Diagnosis of spacer-associated infection using quantitative cultures from sonicated antibiotics-loaded spacers: implications for the clinical outcome.

Recent studies showed that a positive microbiological result from sonication of the PMMA spacer was associated with poor outcome of patients, but no quantitative analysis has yet been performed. For this purpose, a prospective analysis of 50 spacers (46 patients) was performed. All spacers were processed according to a previously described protocol, including centrifugation and quantitative culture. Clinical data and outcome were also analysed. A statistical relationship between the results of the cultures and the outcome of the patient was assessed. Sixteen patients were diagnosed with spacer-associated infection. Thirteen out of 50 spacers gave a positive culture. Nine of 13 presented with growth of an organism not isolated in the first-stage cultures, and in 7 out of 13 the organisms count was high (>10,000 CFU/ml). We have detected a significant statistical relationship between poor outcome and positive cultures, high colony counts, isolation of different organisms, positive periprosthetic cultures and spacer-associated infection. The detection in a sonicated, antibiotic-loaded PMMA spacer of organisms other than those isolated in the first surgical samples or high colony counts of any organisms is diagnostic with regard to spacer-associated infection.

Prolonged incubation time does not increase sensitivity for the diagnosis of implant-related infection using samples prepared by sonication of the implants.

We have designed a prospective study to evaluate the usefulness of prolonged incubation of cultures from sonicated orthopaedic implants. During the study period 124 implants from 113 patients were processed (22 osteosynthetic implants, 46 hip prostheses, 54 knee prostheses, and two shoulder prostheses). Of these, 70 patients had clinical infection; 32 had received antibiotics at least seven days before removal of the implant. A total of 54 patients had sonicated samples that produced positive cultures (including four patients without infection). All of them were positive in the first seven days of incubation. No differences were found regarding previous antibiotic treatment when analysing colony counts or days of incubation in the case of a positive result. In our experience, extending incubation of the samples to 14 days does not add more positive results for sonicated orthopaedic implants (hip and knee prosthesis and osteosynthesis implants) compared with a conventional seven-day incubation period.

[Treatment of deep vein thrombosis with low molecular weight heparins at home]. / Tratamiento en domicilio de trombosis venosa profunda con heparinas de bajo peso molecular. Experiencia de un año.

Treatment of patients with proximal vein thrombosis with low molecular weight heparins is effective and safe. So it allows "hospital at home" care. Among low molecular weight heparins tinzaparin is given once daily, making the compliance easier. The twenty patients with deep vein thrombosis who were assisted in the "hospital at home" unit of the Clínica Nuestra Señora de la Concepción in Madrid from December 1999 to December 2000. The mean of age was 71 + 15. The most frequent risk factors were surgery in past three months (19%), known tumour (15%) and previous venous thrombosis (15%). Eighteen patients were treated with tinzaparin. No patients showed adverse effects nor complications. Low molecular weight heparins, specially tinzaparin, are a safe and effective treatment for deep vein thrombosis in our unit.

Tratamiento en domicilio de trombosis venosa profunda con heparinas de bajo peso molecular. Experiencia de un año / Treatment of deep vein thrombosis with low molecular weight heparins at home. One year experience

La eficacia y seguridad de las heparinas de bajo peso molecular permiten que los pacientes con trombosis venosa profunda puedan tratarse en unidades de hospitalización a domicilio. Entre las heparinas de bajo peso molecular, la tinzaparina se administra en dosis única diaria facilitando el cumplimiento terapéutico. Se revisan los veinte pacientes diagnosticados de trombosis venosa profunda ingresados en la unidad de hospitalización a domicilio de la Clínica de Nuestra Señora de la Concepción de Madrid entre diciembre de 1999 y diciembre de 2000. La edad media de los pacientes fue de 71 + 15. Los factores de riesgo más frecuentes fueron cirugía en los tres meses previos (19 por ciento), presencia de tumores (15 por ciento) y trombosis previa (15 por ciento).Dieciocho pacientes recibieron tratamiento con tinzaparina. Ninguno presentó complicaciones ni efectos adversos. El tratamiento con heparinas de bajo peso molecular y en particular con tinzaparina, es un tratamiento seguro y eficaz para la trombosis venosa profunda en nuestra unidad (AU)

A 4-trifluoromethyl derivative of salicylate, triflusal, stimulates nitric oxide production by human neutrophils: role in platelet function.

BACKGROUND: The thrombotic process is a multicellular phenomenon in which not only platelets but also neutrophils are involved. Recent in vitro studies performed in our laboratory have demonstrated that triflusal, a 4-trifluoromethyl derivative of salicylate, reduced platelet aggregation not only by inhibiting thromboxane A2 production but also by stimulating nitric oxide (NO) generation by neutrophils. The aim of the present study was to evaluate whether oral treatment of healthy volunteers with triflusal could modify the ability of their neutrophils to produce NO and to test the role of the NO released by neutrophils in the modulation of ADP-induced platelet aggregation and alpha-granule secretion. METHODS: The study was performed in 12 healthy volunteers who were orally treated with triflusal (600 mg day-1) for 5 days. Flow cytometric detection of platelet surface expression of P-selectin was used as a measure of the ability of platelets to release the contents of their alpha-granules. RESULTS: After treatment with triflusal, there was an increase in NO production by neutrophils and an increase in endothelial nitric oxide synthase (eNOS) protein expression in neutrophils. A potentiation of the inhibition of platelet aggregation by neutrophils was reversed by incubating neutrophils with both an L-arginine antagonist, NG-nitro-L-arginine methyl ester (L-NAME) and an NO scavenger, 2-(4-carboxyphenyl)-4,4,5,5 tetramethylimidazoline 1-oxyl 3-oxide (C-PTIO). A slight decrease in P-selectin surface expression on platelets was found which was not modified by the presence of neutrophils and therefore by the neutrophil-derived NO. Exogenous NO released by sodium nitroprusside dose-dependently inhibited both ADP-stimulated alpha-granule secretion and platelet aggregation. Therefore, platelet aggregation showed a greater sensitivity to be inhibited by exogenous NO than P-selectin expression. CONCLUSION: Oral treatment of healthy volunteers with triflusal stimulated NO production and eNOS protein expression in their neutrophils. After triflusal treatment, the neutrophils demonstrated a higher ability to prevent ADP-induced platelet aggregation. However, the neutrophils and the endogenous NO generated by them failed to modify P-selectin expression in ADP-activated platelets.