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.

Definition and management of odontogenic maxillary sinusitis

Background

Maxillary sinusitis of odontogenic origin, also known as maxillary sinusitis of dental origin or odontogenic maxillary sinusitis (OMS), is a common disease in dental, otorhinolaryngologic, allergic, general, and maxillofacial contexts. Despite being a well-known disease entity, many cases are referred to otorhinolaryngologists by both doctors and dentists. Thus, early detection and initial diagnosis often fail to detect its odontogenic origin.

Main body

We searched recent databases including MEDLINE (PubMed), Embase, and the Cochrane Library using keyword combinations of "odontogenic," "odontogenic infection," "dental origin," "tooth origin," "sinusitis," "maxillary sinus," "maxillary sinusitis," "odontogenic maxillary sinusitis," "Caldwell Luc Procedure (CLP)," "rhinosinusitis," "functional endoscopic sinus surgery (FESS)," "modified endoscopy-assisted maxillary sinus surgery (MESS)," and "paranasal sinus." Aside from the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) trial, there have been very few randomized controlled trials examining OMS. We summarized the resulting data based on our diverse clinical experiences.

Conclusion

To promote the most efficient and accurate management of OMS, this article summarizes the clinical features of rhinosinusitis compared with OMS and the pathogenesis, microbiology, diagnosis, and results of prompt consolidated management of OMS that prevent anticipated complications. The true origin of odontogenic infections is also reviewed.

Will we ever cure nasal polyps?

BACKGROUND

Nasal polyposis is a benign hyperplastic growth of nasal mucosa. There is a paucity of evidence on the prevalence and incidence of nasal polyposis. Although nasal polyps can be asymptomatic, they can cause a spectrum of nasal problems including nasal obstruction, rhinorrhoea, nasal congestion, anosmia resulting in ageusia. Nasal polyps are mostly associated with chronic rhinosinusitis, The current management of chronic rhinosinusitis with nasal polyps is controversial and is not curative.

METHODS

A Medline search was conducted, using the keywords 'rhinosinusitis', 'sinusitis', 'classification' and ''aetiology.

FINDINGS

The current treatment of nasal polyposis in chronic rhinosinusitis with nasal polyps is still challenging. Emerging research through endotypes profiling aims to better understand the complexities of this heterogeneous disease to personalise treatment and provide a cure. Randomised controlled trials aim to provide robust evidence for current management options.

Understanding the Role of Biofilms and Superantigens in Chronic Rhinosinusitis

PURPOSE OF REVIEW

This review explores recent discoveries in our understanding of how biofilms and superantigens contribute to the pathogenesis of chronic rhinosinusitis (CRS). It also examines clinical implications and novel treatment approaches for biofilm associated CRS.

RECENT FINDINGS

While the role of biofilms in CRS has been studied for 14 years, research interest has now turned toward elucidating new methods of biofilm detection, microbial diversity, and novel treatment approaches. Recent studies on biofilm superantigens aim to clarify the immunological mechanisms of upper airway inflammation, particularly the type-2 response seen in nasal polyposis.

SUMMARY

Biofilms are a topic of research interest for their role in the pathogenesis of chronic rhinosinusitis, particularly when they elute superantigens. New studies on this topic focus on the molecular and cellular mechanisms at play.

Chronic Rhinosinusitis and Aspirin-Exacerbated Respiratory Disease

Patients with severe asthma and concomitant chronic rhinosinusitis often have severe, refractory upper and lower airway inflammation. This inflammation has been proposed to be similar throughout the upper and lower airways leading to the unified airways concept. This article reviews chronic rhinosinusitis with and without nasal polyps, and the subgroup with aspirin-exacerbated respiratory disease, while focusing on the relationship with asthma. Additionally, diagnosis and treatment with current and newer therapies are discussed.

The effectiveness of topical colloidal silver in recalcitrant chronic rhinosinusitis: a randomized crossover control trial

Background

Recalcitrant chronic rhinosinusitis without polyposis (CRSsP) is a challenging condition to manage as traditional medical therapies and surgery fail to provide satisfactory clinical improvements. Colloidal silver (CS), a widely used naturopathic agent, has recently shown anti-biofilm properties both in vitro and within a rhinosinusitis animal model. To date, no trials involving humans have been published in world literature. The purpose of this study was to assess the efficacy of CS as a topical nasal spray in patients with refractory CRSsP.

Methods

A prospective cohort study was conducted using a convenience sample of 20 randomized patients with crossover methodology, comparing nasal sprays with CS versus saline. Patients sprayed twice daily for six weeks with the first intervention and then switched to the second for the next six weeks, with measurements made at baseline and each time point. Primary outcomes were changes in SNOT-22 and Lund-Kennedy (LK) endoscopic scores. All analysis was non-parametric and was conducted using STATA 14.

Results

Twenty-two patients were enrolled in the study with 20 completing the entire protocol. Mean 6-week change in SNOT-22 scores were −2.8 and 1.0 for saline and CS, respectively (p = 0.373). Similarly, mean 6-week change in LK scores were −1.4 and −1.1 for saline and CS, respectively (p = 0.794). Significant period effects were observed with the SNOT-22 score between the randomized groups. No participants experienced negative health effects directly attributable to the administration of intranasal CS.

Conclusion

Commercially available CS nasal spray did not demonstrate any meaningful subjective or objective improvements in patients with recalcitrant CRSsP.

Trial registration

NCT02403479. Registered on March 1, 2015.

Chronic Rhinosinusitis without Nasal Polyps

Chronic rhinosinusitis without nasal polyps (CRSsNP) is more prevalent than chronic rhinosinusitis with nasal polyps (CRSwNP). Certain diseases predispose to whereas others are associated with CRSsNP. Predisposing diseases include allergic and nonallergic upper and lower airway diseases, epithelial cell disorders, immunodeficiencies, autoimmune diseases, and some infectious diseases. In addition, environmental and host factors, examples of which include smoking, a higher incidence of abnormal biofilms, and innate immune defects, play a role in the pathogenesis of this disease. CRSsNP is characterized by histologic abnormalities, including basement membrane thickening (fibrosis) and goblet cell hyperplasia. Neutrophils and several chemokines, TGF-β and C-X-C motif chemokine ligand (CXCL)-8, play a role in CRSsNP remodeling. However, there are conflicting data about CRSsNP endotypes, for example, whether it is characterized by neutrophilia or eosinophilia or both. In spite of advancements and the understanding of the pathogenesis of this disease, additional study is necessary to better comprehend its underlying mechanisms, endotypes, and evidence-based treatment strategies.

Rhinitis Subtypes, Endotypes, and Definitions

Rhinitis is often seen as posing a small burden. However, rhinitis is a complex disease that is underpinned by a plethora of different mechanisms and causes. Rhinitis is frequently associated with other comorbid conditions but, by itself, is a source of considerable morbidity for patients and creates a significant financial burden on health systems worldwide. This article approaches this condition from both a phenotypic and mechanistic standpoint, focusing on the complexity of characterizing these subtypes. Developing a clearer demarcation of the currently obscure rhinitis phenotypes and endotypes will substantially improve their future prevention and treatment.

Biofilm formation by clinical isolates and its relevance to clinical infections

Reports of biofilms have increased exponentially in the scientific literature over the past two decades, yet the vast majority of these are basic science investigations with limited clinical relevance. Biofilm studies involving clinical isolates are most often surveys of isolate collections, but suffer from lack of standardization in methodologies for producing and assessing biofilms. In contrast, more informative clinical studies correlating biofilm formation to patient data have infrequently been reported. In this chapter, biofilm surveys of clinical isolates of aerobic and anaerobic bacteria, mycobacteria, and Candida are reviewed, as well as those pertaining to the unique situation of cystic fibrosis. In addition, the influence of host components on in vitro biofilm formation, as well as published studies documenting the clinical impact of biofilms in human infections, are presented.

Role of biofilm in children with recurrent upper respiratory tract infections

Recurrent respiratory tract infections (RRTIs) are very common in children and a major challenge for pediatricians. In the last few years, bacterial biofilms have been linked to RRTIs and antibiotic resistance, and have raised serious concerns regarding the therapeutic management of recurrent middle ear diseases, chronic rhinosinusitis, and recurrent pharyngotonsillitis. This paper aims to review the new insights into biofilm-related upper respiratory tract infections in children and possible therapeutic strategies. It focuses on the clinical implications for recurrent disease and on studies in pediatric patients. Analysis of the literature showed that the involvement of bacterial biofilm in recurrent upper airway tract infections is an emerging problem that may lead to serious concerns about infection control. Despite the large amount of research within this field, detailed insight into the complex structure of bacterial biofilms and the ultrastructural and biochemical mechanisms responsible for its evasion of the immune system and resistance to treatments is currently lacking. In the future, additional emphasis should be placed on biofilm management as a component of therapeutic strategies. This goal can be attained by finding feasible methods for detecting biofilms in vivo and identifying effective methods for administering treatments that eradicate preexisting bacterial biofilms or hinder bacterial adhesion to respiratory cells.

Biofilms in chronic rhinosinusitis with polyps: is eradication possible?

The objective of the study was to reveal if mometasone furoate nasal spray as monotherapy or combined with long-term oral clarithromycin have influence on biofilms in chronic rhinosinusitis with polyps. The study is a randomized controlled trial in a tertiary referral hospital. Thirty-four patients with chronic rhinosinusitis completed the study. In the first group, 19 patients received mometasone furoate nasal spray 200 μg once daily for 8 weeks. In the second group, 15 patients received oral clarithromycin 500 mg twice daily for 2 weeks and continued once daily 250 mg tablet for subsequent 6 weeks, plus mometasone furoate. Scanning electron microscopy was the primary outcome measure. Secondary outcome measures included computerized tomography and sinonasal outcome test-20 items. Mucosal biofilms were detected in 23 of 34 (68%) patients on pretreatment polyp samples. After the treatment, biofilms disappeared in 1 of 11 patients in the first group, whereas the eradication of biofilms was evident in 6 of 12 (50%) patients in the second group. Tomography scores improved in eight patients of each group (42.1 and 53.4%, respectively). The comparison of improvements did not reveal significant difference between the groups. The overall symptom scores improved compared to the baseline levels. The mean changes of -8.8421 and -11.4000 in the first and second group, respectively, were not statistically different. Adding long-term low-dose oral macrolides to nasal steroids was effective in the eradication of biofilm. However, we were not able to demonstrate that combined therapy was superior in terms of the improvement in tomography and symptom scores.

Chronic rhinosinusitis in children

Chronic rhinosinusitis (CRS) affects nearly 37 million people in the United States each year and accounts for approximately $6 billion in direct and indirect health care costs. Despite its prevalence and significant impact, little is known about its exact cause and pathophysiology, and significant controversy remains regarding appropriate treatment options. Basic science research, however, has shown recent promise toward improving understanding of the innate and environmental factors underlying the pathophysiology of CRS. The hope is that this will also lead to advances in treatment for children adversely affected by this common yet complicated disease.