Analysis of Sinonasal Microbiota in Exacerbations of Chronic Rhinosinusitis Subgroups

Rare constituents of the nasal microbiome contribute to the acute exacerbation of chronic rhinosinusitis

BACKGROUND

Dysbiosis of the nasal microbiome is considered to be related to the acute exacerbation of chronic rhinosinusitis (AECRS). The microbiota in the nasal cavity of AECRS patients and its association with disease severity has rarely been studied. This study aimed to characterize nasal dysbiosis in a prospective cohort of patients with AECRS.

METHODS

We performed a cross-sectional study of 28 patients with AECRS, 20 patients with chronic rhinosinusitis (CRS) without acute exacerbation (AE), and 29 healthy controls using 16S rRNA gene sequencing. Subjective and objective assessments of CRS disease severity during AE were also collected.

RESULTS

Compared to healthy controls and patients with CRS without AE, AECRS presented with a substantial decrease of the Corynebacterium_1 and a significant increase of Ralstonia and Acinetobacter at the genus level (LDA score > 2.0 [P < 0.05]). Furthermore, genera with a mean relative abundance (MRA) of less than 1% were defined as rare components based on published studies, then 29 genera with a substantial alteration in AECRS were rare constituents of the microbiome, of which 18 rare genera were highly associated with subjective and objective disease severity. Moreover, a combination of 15 genera could differentiate patients with AECRS with an area under the curve of 0.870 (95% CI = 0.784-0.955). Prediction of microbial functional pathways involved significantly enhanced lipopolysaccharide biosynthesis pathways and significantly decreased folate biosynthesis, sulfur relay system, and cysteine and methionine metabolism pathways in patients with AECRS.

CONCLUSIONS

The rare nasal microbiota (MRA < 1%) correlated with disease status and disease severity in patients with AECRS. The knowledge about the pattern of the nasal microbiome and its metabolomic pathway may contribute to the fundamental understanding of AECRS pathophysiology.

Characterising the allergic fungal rhinosinusitis microenvironment using full-length 16S rRNA gene amplicon sequencing and fungal ITS sequencing

INTRODUCTION

Allergic fungal rhinosinusitis (AFRS) is a severe phenotype of chronic rhinosinusitis with nasal polyposis (CRSwNP), characterised by localised and exaggerated type 2 inflammation. While fungal antigenic stimulation of unregulated Th2-mediated inflammation is the core pathophysiological mechanism, the direct and synergistic role of bacteria in disease modification is a pervasive hypothesis. We set out to define the microenvironment of AFRS to elucidate virulent organisms that may be implicated in the pathophysiology of AFRS.

METHODOLOGY

We undertook a cross-sectional study of AFRS patients and non-fungal CRSwNP patients. Demographics, disease severity, culture and microbiome sequences were analysed. Multimodality microbiome sequencing included short-read next-generation sequencing (NGS) on the Illumina Miseq (16S rRNA and ITS) and full-length 16S rRNA sequencing on the Oxford Nanopore Technologies GridION (ONT).

RESULTS

Thirty-two AFRS and 29 non-fungal CRSwNP patients (NF) were included in this study. Staphylococcus aureus was the dominant organism cultured and sequenced in both AFRS and NF groups (AFRS 27.54%; NF 18.04%; p = .07). Streptococcus pneumoniae (AFRS 12.31%; NF 0.98%; p = .03) and Haemophilus influenzae (AFRS 15.03%; NF 0.24%; p = .005) were significantly more abundant in AFRS. Bacterial diversity (Shannon's index) was considerably lower in AFRS relative to NF (AFRS 0.6; NF 1.0, p = .008). Aspergillus was the most cultured fungus in AFRS (10/32, 31.3%). The AFRS sequenced mycobiome was predominantly represented by Malassezia (43.6%), Curvularia (18.5%) and Aspergillus (16.8%), while the NF mycobiome was nearly exclusively Malassezia (84.2%) with an absence of Aspergillus or dematiaceous fungi.

CONCLUSION

A low diversity, dysbiotic microenvironment dominated by Staphylococcus aureus, Streptococcus pneumoniae and Haemophilus influenzae characterised the bacterial microbiome of AFRS, with a mycobiome abundant in Malassezia, Aspergillus and Curvularia. While Staphylococcus aureus has been previously implicated in AFRS through enterotoxin superantigen potential, Streptococcus pneumoniae and Haemophilus influenzae are novel findings that may represent alternate cross-kingdom pathophysiological mechanisms.

Definition of sinonasal and otological exacerbation in patients with primary ciliary dyskinesia: an expert consensus

Background

Recurrent infections of the nose, sinuses and ears are common problems for people with primary ciliary dyskinesia. While pulmonary exacerbations in primary ciliary dyskinesia are defined, there is no definition for ear-nose-throat exacerbations, a potential outcome for research and clinical trials.

Methods

We set up an expert panel of 24 ear-nose-throat specialists, respiratory physicians, other healthcare professionals and patients to develop consensus definitions of sinonasal and otological exacerbations in children and adults with primary ciliary dyskinesia for research settings. We reviewed the literature and used a modified Delphi approach with four electronic surveys.

Results

Definitions for both sinonasal and otological exacerbations are based on a combination of major and minor criteria, requiring three major or two major and at least two minor criteria each. Major criteria for a sinonasal exacerbation are 1) reported acute increase in nasal discharge or change in colour, 2) reported acute pain or sensitivity in the sinus regions and 3) mucopurulent discharge on examination. Minor criteria include reported symptoms, examination signs, doctor's decision to treat and improvement after at least 14 days. Major criteria for the otological exacerbation are 1) reported acute ear pain or sensitivity, 2) reported acute ear discharge, 3) ear discharge on examination and 4) signs of otitis media in otoscopy. Minor criteria are reported acute hearing problems, signs of acute complication, and doctor's decision to treat.

Conclusion

These definitions might offer a useful outcome measure for primary ciliary dyskinesia research in different settings. They should be validated in future studies and trials together with other potential outcomes, to assess their usability.

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.

Comparison of Fungal and Non-Fungal Rhinosinusitis by Culture-Based Analysis

BACKGROUND

Incidence of fungal rhinosinusitis has increased in recent few years. We investigated the differences in microbiological findings between patients with fungal and non-fungal rhinosinusitis by growing microbiological cultures from samples obtained from sinus surgery.

METHODS

Using the Chang Gung Research Database, we enrolled all chronic rhinosinusitis (CRS) patients who had ever undergone sinus surgery from 2001 to 2019 and had microbiological culture during sinus surgery. Enrolled patients were divided into fungal and non-fungal groups, based on fungal culture and surgical pathology.

RESULTS

A total of 898 patients were diagnosed with fungal rhinosinusitis and 2884 with non-fungal rhinosinusitis. The fungal group had a higher age distribution (56.9 ± 13.1 vs. 47.0 ± 14.9), a larger proportion of females (62.4% vs. 37.0%), more unilateral lesions (80.4% vs. 41.6%), a lower incidence of the need for revision surgery (3.6% vs. 6.0%, p = 0.004), and a higher proportion of Pseudomonas aeruginosa in the culture (14.3% vs. 4.6%, p < 0.001).

CONCLUSIONS

This large-scale study showed that Pseudomonas aeruginosa are more commonly found in patients with fungal rhinosinusitis and in patients who needed revision surgery, suggesting that efforts aimed at eliminating Pseudomonas are needed in order to improve the disease outcomes of patients with fungal rhinosinusitis.

Acute exacerbations of chronic rhinosinusitis: The current state of knowledge

Objectives

Acute exacerbations of chronic rhinosinusitis (AECRS) are distinct from baseline symptomatology related to chronic rhinosinusitis (CRS). In this review, we seek to examine the literature on AECRS to synthesize the definition, epidemiology, pathophysiology, treatment, and impact of AECRS on CRS patients.

Methods

A comprehensive narrative review of the scientific literature, identified by searching PubMed from inception through April 2022, was performed.

Results

AECRS is defined in consensus guidelines as a worsening of chronic sinus disease symptomatology, with a return to baseline, typically after intervention with systemic antibiotics and/or corticosteroids. The working definition used across the literature, however, is broad and heterogeneous. The pathophysiology of AECRS is incompletely understood but is hypothesized to include an interplay of environmental and patient-specific factors. AECRS have been found to have a negative impact on quality-of-life measures, independent of baseline CRS symptomatology, and impact how patients and physicians view overall disease control. Treatment for AECRS includes oral antibiotics and systemic corticosteroids, although their efficacy for AECRS is unclear. Appropriate use of medical and surgical treatment for CRS can reduce the frequency of AECRS.

Conclusions

AECRS are a distinct entity in CRS patients and should be independently assessed when evaluating patients for CRS control. The efficacy of systemic medication usage for AECRS is currently unclear, but appropriate medical management of baseline CRS can reduce the frequency of AECRS. More research is needed to further understand this phenomenon, including a more precise and prospective definition, defined epidemiology, and how to appropriately treat.

Level of Evidence

5.

The Microbiology of Acute Exacerbations in Chronic Rhinosinusitis - A Systematic Review

Background

Acute exacerbations (AE) in chronic rhinosinusitis (CRS) are a common and important clinical issue. However, relatively little is known regarding the underlying microbiology that drives exacerbations or how it relates to the microbiome of CRS. The purpose of this study is to examine the literature to characterize the microbiome associated with acute exacerbations in a chronic rhinosinusitis setting. Understanding this disease process may facilitate targeted antibiotic therapy, reduced antibiotic resistance, and offer more effective disease control and treatment efficacy.

Objective

To characterize the microbiome associated with acute exacerbations of chronic rhinosinusitis (AECRS).

Methods

We conducted a systematic review of the literature on Medline, Embase, and Web of Science databases from January 1990-June 2021 to identify studies related to AE in CRS. Exclusion criteria include non-English, non-human studies, and case reports. Studies without culture or PCR data were also excluded.

Results

Fourteen studies were identified which provided detailed data regarding sinus microbiome in AECRS patients. In these patients, a total of 1252 individual isolates were identified. While common acute pathogens were identified in high frequencies in the sinonasal cultures (Staphylococcus pneumonia, Haemophilus influenza), the predominant bacteria were Staphylococcus aureus (including methicillin-sensitive Staphylococcus aureus) and Pseudomonas aeruginosa. Patient characteristics that may represent higher risk phenotypes were not consistently collected in the studies. Discussion of antimicrobial sensitivities and/or resistance were included in 7/14 studies.

Conclusions

This systematic review identifies the predominant microbiology species that may contribute to AECRS. Further studies are needed to understand the pathogenic role of bacteria and viruses in AECRS and to identify associated comorbidities and patient phenotypes that may predispose to AE. The optimal treatment regimen for AECRS remains unclear.

Nasopharyngeal bacterial and fungal microbiota in normal horses and horses with nasopharyngeal cicatrix syndrome

Background

The nasopharyngeal bacterial and fungal microbiota of normal horses and those with nasopharyngeal cicatrix syndrome (NCS) are unknown.

Hypotheses/Objectives

To describe the microbiota from nasopharyngeal washes of healthy horses and of horses acutely affected with NCS.

Animals

Twenty‐six horses acutely affected with NCS horses and 14 unaffected horses.

Methods

Prospective, observational cohort study. Horses were recruited by investigators through personal communications in central Texas. Bacterial (16s RNA) and fungal (internal transcribed spacer) microbiota from nasopharyngeal washes were evaluated. Polymerase chain reaction for detection of Pythium insidiosum was performed.

Results

Results indicated that 6 fungal genera (Alternaria, Bipolaris, Microascus, Spegazzinia, Paraconiothyrium, Claviceps) and 1 bacterial genera (Staphylococcus) were significantly different between affected and unaffected horses. The fungal genus Bipolaris had increased abundance in NCS affected horses and on NCS affected farms. Pythium insidiosum was absent in the nasopharyngeal wash of all horses, irrespective of health status.

Conclusion and Clinical Importance

Significant differences were identified in the fungal microbiota in horses affected with NCS and farms affected with NCS compared to those unaffected. Therefore, Bipolaris warrants further investigation.

The bacteriology of recurrent acute exacerbations of chronic rhinosinusitis: a longitudinal analysis

PURPOSE

The purpose of this study was to describe the microbiology of recurrent acute exacerbations of chronic rhinosinusitis over time.

METHODS

Retrospective review of patients with recurrent acute exacerbations of chronic rhinosinusitis who underwent endoscopic-guided cultures during acute exacerbations of chronic rhinosinusitis.

RESULTS

386 cultures were obtained from 112 patients during recurrent acute exacerbations of CRS. A change of bacterial isolates during the course of recurrent exacerbations was observed in 68% (76/112) of patients, necessitating a change of treatment in 40% (45/112). The main risk factor for the subsequent change in cultures was polymicrobial growth. Sinus surgery was not associated with subsequent change in cultured isolates. Resistant strains developed in 11.6% (13/112) of patients, of whom those with abnormal mucociliary clearance being at the highest risk.

CONCLUSION

Repeated middle meatal cultures should be considered in patients with recurrent exacerbations of CRS, particularly in cases not responding to standard therapy.