Bioelectric Silver-Zinc Dressing Equally Effective to Chlorhexidine in Reducing Skin Bacterial Load in Healthy Volunteers.

PURPOSE: The aim of the present study was to evaluate and compare the effectiveness of the silver-zinc bioelectric dressing as compared with skin preparation with 2% chlorhexidine or 4% chlorhexidine in reducing the bacterial count on the knee. METHODS: Three groups consisting of 48 healthy volunteers were included. Age range was 23 to 54 years old and 60% of participants were male. Each subject had 1 knee serve as the test and the contralateral as the control. The test site was prepared with either 2% chlorhexidine, 4% chlorhexidine, or a silver-zinc bioelectric dressing and after 24 hours skin cultures were taken and examined for bacterial growth. RESULTS: In the 2% chlorhexidine group 23 of 48 unprepped knees had positive cultures, compared with 9 of 48 prepped knees (P = .003; risk reduction, 4.0 times). In the 4% chlorhexidine group 25 of 48 unprepped knees had positive cultures, compared with 14 of 48 prepped knees (P = .027; risk reduction, 2.6 times). In the silver-zinc bioelectric dressing group 29 of 48 unprepped knees had positive cultures, compared with 7 of 48 prepped knees (P < .001; risk reduction, 8.9 times). There was no difference in the positive skin culture rate between the 3 methods. CONCLUSIONS: Application of the silver-zinc bioelectric dressing was equally effective at reducing skin bacterial load when compared with skin preparation with 2% chlorhexidine or 4% chlorhexidine in healthy volunteers. LEVEL OF EVIDENCE: Basic Science - Microbiology. CLINICAL RELEVANCE: The findings of this study indicate that the use of a bioelectric dressing after knee surgery can match the standard of care of preparing the skin with an antiseptic before surgery.

Differential regulation of primitive myelopoiesis in the zebrafish by Spi-1/Pu.1 and C/ebp1.

The zebrafish has become a powerful tool for analysis of vertebrate hematopoiesis. Zebrafish, unlike mammals, have a robust primitive myeloid pathway that generates both granulocytes and macrophages. It is not clear how this unique primitive myeloid pathway relates to mammalian definitive hematopoiesis. In this study, we show that the two myeloid subsets can be distinguished using RNA in situ hybridization. Using a morpholino-antisense gene knockdown approach, we have characterized the hematopoietic defects resulting from knockdown of the myeloid transcription factor gene pu.1 and the unique zebrafish gene c/ebp1. Severe reduction of pu.1 resulted in complete loss of primitive macrophage development, with effects on granulocyte development only with maximal knockdown. Reduction of c/ebp1 did not ablate initial macrophage or granulocyte development, but resulted in loss of expression of the secondary granule gene lys C. These data reveal strong functional conservation of pu.1 between zebrafish primitive myelopoiesis and mammalian definitive myelopoiesis. Further, these results are consistent with a conserved role between c/ebp1 and mammalian C/EBPE, whose ortholog in zebrafish has not been identified. These studies validate the examination of zebrafish primitive myeloid development as a model for human myelopoiesis, and form a framework for identification and analysis of myeloid mutants.