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Background: The goal of this pilot study was to design an external quality assessment (EQA) scheme for German cystic fibrosis (CF) clinical microbiology laboratories. Therefore, a multicentre-study of 18 German CF laboratories was performed to evaluate their proficiency in analysing CF respiratory secretions. Methods:Simulated clinical specimens containing a set of four frequent CF pathogens, namely two Pseudomonas aeruginosa strains differing in morphotype (mucoid versus non-mucoid) and resistotype, one Staphyloccocus aureus strain and one Burkholderia multivorans strain, were distributed to each laboratory. Isolation, identification and antimicrobial susceptibility testing (AST) of any bacterial pathogen present and completion of a questionnaire about applied microbiological protocols were requested.Results: Three of four strains were isolated and identified correctly by almost all laboratories. B. multivorans was once misidentified as B. cenocepacia. Fourteen laboratories failed to detect the second multidrug resistant P. aeruginosa isolate. AST errors occured most often for P. aeruginosa 2 followed by B. cepacia complex, P. aeruginosa 1 and S. aureus.Evaluation of the questionnaires revealed major differences in cultivation and identification techniques applied by the participating laboratories. Conclusions:A periodical EQA programme for German CF laboratories and standardized microbiological procedures seem to be necessary to advance diagnostic microbiology employed on CF respiratory tract specimens and may help to improve antiinfective treatment and infection control practices for CF patients.3

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The goal of this study was to examine the microarchitecture of the trabecular bone of the canine femoral head using microcomputed tomography (micro-CT) technology. Specifically, we assessed changes seen in the femoral head in dogs with Legg-Calvé-Perthes disease and compared this with changes seen in dogs with hip dysplasia and coxofemoral luxation. Femoral heads from healthy animals were examined as a control. In total, 38 femoral heads were studied. Rules for defining spherical volumes (region of interest) for determination of the structural parameters within the trabecular structure were established using micro-CT images. The following parameters were determined directly in three dimensions: bone volume fraction, surface volume fraction, trabecula thickness, trabecular count, trabecular spacing, and connectivity. Characteristic femoral head changes were found for each condition. An unexpected result was found that contradicts the prevailing understanding of Legg-Calvé-Perthes disease. Instead of observing a thickening of the bone trabeculae caused by layering of new bone matrix on top of necrotic trabeculae, we observed an increase in trabecular count and a smaller trabecular thickness. From this it may be concluded that trabecular regeneration is more prominent or prevails over the characteristically described layering processes in the revascularization and repair processes occurring in this illness.

The present study showed that TSF is a viable solution to correct severe foot deformities but we believe a surgeon should be aware of the possible complications.