Methods for Removing Bacterial Biofilms: In Vitro Study using Clinical Chronic Rhinosinusitis Specimens

Nanotechnology-enabled topical delivery of therapeutics in chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a chronic inflammatory disease of the paranasal sinuses which represents a significant health burden due to its widespread prevalence and impact on patients' quality of life. As the molecular pathways driving and sustaining inflammation in CRS become better elucidated, the diversity of treatment options is likely to widen significantly. Nanotechnology offers several tools to enhance the effectiveness of topical therapies, which has been limited by factors such as poor drug retention, mucosal permeation and adhesion, removal by epithelial efflux pumps and the inability to effectively penetrate biofilms. In this review, we highlight the successful application of nanomedicine in the field of CRS therapeutics, discuss current limitations and propose opportunities for future work.

Murine model for chronic rhinosinusitis: an interventional study

BACKGROUND

Chronic rhinosinusitis (CRS) is a complex inflammatory disease of the sinonasal tract. To understand this disease entity and develop targeted treatments, a reproducible animal model is paramount.

AIMS/OBJECTIVES

To optimize a murine model of eosinophilic CRS by establishing benchmark histological markers and validate its fidelity in evaluating intranasal treatments.

MATERIAL AND METHODS

Forty-five Balb/c mice were included in the 7-week protocol. Experimental animals (n = 20) were induced a CRS disease state upon receiving intraperitoneal sensitization with ovalbumin (OVA), followed by intranasal OVA with Aspergillus oryzae protease. Analysis of complete blood count with differential, peripheral blood smear, and histological markers from the nasal cavity mucosa were performed. CRS mice were additionally treated with intranasal saline (n = 5) or mometasone (n = 10) and compared with control groups of untreated CRS (n = 5) and healthy (n = 5) mice after week 7.

RESULTS

Histological analysis of experimental animal nasal mucosa revealed significantly higher levels of eosinophilic tissue infiltration/degranulation, hyaline droplets, Charcot-Leyden crystals, and respiratory epithelial thickness compared to healthy controls. Treatment with mometasone significantly reversed the histopathological changes observed in CRS mice.

CONCLUSION AND SIGNIFICANCE

This murine model induced substantial local eosinophilic inflammation within sinonasal mucosa, that was reversible with mometasone. This model may be used to evaluate the efficacy of therapeutics designed to target CRS.

Novel strategies for inhibition of bacterial biofilm in chronic rhinosinusitis

An important role has been recently reported for bacterial biofilm in the pathophysiology of chronic diseases, such as chronic rhinosinusitis (CRS). CRS, affecting sinonasal mucosa, is a persistent inflammatory condition with a high prevalence around the world. Although the exact pathological mechanism of this disease has not been elicited yet, biofilm formation is known to lead to a more significant symptom burden and major objective clinical indicators. The high prevalence of multidrug-resistant bacteria has severely restricted the application of antibiotics in recent years. Furthermore, systemic antibiotic therapy, on top of its insufficient concentration to eradicate bacteria in the sinonasal biofilm, often causes toxicity, antibiotic resistance, and an effect on the natural microbiota, in patients. Thus, coming up with alternative therapeutic options instead of systemic antibiotic therapy is emphasized in the treatment of bacterial biofilm in CRS patients. The use of topical antibiotic therapy and antibiotic eluting sinus stents that induce higher antibiotic concentration, and decrease side effects could be helpful. Besides, recent research recognized that various natural products, nitric oxide, and bacteriophage therapy, in addition to the hindered biofilm formation, could degrade the established bacterial biofilm. However, despite these improvements, new antibacterial agents and CRS biofilm interactions are complicated and need extensive research. Finally, most studies were performed in vitro, and more preclinical animal models and human studies are required to confirm the collected data. The present review is specifically discussing potential therapeutic strategies for the treatment of bacterial biofilm in CRS patients.

ZIF-8@s-EPS as a novel hydrophilic multifunctional biomaterial for efficient scale inhibition, antibacterial and antifouling in water treatment

The hydrophilic biomaterial was constructed based on the soluble extracellular polysaccharides (s-EPS) secreted by Bacillus megaterium and zeolitic imidazolate framework-8 (ZIF-8), namely ZIF-8@s-EPS, wrapped in s-EPS shell with ZIF-8 as the core. ZIF-8@s-EPS was used as a novel multifunctional biomaterial in water treatment for the first time. Unexpectedly, results showed ZIF-8@s-EPS with strong synergistic effect presented multifunctional performances including descaling, antifouling and antibacterial. Scale inhibition efficiency reached 98.63% for CaCO₃ and as high as 99.40% for CaSO₄ at concentration 20.00 mg/L. The synergy of s-EPS and ZIF-8 demonstrated effective antibacterial activity against Pseudomonas aeruginosa and inhibitory effect on biofilms, and result presented that ZIF-8@s-EPS could inhibit the growth of nearly 89.4% P. aeruginosa. Therefore, the obtained insights will shed light on the development of s-EPS modified biomaterials in water treatment.

Efficacy of common antiseptic solutions against clinically relevant microorganisms in biofilm

AIMS

Periprosthetic joint infections (PJIs) are among the most devastating complications after joint arthroplasty. There is limited evidence on the efficacy of different antiseptic solutions on reducing biofilm burden. The purpose of the present study was to test the efficacy of different antiseptic solutions against clinically relevant microorganisms in biofilm.

METHODS

We conducted an in vitro study examining the efficacy of several antiseptic solutions against clinically relevant microorganisms. We tested antiseptic irrigants against nascent (four-hour) and mature (three-day) single-species biofilm created in vitro using a drip-flow reactor model.

RESULTS

With regard to irrigant efficacy against biofilms, Povidone-iodine treatment resulted in greater reductions in nascent MRSA biofilms (logarithmic reduction (LR) = 3.12; p < 0.001) compared to other solutions. Bactisure treatment had the greatest reduction of mature Pseudomonas aeruginosa biofilms (LR = 1.94; p = 0.032) and a larger reduction than Vashe or Irrisept for mature Staphylococcus epidermidis biofilms (LR = 2.12; p = 0.025). Pooled data for all biofilms tested resulted in Bactisure and Povidone-iodine with significantly greater reductions compared to Vashe, Prontosan, and Irrisept solutions (p < 0.001).

CONCLUSION

Treatment failure in PJI is often due to failure to clear the biofilm; antiseptics are often used as an adjunct to biofilm clearance. We tested irrigants against clinically relevant microorganisms in biofilm in vitro and showed significant differences in efficacy among the different solutions. Further clinical outcome data is necessary to determine whether these solutions can impact PJI outcome in vivo. Cite this article: Bone Joint J 2021;103-B(5):908-915.

International consensus statement on allergy and rhinology: rhinosinusitis 2021

I.

EXECUTIVE SUMMARY

BACKGROUND: The 5 years since the publication of the first International Consensus Statement on Allergy and Rhinology: Rhinosinusitis (ICAR-RS) has witnessed foundational progress in our understanding and treatment of rhinologic disease. These advances are reflected within the more than 40 new topics covered within the ICAR-RS-2021 as well as updates to the original 140 topics. This executive summary consolidates the evidence-based findings of the document.

METHODS

ICAR-RS presents over 180 topics in the forms of evidence-based reviews with recommendations (EBRRs), evidence-based reviews, and literature reviews. The highest grade structured recommendations of the EBRR sections are summarized in this executive summary.

RESULTS

ICAR-RS-2021 covers 22 topics regarding the medical management of RS, which are grade A/B and are presented in the executive summary. Additionally, 4 topics regarding the surgical management of RS are grade A/B and are presented in the executive summary. Finally, a comprehensive evidence-based management algorithm is provided.

CONCLUSION

This ICAR-RS-2021 executive summary provides a compilation of the evidence-based recommendations for medical and surgical treatment of the most common forms of RS.

Current Perspective on Nasal Delivery Systems for Chronic Rhinosinusitis

Chronic rhinosinusitis is an upper respiratory disease during which topical drug treatment via the nasal cavity is the most actively utilized therapeutic strategy. In addition to steroids, antibiotics, and antifungal agents, which are widely used in clinical practice, research on novel topical agents to improve the bacterial biofilm or mucociliary clearance remains ongoing. Moreover, owing to the complex structure of the nasal cavity, the effects of nasal drug delivery vary depending on factors related to delivery fluid dynamics, including device, volume, and compounds. In this article, we review methods and compounds that have been applied to chronic rhinosinusitis management and introduce recent advances and future perspectives in nasal drug delivery for upper respiratory diseases.

Future topical medications in chronic rhinosinusitis

BACKGROUND

Research has progressed rapidly in recent decades to better understand the etiopathogenesis and management paradigms of chronic rhinosinusitis (CRS). Although oral antibiotics often mitigate symptoms in acute CRS exacerbations, eradication of polymicrobial biofilms and multidrug-resistant bacteria remains a challenge. The goal of this review is to summarize and discuss the potential and pitfalls of topical medications in the treatment of CRS.

METHODS

A related literature review was performed using PubMed and Scopus, with only the English database included.

RESULTS

The main therapies were selected and separated in sections. Details regarding future topical treatments of CRS were summarized and discussed.

CONCLUSION

The ease of access of the sinonasal mucosa positions CRS as a disease with high potential for local topical treatment. The ultimate adoption of topical agents will require continued expansion of our understanding of novel local targets in CRS as well as improved methods to deliver and retain the drug of interest at the site of activity.

Effect of Denture Cleansers on Cobalt-Chromium Alloy Surface: A Simulated Period of 5 Years' Use

PURPOSE

To compare the effect of solutions of effervescent tablets (ET), cetylpyridinium chloride (CPC), and experimental solutions of Ricinus communis on the surface of cobalt-chromium (Co-Cr) alloys.

MATERIALS AND METHODS

Fifty-five specimens of Co-Cr were prepared by the lost-wax casting method using circular patterns (∅12 × 3 mm). The specimens were randomly divided into 5 groups: deionized water (control); 2% R. communis; 10% R. communis; ET, and CPC. The surface roughness of specimens (n = 10) was evaluated before immersion (baseline), and at simulated times of ½, 1, 2, 3, 4, and 5 years, by laser confocal microscope (Sa, μm) and profilometer (Ra, μm). The surface topography and chemical composition (n = 1) was qualitatively analyzed with scanning electron microscopy (SEM), and energy dispersive X-ray spectrometry (EDS). Data were subjected to Kruskal-Wallis followed by Dunn tests, and Friedman followed by Wilcoxon tests (α = 0.05).

RESULTS

For Sa, there was no difference for the solution factor. For the time factor a significant difference was found with 2% R. communis solution among baseline and ½, 2, 3, and 5 years (p < 0.001) and with 10% R. communis solution between 1 and 2 years (p = 0.007), with decreasing roughness over time. For Ra, cetylpyridinium chloride exhibited less roughness than 10% R. communis solution in ½ (p = 0.048) and 5 years (p = 0.013). In the SEM and EDS analysis the solutions did not present deleterious effects or changes in the chemical composition on the surfaces.

CONCLUSIONS

Although a significant difference was found for the roughness, the results, below 0.2 μm, are clinically acceptable. Thus, all solutions can be used safely in removable partial denture cleaning for a period of 5 years.

Chronic rhinosinusitis: Endotypes, biomarkers, and treatment response

It is increasingly recognized that chronic rhinosinusitis (CRS) comprises a spectrum of different diseases with distinct clinical presentations and pathogenic mechanisms. Defining the distinct phenotypes and endotypes of CRS affects prognosis and, most importantly, is necessary as the basis for making therapeutic decisions. The need for individualized definitions of pathogenic mechanisms before initiating therapy extends to virtually all therapeutic considerations. This is clearly crucial with antibiotics, where, barring an influence from their off-target anti-inflammatory pharmacologic effects, an understanding of the role of the individual biome predicts likelihood of therapeutic benefit. However, this need for identifying individual phenotypes and endotypes also extends to the agent that is currently considered the mainstay of treatment of CRS, specifically glucocorticoids. As with asthma, it is recognized that a large minority of patients with CRS have a steroid-resistant phenotype, identification of which will preclude use of these agents with their potential side effects. Identification of endotypes is also becoming increasingly imperative because targeted biotherapeutic agents, such as anti-IgE and anti-cytokine antibodies, are becoming available. These agents are likely to benefit patients in whom the targeted mediator is not only expressed but demonstrably driving a central mechanism in that patient. In summary, the treatment of CRS is at an exciting crossroad. On the positive side, numerous therapeutics are in development that seem likely to have a positive effect in our patients with this condition. The challenge is that these therapies will require targeted individualized treatments based on identifying subjects with the relevant endotype.

Efficacy of silk fibroin-nano silver against Staphylococcus aureus biofilms in a rabbit model of sinusitis

BACKGROUND

Staphylococcus aureus biofilms contribute significantly to the recalcitrant nature of chronic rhinosinusitis. In previous studies, it has been shown that silk fibroin-nano silver solution can eliminate S. aureus biofilms in vitro, which suggests a potential role of this novel agent in the treatment of biofilm-associated diseases, such as sinusitis.

OBJECTIVE

The aim of this study was to investigate the efficacy of silk fibroin-nano silver solution as a topical anti-biofilm agent in a rabbit model of sinusitis.

METHODS

Biofilm-associated sinusitis models were established in 24 New Zealand White rabbits by gelatin sponge placement and S. aureus inoculation through a hole drilled into the anterolateral wall of the right maxillary sinus. After 4 weeks, indwelling catheters were placed into the maxillary sinus. Different concentrations of silk fibroin-nano silver solution or normal saline were irrigated slowly into the maxillary sinus via the indwelling catheters. After 7 days of irrigation, the rabbits were sacrificed. The sinus mucosa was harvested and examined for biofilm biomass as well as morphological integrity of the epithelium by scanning electron microscopy.

RESULTS

Silk fibroin-nano silver solution was found to be most effective in reducing the biomass of the S. aureus biofilms at a concentration of 384 mg/L, followed by the concentration of 153.6 mg/L, when compared with saline. After treatment with 384 mg/L silk fibroin-nano silver solution, the biofilms were completely eliminated and the injured epithelium was almost restored with regenerated cilia on the surface.

CONCLUSION

Silk fibroin-nano silver solution was found to be an effective topical agent against S. aureus biofilms in the rabbit model of sinusitis, and its effect was concentration-dependent.

Topical Therapies for Refractory Chronic Rhinosinusitis

Topical therapy has become an important tool in the otolaryngologist's armamentarium for refractory chronic rhinosinusitis (CRS). Daily high-volume sinonasal saline irrigation and standard metered-dose topical nasal steroid therapy are supported by the most evidence. Nonstandard topical sinonasal steroid therapies are a potential option for refractory CRS. Current evidence recommends against the use of topical antifungal therapy and topical antibiotic therapy delivered using spray and nebulized techniques in routine cases of CRS. Stents are a new modality with preliminary data showing they are an option when traditional treatment has failed. Further research with long-term effects and outcomes studies for refractory CRS are needed.

Evaluation of a 2-aminoimidazole variant as adjuvant treatment for dermal bacterial infections

2-Aminoimidazole (2-AI)-based compounds have been shown to efficiently disrupt biofilm formation, disperse existing biofilms, and resensitize numerous multidrug-resistant bacteria to antibiotics. Using Pseudomonas aeruginosa and Staphylococcus aureus, we provide initial pharmacological studies regarding the application of a 2-AI as a topical adjuvant for persistent dermal infections. In vitro assays indicated that the 2-AI H10 is nonbactericidal, resensitizes bacteria to antibiotics, does not harm the integument, and promotes wound healing. Furthermore, in vivo application of H10 on swine skin caused no gross abnormalities or immune reactions. Taken together, these results indicate that H10 represents a promising lead dermal adjuvant compound.

Biofilms in chronic rhinosinusitis: Pathophysiology and therapeutic strategies

BACKGROUND

There is increasing evidence that biofilms are critical to the pathophysiology of chronic infections including chronic rhinosinusitis (CRS). Until relatively recently, our understanding of biofilms was limited. Recent advances in methods for biofilm identification and molecular biology have offered new insights into the role of biofilms in CRS. With these insights, investigators have begun to investigate novel therapeutic strategies that may disrupt or eradicate biofilms in CRS.

OBJECTIVE

This review seeks to explore the evidence implicating biofilms in CRS, discuss potential anti-biofilm therapeutic strategies, and suggest future directions for research.

RESULTS

The existing evidence strongly supports the role of biofilms in the pathogenesis of CRS. Several anti-biofilm therapies have been investigated for use in CRS and these are at variable stages of development. Generally, these strategies: 1) neutralize biofilm microbes; 2) disperse existing biofilms; or 3) disrupt quorum sensing. Several of the most promising anti-biofilm therapeutic strategies are reviewed.

CONCLUSIONS

A better understanding of biofilm function and their contribution to the CRS disease process will be pivotal to the development of novel treatments that may augment and, potentially, redefine the CRS treatment paradigm. There is tremendous potential for future research.

Current trends in topical therapies for chronic rhinosinusitis: update and literature review

INTRODUCTION

Chronic rhinosinusitis (CRS) affects millions of patients worldwide. The disease is multifactorial with influences including anatomic factors, immunological disturbances, and altered sinonasal microbiome. Although oral medications are effective in controlling some symptoms, they are associated with side effects and long-term use is not ideal. Thus, topical therapies have emerged as an alternative delivery method for localized, high-concentration medication with less side effects. Areas covered: This is a review of the various topical therapies available or under investigation for the management of CRS. Common medications such as saline, steroids, and antimicrobials will be discussed. Furthermore, additives including manuka honey, xylitol, surfactant, N-chlorotaurine, Dead Sea salt, and sodium hyaluronate will be addressed. Innovations in topical therapies, such as drug-eluting biomaterials and photodynamic therapy, will also be reviewed. Expert opinion: Although topical therapies provide a high dose of active substance at the site of disease, their efficacy in CRS is not clear. Topical saline and intranasal steroids appear to consistently demonstrate therapeutic benefits. However, other topical medications require further investigation to determine long-term clinical efficacy and safety. A better understanding of their effects on the sinonasal mucociliary system is needed before they become the standard of care in CRS.

Innate immunity and chronic rhinosinusitis: What we have learned from animal models

OBJECTIVE

Chronic rhinosinusitis (CRS) is a heterogeneous and multifactorial disease characterized by dysregulated inflammation. Abnormalities in innate immune function including sinonasal epithelial cell barrier function, mucociliary clearance, response to pathogen-associated molecular patterns (PAMPs) via pattern recognition receptors (PRRs), and the contribution of innate immune cells will be highlighted in this review.

DATA SOURCES

PubMed literature review.

REVIEW METHODS

A review of the literature was conducted to determine what we have learned from animal models in relation to innate immunity and chronic rhinosinusitis.

RESULTS

Dysregulation of innate immune mechanisms including sinonasal barrier function, mucociliary clearance, PAMPs, and innate immune cells such as eosinophils, mast cells, and innate lymphoid cells may contribute to CRS pathogenesis. Sinonasal inflammation has been studied using mouse, rat, rabbit, pig, and sheep explant or in vivo models. Study using these models has allowed for analysis of experimental therapeutics and furthered our understanding of the aforementioned aspects of the innate immune mechanism as it relates to sinonasal inflammation. These include augmenting mucociliary clearance through activation of the cystic fibrosis transmembrane conductance regulator (CFTR) and study of drug toxicity on ciliary beat frequency. Knockout models of Toll-like receptors (TLR) have demonstrated the critical role these PRRs play in allergic inflammation as loss of TLR2 and TLR4 leads to decreased lower airway inflammation. Mast cell deficient mice are less susceptible to ovalbumin-induced sinonasal inflammation.

CONCLUSION

Animal models have shed light as to the potential contribution of dysregulated innate immunity in chronic sinonasal inflammation.

An in vivo safety and efficacy demonstration of a topical liposomal nitric oxide donor treatment for Staphylococcus aureus biofilm-associated rhinosinusitis

The burden of drug resistance emerges in the wake of chronic and repeated antibiotic use. This underpins the importance of discovering alternatives to current antibiotic regimens. In chronic rhinosinusitis (CRS), topical therapy such as nasal douches and steroid sprays is the mainstay of treatment. However, bacterial sinusitis such as those with Staphylococcus aureus biofilm infection point to more recalcitrant CRS subtypes, focusing research efforts into topical antimicrobial therapies. In the sinuses, both local mucosal and systemic effects must be considered in designing any new topical medication. Nitric oxide (NO), an endogenous antimicrobial agent, is found at extremely low levels in CRS sinuses and high levels in healthy sinuses. As a novel treatment modality, we have designed a liposomal formulation of an NO donor (LFNO) using isosorbide mononitrate, as a topical sinus wash in a sheep model of S. aureus biofilm rhinosinusitis. Heart rate (HR), blood pressure, mean arterial pressure (MAP), and histologic and ciliary analyses were assessed in the safety component. Efficacy was assessed by quantifying biofilm biomass post-treatment. LFNO-treated sheep had lesser inflammation (P = 0.02), and comparable ciliary preservation (P = 0.86) than the control group. A transient increase in HR and decrease in MAP were observed in the LFNO group (P < 0.05), but this was not accompanied by observable side effects. LFNO sheep had significantly lower biofilm biomass vs controls (P = 0.044). Our findings demonstrate the localized and systemic safety of LFNO in an animal model despite using high NO concentrations, thus warranting further investigation for its possible therapeutic role in CRS.

Impact of intraoperative hydrodebrider treatment on postoperative sinonasal inflammation

BACKGROUND

The impact of intraoperative hydrodebrider sinus irrigation (HSI) during endoscopic sinus surgery (ESS) on postoperative inflammation, endoscopy, and patient-reported outcomes has not been studied.

METHODS

A clinical trial of 12 patients with symmetric chronic rhinosinusitis were prospectively randomized to HSI on one side after undergoing bilateral ESS. The contralateral side was not treated with any irrigation and served as an internal control. Preoperative computed tomography, endoscopic, 22-item Sino-Nasal Outcome Test (SNOT-22), and symptom visual analog scale (VAS) scores for each side were obtained. At 1 and 3 months postsurgery, endoscopy, SNOT-22, and sinus VAS were recorded. Sinonasal mucus levels of interleukin (IL)-6, IL-10, IL-17a, and tumor necrosis factor (TNF) alpha were measured at the time of surgery, 1 and 3 months, postoperatively, from each side.

RESULTS

VAS scores improved on both sides (p < 0.05) and SNOT-22 improved at all postoperative time points (p < 0.05). Endoscopic scores of HSI-treated sides did not improve compared with baseline. HSI had no additional significant impact on postoperative VAS at any time point. HSI significantly decreased IL-17a levels when compared with the control side at 1 month (p = 0.034) and 3 months (p = 0.031). No significant change was seen in TNF-alpha, IL-6, or IL-10 on either side at any time point.

CONCLUSION

Intraoperative HSI at the time of ESS failed to establish any improvement in postoperative endoscopy or most local cytokine levels after ESS.

Topical anti-infective sinonasal irrigations: update and literature review

BACKGROUND

Sinonasal anti-infective irrigations have emerged as a promising therapeutic modality in the comprehensive management of chronic rhinosinusitis (CRS), particularly in the context of recalcitrant disease. The purpose of this article was to delineate the current spectrum of topical anti-infective therapies available and evaluate their role in the treatment of CRS.

METHODS

A systematic literature review was performed on all studies investigating the use of topical antimicrobial solutions in the medical therapy of CRS. Anti-infective irrigations were stratified into topical antibacterial, antifungal, and additive preparations according to their composition and respective microbicidal properties.

RESULTS

The use of topical antibiotic irrigations has been supported by low-level studies in the treatment of refractory CRS, with optimal results achieved in patients who have undergone prior functional endoscopic sinus surgery and received culture-directed therapy. Multiple evidence-based reviews have not established any clinical benefit with the administration of topical antifungals, and their use is not currently recommended in the management of routine CRS. Topical additives including surfactants may be beneficial as adjunctive treatment for recalcitrant CRS, but additional research is needed to investigate their efficacy in comparison with other agents and establish safety profiles.

CONCLUSION

Topical anti-infective solutions are not recommended as first-line therapy for routine CRS but may be considered as a potential option for patients with refractory CRS who have failed traditional medical and surgical intervention. Additional research is necessary to determine which patient populations would derive the most benefit from each respective irrigation regimen and identify potential toxicities associated with prolonged use.

When and how should we treat biofilms in chronic sinusitis?

PURPOSE OF REVIEW

Biofilms have been observed on the sinus mucosa of patients with chronic rhinosinusitis and are associated with poor clinical outcomes after surgery. This article summarizes the recent studies which describe the efficacy of treating biofilms in chronic rhinosinusitis.

RECENT FINDINGS

Biofilms are polymicrobial communities comprised of bacteria that tend to be more antibiotic-resistant than when in planktonic forms. Antibiotic therapy against biofilms is usually associated with relapse following cessation of treatment and may also have an adverse effect on normal commensal microflora. Surfactants can improve clinical symptoms, but their use has been limited by side effects. Other treatment modalities that physically remove or disrupt biofilms, such as ultrasound, have shown some efficacy in small trials. The impact of surgery on biofilms has not been extensively investigated.

SUMMARY

The nature of biofilms makes their removal difficult. No currently available treatment directed against them has demonstrated lasting efficacy.

Efficacy of citric acid denture cleanser on the Candida albicans biofilm formed on poly(methyl methacrylate): effects on residual biofilm and recolonization process

BACKGROUND

It is well known that the use of denture cleansers can reduce Candida albicans biofilm accumulation; however, the efficacy of citric acid denture cleansers is uncertain. In addition, the long-term efficacy of this denture cleanser is not well established, and their effect on residual biofilms is unknown. This in vitro study evaluated the efficacy of citric acid denture cleanser treatment on C. albicans biofilm recolonization on poly(methyl methacrylate) (PMMA) surface.

METHODS

C. albicans biofilms were developed for 72 h on PMMA resin specimens (n = 168), which were randomly assigned to 1 of 3 cleansing treatments (CTs) overnight (8 h). CTs included purified water as a control (CTC) and two experimental groups that used either a 1:5 dilution of citric acid denture cleanser (CT5) or a 1:8 dilution of citric acid denture cleanser (CT8). Residual biofilms adhering to the specimens were collected and quantified at two time points: immediately after CTs (ICT) and after cleaning and residual biofilm recolonization (RT). Residual biofilms were analyzed by quantifying the viable cells (CFU/mL), and biofilm architecture was evaluated by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). Denture cleanser treatments and evaluation periods were considered study factors. Data were analyzed using two-way ANOVA and Tukey's Honestly Significant Difference (HSD) test (α = 0.05).

RESULTS

Immediately after treatments, citric acid denture cleansing solutions (CT5 and CT8) reduced the number of viable cells as compared with the control (p < 0.01). However, after 48 h, both CT groups (CT5 and CT8) showed biofilm recolonization (p < 0.01). Residual biofilm recolonization was also detected by CLSM and SEM analysis, which revealed a higher biomass and average biofilm thickness for the CT8 group (p < 0.01).

CONCLUSION

Citric acid denture cleansers can reduce C. albicans biofilm accumulation and cell viability. However, this CT did not prevent biofilm recolonization.

Using surface plasmon resonance imaging to study bacterial biofilms

This paper describes the use of Surface Plasmon Resonance imaging (SPRi) as an emerging technique to study bacterial physiology in real-time without labels. The overwhelming majority of bacteria on earth exist in large multicellular communities known as biofilms. Biofilms are especially problematic because they facilitate the survival of pathogens, leading to chronic and recurring infections as well as costly industrial complications. Monitoring biofilm accumulation and removal is therefore critical in these and other applications. SPRi uniquely provides label-free, high-resolution images of biomass coverage on large channel surfaces up to 1 cm(2) in real time, which allow quantitative assessment of biofilm dynamics. The rapid imaging capabilities of this technique are particularly relevant for multicellular bacterial studies, as these cells can swim several body lengths per second and divide multiple times per hour. We present here the first application of SPRi to image Escherichia coli and Pseudomonas aeruginosa cells moving, attaching, and forming biofilms across a large surface. This is also the first time that biofilm removal has been visualized with SPRi, which has important implications for monitoring the biofouling and regeneration of fluidic systems. Initial images of the removal process show that the biofilm releases from the surface as a wave along the direction of the fluid flow.

Surfactants in the management of rhinopathologies

BACKGROUND

Surfactants are a class of amphiphilic surface active compounds that show several unique physical properties at liquid-liquid or liquid-solid surface interfaces including the ability to increase the solubility of substances, lower the surface tension of a liquid, and decrease friction between two mediums. Because of these unique physical properties several in vitro, ex vivo, and human trials have examined the role of surfactants as stand-alone or adjunct therapy in recalcitrant chronic rhinosinusitis (CRS).

METHODS

A review of the literature was performed.

RESULTS

The data from three different surfactants have been examined in this review: citric acid zwitterionic surfactant (CAZS; Medtronic ENT, Jacksonville FL), Johnson's Baby Shampoo (Johnson & Johnson, New Brunswick NJ), and SinuSurf (NeilMed Pharmaceuticals, Santa Rosa, CA). Dilute surfactant therapy shows in vitro antimicrobial effects with modest inhibition of bacterial biofilm formation. In patients with CRS, surfactants may improve symptoms, most likely through its mucolytic effects. In addition, surfactants have several distinct potential benefits including their ability to improve an irrigant's penetration of the nonoperated sinus and their synergistic effects with antibiotics. However, surfactants potential for nasal irritation and possible transient ciliotoxicity may limit their use.

CONCLUSION

Recent data suggest a possible therapeutic role of surfactants in treating rhinopathologies associated with mucostasis. Further investigation, including a standardization of surfactant formulations, is warranted to further elucidate the potential benefits and drawbacks of this therapy.

Safety evaluation of a sinus surfactant in an explant-based cytotoxicity assay

OBJECTIVES/HYPOTHESIS

Biofilms are associated with clinical relapse following surgery for chronic rhinosinusitis. Encased bacteria are protected from innate immunity and antimicrobial therapy. Surfactants can disperse the biofilm into its planktonic phenotype so that traditional treatments may be effective. The aim of this study was to assess a surfactant for its cytotoxicity profile.

STUDY DESIGN

In vitro explant-based cytotoxicity study.

METHODS

Sinonasal mucosa harvested from patients undergoing sinus surgery was tested using an air-liquid interface explant system. Surfactant at 1×, 2×, and 3× manufacturer's recommended concentrations were compared to control (saline) and Zinc Sulphate (ZnSO4 ), a known cytotoxic agent. Culture supernatant was analyzed for lactate dehydrogenase (LDH) as a marker of cellular toxicity. After 7 days, specimens were imaged using structured histopathology and scanning electron microscopy.

RESULTS

Application of surfactant at 1× concentration did not elicit an elevation in LDH, whereas ZnSO4 caused a significant rise 1 day after application. Specimens tested with a 2× and 3× surfactant demonstrated LDH rises 4 days and 2 days after application, respectively. Mucosa tested with the 1× surfactant and control demonstrated intact cellular structures on histopathology and preserved cilial ultrastructure on SEM. In ZnSO4 -treated specimens, marked cellular degradation and ciliary denudation occurred.

CONCLUSION

The surfactant does not appear to elicit cellular toxicity using an in vitro explant model at the manufacturer's recommended concentration. At higher concentrations, there may be dose-related toxicity that requires further investigation. In vivo testing is required to prove its efficacy in the treatment of recalcitrant chronic rhinosinusitis.

LEVEL OF EVIDENCE

N/A.

Topical Drug Delivery for Chronic Rhinosinusitis

Chronic rhinosinusitis is a multifactorial disorder that may be heterogeneous in presentation and clinical course. While the introduction of endoscopic sinus surgery revolutionized surgical management and has led to significantly improved patient outcomes, medical therapy remains the foundation of long-term care of chronic rhinosinusitis, particularly in surgically recalcitrant cases. A variety of devices and pharmaceutical agents have been developed to apply topical medical therapy to the sinuses, taking advantage of the access provided by endoscopic surgery. The goal of topical therapy is to address the inflammation, infection, and mucociliary dysfunction that underlies the disease. Major factors that impact success include the patient's sinus anatomy and the dynamics of the delivery device. Despite a growing number of topical treatment options, the evidence-based literature to support their use is limited. In this article, we comprehensively review current delivery methods and the available topical agents. We also discuss biotechnological advances that promise enhanced delivery in the future, and evolving pharmacotherapeutical compounds that may be added to rhinologist's armamentarium. A complete understand of topical drug delivery is increasingly essential to the management of chronic rhinosinusitis when traditional forms of medical therapy and surgery have failed.

Efficacy of NVC-422 against Staphylococcus aureus biofilms in a sheep biofilm model of sinusitis

BACKGROUND

Bacterial biofilms are a major obstacle in management of recalcitrant chronic rhinosinusitis. NVC-422 is a potent, fast-acting, broad-spectrum, nonantibiotic, antimicrobial with a new mechanism of action effective against biofilm bacteria in in vitro conditions. The aim of this study was to investigate the safety and efficacy of NVC-422 as local antibiofilm treatment in a sheep model of rhinosinusitis.

METHODS

After accessing and occluding frontal sinus ostia in 24 merino sheep via staged endoscopic procedures, S. aureus clinical isolate was instilled in frontal sinuses. Following biofilm formation, ostial obstruction was removed and sinuses irrigated with 0.1% and 0.5% NVC-422 in 5 mM acetate isotonic saline at pH 4.0. Sheep were monitored for adverse effects and euthanized 24 hours after treatment. Frontal sinuses were assessed for infection and changes in mucosa after the treatment. S. aureus biofilms were identified with Baclight-confocal scanning microscopy protocol and the biofilm biomass assayed by applying the COMSTAT2 program to recorded image stacks.

RESULTS

After 2 irrigations with 0.1% NVC-422, S. aureus biofilm biomass was reduced when compared to control sinuses (p = 0.0001), though this effect was variable in samples. NVC-422 0.5% solution irrigations reduced biofilm even more significantly and consistently over all samples (p < 0.0001). NVC-422 0.5% was also more effective than 0.1% NVC-422, vehicle control, and normal saline sinus irrigations in reducing biofilm biomass (p < 0.05 for all subgroups). No adverse events were observed in sheep after sinus irrigations with 0.1% and 0.5% NVC-422 solutions.

CONCLUSION

NVC-422 is an effective topical agent against S. aureus biofilms, with dose-dependent efficacy in this animal model of biofilm-associated sinusitis.

Development and application of a polymicrobial, in vitro, wound biofilm model

AIMS

The goal of this investigation was to develop an in vitro, polymicrobial, wound biofilm capable of supporting the growth of bacteria with variable oxygen requirements.

METHODS AND RESULTS

The strict anaerobe Clostridium perfringens was isolated by cultivating wound homogenates using the drip-flow reactor (DFR), and a three-species biofilm model was established using methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa and Cl. perfringens in the colony-drip-flow reactor model. Plate counts revealed that MRSA, Ps. aeruginosa and Cl. perfringens grew to 7·39 ± 0·45, 10·22 ± 0·22 and 7·13 ± 0·77 log CFU per membrane, respectively. The three-species model was employed to evaluate the efficacy of two antimicrobial dressings, Curity™ AMD and Acticoat™, compared to sterile gauze controls. Microbial growth on Curity™ AMD and gauze was not significantly different, for any species, whereas Acticoat™ was found to significantly reduce growth for all three species.

CONCLUSIONS

Using the colony-DFR, a three-species biofilm was successfully grown, and the biofilms displayed a unique structure consisting of distinct layers that appeared to be inhabited exclusively or predominantly by a single species.

SIGNIFICANCE AND IMPACT OF THE STUDY

The primary accomplishment of this study was the isolation and growth of an obligate anaerobe in an in vitro model without establishing an artificially anaerobic environment.

The effect of dilute baby shampoo on nasal mucociliary clearance in healthy subjects

BACKGROUND

Biofilm formation has been implicated as an etiologic factor in the development of chronic rhinosinusitis (CRS). Nasal irrigation with surfactants including dilute baby shampoo have been proposed as an antibiofilm treatment for CRS patients. The effect of dilute baby shampoo on normal sinonasal mucosal function is unknown.

METHODS

Mucociliary clearance time (MCT), as measured by the time in minutes for a subject to detect a sweet taste after the application of a saccharin granules at the anterior part of the inferior turbinate, was performed before and shortly after nasal irrigation with 50 ml of 1% baby shampoo (Johnson & Johnson, New Brunswick, NJ) in 27 healthy volunteers.

RESULTS

Mean MCTs before and after irrigation were 12.09 (±4.83 minutes) and 15.45 (±7.71 minutes) minutes, respectively. The mean difference, 3.37 minutes, was statistically significant (p = 0.031). Pre- and post-MCTs for each subject were not correlated (r = 0.324; p = 0.100).

CONCLUSION

Nasal irrigations with dilute baby shampoo increase MCTs in healthy subjects. The impact of such interventions in CRS patients warrants additional investigation.

Efficacy of Using a Hydrodebrider and of Citric Acid/Zwitterionic Surfactant on a Staphylococcus Aureus Bacterial Biofilm in the Sheep Model of Rhinosinusitis

Background

Biofilms in chronic rhinosinusitis (CRS) patients are associated with recalcitrant disease patterns. Citric acid/zwitterionic surfactant (CAZS) has been shown to have significant efficacy at in vitro biofilm eradication. Unique hydrodebrider systems have been shown to have effective antibiofilm efficacy. The aim of this study was to evaluate the efficacy of the CAZS/hydrodebrider treatment on Staphylococcus aureus biofilms in the sheep model of CRS.

Methods

Forty-two sheep frontal sinuses were inoculated with S. aureus, followed by 7 days of biofilm growth. Sinuses were randomized to one of nine treatment groups: control, hydrodebrider with saline or CAZS (killed on day 0 or day 7 posttreatment), CAZS, or saline flush (killed on day 0 or day 7 posttreatment). Confocal scanning laser microscopy (CSLM) was used to confirm extent of biofilm reduction. Samples of each sinus were taken, assessing cilia morphology using electron microscopy.

Results

A mean of 37.22 ± 9.65% of control (no treatment) CSLM images taken showed biofilms. Both CAZS flush and CAZS/hydrodebrider treatments showed initial improvements in biofilms but biofilm regrowth followed treatment, 14.74 ± 9.58% to 18.91 ± 12.14% and 15.60 ± 13.92% to 24.70 ± 3.66%, respectively (p > 0.05). Saline/hydrodebrider treatments showed a nonsignificant improvement in biofilm treatment, which was maintained, 18.34 ± 11.85% to 12.04 ± 10.28% (p > 0.05). Cilial morphology grade was significantly worse in the CAZS treatment groups (p < 0.05).

Conclusion

CAZS solution (with and without a hydrodebrider system) can significantly adversely affect cilia morphology. The hydrodebrider system, when combined with saline, may be a useful treatment adjunct for mucosal biofilms.

Do biofilms contribute to the initiation and recalcitrance of chronic rhinosinusitis?

Chronic rhinosinusitis is a common disease whose underlying aetiopathogenesis has not been completely understood. Amongst a range of other potential environmental triggers in this disease, a role has recently been proposed for bacterial biofilms. Adopting the biofilm paradigm to explain the initiation and maintenance of this disease may help to clarify previous inconsistencies in this disease that have resulted in the role of bacteria being questioned. Of particular interest is the association of bacterial biofilms with recalcitrant disease states. Over the last five years, research has progressed rapidly since biofilms were first identified on the surface of diseased sinonasal mucosa. Their presence there has now been associated with more severe disease that is often recalcitrant to current management paradigms. Technological advances are allowing accurate characterization of the bacterial and fungal species within these biofilms, which would appear to be an important step in improving our understanding of how these bacterial communities might interact with the host to cause disease. This is an unanswered, yet highly important, question in this field of research that will undoubtedly be an area of investigation in the near future. As the body of evidence suggesting biofilms may be involved in this disease grows, research interest has switched to the development of antibiofilm therapies. Given the unique properties of bacteria existing in this form, biofilm eradication strategies will need to incorporate novel medical therapies into established surgical practices as we attempt to improve the outcomes of our most difficult patients.

Genetics and phenotyping in chronic sinusitis

Chronic sinusitis with nasal polyposis historically has been treated as a single monolithic clinical disorder. Just as asthma is now accepted as numerous heterogeneous diseases, chronic sinusitis should also be viewed as comprising several diseases with varying causes, with each one characterized by distinct histologic and gene and protein expression patterns. This includes recognition of the need to define these diseases based on the presence or absence of an eosinophilic infiltrate but also on additional distinctions based on unique agents that drive their development and perpetuation. As a collection of heterogeneous diseases, proper differential diagnosis is required to delineate appropriate therapeutic intervention. This review will focus on recognized distinct presentations of chronic sinus disease, including distinguishing the clinical presentations, cellular and molecular characteristics, genetic differences, and current treatment options for each.

The impact of intraoperative saline irrigations on bacterial load within the maxillary sinus

BACKGROUND

Saline irrigations are routinely employed during endoscopic sinus surgery to remove mucous and debris from the sinus cavities. What is unknown is whether this results in a quantitative reduction in pathologic bacteria within the sinus mucosa. The objectives of this study were to quantify the amount of 5 different bacteria (Staphylococcus aureus, Haemophilus influenzae, Pseudomonas aeruginosa, coagulase-negative Staphylococcus (CNS), and Streptococcus pneumoniae) within the maxillary sinus and to determine the impact of saline irrigations on bacterial counts.

METHODS

Twenty patients with chronic rhinosinusitis were prospectively enrolled. After bilateral maxillary antrostomies, biopsies were taken of the maxillary sinus mucosa prior to any irrigation. In each patient, the left maxillary sinus was then irrigated with 250 cc of normal saline (NS) with a pressurized pulse-irrigation device and the right side was irrigated with 250 cc of NS using a 30-cc syringe attached to a curved suction tip. Repeat maxillary sinus mucosal biopsies were then taken from each side. Each biopsy was analyzed using quantitative polymerase chain reaction to determine the presence and amount of each of the bacteria.

RESULTS

Saline irrigations were found to significantly reduce the amount of S. aureus, P. aeruginosa, and S. pneumoniae found within the maxillary sinus mucosa. No difference was found for H. influenzae or CNS. No difference in bacterial load reduction was able to be shown between the pressurized saline flushes and manual saline rinse methods.

CONCLUSION

Intraoperative saline irrigations are able to significantly reduce the amount of potentially pathogenic bacteria within the diseased sinus mucosa.

Laser disruption and killing of methicillin-resistant Staphylococcus aureus biofilms

OBJECTIVE

The aim of the study was to study the efficacy of 2 different lasers in vitro, in disrupting biofilm and killing planktonic pathogenic bacteria.

MATERIALS AND METHODS

Biofilms of a stable bioluminescent of Staphylococcus aureus Xen 31 were grown in a 96-well microtiter plate for 3 days. The study included 7 arms: (a) control; (b) ciprofloxacin (3 mg/L, the established minimum inhibitory concentration [MIC]) alone; (c) shock wave (SW) laser alone; (d) near-infrared (NIR) laser alone; (e) SW laser and ciprofloxacin; (f) SW and NIR lasers; (g) SW, NIR lasers, and ciprofloxacin. The results were evaluated with an in vivo imaging system (IVIS) biophotonic system (for live bacteria) and optical density (OD) for total bacteria.

RESULTS

Without antibiotics, there was a 43% reduction in OD (P < .05) caused by the combination of SW and NIR suggesting that biofilm had been disrupted. There was an 88% reduction (P < .05) in live biofilm. Ciprofloxacin alone resulted in a decrease of 28% of total live cells (biofilm remaining attached) and 58% of biofilm cells (both P > .05). Ciprofloxacin in combination with SW and SW + NIR lasers caused a decrease of more than 60% in total live biomass and more than 80% of biofilm cells, which was significantly greater than ciprofloxacin alone (P < .05).

CONCLUSIONS

We have demonstrated an effective nonpharmacologic treatment method for methicillin-resistant Staphylococcus aureus (MRSA) biofilm disruption and killing using 2 different lasers. The preferred treatment sequence is a SW laser disruption of biofilm followed by NIR laser illumination. Treatment optimization of biofilm is possible with the addition of ciprofloxacin in concentrations consistent with planktonic MIC.

Eradicating chronic ear, nose, and throat infections: a systematically conducted literature review of advances in biofilm treatment

OBJECTIVE

Bacteria can grow as individual, planktonic organisms or as complex biofilm communities that are more resistant to treatment. This review was designed to systematically search to identify recent laboratory studies on eradication of biofilms in otolaryngologic infections to highlight promising advances in biofilm treatment.

DATA SOURCES

A systematic electronic literature search of Medline/PubMed, CINHAL, and Web of Science was conducted for articles describing the treatment of biofilm infections in ear, nose, and throat (ENT) diseases through March 2010. English-language articles and articles with an English abstract that focused on biofilm treatment were considered for review.

REVIEW METHODS

Each included article was reviewed by one of the authors for study design, treatment intervention, and outcome. Data from in vitro and animal studies were considered separately from human studies.

RESULTS

A total of 30 articles were identified for this review, including 5 studies that included a human treatment component. In general, antibiotics were relatively ineffective for eradicating biofilm infections. Markedly higher antibiotic dosages were required to reduce biofilm presence compared with doses that were effective in eradicating planktonic bacteria. Mupirocin irrigation, gentian violet, and thiamphenicol glycinate acetylcysteine effectively eradicated biofilms. Physical disruption, surfactants, and probiotics were also shown to be beneficial in both nonhuman and human studies.

CONCLUSION

Eradicating ENT biofilms is difficult when treating single-organism or mixed flora biofilms. Antibiotic therapy is often ineffective against biofilms, and clinical treatment may need to focus on nonantibiotic therapies that reduce, disrupt, or eradicate ENT biofilms.

Biofilm maturity studies indicate sharp debridement opens a time- dependent therapeutic window

OBJECTIVE

To investigate the hypothesis that newly formed wound biofilms (or bioburdens) are more susceptible to antimicrobial treatment.

METHOD

Four separate and distinct models were performed by four separate biofilm research laboratories to evaluate the resistance of biofilms to antimicrobial treatments over time. These included a drip-flow biofilm model along with a hydrodebridement study, a porcine skin punch biopsy ex vivo model, a mouse chronic wound model and clinical longitudinal debridement study.

RESULTS

All four models showed that, within the first 24 hours, the biofilm community was more susceptible to the selected antibiotics, and after maturing for up to 48 hours became increasingly tolerant. In each model, there was at least a 24-hour period in which the biofilms were more resistant to antibiotics. Each of the models utilised showed a significant decrease in the resistance of the biofilm/ burden to gentamicin for up to 24 hours with a confidence interval of at least 95%. The resistance increased in each of the models by 48 hours and reached original resistance levels by 72 hours.

CONCLUSION

These data suggest the principles of biofilm-based wound care, along with the use of serial debridement to continually remove mature biofilm, followed by biofilm wound management strategies, including topical antibiotics while the bioburden is still immature and more susceptible, are valid.

Role of maximal endoscopic sinus surgery techniques in chronic rhinosinusitis

There remains a continued debate regarding the extent of endoscopic sinus surgery (ESS) required for patients with chronic rhinosinusitis (CRS). By examining anatomic, etiologic, and postoperative factors that may lead to recalcitrant CRS, this article aims to highlight some of the reasons for performing maximal techniques in ESS. This concept is further expanded in various surgical maneuvers including wide maxillary antrostomy, extended frontal sinus procedures, and intraoperative computed tomography-guided ESS.

Biofilms

Bacterial biofilms are 3-dimensional aggregates of bacteria that have been shown to play a major role in many chronic infections. Evidence is growing that bacterial biofilms may play a role in certain cases of recalcitrant chronic sinusitis that do not respond to traditional medical and surgical therapies. Novel therapies may have clinical applications to prevent and destabilize biofilms. Future research will determine if topical antimicrobials, surfactants, and other adjuvant therapies can be used to treat biofilm-associated chronic rhinosinusitis.

Evolving materials and techniques for endoscopic sinus surgery

Functional endoscopic sinus surgery was initially introduced as a minimally invasive procedure to treat chronic rhinosinusitis (CRS) in patients for whom medical management failed. Sinus surgery has been deemed an extremely effective part of the overall management of chronic sinus disease with symptomatic improvement in the vast majority of patients. At the forefront, technologic advances have been critical in advancing endoscopic sinus surgical procedures. With the introduction of improved optics and lighting, advanced instrumentation, and image-guided surgical navigation, the limitations of endoscopic procedures have been significantly reduced. Endoscopic techniques have evolved to include the management of both malignant and benign neoplasms of the sinuses and anterior skull base. This article highlights some of the newest advances in technology, materials, and medical/surgical techniques used in endoscopic sinus and skull base procedures and illustrates how they advance overall patient care to help minimize morbidity and complications.

Local drug delivery

Topical drug delivery for sinonasal disorders is influenced by a variety of factors. Macroscopically (or anatomically), the ability of the drug to reach the appropriate region of the paranasal system is paramount. Delivery techniques, surgical state of the sinus cavity, delivery device, and fluid dynamics (volume, pressure, position) have a significant impact on the delivery of topical therapies to the sinus mucosa. Once topical therapeutics actually reach the desired site, factors within the local microenvironment heavily influence local drug delivery. The presence and composition of the mucus blanket, mucociliary clearance, direct mucin-drug binding, and the permeability of pharmaceutical compounds will all impact drug delivery. In addition, the general therapeutic goal of topical management may lie between the potentially competing actions of mechanical lavage and pharmaceutical intervention. Techniques for the mechanical removal of mucus, antigen, and inflammatory products may not be the most efficient approach for pharmaceutical delivery. This article reviews the evolving concepts in local drug therapy, both for the factors that influence anatomic distribution within the sinonasal system and those that affect mucosal absorption.

Diagnosis and management of chronic rhinosinusitis in adults

Chronic rhinosinusitis (CRS) is characterized by mucosal inflammation affecting both the nasal cavity and paranasal sinuses; its causes are potentially numerous, disparate, and frequently overlapping. The more common conditions that are associated with CRS are perennial allergic and nonallergic rhinitis, nasal polyps, and anatomical mechanical obstruction (septum/turbinate issues). Other less common etiologies include inflammation (eg, from superantigens), fungal sinusitis or bacterial sinusitis with or without associated biofilm formation, gastroesophageal reflux, smoke and other environmental exposures, immune deficiencies, genetics, and aspirin-exacerbated respiratory disease. A diagnosis of CRS is strongly suggested by a history of symptoms (eg, congestion and/or fullness; nasal obstruction, blockage, discharge, and/or purulence; discolored postnasal discharge; hyposmia/anosmia; facial pain and/or pressure) and their duration for > 3 months. A definitive diagnosis requires physical evidence of mucosal swelling or discharge appreciated during physical examination coupled with CT imaging if inflammation does not involve the middle meatus or ethmoid bulla. Multivariant causation makes the diagnosis of CRS and selection of treatment complex. Furthermore, various types of health care providers including ear, nose, and throat (ENT) specialists, allergists, primary care physicians, and pulmonologists treat CRS, and each is likely to have a different approach. A structured approach to the diagnosis and management of CRS can help streamline and standardize care no matter where patients present for evaluation and treatment. A 2008 Working Group on CRS in Adults, supported by the American Academy of Otolaryngic Allergy (AAOA), developed a series of algorithms for the differential diagnosis and treatment of CRS in adults, based on the evolving understanding of CRS as an inflammatory disease. The algorithms presented in this paper address an approach for all CRS patients as well as approaches for those with nasal polyps, edema observed on nasal endoscopy, purulence observed on nasal endoscopy, an abnormal history and physical examination, and an abnormal history and normal physical examination.

Biofilms in pediatric respiratory and related infections

Bacteria can grow as free-floating, planktonic bacteria or complex communities called biofilms. Biofilms promote bacterial growth and diversity and offer bacteria unique environments, including aerobic and anaerobic layers, that facilitate resistance to antimicrobial therapies. Respiratory and related structures provide ideal environments for the development of bacterial biofilms, which predispose patients to recurrent and chronic infections. Biofilms are important for the persistence of chronic rhinosinusitis, pulmonary infections in cystic fibrosis, chronic otitis media, and device-related infections. Antimicrobial therapy that is proven effective against planktonic bacteria is often insufficiently effective against the defenses of biofilms. Furthermore, biofilms modify themselves following exposure to antimicrobial therapy, thus developing increased resistance. Understanding the nature of biofilms in common pediatric infections is essential to comprehending the expected course of bacterial illness and identifying treatments that are most likely to be beneficial against more resistant biofilms.

In Vivo Effects of Citric Acid/Zwitterionic Surfactant Cleansing Solution on Rabbit Sinus Mucosa

Background

Chronic rhinosinusitis that is refractory to medical or surgical intervention may involve a particularly resistant form of infection known as a bacterial biofilm that is recalcitrant to antibiotics secondary to physical barrier characteristics. Recently, a novel sinus cleansing solution, citric acid/zwitterionic surfactant (CAZS) was shown to be extremely effective in disrupting biofilms in vitro. The purpose of this study was to determine the effects of CAZS on sinonasal epithelium in vivo compared with normal saline.

Methods

Indwelling catheters were placed into the right maxillary sinus of New Zealand white rabbits. CAZS solution or normal saline (10 mL) was instilled at a rate of 20 mL/minute into the sinus followed by aspiration. Rabbits were killed 1, 3, and 6 days after treatment. Mucosa from both maxillary sinuses was harvested and evaluated for physiological activity (ciliary beating) as well as morphological integrity of the epithelium by scanning electron microscopy.

Results

One day after treatment, beating cilia was evident with morphological analysis shown intact epithelium with 80–85% denudation of cilia compared with saline. Three days after treatment, ciliary activity was again noted with morphological evidence of persistent denuded cilia. By day 6 after treatment, the epithelium had regenerated cilia over the apical surface. Throughout the recovery period beating cilia was evident in CAZS-treated sinuses.

Conclusion

This study shows that although CAZS acutely denudes respiratory cilia, the remaining cilia are active. Additionally, the epithelial barrier appears intact with active ciliogenesis, and reciliation of the mucosal surface occurring 6 days after treatment.