The role of infection in chronic rhinosinusitis

Toll-like receptor 4 plays an important role to enhance bacterial clearance from the nose in synergy with triggering receptor expressed on myeloid cells (TREM)-1 expression on polymorphonuclear neutrophils

OBJECTIVE

Acute rhinosinusitis (ARS) is among the most common infectious diseases. Neutrophils play a major role in innate host defenses against pathogenic microorganisms such as fungi and bacteria. Recently, in neutrophils, ligation of the triggering receptor expressed on myeloid cells (TREM)-1 was found to activate the full spectrum of neutrophil effector mechanisms, including the release of inflammatory mediators, degranulation, phagocytosis, and oxidative burst in synergy with Toll-like receptors (TLRs). In this study, we investigated the effect of TREM-1 on the functions of neutrophils in relation to TLR4 in a nasal and nasopharyngeal inflammation mouse model via nontypeable Haemophilus influenzae (NTHi) intranasal inoculation.

METHODS

We used C3H/HeJ (TLR4-deficient) mice, which arose spontaneously and have non-functional TLR4 protein, and normal wild-type (WT) C3H/HeN mice. Mice were inoculated intranasally with NTHi (10⁷ cfu/mouse) to investigate the effects of TLR4 on the function of Neutrophils. We examined the kinetics of bacterial clearance and inflammatory cell infiltration in nasal washes at 6, 12, 24, and 72 h after inoculation. The expression of TREM-1 on neutrophils, and TREM-1 mRNA expression in neutrophils in the nasal washes were examined by flow cytometric analysis and RT-PCR.

RESULTS

Bacterial counts of NTHi from nasal washes were significantly lower in WT mice than in TLR4-mutant mice after inoculation. The numbers of inflammatory cells in nasal washes were significantly higher in WT mice at 6 h, 12 h, and 24 h after inoculation than in TLR4-deficient mice. The expression of TREM-1 protein on neutrophils and the mRNA levels were greater in WT mice than in TLR4-mutant mice. The concentrations of soluble TREM-1 in WT nasal washes were also significantly higher than in those of TLR4-deficient mice.

CONCLUSION

TREM-1 may play an important role together with TLR4 in the nasopharyngeal clearance of NTHi by neutrophils. Further studies will need to clarify the innate immune responses of neutrophils via TLR4 to prevent NTHi infection.

The role of antibiotics in pediatric chronic rhinosinusitis

Objectives

Presenting the role of antibiotics in pediatric chronic rhinosinusitis based on its pathophysiology and microbiology.

Data source

Review of the literature searching PubMed for microbiology and treatment of pediatric chronic rhinosinusitis.

Results

Chronic rhinosinusitis (CRS) is an inflammatory condition of the paranasal sinuses that persists for 12 weeks or longer, despite medical management. The microbiology of rhinosinusitis evolves through several stages. The early phase (acute) is generally caused by a virus that may be followed by an aerobic bacterial infection in 2% to 10% of patients. Aerobic (Staphylococcus aureus) and anaerobic (Prevotella and Fusobacteria) members of the oral flora emerge as predominant sinus cavity isolates. Antimicrobials are one component of comprehensive medical and surgical management for this disorder. Because most of these infections are polymicrobial and many include beta‐lactamase producing aerobic and anaerobic organisms, amoxicillin‐clavulanate is the first‐line regimen for most patients. Clindamycin is adequate for penicillin‐allergic children and is also generally appropriate for methicillin resistant Staphylococcus aureus treatment is administered for at least three weeks and may be extended for up to 10 weeks in refractory cases. A culture preferably from the sinus cavity should be obtained from individuals who have not shown improvement or deteriorated despite therapy.

Conclusions

Antimicrobial therapy of pediatric chronic rhinosinusitis should be adequate against the potential aerobic and anaerobic pathogens.

Level of Evidence

7.

A systematic review of the sinonasal microbiome in chronic rhinosinusitis

BACKGROUND

The interaction between the host and microorganisms in chronic rhinosinusitis (CRS) is poorly understood and is a growing area of interest. More recently, methodologies have been developed to assess the microbiome without the use of culture by analyzing the bacterial 16S ribosomal RNA gene. We reviewed the microbiome literature to better understand the role of microbes in CRS.

METHODS

Systematic review of studies that used the 16S ribosomal RNA gene deep sequencing.

RESULTS

Nine publications met the search criteria. Eight studies evaluated the microbiome in controls (total, 83 subjects; range, 3-28 per study), whereas six of the studies included patients with CRS (total, 121 patients; range, 7-43 per study). Various sequencing techniques, primers, sample sites, and extraction methods were used. Of the articles that specified the number of taxa in controls, an average of 1587 taxa were identified (range, 911-2330). Significant heterogeneity was noted among the studies; however, Firmicutes, Actinobacteria, and Bacteroides phyla were identified in every sample of control patients and patients with CRS. Three of the studies showed enrichment to some degree of Staphylococcus aureus in patients with CRS. The total bacterial burden in CRS was similar to the controls. One study demonstrated a decrease in diversity, whereas other studies did not show any changes in CRS when compared with controls.

CONCLUSION

Although there are common phyla present in both control patients and patients with CRS, no consistent enrichment of any particular taxon was identified. Our findings indicated that there was no clear single causative microbe in CRS. More studies are needed to better understand the significance of the host interaction with the microbiome and the role it plays in CRS.

ICON: chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a public health problem that has a significant socio-economic impact. Moreover, the complexity of this disease due to its heterogeneous nature based on the underlying pathophysiology - leading to different disease variants - further complicates our understanding and directions for the most appropriate targeted treatment strategies. Several International/national guidelines/position papers and/or consensus documents are available that present the current knowledge and treatment strategies for CRS. Yet there are many challenges to the management of CRS especially in the case of the more severe and refractory forms of disease. Therefore, the International Collaboration in Asthma, Allergy and Immunology (iCAALL), a collaboration between EAACI, AAAAI, ACAAI, and WAO, has decided to propose an International Consensus (ICON) on Chronic Rhinosinusitis. The purpose of this ICON on CRS is to highlight the key common messages from the existing guidelines, the differences in recommendations as well as the gaps in our current knowledge of CRS, thus providing a concise reference. In this document we discuss the definition of the disease, its relevance, pharmacoeconomics, pathophysiology, phenotypes and endotypes, genetics and risk factors, natural history and co-morbidities as well as clinical manifestations and treatment options in both adults and children comprising pharmacotherapy, surgical interventions and more recent biological approaches. Finally, we have also highlighted the unmet needs that wait to be addressed through future research.

A pooling-based genomewide association study identifies genetic variants associated with Staphylococcus aureus colonization in chronic rhinosinusitis patients

BACKGROUND

Staphylococcus aureus (S. aureus) has been implicated in the pathogenesis of chronic rhinosinusitis (CRS). However, host factors contributing to susceptibility to S. aureus colonization in CRS remain unknown. We wish to investigate, using a pooled genomewide association study (pGWAS), single-nucleotide polymorphisms (SNPs) associated with S. aureus carriage in CRS patients.

METHODS

An existing population of 408 CRS patients and 190 controls was prospectively recruited for genetic association studies. All CRS patients had an endoscopic swab culture as part of phenotyping. A pGWAS compared DNA pools from patients with and without S. aureus colonization using the Illumina HumanHap 1M BeadChip, which interrogates 1 million SNPs. Top-ranked SNPs associated with S. aureus colonization were selected according to biallelic differences and silhouette rank, and confirmed by individual genotyping using the Sequenom platform. PLINK software was used for genetic association tests. Ingenuity pathway analysis was used to identify canonical and signaling pathways enriched for genes neighboring associated SNPs, as well as identification of the underlying biological mechanisms.

RESULTS

Thirty-nine top priority SNPs were selected for individual genotyping. Out of 39 SNPs, 23 were associated (p < 0.05) with S. aureus colonization in CRS patients. These SNPs are located within or near 21 genes reported to be implicated in several diseases, endocytic internalization, and bacterial recognition.

CONCLUSION

These results suggest novel host genetic factors influencing susceptibility to S. aureus colonization in CRS. Identifying implicated mechanisms may offer new insights into pathogenesis of CRS.

Correlation between culture-identified bacteria in the middle nasal meatus and CT score in patients with chronic rhinosinusitis

The aim of this study was to compare bacteriological findings in the middle nasal meatus in patients with chronic rhinosinusitis (CRS) with nasal polyps (CRSwNP) and without nasal polyps (CRSsNP) and healthy controls, and to investigate the correlation between the prevalence of culture-identified bacteria and the severity of sinus disease. Bacterial culture was performed using a swab from the middle nasal meatus under endoscopic control in 72 patients with CRSwNP, 25 patients with CRSsNP and 59 healthy controls. Computed tomography (CT) scans were graded for severity using the Lund-Mackay scoring system. Patients with more severe forms of CRS with and without nasal polyps had significantly higher rates of pathogenic bacteria in the middle nasal meatus compared with patients with lower CT scores of the paranasal sinuses. There were no significant differences in bacterial species among CRSwNP, CRSsNP and control patients. These results demonstrate, for the first time, that colonization by pathogenic bacteria in patients with CRSwNP and CRSsNP is associated with a more severe form of the disease, as assessed by a pre-operative CT scan of the paranasal sinuses. The results suggest a role for bacterial infection in the pathogenesis of CRS. However, bacteria do not appear to play a role in the development of nasal polyposis in patients with CRS.

Role of antibiotics in sinusitis

PURPOSE OF REVIEW

Sinusitis is a leading reason for outpatient antibiotic use, but symptoms are nonspecific. We review potential methods that might enhance the ability to appropriately prescribe antibiotics.

RECENT FINDINGS

The evidence base for antibiotic use in acute rhinosinusitis is strongest in studies with stringent entry criteria. In less restrictive studies antibiotics and placebo perform equally. Bacteria from nasopharyngeal swabs in adults correlate with sinus cultures. A recent study showed that antibiotics shortened the duration of acute rhinosinusitis (ARS) symptoms in children. Tellingly, over 2000 children with symptoms were screened to enroll less than 10% who fulfilled the study's stringent criteria. In chronic rhinosinusitis (CRS), two grade 1 studies on efficacy of long-term macrolide therapy showed conflicting results. Odontogenic sinusitis is underappreciated and frequently fails to grow on culture because of presumed difficulty in growing anaerobes.

SUMMARY

There is currently no grade 1 evidence to support antibiotic use in CRS; however, studies to date have not been conducted in patients with isolated purulent sinusitis. Future use of cultures to direct antibiotic therapy, such as nasopharyngeal swabs in adults with ARS or endoscopically guided cultures, may aid in targeting antibiotic therapy more effectively.

Negative impact of occupational exposure on surgical outcome in patients with rhinosinusitis

BACKGROUND

Chronic rhinosinusitis (CRS) is a frequent condition that is treated by functional endoscopic sinus surgery (FESS) when medical treatment fails. Endogenous as well as exogenous factors may be responsible for persisting symptoms after FESS. The role of occupational exposures on success of FESS has never been investigated.

METHODS

In this case-control study, we tested the hypothesis that the outcome of FESS procedures is related to exposures at work. Questionnaires were sent to 890 patients who had undergone one or more FESS procedures and to 182 controls. Three independent experts assessed blindly the reported work exposures to inhaled agents. The relationship between exposure and the number of FESS procedures was analyzed.

RESULTS

Relevant occupational exposure was reported by 25% of all responding patients undergoing FESS (n = 467) and 12% of controls (n = 69). The prevalence of occupational exposures increased linearly with the number of FESS procedures from 21% in those who had one FESS to 44% in those who had four or more FESS (χ(2)  = 12.74, P < 0.001). Logistic regression analysis with adjustments for potential confounders, including smoking, atopy, and asthma, confirmed that the odds ratio (OR) for reporting occupational exposures was significantly higher in those needing more than one FESS (OR = 1.64) or more than two FESS (OR = 1.97). These results were mainly driven by exposure to low molecular weight agents.

CONCLUSION

Exposure at work appears to be a risk factor for the occurrence of CRS and for its recurrence or persistence, as evidenced by the need for revision surgery.

The effect of endoscopic sinus surgery on bacterial biofilms in chronic rhinosinusitis

OBJECTIVE

To determine whether or not endoscopic sinus surgery (ESS) alters bacterial biofilms in patients with chronic rhinosinusitis (CRS) after three months of follow-up.

STUDY DESIGN

Prospective study.

SETTING

Department of Otorhinolaryngology-Head and Neck Surgery, University of Queensland.

SUBJECTS AND METHODS

Participants with CRS from the Princess Alexandra Hospital Department of Otorhinolaryngology-Head and Neck Surgery and from Logan Hospital were enrolled in the study (2008-2009). The total number of patients was 28, and the age range was 18 to 65 years. All patients underwent pre- and post-ESS questionnaires, endoscopic scoring, and nasal swabs for bacterial culture. Crystal violet staining was used to assess biofilm formation on a 96-well culture plaque.

RESULTS

ESS resulted in a statistically significant improvement in quality-of-life, subjective, and objective outcome measures after three months. A significant reduction was observed in biofilm density before and after ESS (2.63 versus 1.3, P = 0.043). No correlations between the reduction of bacterial biofilms with any of the subjective, objective, and quality-of-life outcomes were seen in our study.

CONCLUSION

ESS was shown to be capable of reducing the prevalence of bacterial biofilms but did not eliminate them entirely. There was no correlation between altered biofilm formation and improved outcome measures in individual patients.

Antibiotics for the allergist: part 1

OBJECTIVE

To review antibiotic use and selection for disorders commonly seen in allergy practice.

DATA SOURCES

MEDLINE searches were performed cross-referencing the keywords antibiotic, antimicrobial, management, and treatment with multiple disorders commonly seen in allergy practice. References of the chosen articles were also examined.

STUDY SELECTION

Articles were selected based on their relevance to the subject matter.

RESULTS

A large body of research is available that is relevant to both conventional and novel uses of antibiotics. The use of antibiotics is in question for some disorders, whereas novel approaches to therapy with macrolide antibiotics are areas of active investigation. Meanwhile, patterns of microbial resistance continue to evolve.

CONCLUSION

For decades, antibiotics have been traditional first-line treatments for many disorders. Recently, this paradigm appears to be shifting as periods of observation come into favor and nonbacterial causes of inflammation are under greater scrutiny. Nonetheless, appropriate antibiotic selection often remains a key element in the treatment of these disorders. Knowledge of the relevant microbiology is an inherent requirement in selecting antibiotic therapies and necessitates awareness of current trends in bacterial resistance.

Cyclooxygenases and the pathogenesis of chronic rhinosinusitis and nasal polyposis

Cyclooxygenase (COX) enzymes catalyze the rate-limiting steps in prostaglandin synthesis. Prostaglandins have an important role in several physiological processes such as maintenance of gastrointestinal integrity and pathological processes such as inflammation and neoplasia. Several mechanisms have been proposed for the development of chronic rhinosinusitis, but the common final pathway seems to be an integrated process involving the mucosal epithelium, matrix, and inflammatory cells and mediators. Upper and lower airway pathologies coexist and share common etiopathogenic mechanisms, and nasal polyposis is often associated with asthma and aspirin sensitivity. The cellular source of COX activity in acute and chronic inflammation, as in chronic rhinosinusitis, is poorly understood. COX theory postulated that inhibition of COX broke down biochemical reactions that lead to the development of asthma attacks. This article focuses on COX in the pathogenesis of chronic rhinosinusitis and nasal polyposis.

Assessment of Trends in Antimicrobial Resistance in Chronic Rhinosinusitis

Objectives:

We performed a cross-sectional review of a prospective database to determine the contemporary incidence and temporal patterns of antimicrobial resistance in chronic rhinosinusitis (CRS).

Methods:

A microbiological database was retrospectively reviewed to extract all endoscopically obtained paranasal sinus cultures from 2001 through 2005 in adult patients with CRS. The culture data were tabulated according to bacterial species and representative antibiotic resistances for methicillin, erythromycin, clindamycin, gentamicin, tetracycline, sulfamethoxazole, and levofloxacin. The data were analyzed to determine whether increasing rates of antibiotic resistance developed over the study years. Further analysis was conducted for methicillin-resistant Staphylococcus aureus (MRSA) species to determine prevalence trends and antibiotic resistance trends for MRSA versus other species.

Results:

We analyzed 701 bacterial isolates among 392 culture samples. Staphylococcus aureus was the most commonly isolated organism (19.0%). Antibiotic resistance significantly increased for erythromycin over the study (maximum resistance rate, 69.7% in 2005; p = .009), remained unchanged for methicillin, clindamycin, levofloxacin, and sulfamethoxazole (p = .366 to p = .397), and trended downward for gentamicin (p = .180) and tetracycline (p = .120). Nineteen percent of S aureus species were found to be MRSA, but MRSA-specific antibiotic resistance rates did not change over the course of the study (all p ≥ .222). In aggregate, MRSA species exhibited statistically significant higher rates of resistance to each antibiotic tested than did non-MRSA bacteria.

Conclusions:

Antibiotic resistance seems to be emerging for erythromycin at a rate higher than for other antibiotics. Although not increasing in prevalence, MRSA maintains a significant presence in CRS with associated increased levels of antibiotic resistance.

Imaging of chronic and exotic sinonasal disease: review

OBJECTIVE

Chronic sinusitis is one of the most commonly diagnosed illnesses in the United States. The educational objectives of this review article are for the participant to exercise, self-assess, and improve his or her understanding of the imaging evaluation of sinonasal disease.

CONCLUSION

This article describes the anatomy, pathophysiology, microbiology, and diagnosis of sinonasal disease, including chronic and fungal sinusitis, juvenile nasopharyngeal angiofibroma, inverted papilloma, and chondrosarcoma.

The role of sinus disease in asthma

PURPOSE OF REVIEW

Some time ago, a link between upper and lower respiratory disease was described, which gave rise to the concept of 'united airways disease'. This concept primarily refers to the well established link between allergic rhinitis and asthma, but it also covers a possible link between sinus disease and asthma (allergic or nonallergic) and other lower airway disease.

RECENT FINDINGS

The current classification of chronic rhinosinusitis (CRS) includes disease without and with nasal polyps, which are considered subgroups of CRS. Different patterns of inflammatory and regulatory cytokines (involving distinguishable T-helper lymphocyte populations) and of remodelling markers, however, were recently described to differentiate nasal polyposis from CRS, yielding two discrete entities. These patterns resemble those of lower airway diseases, such as asthma and chronic obstructive pulmonary disease, and suggest a common aetiological/pathogenetic background. Whereas the link between nasal polyps and asthma is well established (indeed, asthma improves after medical or surgical treatment of sinus disease), that between CRS and lower airway disease is not well understood. Recently, Staphylococcus aureus enterotoxins, acting as superantigens, were identified as a possible link between nasal polyps and asthma, resulting in severe disease manifestations in both upper and lower airways.

SUMMARY

The role played by sinus disease in asthma is only partially understood, largely because of deficits in the clinical classification and in basic knowledge of pathophysiological pathways. Recent research into upper airway and sinus inflammation and remodelling may reveal new perspectives and lead to a classification of sinus disease, which will facilitate appropriate clinical and epidemiological studies.

Functional endoscopic sinus surgery for chronic rhinosinusitis

BACKGROUND

Rhinosinusitis is a well-recognised clinical syndrome affecting patients of all ages and gender. FESS has now become a well-established strategy, comprising several techniques, for the treatment of chronic rhinosinusitis refractory to medical treatment.

OBJECTIVES

The aim of this review was to assess the effectiveness of functional endoscopic sinus surgery as a treatment for patients with chronic rhinosinusitis.

SEARCH STRATEGY

The Cochrane Ear, Nose and Throat Disorders Group Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (1966 to January 2006) and EMBASE (1974 to January 2006) were searched. Reference lists were handsearched and experts in the field contacted to identify further studies.

SELECTION CRITERIA

Randomised controlled trials. Inclusion criteria were any of the following criteria singly or in combination: patients with chronic rhinosinusitis diagnosed by a health professional; patients with sinusitis symptoms for more than 12 weeks; endoscopic evidence of sinusitis or radiological evidence of sinusitis. Exclusion criteria were immune suppression; cystic fibrosis; Wegener's disease; previous sinus surgery or sinonasal malignancy.

DATA COLLECTION AND ANALYSIS

All studies meeting the inclusion criteria underwent validity assessment and the data were extracted independently by the two authors. Comparisons were:FESS versus medical treatmentFESS versus conventional sinus surgeryFESS + medical treatment versus medical treatmentFESS + medical treatment versus conventional sinus surgery + medical treatment

MAIN RESULTS

The three included studies were randomised controlled trials. The evidence available does not demonstrate that FESS, as practiced in the included trials, is superior to medical treatment with or without sinus irrigation in patients with chronic rhinosinusitis. A middle meatal antrostomy fashioned by FESS was also not shown to be superior to an inferior meatal antrostomy formed by traditional sinus surgery techniques, although the small sample size in the study does not exclude a type II error. In one study there was a relapse rate of 2.4% in the FESS and sinus irrigation group compared to 5.6% in the sinus irrigation only group. The relapse rates were not mentioned in the other studies. There were no major complications such as orbital injury or cerebrospinal fluid leak reported in any of the included trials.

AUTHORS' CONCLUSIONS

FESS as currently practiced is a safe surgical procedure. The limited evidence available suggests that FESS as practiced in the included trials does not confer additional benefit to that obtained by medical treatment (+/- sinus irrigation) in chronic rhinosinusitis. More randomised controlled trials comparing FESS with medical and other treatments, with long-term follow up, are required.

Allergic rhinoconjunctivitis: epidemiology

Allergic rhinoconjunctivitis has been studied much less frequently than asthma using epidemiologic approaches. Population-based studies are difficult to conduct because of misclassification arising from the reliance on self-reported questionnaires that use terms such as allergic rhinitis or hay fever to establish the diagnosis. In addition, many epidemiologic studies focus on diagnostic skin testing or allergen-specific IgE antibodies (RASTs) as an objective outcome to assess for hay fever. These techniques are helpful but not perfect measures for predicting hay fever outcomes in epidemiologic studies. It is generally accepted, however, that allergic rhinoconjunctivitis is one of the most common of chronic diseases and is the most common atopic disorder. This article reviews the definition of allergic rhinoconjunctivitis, the epidemiology of this disorder from infancy into adulthood, and environmental risk factors for development of sensitization to certain allergens.