and regenerative cell therapy. Both chondrocytes and MSCs can be regulated by the Wnt and TGFβ pathways. Dishevelled Binding Antagonist of Beta-Catenin (Dact) family of proteins is an important modulator of Wnt and TGFβ pathways. These pathways are key to MSC and chondrocyte function but, to our knowledge, the role of DACT protein has not been studied in these cells. DACT1 and DACT2 were localised by immunohistochemistry in the developing joints of mouse embryos and in adult human cartilage obtained from knee replacement. RNAi of DACT1 and DACT2 was performed on isolated chondrocytes and MSCs from human bone marrow. Knockdown efficiency and cell morphology was confirmed by qPCR and immunofluorescence. To understand which pathways are affected by DACT1, we performed