Human serum potentiates the expression of genes associated with antifungal drug resistance in C. albicans biofilms on central venous catheters.

Candida albicans is a major agent of fungaemias and frequently causes systemic disease through seeded, blood stream dissemination. These infections, particularly common in hospitalized patients with central venous catheters (CVCs), appear to persevere due to biofilm reservoirs of the yeast that tend to develop on the device. Although it is known that candidal biofilms are intrinsically resistant to antifungals compared with their planktonic counterparts, there is a paucity of data on the expression of antifungal drug resistance genes (DRGs) in candidal biofilms in CVC reservoirs. Furthermore, notwithstanding the fact that CVCs are constantly bathed in human serum, there are no studies on the effect of the latter on the DRG expression in candidal biofilms. Hence, we developed in vitro biofilms of three different C. albicans strains on silicone CVC discs immersed in human serum and evaluated the temporal expression of nine antifungal DRGs. In an attempt to evaluate the effect of hyphal elements on DRG expression, we incorporated a hyphal mutant (HM) and its wild-type (WT) counterpart, as well as a fresh clinical isolate in the studies. Human serum significantly up-regulated DRG transcripts in Candida biofilms on CVCs, at different stages of biofilm growth, while the WT strain over-expressed more DRGs than the HM strain. Here, we report, for the first time, that both human serum and the hyphal elements of the yeast have a profound modulatory effect on DRG expression in C. albicans biofilms on CVCs.

Influence of smoking on clinical parameters and gingival crevicular fluid volume in patients with chronic periodontitis.

BACKGROUND: Tobacco smoking is regarded as one of the most significant risk factors for the development and progression of periodontal disease. In particular, studies have shown an alteration in Gingival Crevicular Fluid (GCF) volume and its components in smokers. OBJECTIVE: The purpose of this study was to compare the GCF volume in smoking and non-smoking Saudi subjects with chronic periodontitis. METHODS: In this study, 30 smoking patients and 30 non-smoking patients with chronic periodontitis were enrolled. Periodontal Probing Depth (PPD), Clinical Attachment Level (CAL), Plaque Index (PI), and Bleeding on Probing (BOP) were measured to assess the pattern of periodontal destruction for each patient at six sites in selected teeth. Gingival inflammation was registered at six sites, where Gingival Crevicular Fluid (GCF) was also collected. The GCF volume was measured with a Periotron 8000®. Comparisons were made between smoking and non-smoking groups with periodontitis. RESULTS: Smokers demonstrated significantly deeper periodontal pockets (4.64±0.30 mm) than non-smokers (4.24±0.38 mm). Smoking subjects also presented significantly greater attachment loss (3.08±0.28 mm) than non-smoking subjects (2.74±0.42 mm), whereas the GCF volume was found to be significantly lower in smokers (0.25±0.04 µl) than in non-smokers (0.31±0.05 µl) (P<0.01). Among smoking subjects, lingual sites showed reduced GCF levels compared to facial sites (0.22±0.03 µl vs. 0.25±0.03 µl). CONCLUSION: Smoking appears to have considerable adverse effects on the inflammatory process, thereby promoting the progression of periodontal disease in smokers. CLINICAL SIGNIFICANCE: The adverse effect of smoking on the initiation and progression of periodontal disease is highlighted in this study. In particular, estimation of the GCF volume may serve as an indicator to assess the severity as well as the prognosis of periodontitis in smokers.