Andrew Foreman

The microbiome of chronic rhinosinusitis: culture, molecular diagnostics and biofilm detection

BackgroundBacteria and fungi are believed to influence mucosal inflammation in chronic rhinosinusitis (CRS). However their presence and relationship to disease is debated. This study used multiple detection methods to compare microbial diversity and microbial abundance in healthy and diseased sinonasal mucosa. The utility of contemporary detection methods is also examined.MethodsSinonasal mucosa was analyzed from 38 CRS and 6 controls. Bacterial and fungal analysis was performed using conventional culture, molecular diagnostics (polymerase chain reaction coupled with electrospray ionization time-of-flight mass spectrometry) and fluorescence in situ hybridization.ResultsMicrobes were detected in all samples, including controls, and were often polymicrobial. 33 different bacterial species were detected in CRS, 5 in control patients, with frequent recovery of anaerobes. Staphylococcus aureus and Propionibacterium acnes were the most common organisms in CRS and controls, respectively. Using a model organism, FISH had a sensitivity of 78%, and a specificity of 93%. Many species were detected in both CRS and controls however, microbial abundance was associated with disease manifestation.ConclusionsThis study highlights some cornerstones of microbial variations in healthy and diseased paranasal sinuses. Whilst the healthy sinus is clearly not sterile, it appears prevalence and abundance of organisms is critical in determining disease. Evidence from high-sensitivity techniques, limits the role of fungi in CRS to a small group of patients. Comparison with molecular analysis suggests that the detection threshold of FISH and culture is related to organism abundance and, furthermore, culture tends to select for rapidly growing organisms.

Characterization of bacterial and fungal biofilms in chronic rhinosinusitis.

Background Conclusive evidence exists that biofilms are present on the mucosa of chronic rhinosinusitis (CRS) patients. Less is known about the species constituting these biofilms. This study developed a fluorescence in situ hybridization (FISH) protocol for characterization of bacterial and fungal biofilms in CRS. Methods Fifty CRS patients and 10 controls were recruited. Bacteria FISH probes for Staphylococcus aureus, Haemophilus influenzae, and Pseudomonas aeruginosa and a universal probe for fungi were applied to sinus mucosal specimens and then analyzed using confocal scanning laser microscopy. Results Thirty-six of 50 CRS patients had biofilms present in contrast to 0/10 controls, suggesting a role for biofilms in the pathogenesis of this disease. S. aureus was the most common biofilm-forming organism. Eleven of 50 CRS patients had characteristic fungal biofilms present. Conclusion This is the largest study of biofilms in CRS. It has validated mucosal tissue cryopreservation for delayed biofilm analysis. Fungal biofilms have been identified and the importance of S. aureus biofilms in the polymicrobial etiology of CRS is highlighted.

Different biofilms, different disease? A clinical outcomes study.

A potential role for biofilms in Chronic Rhinosinusitis (CRS) has been proposed, and the adverse impact they have on disease severity and postoperative outcomes has also been well described. Recent advances have allowed the species within the biofilms of CRS patients to be clearly characterized. This study investigates whether different biofilm species have different disease outcomes.

Staphylococcus aureus biofilms: Nemesis of endoscopic sinus surgery.

Chronic rhinosinusitis (CRS) patients with biofilms have persistent postoperative symptoms, ongoing mucosal inflammation, and recurrent infections. Recent evidence suggests that biofilms of differing species confer varying disease profiles in CRS patients. We aimed to prospectively investigate the effects of Staphylococcus aureus, Pseudomonas aeruginosa, Haemophilus influenzae, and fungal biofilms on outcomes following endoscopic sinus surgery (ESS).

Adaptive immune responses in Staphylococcus aureus biofilm–associated chronic rhinosinusitis

To cite this article: Foreman A., Holtappels G., Psaltis A.J., Jervis‐Bardy J., Field J., Wormald P.‐J., Bachert C. Adaptive immune responses in Staphylococcus aureus biofilm–associated chronic rhinosinusitis. Allergy 2011; 66: 1449–1456.

The Impact of Biofilms on Outcomes after Endoscopic Sinus Surgery

Background Although biofilms have been implicated in the pathogenesis of chronic rhinosinusitis (CRS), there is little evidence that their presence or absence has any effect on the outcomes of endoscopic sinus surgery (ESS). The aim of this study was to investigate the effect of biofilms on postsurgical outcomes after ESS. Methods A prospective, blinded study of 51 consecutive patients undergoing ESS for CRS was conducted. Preoperatively, patients assessed their symptoms using internationally accepted standardized symptom scoring systems and quality-of-life (QOL) measures, i.e., the 10-point Visual Analog Scale (VAS), Sino-Nasal-Outcome-Test 20, and global severity of CRS. Their sinonasal mucosa was graded using the Lund-Kennedy scale and the extent of radiological disease on computed tomography scans was scored using the Lund-McKay scale. Random sinonasal tissue samples were assessed for biofilm presence using confocal laser microscopy. At each postoperative visit, patients reassessed their sinus symptoms and completed QOL measures. Postsurgical state of their sinonasal mucosa was graded endoscopically. Results Bacterial biofilms were found in 36 of 51 (71%) CRS patients. Patients with biofilms presented with significantly worse preoperative radiology and nasendoscopy scores (p = 0.003 and 0.01, respectively). After a median follow-up period of 16 months postsurgery, biofilm-positive patients had statistically worse sinus symptoms (VAS, p = 0.002) and worse nasendoscopy scores (p = 0.026). They also required extra postoperative visits and multiple antibiotic treatments deviating from the standard postoperative care required by biofilm-negative patients. Conclusion This study has shown that patients with biofilms have more severe disease preoperatively and persistence of postoperative symptoms, ongoing mucosal inflammation, and infections. This study strengthens the evidence for the role that biofilms may play in recalcitrant CRS.

Do biofilms contribute to the initiation and recalcitrance of chronic rhinosinusitis

Chronic rhinosinusitis is a common disease whose underlying aetiopathogenesis has not been completely understood. Amongst a range of other potential environmental triggers in this disease, a role has recently been proposed for bacterial biofilms. Adopting the biofilm paradigm to explain the initiation and maintenance of this disease may help to clarify previous inconsistencies in this disease that have resulted in the role of bacteria being questioned. Of particular interest is the association of bacterial biofilms with recalcitrant disease states. Over the last five years, research has progressed rapidly since biofilms were first identified on the surface of diseased sinonasal mucosa. Their presence there has now been associated with more severe disease that is often recalcitrant to current management paradigms. Technological advances are allowing accurate characterization of the bacterial and fungal species within these biofilms, which would appear to be an important step in improving our understanding of how these bacterial communities might interact with the host to cause disease. This is an unanswered, yet highly important, question in this field of research that will undoubtedly be an area of investigation in the near future. As the body of evidence suggesting biofilms may be involved in this disease grows, research interest has switched to the development of antibiofilm therapies. Given the unique properties of bacteria existing in this form, biofilm eradication strategies will need to incorporate novel medical therapies into established surgical practices as we attempt to improve the outcomes of our most difficult patients.

Methylglyoxal‐infused honey mimics the anti‐Staphylococcus aureus biofilm activity of manuka honey: Potential Implication in Chronic Rhinosinusitis

Low pH, hydrogen peroxide generation, and the hyperosmolarity mechanisms of antimicrobial action are ubiquitous for all honeys. In addition, manuka honey has been shown to contain high concentrations of methylglyoxal (MGO), contributing the relatively superior antimicrobial activity of manuka honey compared to non‐MGO honeys. In high concentrations, manuka honey is effective in killing Staphylococcus aureus biofilms in vitro. Lower concentrations of honey, however, are desirable for clinical use as a topical rinse in chronic rhinosinusitis in order to maximize the tolerability and practicality of the delivery technique. This study, therefore, was designed to evaluate the contribution of MGO to the biofilm‐cidal activity of manuka honey, and furthermore determine whether the antibiofilm activity of low‐dose honey can be augmented by the addition of exogenous MGO.

Impaired mucosal healing and infection associated with Staphylococcus aureus after endoscopic sinus surgery

Background Differentiating normal nasal discharge and postoperative crust from infection after endoscopic sinus surgery (ESS) can be difficult. We investigated whether bacteria cultured at operation was predictive for postoperative mucosal infection—defined as frank pus, thick mucus, and/or abnormal crusting seen on endoscopic examination associated with positive microbiology. Methods The records of 48 patients with chronic rhinosinusitis (CRS) with infection at the time of ESS were retrospectively reviewed. Results of intraoperative cultures were compared with those taken at the time of postoperative mucosal infection. Results Fourteen of 16 patients (87.5%) with intraoperative infection with Staphylococcus aureus progressed to postoperative mucosal infection with S. aureus, whereas patients who cultured “other” bacteria intraoperatively progressed to postoperative mucosal infection in 6/19 cases (31.6%), with S. aureus cultured in only 3/19 cases (15.8%; p = 0.0001). Conclusion S. aureus infection at ESS predicts for abnormal, S. aureus–associated mucosal healing and infection post-ESS. Although a prospective trial is warranted, these findings suggest a future role for aggressive anti–S. aureus therapy peri- and/or postoperatively in patients who culture positive for this organism to improve postsurgical outcomes.

Role of Bacterial and Fungal Biofilms in Chronic Rhinosinusitis

Chronic rhinosinusitis (CRS) is a very common condition that remains poorly understood from a pathogenic standpoint. Recent interest has been sparked by a potential role for biofilms in this process, with a significant body of evidence implicating them in inciting sinonasal inflammation. Biofilms are clearly present on the sinus mucosa of CRS patients, and their presence there is associated with severe disease characteristics and surgical recalcitrance. We are beginning to understand the importance of the species within these biofilms, but there may be other as-yet-unidentified factors at play in influencing disease outcomes. Recent exciting research has emerged documenting the immune response to the presence of biofilms—research that will ultimately solidify the nature and extent of the contribution of biofilms in CRS pathogenesis. Future research should focus on evidence-based antibiofilm treatments with reference to efficacy and timing of treatment.