Multiple displacement amplification as an adjunct to PCR-based detection of Staphylococcus aureus in synovial fluid

<p>Abstract</p> <p>Background</p> <p>Detection of bacterial nucleic acids in synovial fluid following total joint arthroplasty with suspected infection can be difficult; among other technical challenges, inhibitors in the specimens require extensive sample preparation and can diminish assay sensitivity even using polymerase chain reaction (PCR)-based methods. To address this problem a simple protocol for prior use of multiple displacement amplification (MDA) as an adjunct to PCR was established and tested on both purified <it>S. aureus </it>DNA as well as on clinical samples known to contain <it>S. aureus </it>nucleic acids.</p> <p>Findings</p> <p>A single round of MDA on purified nucleic acids resulted in a > 300 thousand-fold increase in template DNA on subsequent quantitative PCR (qPCR) analysis. MDA use on clinical samples resulted in at least a 100-fold increase in sensitivity on subsequent qPCR and required no sample preparation other than a simple alkali/heat lysis step. Mixed samples of <it>S. aureus </it>DNA with a 10³- 10⁴-fold excess of human genomic DNA still allowed for MDA amplification of the minor bacterial component to the threshold of detectability.</p> <p>Conclusion</p> <p>MDA is a promising technique that may serve to significantly enhance the sensitivity of molecular assays in cases of suspected joint infection while simultaneously reducing the specimen handling required.</p

Distal tibia fractures: management and complications of 101 cases

Distal tibia fractures are complex injuries with a high complication rate. In this retrospective and multicentre study we attempted to detail complications and outcomes of this type of injury in order to determine predictive factors of poor results. Between 2002 and 2004, 104 patients were admitted for 105 distal tibia fractures. One hundred patients (101 fractures) were reviewed with an average follow-up of 19 months (range, 12–46). Internal fixation, external fixation, limited internal fixation (K-wires or screws), intramedullary nailing and conservative treatment were used. Outcome parameters included occurrence of complications, radiographic analysis, evaluation of the American Orthopaedic Foot and Ankle Society (AOFAS) ankle score and measures of the ankle range of motion. The average functional score was 76 points (range, 30–100 points), and complications occurred in 30 patients. Predictive factors of poor results were fracture severity, complications, malunion and the use of external fixation. We believe that external fixation must be reserved for trauma with severe skin injury, as a temporary solution in a two-staged protocol. For other cases, we recommend ORIF with early mobilisation