Changes in the bacterial microbiome of patients with chronic rhinosinusitis after endoscopic sinus surgery

The Role of the Gut and Airway Microbiota in Chronic Rhinosinusitis with Nasal Polyps: A Systematic Review

In recent years, there has been growing interest in understanding the potential role of microbiota dysbiosis or alterations in the composition and function of human microbiota in the development of chronic rhinosinusitis with nasal polyposis (CRSwNP). This systematic review evaluated the literature on CRSwNP and host microbiota for the last ten years, including mainly nasal bacteria, viruses, and fungi, following the PRISMA guidelines and using the major scientific publication databases. Seventy original papers, mainly from Asia and Europe, met the inclusion criteria, providing a comprehensive overview of the microbiota composition in CRSwNP patients and its implications for inflammatory processes in nasal polyps. This review also explores the potential impact of microbiota-modulating therapies for the CRSwNP treatment. Despite variability in study populations and methodologies, findings suggest that fluctuations in specific taxa abundance and reduced bacterial diversity can be accepted as critical factors influencing the onset or severity of CRSwNP. These microbiota alterations appear to be implicated in triggering cell-mediated immune responses, cytokine cascade changes, and defects in the epithelial barrier. Although further human studies are required, microbiota-modulating strategies could become integral to future combined CRSwNP treatments, complementing current therapies that mainly target inflammatory mediators and potentially improving patient outcomes.

Bacterial and fungal communities in chronic rhinosinusitis with nasal polyps

OBJECTIVE

Multiple inflammatory mechanisms dynamically interact in the development of chronic rhinosinusitis with nasal polyps (CRSwNP). Disruption of the relationship between host and environmental factors on the mucosal surface leads to the development of inflammation. Microorganisms constitute the most important part of environmental factors.

METHODS

28 volunteers (18 CRSwNP patients and 10 healthy individuals) were included in the study. Eight patients were recurrent nasal polyposis cases, and the remaining were primary cases. Swab samples were taken from the middle meatus under endoscopic examination from all participants. After DNA extraction, a library was created with the Swift Amplicon 16S + ITS kit and sequenced with Illumina Miseq. Sequence analysis was performed using QIIME, UNITE v8.2 database for ITS and Silva v138 for 16S rRNA.

RESULTS

The predominant bacteria in all groups were Firmicutes, Proteobacteria, Actinobacteria as phyla and Staphylococcus, Corynebacterium, Sphingomonas as genera. Comparison of bacterial communities of CRSwNP patients and control group highlighted Corynebacterium, as the differentiating taxa for control group and Streptococcus, Moraxella, Rothia, Micrococcus, Gemella, and Prevotella for CRSwNP patients. The predominant fungal genus in all groups was Malassezia. Staphylococcus; showed a statistically significant negative correlation with Dolosigranulum. Corynebacterium had a positive correlation with Anaerococcus, and a negative correlation with Neisseria, Prevotella, Fusobacterium and Peptostreptococcus.

CONCLUSION

Nasal microbiome of CRSwNP patients shows greater inter-individual variation than the control group. Corynebacterium is less abundant in patients with CRSwNP compared to the control group. Malassezia is the predominant fungus in the nasal cavity and paranasal sinuses and correlates positively with the abundance of Corynebacterium.

The Effect of Corticosteroids on Sinus Microbiota in Chronic Rhinosinusitis Patients with Nasal Polyposis

BACKGROUND

Chronic rhinosinusitis with nasal polyposis (CRSwNP) is a multifactorial disease with no known single cause, but it is thought that bacteria play a role in the disease process.

OBJECTIVE

This pilot study aims to assess the longitudinal effect of corticosteroid therapy on sinus microbiota in chronic rhinosinusitis patients with nasal polyposis (CRSwNP).

METHODS

A longitudinal prospective case-control study was done on patients with CRSwNP and healthy controls. Patients with CRSwNP were randomly allocated to a corticosteroids and antibiotics treatment group (CRSwNP-SA) or a corticosteroid-only treatment group (CRSwNP-S). Data were collected at three-time points (before treatment, 1, and 3 months after treatment). Specimens were cultured and matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry (MS) was used as a bacterial detection method.

RESULTS

Data from 29 patients with CRSwNP (16 CRSwNP-SA and 13 CRSwNP-S) was compared to 15 healthy subjects. Patients reported significant symptom improvement initially (1 month), but not in the long-term (3 months). This result was found in both treatment groups, whether or not antibiotics were used. After 3 months from treatment, the prevalence of Corynebacterium genera tended to increase in the CRSwNP-SA, while Staphylococcus and Gram-negative genera (Pseudomonas) tended to increase in the CRSwNP-S. Smoking, aspirin sensitivity, and previous endoscopic sinus surgery were found to be co-factors significantly associated with the response to systemic corticosteroid therapy.

CONCLUSION

In this pilot study, both treatment options were effective to improve symptoms in the short-term but not in the long-term, and were not linked to any clear sinus microbiota response. As a result, this study supports the avoidance of systemic antibiotics without evidence of active infection.

Analysis of microbiota profile and nutritional status in male professional football players

BACKGROUND

The interest in the effect of gut microbiota on athlete health has increased in recent years. Available data indicate a relationship between gut microbiota composition and physical activity, suggesting that changes in the microbiota may contribute to the host's physical performance. Studies show that leaky gut syndrome is highly correlated with upper respiratory infections and gastrointestinal disorders in endurance sports. This study aims to reveal the relationship between microbiota profiles, and the nutritional status of football players who perform endurance exercises.

METHODS

Twenty male professional football players playing in one of the Turkish Football Federation Second League clubs participated in the study. Fecal samples were collected and stored at -86 °C, and the fecal microbiota was analyzed through 16s rRNA gene sequencing. The body composition of the football players was measured using a bioelectrical impedance analyzer. In addition, the 3-day food intake of the participants was recorded with the help of a dietitian.

RESULTS

In the microbiota of football players, four phyla, 10 genera, and four species with densities above 1% were found. Body fat percentage was observed to be negatively correlated with the species of Faecalibacterium prausnitzii and Bacteroides vulgatus and the genus of Faecalibacterium (P<0.05). Considering the nutritional status, the fat intake was found to be positively correlated with Actinobacteria and Blautia coccoides; energy and fiber intake with Prevotella and Prevotella copri (P<0.05). In addition, there was a negative correlation between carbohydrate intake and Faecalibacterium (P<0.05).

CONCLUSIONS

Our study is the first to reveal the microbiota profile of professional Turkish football players. It was found that football players' nutritional status and anthropometric measurements of are significantly related to phylum, genus and species ranks in the microbiota. These results support the bidirectional interaction between microbiota and sports. The relationship between microbiota and sports health/performance is thought to be further clarified with future studies.

Alterations of nasal microbiome in eosinophilic chronic rhinosinusitis

BACKGROUND

Exposure to microbes may be important in the development of chronic rhinosinusitis (CRS). Dysbiosis of the nasal microbiome is considered to be related to CRS with nasal polyps (CRSwNP). The link between the nasal microbiota and eosinophilic CRSwNP (eCRSwNP) has rarely been studied.

OBJECTIVE

The aim of this study was to rigorously characterize nasal dysbiosis in a cohort of patients with eCRSwNP and compare the nasal microbiomes of these patients with those of healthy controls (HCs).

METHODS

We performed a cross-sectional study of 34 patients with eCRSwNP, 10 patients without CRSwNP, and 44 HCs by using 16S rRNA gene sequencing. An independent cohort of 14 patients with eCRSwNP, 9 patients without CRSwNP, and 11 HCs was used to validate the results.

RESULTS

Compared with the nasal microbiome of healthy controls, the nasal microbiome of patients with eCRSwNP was characterized by higher α-diversity (Shannon and Chao1 index) and a distinct composition of microbes. Notably, the distinct differences in microbial composition between patients with eCRSwNP and HCs were significantly correlated with eCRSwNP disease status. Furthermore, in a diagnostic model generated by using these differences, a combination of 15 genera could be used to distinguish patients with eCRSwNP from HCs, with an area under the curve of approximately 0.8 in both the exploration and validation cohorts.

CONCLUSION

Our study establishes the compositional alterations in the nasal microbiome in eCRSwNP and suggests the potential for using the nasal microbiota as a noninvasive predictive classifier for the diagnosis of eCRSwNP.

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.

Unravelling the role of the microbiome in chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a complex, heterogenous condition with likely infectious and inflammatory causative factors. Renewed interest in the role that microbes play in this condition has stemmed from advancements in microbe identification and parallel research that has implicated the role of the microbiome in other chronic inflammatory conditions. This clinical commentary provides a review of the current literature relevant to chronic rhinosinusitis. Particular focus is paid to factors specific to the investigation of the sinonasal microbiome, evidence for the role of dysbiosis in the disease state and influences that may impact the microbiome. Possible mechanisms of disease and therapeutic implications through microbial manipulation are also reviewed, as are deficiencies and limitations of the current body of research.

Variations in facial conformation are associated with differences in nasal microbiota in healthy dogs

BACKGROUND

Extrinsic and intrinsic factors have been shown to influence nasal microbiota (NM) in humans. Very few studies investigated the association between nasal microbiota and factors such as facial/body conformation, age, and environment in dogs. The objectives are to investigate variations in NM in healthy dogs with different facial and body conformations. A total of 46 dogs of different age, living environment and from 3 different breed groups were recruited: 22 meso-/dolichocephalic medium to large breed dogs, 12 brachycephalic dogs and 12 terrier breeds. The nasal bacterial microbiota was assessed through sequencing of 16S rRNA gene (V1-V3 regions) amplicons.

RESULTS

We showed major differences in the NM composition together with increased richness and α-diversity in brachycephalic dogs, compared to meso-/dolichocephalic medium to large dogs and dogs from terrier breeds.

CONCLUSION

Healthy brachycephalic breeds and their unique facial conformation is associated with a distinct NM profile. Description of the NM in healthy dogs serves as a foundation for future researches assessing the changes associated with disease and the modulation of NM communities as a potential treatment.

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.

Antibiotic-Dependent Relationships Between the Nasal Microbiome and Secreted Proteome in Nasal Polyps

PURPOSE

Chronic rhinosinusitis (CRS) is a heterogeneous chronic inflammatory condition of the paranasal sinuses and nasal passages. Although antibiotics are used to reduce inflammation or to treat an episode of acute rhinosinusitis, their effects on the nasal environment and host response in CRS is unclear.

METHODS

We analyzed the effects of antibiotics on the nasal microbiome and secreted proteome in CRS using multi-omic analysis. Nasal secretions were collected from 29 controls, 30 CRS patients without nasal polyps (NP), and 40 CRS patients with NP. A total of 99 subjects were divided into 2 groups that included subjects who had taken antibiotics 3 months prior to sampling and those who had not. We performed 16S ribosomal DNA sequence analyses and Orbitrap mass spectrometry-based proteomic analyses. Spearman correlation was used to assess the correlations between the nasal microbiome and secreted proteome.

RESULTS

The associations between the nasal microbiome and secreted proteome were noted in subjects who had used antibiotics. Antibiotics could have stronger effects on their associations in patients with CRS with NP than in those without. It remains unknown whether these holistic changes caused by antibiotics are beneficial or harmful to CRS, however, the associations could be differentially affected by disease severity.

CONCLUSION

These findings provide new insight into the nasal environment and the host response in CRS.

Longitudinal analysis of sinus microbiota post endoscopic surgery in patients with cystic fibrosis and chronic rhinosinusitis: a pilot study

BACKGROUND

Cystic fibrosis is a debilitating, autosomal recessive disease which results in chronic upper and lower airway infection and inflammation. In this study, four adult patients presenting with cystic fibrosis and chronic rhinosinusitis were recruited. Culture and molecular techniques were employed to evaluate changes in microbial profiles, host gene expression and antimicrobial resistance (AMR) in the upper respiratory tract over time.

METHODS

Swab samples from the sinonasal cavity were collected at the time of surgery and at follow-up clinics at regular time intervals for up to 18 months. Nucleic acids were extracted, and DNA amplicon sequencing was applied to describe bacterial and fungal composition. In parallel, RNA was used to evaluate the expression of 17 AMR genes and two inflammatory markers (interleukins 6 and 8) using custom qPCR array cards. Molecular results were compared with routine sinus and sputum culture reports within each patient.

RESULTS

Bacterial amplicon sequencing and swab culture reports from the sinonasal cavity were mostly congruent and relatively stable for each patient across time. The predominant species detected in patients P02 and P04 were Pseudomonas aeruginosa, Staphylococcus aureus in patient P03, and a mixture of Enterobacter and S. aureus in patient P01. Fungal profiles were variable and less subject specific than bacterial communities. Increased expressions of interleukins 6 and 8 were observed in all patients throughout the sampling period compared with other measured genes. The most prevalent AMR gene detected was ampC. However, the prevalence of AMR gene expression was low in all patient samples across varying time-points.

CONCLUSIONS

We observed a surprising degree of stability of sinonasal microbial composition, and inflammatory and AMR gene expression across all patients post sinus surgery.

The influence of nasal microbiome diversity and inflammatory patterns on the prognosis of nasal polyps

To understand the inflammatory microenvironment and microbiome factors for prognosis of chronic rhinosinusitis with polyps (CRSwNP), we explored the difference in characteristics of the microbiome of the nasal sinuses and inflammatory cytokines between recurrent and non-recurrent groups. We collected nasal secretions and polyp tissue from 77 CRSwNP patients. Then, we extracted microbial DNA from cotton swabs, performed high-throughput sequencing based on 16S rRNA to detect bacterial community composition, and analyzed cytokines such as IL-5, IL-8, IL-17a, IL-17e, IL-18, IL-27 and INF-gamma from polyp tissue using Luminex. The eosinophil and neutrophil cells in the peripheral blood and polyp tissue were counted. Postoperative follow-up of patients with CRSwNP for 1 year was conducted to record the recurrence of nasal polyps and analyze the correlation between the recurrence of nasal polyps and the characteristics of inflammatory cytokines, inflammatory cell count and nasal microbial diversity. After 1 year of follow-up, there were 12 recurrent patients, including 5 males and 7 females. Postoperative recurrence of nasal polyps was not significantly correlated with age, sex, asthma, allergic rhinitis or other allergic diseases in CRSwNP patients. In terms of the total nasal symptom score, the recurrent group was significantly higher than the non-recurrent group. In nasal polyp tissues, eosinophils (40.83/HP) and neutrophils (30.83/HP) in patients with CRSwNP in the recurrent group were significantly higher than those in the non-recurrent group (13.72/HP), and neutrophils (18.5/HP) were also significantly higher in the recurrent group than the non-recurrent group. The expression levels of IFN-, IL-17A, IL-17E and IL-18 were significantly higher in the recurrent group than in the non-recurrent group, and the positive rates were not different. In Southwest China, Enterobacteria and anaerobic bacteria may be correlated with the inflammatory pattern expression of nasal polyps. The neutrophil-mediated inflammatory response plays an important role in patients with CRSwNP in Southwest China and is correlated with nasal polyp recurrence. Recurrence of nasal polyps after endoscopic sinus surgery may be potentially associated with a reduced abundance of protective microorganisms and an increased number of pathogenic microorganisms.

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.

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.

Comparison of bacterial maxillary sinus cultures between odontogenic sinusitis and chronic rhinosinusitis

BACKGROUND

Bacterial odontogenic sinusitis (ODS) is distinct from other forms of rhinosinusitis. Diagnosing ODS can be challenging because of nonspecific clinical presentations and underrepresentation in the literature. The purpose of this study was to compare maxillary sinus bacterial cultures between patients with ODS and chronic rhinosinusitis (CRS), to determine whether certain bacteria are associated with ODS.

METHODS

This was a retrospective case-control study of 276 consecutive patients from August 2015 to August 2019 who underwent endoscopic sinus surgery (ESS) for bacterial ODS, CRS without nasal polyps (CRSsNP), or CRS with nasal polyps (CRSwNP). When present, pus was sterilely cultured from maxillary sinuses after maxillary antrostomy, and aerobic and anaerobic cultures were immediately sent for processing. Demographics and culture results were compared between ODS and CRS patients, and then separately between ODS and CRSsNP, and ODS and CRSwNP. ODS culture results were also compared between different dental pathologies (endodontic vs oroantral fistula).

RESULTS

The following bacteria were significantly more likely in ODS compared to CRS: mixed anaerobes, Fusobacterium spp., Eikenella corrodens, Streptococcus intermedius, Streptococcus anginosus, and Streptococcus constellatus. Staphylococcus aureus and Pseudomonas aeruginosa were inversely related to ODS. There were no significant differences in cultures between the different dental pathologies.

CONCLUSION

Certain bacteria were more likely to be associated with ODS compared to CRS when purulence was cultured from the maxillary sinus. Physicians should evaluate for an odontogenic source of sinusitis when these ODS-associated bacteria are identified in maxillary sinus cultures.

A Comparison of the Bacterial Nasal Microbiome in Allergic Rhinitis Patients Before and After Immunotherapy

OBJECTIVES/HYPOTHESIS

Recent research has examined the nasal microbiome in rhinosinusitis and nondiseased states. Given immunologic alterations in allergic rhinitis (AR) and after allergen immunotherapy (IT), we evaluated the nasal microbiome in these conditions.

STUDY DESIGN

Cross-sectional comparison.

METHODS

In this cross-sectional study, nasal swabs for microbiome analysis were collected from three patient groups: IT-naïve AR patients, AR patients undergoing IT for greater than 12 months, and a control group without sinonasal inflammatory disease.

RESULTS

Nasal swabs were successfully collected for 14 IT-naïve AR patients, 20 post-IT patients, and 17 controls. The α diversity showed a statistical difference in evenness but not in richness amongst samples, whereas the β-diversity was significantly different between groups. Corynebacterium and Staphylococcus were the most prevalent bacteria across all groups.

CONCLUSIONS

β-diversity was found to be significantly different across the three groups, but the AR groups were found to be more similar to each other than to the controls. Although there is symptomatic improvement in the AR group undergoing IT, the microbiome does not appear to transition to a healthy microbiome composition.

LEVEL OF EVIDENCE

4 Laryngoscope, 2020.

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.

Microbiota Dysbiosis in Fungal Rhinosinusitis

Fungal rhinosinusitis is a unique phenotype of chronic rhinosinusitis with unique clinical and histological characteristics. The role of bacterial microbiota in various phenotypes chronic rhinosinusitis is not thoroughly understood. Therefore, we conducted 16s rRNA amplification sequencing to determine differences in bacterial communities between phenotypes (fungal vs. non- fungal) and anatomical sites (middle meatus vs. nasopharynx). Endoscope-guided swabs were used to collect samples from the middle meatus and nasopharynx of seven consecutive patients with fungal and 18 consecutive patients with non-fungal rhinosinusitis. DNA was extracted and investigated through 16S rRNA amplification. Among samples from the middle meatus, Shannon diversity was significantly lower in those from the fungal rhinosinusitis group (p = 0.029). However, no significant differences in diversity were noted between nasopharynx samples (p = 0.85). Fungal rhinosinusitis samples exhibited a distinct distribution of taxon relative abundance, which involved not only the absence of rhinosinusitis-associated commensal Corynebacterium and Fusobacterium in the middle meatus but also a significant increase in Haemophilus prevalence and abundance. This is the first study to compare bacterial communities in fungal and non-fungal rhinosinusitis samples. Our findings demonstrated that bacterial community dysbiosis was more apparent in fungal rhinosinusitis samples and was limited to the middle meatus.

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.

Intraoperative bacterial analysis in nasal polyposis: Clinical and functional impact

BACKGROUND

The impact of Staphylococcus aureus on onset of nasal polyposis has been the focus of numerous studies, but there have been few studies of other germs found in the ethmoid of operated patients or of their impact on post-operative results.

MATERIAL AND METHODS

All patients undergoing endoscopic radical ethmoidectomy for nasal polyposis in the teaching hospital of Nantes (France) between 2006 and 2016 had intraoperative ethmoid cavity bacterial sampling. Phenotypic characteristics, pre- and post-operative symptoms and endoscopic findings were analyzed. Mann-Whitney tests and Kruskal-Wallis correlation analysis were used to assess clinical/bacteriological correlations.

OBJECTIVES

The main objective was to describe bacterial colonization of patients undergoing surgery for nasal polyposis, and to assess correlations with phenotypic features, functional results and postoperative clinical course.

RESULTS

One hundred and seven patients were included. A total of 26% were not infected, 55% mono-infected and 19% multi-infected. In 27.3%, staphylococci were isolated; in 30.5%, isolates were gram-negative bacilli. There were no significant correlations between presence or type of pathogen and symptom profile.

CONCLUSION

This study confirmed the high rate of pathogenic bacteria in nasal cavities in case of polyposis, with high frequencies of S. aureus but also of gram-negative bacilli, raising the question of their involvement in the inflammatory reactions underlying the nasal polyposis.

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.

Temporal instability of the post-surgical maxillary sinus microbiota

Background

Chronic rhinosinusitis is an inflammatory disorder in which the role of bacteria remains uncertain. While sinus outflow obstruction is often an initiating event, mucosal inflammation and dysbiosis may persist or develop in sinuses with widely patent surgical openings. Understanding of the relationship between dysbiosis and chronic sinus inflammation is obfuscated by inter-individual microbiota variability and likely intra-individual temporal variation that has yet to be defined. In this study, long-term microbiota stability is investigated within surgically-opened maxillary sinuses of individuals with and without sinus inflammatory disease.

Methods

Maxillary sinus swabs were performed in 35 subjects with longstanding maxillary antrostomies. Subjects with and without active chronic maxillary sinusitis were included. Repeat swabs were obtained from the same sinuses after a prolonged interval (mean 719 ± 383 days). Patients were categorized based on the inflammatory status of the sinus mucosa at times of sample collection, as assessed by nasal endoscopy. Total DNA from swab eluents was extracted, and the microbiota characterized using 16S rRNA gene sequencing followed by taxonomic classification. Prevalence and abundance of genera were determined by analysis of 16S rRNA gene sequences. Taxa were identified that were stably present between two time points in individual subjects.

Results

The overall proportion of stable taxa across time points was 24.5 ± 10.6%. This stability index was consistent across patient groups and not correlated with clinical parameters. Highly prevalent taxa, including Staphylococcus, Corynebacterium, Propionibacterium, and Pseudomonas, were often stably present, but varied in relative abundance. Janthinobacterium, Enterobacter, Lactobacillus, and Acinetobacter were prevalent and moderately abundant taxa in healthy sinuses, but not in inflamed sinuses. Moraxella and Haemophilus were present at low prevalence and proportional abundance in chronically or intermittently inflamed sinuses, but not in healthy sinuses.

Conclusions

A relatively small component of the post-antrostomy maxillary sinus microbiota exhibits long-term stability in individual subjects. Stable bacteria include a limited number of highly prevalent and a larger number of lower prevalence taxa, which vary widely in proportional abundance. The concept of individual-specific core sinus microbiota, durable over time and medical therapy, but fluctuating in proportional abundance, has implications for understanding the role of bacteria in CRS pathogenesis.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-3272-9) contains supplementary material, which is available to authorized users.

The effect of medical treatments on the bacterial microbiome in patients with chronic rhinosinusitis: a pilot study

BACKGROUND

Antibiotics and corticosteroids are prescribed to patients with chronic rhinosinusitis (CRS) to reduce bacterial burden and mucosal inflammation. Unfortunately, clinical improvement is often short-lived and symptoms frequently recur following cessation of treatment. The impact of these systemic therapies on bacterial communities is not well understood. Improved knowledge of how medical therapies influence the intranasal ecosystem may allow for more effective prescribing and the development of more targeted treatments.

METHODS

Twenty patients with CRS were randomized to receive either doxycycline 100 mg twice daily or prednisone 30 mg once daily for 7 days. A further 6 patients with CRS were recruited as untreated controls. Swabs were taken immediately before and after the study period. Symptom scores (22-item Sino-Nasal Outcome Test [SNOT-22]) were recorded. Bacterial communities were characterized using 16S ribosomal RNA (rRNA) gene-targeted amplicon sequencing. Bacterial abundance was estimated using quantitative polymerase chain reaction (PCR) of 16S rRNA gene copies.

RESULTS

Bacterial profiles were dominated by members of the genera Corynebacterium and Staphylococcus. Patients treated with either doxycycline or prednisone had variable and unpredictable changes in communities. The average relative abundance of Propionibacterium increased after treatment in the doxycycline treatment group, and Corynebacterium reduced in the prednisone group. Significant differences in clinical scores, bacterial community richness, diversity, and bacterial abundance were not seen after treatment.

CONCLUSION

The short-term response of bacterial communities to antibiotic or corticosteroid therapy is unpredictable. This study suggests that the use of systemic therapy in patients with stable CRS should be rationalized to minimize antibiotic-associated morbidity and bacterial dysbiosis.

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.

Sinus Microanatomy and Microbiota in a Rabbit Model of Rhinosinusitis

Background: Rabbits are useful for preclinical studies of sinusitis because of similar physiologic features to humans. The objective of this study is to develop a rabbit model of sinusitis that permits assessment of microanatomy and sampling for evaluating shifts in the sinus microbiota during the development of sinusitis and to test how the mucociliary clearance (MCC) defect might lead to dysbiosis and chronic rhinosinusitis (CRS).

Methods: Generation of CRS was accomplished with an insertion of a sterile sponge into the left middle meatus of New Zealand white rabbits (n = 9) for 2 weeks. After sponge removal, 4 rabbits were observed for another 10 weeks and evaluated for CRS using endoscopy, microCT, visualization of the functional micro-anatomy by micro-optical coherence tomography (μOCT), and histopathological analysis of the sinus mucosa. Samples were taken from the left middle meatus and submitted for microbiome analysis.

Results: CT demonstrated opacification of all left sinuses at 2 weeks in all rabbits (n = 9), which persisted in animals followed for another 12 weeks (n = 4). Histology at week 2 showed mostly neutrophils. On week 14, significant infiltration of plasma cells and lymphocytes was noted with increased submucosal glands compared to controls (p = 0.02). Functional microanatomy at 2 weeks showed diminished periciliary layer (PCL) depth (p < 0.0001) and mucus transport (p = 0.0044) compared to controls despite a thick mucus layer. By 12 weeks, the thickened mucus layer was resolved but PCL depletion persisted in addition to decreased ciliary beat frequency (CBF; p < 0.0001). The mucin fermenting microbes (Lactobacillales, Bacteroidales) dominated on week 2 and there was a significant shift to potential pathogens (e.g., Pseudomonas, Burkholderia) by week 14 compared to both controls and the acute phase (p < 0.05).

Conclusion: We anticipate this reproducible model will provide a means for identifying underlying mechanisms of airway-surface liquid (ASL) depletion and fundamental changes in sinus microbial communities that contribute to the development of CRS. The rabbit model of sinusitis exhibited diminished PCL depth with delayed mucus transport and significant alterations and shift in the sinus microbiome during the development of chronic inflammation.

Therapy of Sinonasal Microbiome in CRS: A Critical Approach

PURPOSE OF REVIEW

Perturbations in local microbiota have been demonstrated in many chronic inflammatory diseases including chronic rhinosinusitis (CRS). The purpose of this paper is to review the latest microbiome research as it pertains to CRS and establish whether there is any evidence supporting the microbiome hypothesis for CRS. Treatment factors that may influence the sinonasal microbiome as well as the role of probiotics are also discussed.

RECENT FINDINGS

Despite significant heterogeneity in study design, tissue sampling, processing and bioinformatics analysis, consistent findings have emerged from the recent literature. Healthy individuals and CRS patients have similar overall bacterial burden of disease and share many common phylum. CRS patients, however, routinely show reductions in markers of biodiversity. Both medical and surgical treatments appear to influence the sinonasal microbiome, with certain bacterial strains associated with better treatment outcomes. The presence of microbial dysbiosis in CRS is now supported by numerous studies. Whether this dysbiosis is a cause or rather an association of the disease process still remains unclear. Although probiotic therapies show early promise, much larger studies are required to establish their real role as a treatment for CRS.