Sinonasal Stent Coated with Slow-Release Varnish of Chlorhexidine Has Sustained Protection against Bacterial Biofilm Growth in the Sinonasal Cavity: An In Vitro Study.

Alessandra Cataldo Russomando,Ron Eliashar,Menachem Gross,Michael Friedman,Ronit Vogt Sionov,Irith Gati,Doron Steinberg

doi:10.3390/pharmaceutics13111783

Alessandra Cataldo Russomando, Ron Eliashar + Show 5 more

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https://doi.org/10.3390/pharmaceutics13111783

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Abstract

The aim of the study was to develop a sustained-release varnish (SRV) containing chlorhexidine (CHX) for sinonasal stents (SNS) to reduce bacterial growth and biofilm formation in the sinonasal cavity. Segments of SNS were coated with SRV-CHX or SRV-placebo and exposed daily to bacterial cultures of Staphylococcus aureus subsp. aureus ATCC 25923 or Pseudomonas aeruginosa ATCC HER-1018 (PAO1). Anti-bacterial effects were assessed by disc diffusion assay and planktonic-based activity assay. Biofilm formation on the coated stents was visualized by confocal laser scanning microscopy (CLSM) and high-resolution scanning electron microscopy (HR-SEM). The metabolic activity of the biofilms was determined using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) method. Disc diffusion assay showed that SRV-CHX-coated SNS segments inhibited bacterial growth of S. aureus subsp. aureus ATCC 25923 for 26 days and P. aeruginosa ATCC HER-1018 for 19 days. CHX was released from coated SNS segments in a pH 6 medium up to 30 days, resulting in growth inhibition of S. aureus subsp. aureus ATCC 25923 for 22 days and P. aeruginosa ATCC HER-1018 for 24 days. The MTT assay showed a reduction of biofilm growth on the coated SNS by 69% for S. aureus subsp. aureus ATCC 25923 and 40% for P. aeruginosa ATCC HER-1018 compared to the placebo stent after repeated exposure to planktonic growing bacteria. CLSM and HR-SEM showed a significant reduction of biofilm formation on the SRV-CHX-coated SNS segments. Coating of SNS with SRV-CHX maintains a sustained delivery of CHX, providing an inhibitory effect on the bacterial growth of S. aureus subsp. aureus ATCC 25923 and P. aeruginosa ATCC HER-1018 for approximately 3 weeks.

Highlights

The present study aimed to evaluate the antibacterial and anti-biofilm effects of a sustained release medicated varnish on sinonasal stents using the two pathogens S. aureus subsp. aureus ATCC 25923 and P. aeruginosa ATCC
Anti-bacterial and anti-biofilm effects of SNS coated with slow-release varnish (SRV)-CHX in comparison to SRV-placebo were tested on S. aureus subsp. aureus ATCC 25923 and P. aeruginosa ATCC HER-1018 using agar diffusion assay, planktonic growth, confocal laser scanning microscopy (CLSM), high-resolution scanning electron microscopy (HR-SEM), and metabolic assay
One of the limitations of this study is that we studied the anti-bacterial effect of SRV-CHX in an in vitro model using only two of the most common biofilm-related rhinosinusitis pathogens, while there are other pathogens involved in Chronic rhinosinusitis (CRS)

Summary

Introduction

Chronic rhinosinusitis (CRS) is a clinical manifestation of mucosal inflammation of the paranasal sinuses that has lasted more than 12 weeks, leading to several cardinal sinonasal symptoms including nasal congestion, nasal drainage, facial pain, and anosmia [1]. CRS is a significant health problem and affects 5–12% of the general population [1], with estimated total costs that exceed USD 30 billion per year in the USA, with USD 20 billion accounted for indirect costs primarily due to lost productivity in those suffering from rhinosinusitis [2]. Microbial biofilm formation in the sinonasal cavity plays a pathogenic role in 29 to 72% of the cases [3].

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