Validation of a microwell DNA probe assay for detection of Listeria spp. in foods Performance-tested method 010403.

A new DNA hybridization assay in microwell format for detection of Listeria spp. in foods and environmental samples was developed. This assay uses Listeria-specific oligonucleotide probes labeled with horseradish peroxidase and a photometrically determined end point. Validation studies with 15 different food commodities and a variety of environmental sample types were conducted to compare the performance of this alternative test versus reference methods. Meats, seafood, dairy products, and vegetables comprised the categories of food tested. Food samples were inoculated at 2 levels and refrigerated or frozen for at least 72 h. Uninoculated (negative) control samples were included in each trial. Samples were enriched according to the procedure recommended by either the U.S. Food and Drug Administration (FDA) or the U.S. Department of Agriculture (USDA), Food Safety and Inspection Service (FSIS). Samples enriched for 24 h were transferred to Oxford agar plates and incubated for 24 h. The surface of the plates was then swabbed and any growth present was transferred to phosphate buffer solution for the performance of the DNA assay. A standard confirmation procedure was used to compare the number of positive samples obtained with the DNA method versus reference methods. Statistical analyses of the results indicate that the proposed alternative method performs equally to cultural reference methods. The DNA assay is able to detect as low as 1 colony-forming unit of Listeria in a 25 g food sample, with results available as early as 48 h after the start of sample enrichment.

Internal fixation of diaphyseal fractures of the forearm: a retrospective comparison of hybrid fixation versus dual plating.

OBJECTIVES: To compare open reduction and internal fixation using dual plating to a hybrid fixation construct with intramedullary nailing of the ulna and plate fixation of the radius in both-bone forearm fractures. DESIGN: Retrospective comparison study. SETTING: Level I trauma center. PATIENTS: A total of 56 skeletally mature individuals treated surgically for acute both-bone forearm fractures between July 2005 and December 2009. Monteggia, Galeazzi, and pathologic fractures, patients treated with external fixation and patients with traumatic brain injuries were excluded. INTERVENTION: Twenty-seven patients were treated with dual plate fixation, and 29 patients were treated using a hybrid fixation construct. MAIN OUTCOME MEASURES: Time to union, range of motion as assessed using a Grace and Eversmann score, and presence of complications. RESULTS: There was no significant difference in either time to union or Grace and Eversmann scores between the 2 groups. There was 1 nonunion in each of the 2 groups. Nine overall complications, outside nonunions, were reported: 5 in the dual plating group and 4 in the hybrid fixation group. CONCLUSIONS: Hybrid fixation, using open reduction and internal fixation with a plate-and-screw construct on the radius and closed--or minimally open--reduction and interlocked intramedullary fixation of the ulna, is an acceptable method for treating both-bone diaphyseal forearm fractures in skeletally mature patients. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Late presentation of a mycotic popliteal artery pseudoaneurysm in the setting of a revised total knee arthroplasty complicated by both prior infection and periprosthetic fracture: a case report.

Reports of adverse arterial events associated with total knee arthroplasty (TKA), such as ischemia, thrombosis, arterial injury, or pseudoaneurysm, are relatively rare in the orthopedic and vascular literature and are most commonly associated with direct trauma to the vessel. Additionally, arterial complications typically present within a short postoperative time frame. A delayed presentation of a mycotic arterial pseudoaneurysm in the setting of a revision arthroplasty complicated by infection and fracture has not, to the best knowledge of the authors, been described in the literature. We report the delayed presentation of a mycotic pseudoaneurysm in the setting of a revision TKA previously complicated by both infection and periprosthetic fracture. One year after fracture repair, the patient presented with acute thigh swelling and was diagnosed with a mycotic pseudoaneurysm of the right proximal popliteal artery. He was treated with surgical excision, reverse saphenous vein interpositional grafting, and a long-term course of broad-spectrum antibiotics. In the setting of a revision TKA and previous complications, the risk of future complications is increased and may not always involve direct vascular trauma. In patients with previously infected joints and new-onset vascular events, mycotic pseudoaneurysm must be included in the differential diagnosis.