ABSTRACT
Three years into the coronavirus disease 2019 (COVID-19) pandemic, there are still growing concerns with the emergence of different variants, unknown long- and short-term effects of the virus, and potential biological mechanisms underlying etiopathogenesis and increased risk for morbidity and mortality. The role of the microbiome in human physiology and the initiation and progression of several oral and systemic diseases have been actively studied in the past decade. With the proof of viral transmission, carriage, and a potential role in etiopathogenesis, saliva and the oral environment have been a focus of COVID-19 research beyond diagnostic purposes. The oral environment hosts diverse microbial communities and contributes to human oral and systemic health. Several investigations have identified disruptions in the oral microbiome in COVID-19 patients. However, all these studies are cross-sectional in nature and present heterogeneity in study design, techniques, and analysis. Therefore, in this undertaking, we (a) systematically reviewed the current literature associating COVID-19 with changes in the microbiome; (b) performed a re-analysis of publicly available data as a means to standardize the analysis, and (c) reported alterations in the microbial characteristics in COVID-19 patients compared to negative controls. Overall, we identified that COVID-19 is associated with oral microbial dysbiosis with significant reduction in diversity. However, alterations in specific bacterial members differed across the study. Re-analysis from our pipeline shed light on Neisseria as the potential key microbial member associated with COVID-19.
ABSTRACT
BACKGROUND: Pseudomonas aeruginosa, a major respiratory pathogen, has been isolated from peri-implant sites and is associated with dental implant failure. This in-vitro study (part 1) aimed to fabricate a novel mucoadhesive silver nanoparticle-based local drug delivery chip, evaluate its antimicrobial efficacy against P. aeruginosa, and its safety for the treatment of peri-implantitis. MATERIALS AND METHODS: Silver nanoparticles were synthesized and characterized using a transmission electron microscope (TEM). The local drug delivery chip was fabricated using gelatin, glycerol, silver nanoparticle solution (2.5 µg/ml, 5 µg/ml, 7.5 µg/ml, and 10 µg/ml), glutaraldehyde, and sodium alginate solution. These chips were evaluated for physical parameters, effect on viability of murine macrophage cell line J774A.1, and antimicrobial activity (using Kirby-Bauer disc diffusion method with 18 h incubation period) against P. aeruginosa ATCC 27853. RESULTS: Silver nanoparticle antimicrobial chip exhibited dimensions of 4 mm × 5 mm x 0.4 mm, 5.8 mg weight, pH 5-6, folding endurance 1.04, and one-year stability. P. aeruginosa was susceptible to ≥ 7.5 µg/ml concentration of silver nanoparticles (spherical shape with particle size ranging from 10 to 100 nm). Murine macrophage cells exhibited 93% viability after 24 h incubation with silver nanoparticle chips. CONCLUSION: The novel silver nanoparticle chip showed dimensional stability, minimal effect on murine macrophage cell viability, and significant antimicrobial activity against P. aeruginosa. With the further establishment of its effective dosage and safety, this chip could be used as an adjunct to mechanical debridement (as a non-aerosol generating procedure) in treating peri-implantitis, especially during the ongoing coronavirus disease 2019 (COVID-19) pandemic.