Objective Chronic, persistent infections complicate otologic procedures utilizing implantable devices such as cochlear implants or tympanostomy tubes. These infections are thought to be due to the establishment of microbial biofilms on implant surfaces. To address this issue, we hypothesized that surface charge modification may inhibit the formation of Pseudomonas aeruginosa biofilms on implant surfaces in vitro and in vivo. Study Design We evaluated the effect of surface charge modification on bacterial biofilm formation by assessing the effect of the surface charge on bacterial adhesion in vitro and bacterial persistence in vivo. Methods To study the effect of surface charge in vitro, the surface wells in culture plates were modified using a layer-by-layer polyelectrolyte assembly method. Bacterial adherence was measured at 30, 60 and 120-minute intervals. To study the effect of surface charge modification in vivo, the surface of titanium micro-screws was similarly modified and then surgically implanted into the dorsal calvaria of adult rats and inoculated with bacteria. Two weeks after implantation and inoculation, the number of bacteria remaining in vivo was evaluated. Results Surface charge modification results in a significant decrease in adherence of bacteria in vitro. Surface charge modification of titanium micro-screw implants also resulted in a significant decrease in P. aeruginosa recovered two weeks after surgical implantation. Conclusion Charge modification decreases the number of bacteria adherent to a surface in vitro and also decreases the risk and severity of implant infection in an in vivo rat infection model. These results have promising biomedical applications.

Objectives: Sialolithiasis is the primary etiology for parotid and submandibular swelling, potentially resulting in discomfort, bacterial infections, and hospitalization. The etiology of sialolith formation is unknown. Currently, the proposed etiologies range from inflammation, coalescence of organic molecules, sialomicrolith formation, pH changes, and biofilm formation. In this study, we performed a descriptive analysis of images obtained through electron microscopy of sialoliths. Based on our findings and descriptive analysis, we hypothesize that sialolith formation is likely multifactorial and begins with biofilm formation. Biofilm formation then triggers a host immune response, and it is the interaction of biofilm with host immune cells and calcium nanoparticles that forms the nidus and creates a favorable environment for calcium precipitation.Methods: Sialoliths were extracted from patients and imaged under light and scanning electron microscopy. Specimens for light microscopy were prepared using a diamond saw. Specimens for electron microscopy were freeze-fractured, thus providing an undisturbed view of the core of the sialolith.Results: We were able to identify clear evidence of biofilm caves at the core of each sialolith. These biofilm caves were complex with the presence of bacteria and dehydrated extrapolysaccharide matrix, host cells (immune cells, platelets and erythrocytes), and calcium nanoparticles.Conclusion: The etiology of sialolith formation is likely multifactorial. We propose that biofilm formation within a single salivary gland or duct leads to local ductal injury, which results in the influx of host immune cells that interact with the biofilm and calcium nanoparticles, creating a scaffold upon which further calcium deposition can occur.

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There is a lack of reporting effect sizes and confidence intervals in the current biomedical literature. The objective of this article is to present a discussion of the recent paradigm shift encouraging the use of reporting effect sizes and confidence intervals. Although P values help to inform us about whether an effect exists due to chance, effect sizes inform us about the magnitude of the effect (clinical significance), and confidence intervals inform us about the range of plausible estimates for the general population mean (precision). Reporting effect sizes and confidence intervals is a necessary addition to the biomedical literature, and these concepts are reviewed in this article.

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