Therapy of Sinonasal Microbiome in CRS: A Critical Approach

Nasal Microbiome in Granulomatosis with Polyangiitis Compared to Chronic Rhinosinusitis

Rhinosinusitis in granulomatosis with polyangiitis (GPA) is categorised as a secondary, diffuse and inflammatory chronic rhinosinusitis (CRS). It is one of the conditions that impacts the nasal microbiota. This study aimed to compare the nasal microbiomes of patients with GPA, CRS and NSP. A total of 31 patients were included in the study (18 GPA, 6 CRS and 7 nasal septum perforation (NSP)). In all patients, SNOT 22, a nasal endoscopy (Lund-Kennedy scale) and a brush swab were performed. The metagenomic analysis was carried out based on the hypervariable V3-V4 region of the 16S rRNA gene. At the genus level, statistically significant differences were observed in two comparisons: the GPA/NSP and the GPA/CRS groups. In the GPA/NSP group, the differences were related to four genera (Actinomyces, Streptococcus, Methylobacterium-Methylorubrum, Paracoccus), while in the GPA/CRS group, they were related to six (Kocuria, Rothia, Cutibacterium, Streptococcus, Methylobacterium-Methylorubrum, Tepidimonas). Patients with GPA had lower diversity compared to CRS and NSP patients. There were no statistically significant differences found for the Staphylococcus family and Staphylococcus aureus between the three groups.

Nasal Microbiota and Sensitivity Pattern in Rhinosinusitis

Aims

To know the microorganism causing rhinosinusitis & to study the antibiotic sensitivity pattern for the isolated nasal microbiota in this region.

Background

Rhinosinusitis is inflammatory condition of nose and paranasal sinuses [1]. It is multifactorial condition, in which microorganisms play pathogenic role [2]. Interactions between microorganisms, mucosa and environmental changes influence on composition of bacterial ecosystem [2]. Though antibiotics are frequently used for medical management of rhinosinusitis, sensitivity directed antibiotics are rarely prescribed. So, this study is directed to know microbial isolate in rhinosinusitis and its antibiotic sensitivity pattern.

Methodology

in this 6 months prospective study during March to September 2022, done at Department of Otorhinolaryngology, Raichur Institute of Medical Sciences, Raichur; patients attending Otorhinolaryngology outpatient department and diagnosed to have rhinosinusitis were selected. Nasal swabs were collected from the middle meatus by diagnostic nasal endoscopy and were sent for culture and sensitivity. Statistical tests were applied for results(Size = 100).

Results

Out of 100 patients, 52 were males, 48 were females; 88 were adults & 12 were paediatric patients. 59 patients had acute, 32 chronic and 9 had recurrent rhinosinusitis. Most common organisms isolated in acute rhinosinusitis was Klebsiella 28%, Staphylococcus aureus 56% & 66% in chronic & recurrent rhinosinusitis respectively. Klebsiella was sensitive to beta lactams & quinolones, while Staphylococcus aureus was sensitive to beta lactams & cephalosporins.

Conclusion

Increase in antibiotic use has led to antibiotic resistance. Hence judicious, sensitivity directed antibiotic usage reduces the risk of antibiotic resistance and unnecessary use of antibiotics.

Role of probiotics in chronic rhinosinusitis: a systematic review of randomised, controlled trials

OBJECTIVE

This review evaluated the safety profile and efficacy of probiotics in chronic rhinosinusitis and was registered with Prospero (Centre for Reviews and Dissemination number: 42020193529).

METHOD

Literature databases were searched through inception to August 2022. Randomised, controlled trials exploring adjunctive probiotics in adult chronic rhinosinusitis patients were included. From 948 records screened, 4 randomised, controlled trials were included.

RESULTS

Probiotics-associated adverse effects comprised epistaxis and abdominal pain. No reduction in Sino-Nasal Outcome Test values before 4 weeks (p = 0.58) or beyond 8 weeks (p = 0.08) of treatment or reduction of severe symptom frequency (p = 0.75) was observed. Symptom relapse in probiotic-treated patients was significantly lower across all timepoints (p = 0.045). Lower sinusitis relapse risks during treatment (risk ratio = 0.49; p = 0.019) and 8 months post-treatment (risk ratio = 0.56, p = 0.013) were observed. Probiotics demonstrated potential in improving Sino-Nasal Outcome Test symptom subscales, including sleep, psychological and rhinology subscales.

CONCLUSION

The optimal mode of probiotic administration, treatment duration and target patient subgroups requires further study to evaluate the utility of probiotics.

The Impact of Antibiotics and Steroids on the Nasal Microbiome in Patients with Chronic Rhinosinusitis: A Systematic Review According to PICO Criteria

BACKGROUND

The nasal microbiome represents the main environmental factor of the inflammatory process in chronic rhinosinusitis (CRS). Antibiotics and steroids constitute the mainstay of CRS therapies. However, their impact on microbial communities needs to be better understood. This systematic review summarizes the evidence about antibiotics' and steroids' impact on the nasal microbiota in patients with CRS.

METHODS

The search strategy was conducted in accordance with the PRISMA guidelines for systematic reviews. The authors searched all papers in the three major medical databases (PubMed, Scopus, and Cochrane Library) using the PICO tool (population, intervention, comparison, and outcomes). The search was carried out using a combination of the key terms "Microbiota" or "Microbiome" and "Chronic Rhinosinusitis".

RESULTS

Overall, 402 papers were identified, and after duplicate removal (127 papers), excluding papers off-topic (154) and for other structural reasons (110), papers were assessed for eligibility; finally, only 11 papers were included and summarized in the present systematic review. Some authors used only steroids, other researchers used only antibiotics, and others used both antibiotics and steroids. With regard to the use of steroids as exclusive medical treatment, topical mometasone and budesonide were investigated. With regard to the use of antibiotics as exclusive medical treatments, clarithromycin, doxycycline, roxithromycin, and amoxicillin clavulanate were investigated. Regarding the use of both antibiotics and steroids, two associations were investigated: systemic prednisone combined with amoxicillin clavulanate and topical budesonide combined with azithromycin.

CONCLUSIONS

The impact that therapies can have on the nasal microbiome of CRS patients is very varied. Further studies are needed to understand the role of the nasal microbiome, prevent CRS, and improve therapeutic tools for personalized medicine tailored to the individual patient.

Autoimmunity: A New Focus on Nasal Polyps

Chronic rhinosinusitis with nasal polyps (CRSwNP) has long been considered a benign, chronic inflammatory, and hyperplastic disease. Recent studies have shown that autoimmune-related mechanisms are involved in the pathology of nasal polyps. Activated plasma cells, eosinophils, basophils, innate type 2 lymphocytes, mast cells, and proinflammatory cytokine in polyp tissue indicate the mobilization of innate and adaptive immune pathways during polyp formation. The discovery of a series of autoantibodies further supports the autoimmune nature of nasal polyps. Local homeostasis dysregulation, infection, and chronic inflammation may trigger autoimmunity through several mechanisms, including autoantigens overproduction, microbial translocation, molecular mimicry, superantigens, activation or inhibition of receptors, bystander activation, dysregulation of Toll-Like Receptors (TLRs), epitope spreading, autoantigens complementarity. In this paper, we elaborated on the microbiome-mediated mechanism, abnormal host immunity, and genetic changes to update the role of autoimmunity in the pathogenesis of chronic rhinosinusitis with nasal polyps.

IL-13-associated epithelial remodeling correlates with clinical severity in nasal polyposis

BACKGROUND

Epithelial remodeling is a histopathologic feature of chronic inflammatory airway diseases including chronic rhinosinusitis (CRS). Cell-type shifts and their relationship to CRS endotypes and severity are incompletely described.

OBJECTIVE

We sought to understand the relationship of epithelial cell remodeling to inflammatory endotypes and disease outcomes in CRS.

METHODS

Using cell-type transcriptional signatures derived from epithelial single-cell sequencing, we analyzed bulk RNA-sequencing data from sinus epithelial brushings obtained from patients with CRS with and without nasal polyps in comparison to healthy controls.

RESULTS

The airway epithelium in nasal polyposis displayed increased tuft cell transcripts and decreased ciliated cell transcripts along with an IL-13 activation signature. In contrast, CRS without polyps showed an IL-17 activation signature. IL-13 activation scores were associated with increased tuft cell, goblet cell, and mast cell scores and decreased ciliated cell scores. Furthermore, the IL-13 score was strongly associated with a previously reported activated ("polyp") tuft cell score and a prostaglandin E2 activation signature. The Lund-Mackay score, a computed tomographic metric of sinus opacification, correlated positively with activated tuft cell, mast cell, prostaglandin E2, and IL-13 signatures and negatively with ciliated cell transcriptional signatures.

CONCLUSIONS

These results demonstrate that cell-type alterations and prostaglandin E2 stimulation are key components of IL-13-induced epithelial remodeling in nasal polyposis, whereas IL-17 signaling is more prominent in CRS without polyps, and that clinical severity correlates with the degree of IL-13-driven epithelial remodeling.

A Review on the Nasal Microbiome and Various Disease Conditions for Newer Approaches to Treatments

Introduction: Commensal bacteria have always played a significant role in the maintenance of health and disease but are being unravelled only recently. Studies suggest that the nasal microbiome has a significant role in the development of various disease conditions. Search engines were used for searching articles having a nasal microbiome and disease correlation. In olfactory dysfunction, dysbiosis of the microbiome may have a significant role to play in the pathogenesis. The nasal microbiome influences the phenotype of CRS and is also capable of modulating the immune response and plays a role in polyp formation. Microbiome dysbiosis has a pivotal role in the development of Allergic Rhinitis; but, yet known how is this role played. The nasal microbiome has a close association with the severity and phenotype of asthma. They contribute significantly to the onset, severity, and development of asthma. The nasal microbiome has a significant impact on the immunity and protection of its host. The nasal microbiome has been a stimulus in the development of Otitis Media and its manifestations. Studies suggest that the resident nasal microbiome is responsible for the initiation of neurodegenerative diseases like Parkinson's Disease.Materials and Methods: Literature search from PubMed, Medline, and Google with the Mesh terms: nasal microbiome AND diseases. Conclusion: With increasing evidence on the role of the nasal microbiome on various diseases, it would be interesting to see how this microbiome can be modulated by pro/pre/post biotics to prevent a disease or the severity of illness.

Wound healing in endoscopic sinus surgery: Phase 1 clinical trial evaluating the role of Chitogel with adjuvants

OBJECTIVES

This study aimed to determine the safety and efficacy of Chitogel, with and without Deferiprone (Def) and Gallium Protoporphyrin (GaPP), as a promoter of wound healing to improve surgical outcomes after endoscopic sinus susgery.

DESIGN

A double-blinded, randomised control human clinical trial was conducted in patients undergoing ESS as a treatment for chronic rhinosinusitis. Participants underwent functional ESS or FESS with drill out as required and were randomised to receive test product Chitogel, Chitogel in combination with Def or Def-GaPP versus no packing (control).

SETTING

Ostial stenosis and persistent inflammation are the main reasons for revision endoscopic sinus surgery (ESS). Post-operative (PO) dressings can improve PO wound healing and patient outcomes after ESS.

PARTICIPANTS

Eighty two patients were included in this study with 79 patients completing the study with 40 undergoing full house FESS and 39 FESS plus frontal drillout.

MAIN OUTCOME MEASURES

Patients were followed up at 2, 6 and 12 weeks PO, and outcome scores such as SNOT-22, VAS and LKS, pre and post-surgery (12 weeks) were compared.

RESULTS

Seventy nine patients completed the study, there was a significant reduction in SNOT-22 score and improvement of VAS at 12 weeks in patients treated with Chitogel compared to control (p < .05). In those patients, the mean ostium area for the Chitogel and the Chitogel + Def + GaPP groups was higher across all three sinuses compared to the no-treatment control group, without statistical significance. Sphenoid sinus ostium was significantly more patent in patients treated with Chitogel compared to the control at the 12-week time point (p < .05).

CONCLUSION

Chitogel as a PO dressing after ESS results in the best patient-reported symptom scores and objective measurements. The combination of Def and GaPP to Chitogel though proving safe, had no effect on the ostium patency or mucosal healing.

Corynebacterium accolens inhibits Staphylococcus aureus induced mucosal barrier disruption

Background

Corynebacterium accolens (C. accolens) is a common nasal colonizer, whereas Staphylococcus aureus (S. aureus) is typically regarded a pathogenic organism in patients with chronic rhinosinusitis (CRS). This study aims to evaluate the interaction of the two bacteria in vitro.

Methods

Clinical isolates of C. accolens and S. aureus from sinonasal swabs, as well as primary human nasal epithelial cells (HNECs) cultured from cellular brushings of both healthy and CRS patients were used for this study. The cell-free culture supernatants of all isolates grown alone and in co-cultures were tested for their effects on transepithelial electrical resistance (TER), FITC-Dextran permeability, lactate dehydrogenase (LDH), and IL-6 and IL-8 secretion of HNECs. Confocal scanning laser microscopy and immunofluorescence were also used to visualize the apical junctional complexes. C. accolens cell-free culture supernatants were also tested for antimicrobial activity and growth on planktonic and biofilm S. aureus growth.

Results

The cell-free culture supernatants of 3\C. accolens strains (at 60% for S. aureus reference strain and 30% concentration for S. aureus clinical strains) inhibited the growth of both the planktonic S. aureus reference and clinical strains significantly. The C. accolens cell-free culture supernatants caused no change in the TER or FITC-Dextran permeability of the HNEC-ALI cultures, while the cell-free culture supernatants of S. aureus strains had a detrimental effect. Cell-free culture supernatants of C. accolens co-cultured with both the clinical and reference strains of S. aureus delayed the S. aureus-dependent mucosal barrier damage in a dose-dependent manner.

Conclusion

Corynebacterium accolens cell-free culture supernatants appear to inhibit the growth of the S. aureus planktonic bacteria, and may reduce the mucosal barrier damage caused by S. aureus.

Probiotics for Otolaryngologic Disorders

Chronic low-level inflammation is a causative factor in many of our common diseases. Switching to an anti-inflammatory diet is an important step that patients can take in for rectifying this risk factor. In this review, the author discusses the essential components of an anti-inflammatory diet and its contribution not only to the overall well-being but also to the body's defense against disease. The human microbiome is reviewed in detail and dietary connections and recommendations are explained for several otolaryngologic conditions.

In vitro and in vivo evaluation of probiotic properties of Corynebacterium accolens isolated from the human nasal cavity

Corynebacterium accolens strains are increasingly recognized as beneficial bacteria that can confer a health benefit on the host. In the current study, the probiotic potential of three C. accolens strains, C779, C781 and C787 derived from a healthy human nasal cavity were investigated. These strains were examined for their adhesion to HNECs, competition with Staphylococcus aureus for adhesion, toxicity, induction of IL-6, antibiotic susceptibility and the presence of antibiotic resistance and virulence genes. Furthermore, the safety and efficacy of strains were evaluated in vivo using Caenorhabditis elegans. The adhesion capacity of C. accolens to HNECs was strain-dependent. Highest adhesion was observed for strain C781. None of the C. accolens strains tested caused cell lysis. All strains were able to outcompete S. aureus for cell adhesion and caused a significant decrease of IL-6 production by HNECs co-exposed to S. aureus when compared to the control groups. All strains were sensitive or showed intermediate sensitivity to 10 different antibiotics. Whole Genome Sequence analysis showed C. accolens C781 and C787 did not possess antibiotic resistance genes whereas strain C779 harboured 5 genes associated with resistance to Aminoglycoside, Chloramphenicol and Erythromycin. In addition, no virulence genes were detected in any of the 3 strains. Moreover, the tested strains had no detrimental effect on worm survival and induced protection from S. aureus-mediated infection. Taken all together, C. accolens strains, C781 and C787 displayed probiotic potential and hold promise for use in clinical applications for combating dysbiosis in chronic rhinosinusitis.

The Upper Airway Microbiota, Environmental Exposures, Inflammation, and Disease

Along with playing vital roles in pathogen exclusion and immune system priming, the upper airways (UAs) and their microbiota are essential for myriad physiological functions such as conditioning and transferring inhaled air. Dysbiosis, a microbial imbalance, is linked with various diseases and significantly impedes the quality of one’s life. Daily inhaled exposures and/or underlying conditions contribute to adverse changes to the UA microbiota. Such variations in the microbial community exacerbate UA and pulmonary disorders via modulating inflammatory and immune pathways. Hence, exploring the UA microbiota’s role in maintaining homeostasis is imperative. The microbial composition and subsequent relationship with airborne exposures, inflammation, and disease are crucial for strategizing innovating UA diagnostics and therapeutics. The development of a healthy UA microbiota early in life contributes to normal respiratory development and function in the succeeding years. Although different UA cavities present a unique microbial profile, geriatrics have similar microbes across their UAs. This lost community segregation may contribute to inflammation and disease, as it stimulates disadvantageous microbial–microbial and microbial–host interactions. Varying inflammatory profiles are associated with specific microbial compositions, while the same is true for many disease conditions and environmental exposures. A shift in the microbial composition is also detected upon the administration of numerous therapeutics, highlighting other beneficial and adverse side effects. This review examines the role of the UA microbiota in achieving homeostasis, and the impact on the UAs of environmental airborne pollutants, inflammation, and disease.

Review: The Nose as a Route for Therapy. Part 2 Immunotherapy

The nose provides a route of access to the body for inhalants and fluids. Unsurprisingly it has a strong immune defense system, with involvement of innate (e.g., epithelial barrier, muco- ciliary clearance, nasal secretions with interferons, lysozyme, nitric oxide) and acquired (e.g., secreted immunoglobulins, lymphocytes) arms. The lattice network of dendritic cells surrounding the nostrils allows rapid uptake and sampling of molecules able to negotiate the epithelial barrier. Despite this many respiratory infections, including SARS-CoV2, are initiated through nasal mucosal contact, and the nasal mucosa is a significant "reservoir" for microbes including Streptococcus pneumoniae, Neisseria meningitidis and SARS -CoV-2. This review includes consideration of the augmentation of immune defense by the nasal application of interferons, then the reduction of unnecessary inflammation and infection by alteration of the nasal microbiome. The nasal mucosa and associated lymphoid tissue (nasopharynx-associated lymphoid tissue, NALT) provides an important site for vaccine delivery, with cold-adapted live influenza strains (LAIV), which replicate intranasally, resulting in an immune response without significant clinical symptoms, being the most successful thus far. Finally, the clever intranasal application of antibodies bispecific for allergens and Intercellular Adhesion Molecule 1 (ICAM-1) as a topical treatment for allergic and RV-induced rhinitis is explained.

Review of probiotic use in otolaryngology

OBJECTIVE

Probiotics have garnered considerable attention as an intervention for various conditions common to otolaryngology. The purpose of this review is to evaluate the current literature to offer recommendations about the safety and efficacy of probiotic management in otolaryngologic conditions.

STUDY DESIGN

Narrative review.

METHODS

PubMed and Google Scholar were queried using pertinent keywords to retrieve relevant studies with particular focus in the recent 5 years. All abstracts were assessed and studies, reviews and meta-analyses achieving evaluation of probiotic therapies or characterization of microbiome changes were included for further review. Studies were categorized by condition or anatomic region across various subspecialties. Key data parameters were extracted and evaluated across studies and treatment types.

RESULTS

Strong evidence exists for the use probiotic agents to improve symptoms for allergic rhinitis, chronic rhinosinusitis and certain dental conditions. Despite promising results, further investigation is needed to evaluate and optimize probiotic delivery for mitigating otitis media, oropharyngeal inflammation and upper respiratory tract infections. Preclinical studies suggest that probiotics may potentially offer benefit for voice prosthesis maintenance, wound healing and mitigation of oral dysplasia.

CONCLUSION

Probiotic therapies may offer clinical benefit in a variety of contexts within the field of otolaryngology, especially for short-term relief of certain inflammatory conditions of the oral cavity, auditory and nasal cavities. Further investigation is warranted for evaluation of long-term outcomes and pathogenic deterrence.

Comparing the nasal bacterial microbiome diversity of allergic rhinitis, chronic rhinosinusitis and control subjects

PURPOSE

Until now, the microbiome of the nasal cavity and its contribution to nasal mucosal disease has remained poorly understood. The advent of cultivation-free molecular methods makes it possible to characterize the total microbiome of the nasal cavity. We sought to assess the microbial diversity and composition of the middle meatus in allergic rhinitis (AR) patients, chronic rhinosinusitis patients without polyps (CRSsNP) and a control population to determine the microbiota associated with the pathogenesis of AR and CRSsNP.

METHODS

Microbial characterization was determined using 16S rRNA gene sequencing of 122 nasal swabs collected from patients with AR (n = 52) and CRSsNP (n = 37), and from healthy controls (n = 33).

RESULTS

There was no difference in nasal microbiome richness and diversity among the three groups, and the dominant phyla were similar among three groups including Firmicutes, Proteobacteria, Actinobacteria and Bacteroidetes. However, Spirochaetae abundance was significantly higher in AR than in the control group after FDR correction (FDR p = 0.021). At the genus level, although there was no statistical significance after FDR correction, there was a trend that Pseudomonas and Peptostreptococcaceae abundance were higher in AR than in controls (p = 0.005, p = 0.005) and CRSsNP (p = 0.023, p = 0.034); Lactobacillus abundance was lower in AR than in controls (p = 0.021); Moraxella abundance was lower in CRSsNP than in controls (p = 0.006); Haemophilus abundance was higher in CRSsNP than in AR (p = 0.003) but lower in AR than in controls (p = 0.018).

CONCLUSION

These results suggested that microbial dysbiosis may play a role in the pathogenesis of heterogeneous nasal mucosal inflammation.

Corynebacterium accolens Has Antimicrobial Activity against Staphylococcus aureus and Methicillin-Resistant S. aureus Pathogens Isolated from the Sinonasal Niche of Chronic Rhinosinusitis Patients

Corynebacterium accolens is the predominant species of the healthy human nasal microbiota, and its relative abundance is decreased in the context of chronic rhinosinusitis (CRS). This study aimed to evaluate the antimicrobial potential of C. accolens isolated from a healthy human nasal cavity against planktonic and biofilm growth of Staphylococcus aureus (S. aureus) and methicillin-resistant S. aureus (MRSA) clinical isolates (CIs) from CRS patients. Nasal swabs from twenty non-CRS control subjects were screened for the presence of C. accolens using microbiological and molecular techniques. C. accolens CIs and their culture supernatants were tested for their antimicrobial activity against eight S. aureus and eight MRSA 4CIs and S. aureus ATCC25923. The anti-biofilm potential of C. accolens cell-free culture supernatants (CFCSs) on S. aureus biofilms was also assessed. Of the 20 nasal swabs, 10 C. accolens CIs were identified and confirmed with rpoB gene sequencing. All isolates showed variable antimicrobial activity against eight out of 8 S. aureus and seven out of eight MRSA CIs. Culture supernatants from all C. accolens CIs exhibited a significant dose-dependent antibacterial activity (p < 0.05) against five out of five representative S. aureus and MRSA CIs. This inhibition was abolished after proteinase K treatment. C. accolens supernatants induced a significant reduction in metabolic activity and biofilm biomass of S. aureus and MRSA CIs compared to untreated growth control (p < 0.05). C. accolens exhibited antimicrobial activity against S. aureus and MRSA CIs in both planktonic and biofilm forms and holds promise for the development of innovative probiotic therapies to promote sinus health.

Microbiomics of irrigation with xylitol or Lactococcus lactis in chronic rhinosinusitis

OBJECTIVE

Topical sinonasal rinse therapies may alter the local microbiome and improve disease control in chronic rhinosinusitis (CRS). The objective of this study was to examine microbiome changes in post-surgical CRS patients when rinsing with commercially available products containing xylitol or Lactococcus lactis.

METHODS

A crossover-type protocol with a washout period was designed. Swab samples from anterior ethmoid cavities of CRS patients were collected prospectively at baseline. Subjects were provided packets containing either L. lactis W136 or xylitol in non-blinded fashion and instructed to add it to their rinse bottles daily for 28 days, after which another swab was taken. A saline wash-out period was completed and a third swab taken. A final 28-day regimen of the opposite product was followed by a final swab. DNA extraction and sequencing of the 16S rRNA gene allowed for global microbiome analysis.

RESULTS

We enrolled 25 subjects with CRS and 10 controls resulting in 70 adequate samples. Increased detection of Lactococcus was observed after use of L. lactis. No significant trends in alpha or beta diversity as a result of treatment were observed. SNOT-22 score did not change significantly following treatment with xylitol, L. lactis, or saline.

CONCLUSION

We did not detect any major clinical or microbiome-level effect due to treatment with two topical rinse products. Further research is needed to elucidate their clinical utility and possible probiotic effect.

LEVEL OF EVIDENCE

3.

[Neutrophil extracellular traps in the pathogenesis of chronic rhinosinusitis]

The review presents the current understanding of the pathogenesis of chronic rhinosinusitis. The causes of damage to the mucous membrane of the paranasal sinuses are most often the result of a combination of immunological, infectious and anatomical factors. This indicates the need for a multidisciplinary approach to the study of the pathogenesis of this pathology. There is no single universally recognized classification of chronic rhinosinusitis, which takes into account histological and immunological changes in the mucous membrane of the paranasal sinuses. The discovery of the mechanism of completion of the life cycle of neutrophils - the formation of a neutrophil extracellular trap or NETosis, different from necrosis and apoptosis, opened up new prospects in the study of the pathogenesis of inflammatory processes, including rhinosinusitis. Neutrophil extracellular traps reduce the permeability of the epithelial barrier in the mucous membrane of the paranasal sinuses. This determines their possible role in the etiopathogenesis of rhinosinusitis. In recent years, more and more attention has been paid to the feasibility, effectiveness and safety of therapy that affects the immune component of the inflammatory process, including NETosis. The data obtained in the study of extracellular traps can be used in clinical practice. It is neutrophil extracellular traps that can become a potential target in the treatment of patients with chronic rhinosinusitis.

The international sinonasal microbiome study: A multicentre, multinational characterization of sinonasal bacterial ecology

The sinonasal microbiome remains poorly defined, with our current knowledge based on a few cohort studies whose findings are inconsistent. Furthermore, the variability of the sinus microbiome across geographical divides remains unexplored. We characterize the sinonasal microbiome and its geographical variations in both health and disease using 16S rRNA gene sequencing of 410 individuals from across the world. Although the sinus microbial ecology is highly variable between individuals, we identify a core microbiome comprised of Corynebacterium, Staphylococcus, Streptococcus, Haemophilus and Moraxella species in both healthy and chronic rhinosinusitis (CRS) cohorts. Corynebacterium (mean relative abundance = 44.02%) and Staphylococcus (mean relative abundance = 27.34%) appear particularly dominant in the majority of patients sampled. Amongst patients suffering from CRS with nasal polyps, a statistically significant reduction in relative abundance of Corynebacterium (40.29% vs 50.43%; P = .02) was identified. Despite some measured differences in microbiome composition and diversity between some of the participating centres in our cohort, these differences would not alter the general pattern of core organisms described. Nevertheless, atypical or unusual organisms reported in short-read amplicon sequencing studies and that are not part of the core microbiome should be interpreted with caution. The delineation of the sinonasal microbiome and standardized methodology described within our study will enable further characterization and translational application of the sinus microbiota.

Low-dose and long-term azithromycin significantly decreases Staphylococcus aureus in the microbiome of refractory CRS patients

BACKGROUND

The sinonasal microbiome is believed to play an important role in the pathophysiology of refractory chronic rhinosinusitis (CRS). We evaluated changes in the microbiome following a 4-month course of low-dose azithromycin. Assessing microbiome alterations following such a treatment may help identify underlying mechanisms of this drug.

METHODS

A total of 48 adults with refractory CRS were enrolled in a double-blind, randomized, placebo-controlled trial. Patients were randomized to 250 mg of azithromycin or placebo 3 times weekly for 4 months. During this time, daily budesonide saline irrigations were continued. Sinonasal swabs were collected by endoscopically-assisted method prior to treatment initiation and at the end of it, and sent for 16S ribosomal RNA gene sequencing. High-resolution ANCHOR pipeline was used to infer and annotate putative species. The 2 patient groups were compared using DESeq2 differential abundance analysis.

RESULTS

From initiation to the end of azithromycin treatment, patients showed a significant difference in beta diversity analysis (p = 0.0004) along with a significant decrease in 71 different operational taxonomic units (OTUs) of Staphylococcus aureus (false discovery rate [FDR] < 0.05) obtained from the differential abundance analysis. This was not observed in placebo-treated patients. By the end of treatments, azithromycin-treated patients had a significant decrease in 29 different OTUs of S. aureus (FDR < 0.05) when compared to placebo.

CONCLUSION

A 4-month course of 250 mg of azithromycin 3 times weekly in patients with refractory CRS significantly decreases S. aureus abundance in the sinonasal microbiome. Considering the pathogenic role of S. aureus in the refractory CRS population, azithromycin may constitute an additional therapeutic option to help control this disease.

Bacterial Flora of the Nose and Paranasal Sinuses Among Patients Over 65 Years Old with Chronic Rhinosinusitis Who Underwent Endoscopic Sinus Surgery

PURPOSE

Chronic rhinosinusitis (CRS) is one of the most common chronic diseases in the geriatric population. However, CRS inflammatory mechanisms in older people have not been thoroughly investigated. Our work aimed to analyze the bacterial flora of the nose and paranasal sinuses in patients with CRS over 65 years of age, including comorbidities, previously performed endoscopic sinus surgery (ESS), presence or absence of polyps and the extent of the inflammatory process.

PATIENTS AND METHODS

The study involved 529 patients between 18 and 84 years of age with chronic rhinosinusitis who underwent endoscopic sinus surgery. There were 101 patients separated over 65 years of age (M = 52, K = 49, mean age 69 ± 0.7 years). The control group consisted of 168 patients aged 18-40 years with CRS. The bacterial culture of material collected from the patients during ESS was analyzed.

RESULTS

In the group of patients over 65 years of age, more frequent occurrence of Proteus spp. and Pseudomonas aeruginosa was found in comparison to younger patients. In older patients with bronchial asthma, the occurrence of S. aureus, Escherichia coli, and Citrobacter spp. was more frequent than in control group. Multiple sinus surgical procedures in older patients were associated with the dominance of Staphylococcus aureus and Escherichia coli, which was not demonstrated in the control group. There were no statistically significant differences between the occurrence of bacterial strain and the presence of polyps, both in the group of patients over 65 years of age as well as in the control group.

CONCLUSION

The bacterial flora of patients with CRS is different in older and younger patients. A different therapeutic approach should be considered in older patients with CRS, but this problem requires further studies.

Association of the sinonasal bacterial microbiome with clinical outcomes in chronic rhinosinusitis: a systematic review

Background

The association between sinonasal microbiome and clinical outcomes of patients with chronic rhinosinusitis (CRS) is unclear. We performed a systematic review of prior studies evaluating the CRS microbiome in relation to clinical outcomes.

Methods

Computerized searches of PubMed/Medline, Cochrane, and EMBASE were updated through October 2019 revealing a total of 9 studies including 244 CRS patients. A systematic review of the literature was performed, including data extraction focusing on sample region, sequencing platforms, predominant organisms, and outcomes measures.

Results

Nine criterion‐meeting studies included 244 CRS patients, with varied results. Eight studies used 16s–ribosomal RNA (16s‐rRNA) gene sequencing to assess the sinonasal microbiome and 1 used 16s‐rRNA PhyloChip analysis. Seven studies used Sino‐Nasal Outcome Test scores, 1 applied another CRS symptom metric, and 1 used need for additional procedures/antibiotics as the primary clinical outcome. Three studies suggest that baseline abundance of phylum Actinobacteria (specifically genus Corynebacterium) was predictive of better surgical outcome. One study found C. tuberculostearicum was positively correlated with symptom severity. Another study revealed genus Escherichia was overrepresented in CRS and had positive correlation with increased symptom scores. In addition, 1 study identified Acinetobacter johnsonii to be associated with improvement in symptom scores while supporting Pseudomonas aeruginosa as having a negative impact on quality of life.

Conclusion

Microbiome data are varied in their association with clinical outcomes of CRS patients. Further research is required to identify if predominance of certain microbes within the microbiome is predictive of CRS patients’ outcomes.

The microbiome of the upper respiratory tract in health and disease

The human upper respiratory tract (URT) offers a variety of niches for microbial colonization. Local microbial communities are shaped by the different characteristics of the specific location within the URT, but also by the interaction with both external and intrinsic factors, such as ageing, diseases, immune responses, olfactory function, and lifestyle habits such as smoking. We summarize here the current knowledge about the URT microbiome in health and disease, discuss methodological issues, and consider the potential of the nasal microbiome to be used for medical diagnostics and as a target for therapy.

Sub-Inhibitory Clindamycin and Azithromycin reduce S. aureus Exoprotein Induced Toxicity, Inflammation, Barrier Disruption and Invasion

Background: Chronic rhinosinusitis (CRS) is defined as a chronic inflammation of the nose and paranasal sinus mucosa associated with relapsing infections—particularly with S. aureus. Long-term treatments with protein synthesis inhibitor antibiotics have been proposed to reduce inflammation in the context chronic severe inflammatory airway pathologies, including CRS. This study assessed the effect of subinhibitory clindamycin and azithromycin on S. aureus exoprotein induced inflammation, toxicity and invasiveness. Methods: S. aureus ATCC51650 and two clinical isolates grown in planktonic and biofilm form were treated with subinhibitory clindamycin and azithromycin. Exoproteins were collected and applied to primary human nasal epithelial cells (HNECs) in monolayers and at air-liquid interface. This was followed by lactate dehydrogenase (LDH), enzyme-linked immunosorbent assay (ELISA), Transepithelial Electrical Resistance (TEER) and paracellular permeability assays to assess the effect on cell toxicity, inflammatory cytokine production and mucosal barrier structure and function, respectively. The effect of these treatments was tested as well on the S. aureus invasiveness of HNECs. Results: Subinhibitory clindamycin reduced S. aureus exoprotein production in planktonic and biofilm form, thereby blocking exoprotein-induced toxicity, reversing its detrimental effects on mucosal barrier structure and function and modulating its inflammatory properties. Sub-inhibitory azithromycin had similar effects—albeit to a lesser extent. Furthermore, clindamycin—but not azithromycin—treated S. aureus lost its invasive capacity of HNECs. Conclusion: Subinhibitory clindamycin and azithromycin reduce S. aureus exoprotein production, thereby modulating the inflammatory cascade by reducing exoprotein-induced toxicity, inflammation, mucosal barrier disruption and invasiveness.

Analysis of Sinonasal Microbiota in Exacerbations of Chronic Rhinosinusitis Subgroups

Objective

Microbiome analyses now allow precise determination of the sinus microbiota of patients with exacerbations of chronic rhinosinusitis (CRS). The aim of this report is to describe the sinus microbiota of acute exacerbations in CRS clinical subgroups (with nasal polyps [CRSwNP], without nasal polyps [CRSsNP], and allergic fungal rhinosinusitis [AFRS]).

Study Design

Retrospective chart review.

Setting

Tertiary rhinology practice.

Subjects and Methods

A retrospective review was performed of all patients whose sinus microbiota were assayed via a commercially available microbiome technology during an acute CRS exacerbation during the 2-year period ending December 31, 2016. All samples were sinus aspirates collected under endoscopic visualization in clinic.

Results

Samples from a total of 134 patients (65 CRSsNP, 55 CRSwNP, and 14 AFRS) were reviewed. The observed richness (number of taxa >2% relative abundance) ranged between 1 and 11 taxa, with an average of 3 taxa per specimen. The most common bacteria in all groups were Staphylococcal spp (including Staphylococcus aureus), Streptococcus spp, Pseudomonas spp, and Escherichia spp. S aureus had an increased prevalence in CRSsNP and AFRS as compared with CRSwNP. Otherwise, the sinus microbiota were markedly similar among all 3 clinical subgroups.

Conclusions

Many bacterial types are identified during acute CRS exacerbation according to DNA-based detection techniques. Bacterial richness was remarkably low in all samples. Few differences in the patterns among clinical subgroups were observed. Further investigation is warranted to determine the clinical significance of these observations and their role in current clinical algorithms.

Kappa-carrageenan sinus rinses reduce inflammation and intracellular Staphylococcus aureus infection in airway epithelial cells

BACKGROUND

Chronic rhinosinusitis (CRS) is a common disease, often refractory to conventional antimicrobial treatment. In this study we investigate the antimicrobial and anti-inflammatory effects of adding kappa-carrageenan to a commercially available sinus rinse.

METHODS

Kappa-carrageenan was added to Flo CRS and Flo Sinus Care sinus rinses and applied directly to air-liquid interface cultured primary human nasal epithelial cells (HNECs) from 10 CRS patients. Inflammatory markers were measured using enzyme-linked immunosorbent assay. Kappa-carrageenan-supplemented sinus rinses were applied to human bronchial epithelial cells (HBEs) in the presence of different Staphylococcus aureus strains to observe the effect on intracellular infection rates.

RESULTS

Flo Sinus Care with kappa-carrageenan rinse solutions resulted in a marked reduction of interleukin-6 (IL-6) production by HNECs from CRS patients (p = 0.007). Both Flo CRS and Flo Sinus Care rinses significantly reduced the S aureus intracellular infection of HBEs (p < 0.0001). The addition of kappa-carrageenan to both Flo CRS and Flo Sinus Care rinses further reduced the intracellular infection rate by an average of 2%.

CONCLUSIONS

The commonly used sinus irrigation product Flo Sinus Care with added kappa-carrageenan reduces IL-6 production by HNECs in vitro. Flo CRS and Flo Sinus Care rinses significantly reduced S aureus intracellular infection rates of HBE cells. Our findings may have clinical relevance for CRS patient management.

The microbiome and chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a multifactorial condition in which the microbiota plays a pathogenic role. The nature of the interaction between the microbiota and the local immune system is very complex and has not been fully elucidated. Recent improvements in the microbiological techniques have greatly advanced our understanding of the complex nature of this interaction. This paper summarizes the current state of the rapidly evolving research on this subject. Defining the nature of the role of the microbiota in CRS is important because of the associated therapeutic implications.

Relative abundance of nasal microbiota in chronic rhinosinusitis by structured histopathology

BACKGROUND

Chronic rhinosinusitis (CRS) is an inflammatory disease process with several different phenotypes. Recent data has shown that CRS phenotypes maintain distinct nasal microbiota that may predict surgical outcomes. Nasal microbiota and structured histopathologic reporting have the potential to further differentiate subtypes and provide additional insight into the pathophysiology of CRS.

METHODS

Sinus swabs collected during functional endoscopic sinus surgery (FESS) were studied by polymerase chain reaction analysis of 16S ribosomal RNA. A structured histopathology report of 13 variables was utilized to analyze sinus tissue removed during FESS. Histopathology variables and relative abundance of nasal microbiota were compared among CRS patients.

RESULTS

A total of 51 CRS patients who underwent FESS were included. Relative abundance of the Firmicutes phylum in nasal microbiota of CRS patients was associated with presence of neutrophilic infiltrate (27.47 ± 44.75 vs 9.21 ± 11.84, p < 0.029), presence of mucosal ulceration (47.67 ± 45.52 vs 13.27 ± 26.48, p < 0.041), presence of squamous metaplasia (5562.70 ± 2715.66 vs 3563.73 ± 2580.84, p < 0.035), and absence of Charcot-Leyden crystals (5423.00 ± 3320.57 vs 679.94 ± 1653.66, p < 0.001). Relative abundance of the Bacteroidetes phylum in nasal microbiota of CRS patients was associated with increased severity of inflammatory degree (p < 0.004) and presence of mucosal ulceration (p < 0.004).

CONCLUSION

Distinct histopathologic features of CRS are associated with relative abundance of nasal microbiota phyla, specifically Firmicutes and Bacteroidetes. These findings contribute to the growing body of literature on microbiota in sinonasal disease and may have important implications for understanding pathophysiologic mechanisms of CRS subtypes and disease management.

Chronic Rhinosinusitis: Potential Role of Microbial Dysbiosis and Recommendations for Sampling Sites

Chronic rhinosinusitis (CRS) is an inflammatory condition that affects up to 12% of the human population in developed countries. Previous studies examining the potential role of the sinus bacterial microbiota within CRS infections have found inconsistent results, possibly because of inconsistencies in sampling strategies. The aim of this study was to determine whether the sinus microbiome is altered in CRS and additionally if the middle meatus is a suitable representative site for sampling the sinus microbiome. Swab samples were collected from 12 healthy controls and 21 CRS patients, including all eight sinuses for CRS patients and between one and five sinuses for control subjects. The left and right middle meatus and nostril swabs were also collected. Significant differences in the sinus microbiomes between CRS and control samples were revealed using high-throughput 16S rRNA gene sequencing. The genus Escherichia was over-represented in CRS sinuses, and associations between control patients and Corynebacterium and Dolosigranulum were also identified. Comparisons of the middle meatuses between groups did not reflect these differences, and the abundance of the genus Escherichia was significantly lower at this location. Additionally, intra-patient variation was lower between sinuses than between sinus and middle meatus, which together with the above results suggests that the middle meatus is not an effective representative sampling site.

The Potential for Topical Probiotic Treatment of Chronic Rhinosinusitis, a Personal Perspective

This review describes the rationale for topical probiotic intervention, the obstacles we are facing and a strategy for future research in the use of probiotics to modify CRS symptoms and disease expression. Recent advances in molecular microbiology has revealed a plethora of microbial DNA in the nasal cavity and sinuses of healthy subjects as well as in chronic sinusitis (CRS) patients. An infection is today rather seen as an imbalance between the commensal microbiome and the bacterial pathogens, resulting in a reduction in commensal bacterial diversity, combined with an increase in the growth of microbes eliciting an inflammatory response. This will in turn lead to the clinical symptoms of sinusitis. Probiotics (microorganisms that confer a health benefit) can be used either as a form of living antibiotics treatment, or as an immune-modulatory intervention. Topical probiotics, which is the focus of this review, have shown efficacy in a limited number of trials in otitis media and tonsillitis, but to date not in CRS. Although bacterial interference capacity against pathogens can be determined in in vitro experiments, it may not translate to a health benefit. This limits the role of laboratory research in identifying probiotic strains with a clinical benefit. To gain more clinical experience without further delay, I recommend future research to focus on empirical clinical trials in well-defined CRS patient populations and study the underlying mechanisms in more detail once a clinical benefit has been established.