Bacterial Biofilms: Do They Play a Role in Chronic Sinusitis?

The therapeutic use of exosomes in children with adenoid hypertrophy accompanied by otitis media with effusion (AHOME): a protocol study

BACKGROUND

The adenoids act as a reservoir of bacterial pathogens and immune molecules, and they are significantly involved in children with otitis media with effusion (OME). As an essential carrier of intercellular substance transfer and signal transduction, exosomes with different biological functions can be secreted by various types of cells. There remains significant uncertainty regarding the clinical relevance of exosomes to OME, especially in its pathophysiologic development. In this study, we will seek to determine the biological functions of exosomes in children with adenoid hypertrophy accompanied by OME (AHOME).

METHODS

The diagnostic criteria for OME in children aged 4-10 years include a disease duration of at least 3 months, type B or C acoustic immittance, and varying degrees of conductive hearing loss. Adenoidal hypertrophy is diagnosed when nasal endoscopy shows at least 60% adenoidal occlusion in the nostrils or when nasopharyngeal lateral X-ray shows A/N > 0.6. Children who meet the indications for adenoidectomy surgery undergo adenoidectomy. Peripheral blood, nasopharyngeal swab, and adenoid tissue will be collected from patients, and the exosomes will be isolated from the samples. Following the initial collection, patients will undergo adenoidectomy and peripheral blood and nasopharyngeal swabs will be collected again after 3 months.

EXPECTED RESULTS

This study aims to identify differences in exosomes from preoperative adenoid tissue and peripheral blood samples between children with AHOME and those with adenoid hypertrophy alone. Additionally, it seeks to determine changes in microbial diversity in adenoid tissue between these groups.

CONCLUSIONS

The findings are expected to provide new insights into the diagnosis and treatment of OME, to identify novel biomarkers, and to enhance our understanding of the pathophysiology of OME, potentially leading to the development of innovative diagnostic and therapeutic approaches.

Novel strategies for inhibition of bacterial biofilm in chronic rhinosinusitis

An important role has been recently reported for bacterial biofilm in the pathophysiology of chronic diseases, such as chronic rhinosinusitis (CRS). CRS, affecting sinonasal mucosa, is a persistent inflammatory condition with a high prevalence around the world. Although the exact pathological mechanism of this disease has not been elicited yet, biofilm formation is known to lead to a more significant symptom burden and major objective clinical indicators. The high prevalence of multidrug-resistant bacteria has severely restricted the application of antibiotics in recent years. Furthermore, systemic antibiotic therapy, on top of its insufficient concentration to eradicate bacteria in the sinonasal biofilm, often causes toxicity, antibiotic resistance, and an effect on the natural microbiota, in patients. Thus, coming up with alternative therapeutic options instead of systemic antibiotic therapy is emphasized in the treatment of bacterial biofilm in CRS patients. The use of topical antibiotic therapy and antibiotic eluting sinus stents that induce higher antibiotic concentration, and decrease side effects could be helpful. Besides, recent research recognized that various natural products, nitric oxide, and bacteriophage therapy, in addition to the hindered biofilm formation, could degrade the established bacterial biofilm. However, despite these improvements, new antibacterial agents and CRS biofilm interactions are complicated and need extensive research. Finally, most studies were performed in vitro, and more preclinical animal models and human studies are required to confirm the collected data. The present review is specifically discussing potential therapeutic strategies for the treatment of bacterial biofilm in CRS patients.

Association between mucosal barrier disruption by Pseudomonas aeruginosa exoproteins and asthma in patients with chronic rhinosinusitis

BACKGROUND

Chronic rhinosinusitis (CRS) is a common chronic respiratory condition, frequently associated with asthma and affecting the majority of cystic fibrosis (CF) patients. Pseudomonas aeruginosa infections and biofilms have been implicated in recalcitrant CRS. One of the mechanisms of action for bacteria in CRS and CF is mucosal barrier disruption by secreted products that contribute to the inflammation. However, the role of biofilm and planktonic forms of P. aeruginosa in this process is not known. The aim is to determine the effect of P. aeruginosa exoproteins isolated from CF and non-CF CRS patients on the mucosal barrier.

METHODS

Exoproteins from 40 P. aeruginosa isolates were collected in planktonic and biofilm forms and applied to air-liquid interface (ALI) cultures of primary human nasal epithelial cells (HNECs). Mucosal barrier integrity was evaluated by transepithelial electrical resistance (TEER), passage of FITC-dextrans and immunofluorescence of tight junction proteins. Cytotoxicity assays were performed to measure cell viability, and IL-6 ELISA was carried out to evaluate pro-inflammatory effects.

RESULTS

Planktonic exoproteins from 20/40 (50%) clinical isolates had a significant detrimental effect on the barrier and significantly increased IL-6 production. Barrier disruption was characterized by a reduced TEER, increased permeability of FITC-dextrans and discontinuous immunolocalization of tight junction proteins and was significantly more prevalent in isolates harvested from patients with comorbid asthma (P < .05).

CONCLUSION

Exoproteins from planktonic P. aeruginosa clinical isolates from asthmatic CRS patients have detrimental effects on the mucosal barrier and induce IL-6 production potentially contributing to the mucosal inflammation in CRS patients.

Otitis media with effusion in children: Pathophysiology, diagnosis, and treatment. A review

Otitis media with effusion (OME) is a frequent paediatric disorder. The condition is often asymptomatic, and so can easily be missed. However, OME can lead to hearing loss that impairs the child's language and behavioural development. The diagnosis is essentially clinical, and is based on otoscopy and (in some cases) tympanometry. Nasal endoscopy is only indicated in cases of unilateral OME or when obstructive adenoid hypertrophy is suspected. Otitis media with effusion is defined as the observation of middle-ear effusion at consultations three months apart. Hearing must be evaluated (using an age-appropriate audiometry technique) before and after treatment, so as not to miss another underlying cause of deafness (e.g. perception deafness). Craniofacial dysmorphism, respiratory allergy and gastro-oesophageal reflux all favour the development of OME. Although a certain number of medications (antibiotics, corticoids, antihistamines, mucokinetic agents, and nasal decongestants) can be used to treat OME, they are not reliably effective and rarely provide long-term relief. The benchmark treatment for OME is placement of tympanostomy tubes (TTs) and (in some cases) adjunct adenoidectomy. The TTs rapidly normalize hearing and effectively prevent the development of cholesteatoma in the middle ear. In contrast, TTs do not prevent progression towards tympanic atrophy or a retraction pocket. Adenoidectomy enhances the effectiveness of TTs. In children with adenoid hypertrophy, adenoidectomy is indicated before the age of 4 but can be performed later when OME is identified by nasal endoscopy. Children must be followed up until OME has disappeared completely, so that any complications are not missed.

Manuka honey sinus irrigation for the treatment of chronic rhinosinusitis: a randomized controlled trial

BACKGROUND

Manuka honey (MH) has been shown in vitro to be effective against biofilm-producing bacteria. This study assessed the effectiveness of MH for patients with active chronic rhinosinusitis (CRS) and prior sinus surgery.

METHODS

This prospective single-blinded (clinician only) randomized controlled trial recruited patients with active CRS and prior sinus surgery. Patients received either MH or saline (SAL) sinus irrigations twice daily for 30 days and were offered oral antibiotics and/or oral/topical steroids as indicated. Outcomes were 22-item Sino-Nasal Outcome Test (SNOT-22) change score (primary), culture negativity, and Lund-Kennedy endoscopic change score.

RESULTS

Forty-two patients were analyzed (MH, n = 20; SAL, n = 22). The SNOT-22 change score achieved a clinically significant improvement in both groups but was similar between MH (median [interquartile range]: -12 [-20, -1]) and SAL (-12.5 [-22, -6]) (p = 0.57). Culture negativity was better on MH (8/19, 42%) compared to SAL (4/21, 19%), nearing statistical significance (p = 0.11). Lund-Kennedy endoscopic change score improved in both groups but was not statistically better on MH (-3 [-5, 0]) compared to SAL (-1 [-2, 0]) (p = 0.20). For patients not receiving oral antibiotics/steroids, culture negativity was statistically better on MH (5/10, 50%) compared to SAL (0/6, 0%) (p = 0.04). MH was well-tolerated. No adverse events were reported.

CONCLUSION

In patients with active CRS and prior sinus surgery, both MH and SAL improved outcomes, but there was no statistically significant difference between these groups. However, in the subset that did not receive oral antibiotics/steroids, culture negativity was statistically better on MH, suggesting that MH alone may be effective for acute exacerbations of CRS.

Clinical effects of topical antifungal therapy in chronic rhinosinusitis: a randomized, double-blind, placebo-controlled trial of intranasal fluconazole

Several studies have been in favor of fungi as a possible pathogenesis of chronic rhinosinusitis (CRS); however, to date, there is no scientific consensus about the use of antifungal agents in disease management. The aim of the present study was to investigate the efficacy of intranasal fluconazole in improving disease symptoms and objective outcomes of patients with CRS. A randomized, double-blind, placebo-controlled study was conducted on 54 patients who were diagnosed with CRS and had not been responsive to routine medical treatments. They were randomly assigned to receive either fluconazole nasal drop 0.2 % or placebo in addition to the standard regimen for a duration of 8 weeks. Patients' outcomes were evaluated according to Sino-Nasal Outcome Test 20 (SNOT-20), endoscopic scores, and Computed Tomography (CT) scores. No statistically significant difference was found in SNOT-20 (p = 0.201), endoscopic (p = 0.283), and CT scores (p = 0.212) of the patients at baseline and after 8-week course of treatment between drug and placebo group. Similar to many studies, the use of topical antifungal treatment for patients with CRS was not shown to be significantly effective. However, further studies are needed to obtain high levels of consistent evidence in order to arrive at a decision whether antifungal therapy is effective in management of CRS or not.

Bacterial biofilm on the sinus mucosa of healthy subjects and patients with chronic rhinosinusitis (with or without nasal polyposis)

OBJECTIVE

To study the presence of bacterial biofilm on the sinus mucosa of healthy individuals (controls) and patients with chronic rhinosinusitis with or without nasal polyposis.

METHODS

An analytical, prospective and observational study was conducted. Tissue samples were obtained from the sinus mucosa. The bacteria were isolated and typified, and the material was examined for biofilm formation using tissue culture plate, Congo red agar detection and tube methods.

RESULTS

A total of 100 cases were analysed for the presence of biofilm. Bacterial biofilm was present in 26 of 50 disease group cases (52 per cent) and in 4 of 50 control group cases (8 per cent) (p < 0.01).

CONCLUSION

The presence of biofilm on the mucosa of chronic rhinosinusitis patients offers a possible cause for the persistent inflammation, and for antibiotics resistance and antimicrobial therapy failure. These findings could change the approach to treatment.

Effect of topical ofloxacin on bacterial biofilms in refractory post-sinus surgery rhino-sinusitis

Bacterial biofilms have been shown to play a major role in many chronic infections, in addition, there is growing evidence that bacterial biofilms may play a role in some forms of refractory CRS that persists despite proper surgery and culture directed antibiotic therapy. The objective is to determine the effect of application of topical ofloxacin on nasal and sinus mucosa in patients with proven existence of bacterial biofilms and persistent chronic sinusitis after FESS. The study design is a prospective controlled study. The study included a total of 12 patients who had refractory CRS in spite of undergoing FESS for that specific reason (study group), and control group (involved 25 patients), for whom FESS was done, with complete improvement postoperatively in 15 of them, and persistence of symptoms in the other ten. Topical ofloxacin eye drops (0.3 %) tds for 12 weeks were prescribed for (study group), culture and sensitivity and scanning electron microscopy were done for middle meatal mucosal specimens for all patients and controls, all of them were followed up for a minimum of 9 months (range 9-18 months). Of the study group, 80 % showed marked improvement in the structure of the mucosa, with the regaining of normal respiratory epithelium, with complete disappearance of the biofilm surface, and the remaining 20 % showed only reduction in the number of inflammatory cells and regaining cilia with scattered patches of very thin biofilm. Biofilms formation plays an active role in perpetuating inflammation in CRS patients and enhanced the recurrence and resistance in those patients, we found a statistically significant improvement in patients' group (P < 0.001), after 12 weeks of topical ofloxacin (without any evidence of any side effects). So, we concluded that topical ofloxacin seems to be an effective, tolerable, convenient, cheap and even safe mode of treatment of refractory CRS after FESS due to biofilms' formation. Thus, we recommend such modality of treatment postoperatively especially in refractory cases of 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.

Damage-associated molecular patterns stimulate interleukin-33 expression in nasal polyp epithelial cells

BACKGROUND

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a disorder characterized by eosinophilic inflammation and local T-helper 2 (Th2) cytokine production. Innate lymphoid cells that elaborate Th2 cytokines have recently been characterized within nasal polyps. These cells can be activated by the epithelial cell-derived cytokine interleukin-33 (IL-33). The objective of this study is to determine whether 2 molecules associated with tissue damage (high mobility group box-1 [HMGB-1] and adenosine triphosphate [ATP]) elicit expression of IL-33 in sinonasal epithelial cells (SNECs) derived from recalcitrant CRSwNP patients.

METHODS

Ethmoid tissue was obtained from 8 recalcitrant CRSwNP and 9 control subjects during endoscopic sinus surgery (ESS). Tissue was prepared for immunohistochemistry and for SNEC air-liquid interface culture. After exposure to either HMGB1 or ATP in vitro, SNECs were processed for messenger RNA (mRNA) extraction and immunocytochemistry. IL-33 levels were determined by real-time polymerase chain reaction (PCR) and by immunochemical staining with anti-IL-33 antibody.

RESULTS

Intranuclear IL-33 is normally expressed in basal epithelial cells, but is present in more apical cells and outside the nucleus in CRSwNP. Exposure of SNECs to HMGB-1 or ATP resulted in a statistically significant increase in IL-33 mRNA expression in SNECs derived from recalcitrant CRSwNP patients. This increase was reflected at the protein level by immunochemical staining of IL-33.

CONCLUSION

Tissue damage is a nonspecific trigger of epithelial IL-33 production in treatment-recalcitrant polyps, which may be responsible for perpetuating eosinophilic inflammation in CRSwNP. This common pathway may help explain why multiple environmental and infectious agents have been implicated in CRSwNP exacerbation.

Chronic pulmonary pseudomonal infection in patients with cystic fibrosis: A model for early phase symbiotic evolution

Gain of "antimicrobial resistance" and "adaptive virulence" has been the dominant view of Pseudomonas aeruginosa (Pa) in cystic fibrosis (CF) in the progressively damaged host airway over the course of this chronic infection. However, the pathogenic effects of CF airway-adapted Pa strains are notably reduced. We propose that CF Pa and other bacterial cohabitants undergo host adaptation which resembles the changes found in bacterial symbionts in animal hosts. Development of clonally selected and intraspecific isogenic Pa strains which display divergent colony morphology, growth rate, auxotrophy, and antibiotic susceptibility in vitro suggests an adaptive sequence of infective exploitation-parasitism-symbiotic evolution driven by host defenses. Most importantly, the emergence of CF pseudomonal auxotrophy is frequently associated with a few specific amino acids. The selective retention or loss of specific amino acid biosynthesis in CF-adapted Pa reflects bacterium-host symbiosis and coevolution during chronic infection, not nutrient availability. This principle also argues against the long-standing concept of dietary availability leading to evolution of essential amino acid requirements in humans. A novel model of pseudomonal adaptation through multicellular bacterial syntrophy is proposed to explain early events in bacterial gene decay and decreased (not increased) virulence due to symbiotic response to host defense.

Clinical characteristics of biofilms in patients with chronic rhinosinusitis: a prospective case-control study

Recent studies have indicated that biofilms are involved in the pathogenesis of recurrent and recalcitrant chronic rhinosinusitis (CRS). The present study was performed to evaluate the presence of biofilms and to evaluate the relationships between the presence of biofilms and clinical features of CRS. A total of 33 patients were included in this study. Maxillary sinus mucosa from 26 CRS patients and the ethmoid mucosa from 7 patients undergoing septoplasty were collected. Biofilms were evaluated by scanning electron microscopy. Preoperative symptom scores, preoperative and intraoperative nasoendoscopic findings, and postoperative healing period were compared between the groups. Biofilms were detected in 14 (42.4 %) of the 33 patients. Biofilms were present in 13 (50 %) of the 26 patients in the CRS group, but in only one (14.3 %) of the seven patients in the control group. There were no significant differences in preoperative symptom scores or preoperative nasal Lund-Kennedy endoscopic scores between the groups. However, the average Lund-Mackay and intraoperative sinus Lund-Kennedy endoscopic scores were significantly higher in biofilm-positive than biofilm-negative patients (P < 0.05). In the follow-up period, the healing time was significantly longer in biofilm-positive than biofilm-negative patients (P < 0.05). This study suggested that the presence of bacterial biofilms may contribute to the pathogenesis of CRS and the clinical characteristics of CRS patients after endoscopic sinus surgery.

Evidence of Bacterial Biofilms among Infected and Hypertrophied Tonsils in Correlation with the Microbiology, Histopathology, and Clinical Symptoms of Tonsillar Diseases

Diseases of the tonsils are becoming more resistant to antibiotics due to the persistence of bacteria through the formation of biofilms. Therefore, understanding the microbiology and pathophysiology of such diseases represent an important step in the management of biofilm-related infections. We have isolated the microorganisms, evaluated their antimicrobial susceptibility, and detected the presence of bacterial biofilms in tonsillar specimens in correlation with the clinical manifestations of tonsillar diseases. Therefore, a total of 140 palatine tonsils were collected from 70 patients undergoing tonsillectomy at University Malaya Medical Centre. The most recovered isolate was Staphylococcus aureus (39.65%) followed by Haemophilus influenzae (18.53%). There was high susceptibility against all selected antibiotics except for cotrimoxazole. Bacterial biofilms were detected in 60% of patients and a significant percentage of patients demonstrated infection manifestation rather than obstruction. In addition, an association between clinical symptoms like snore, apnea, nasal obstruction, and tonsillar hypertrophy was found to be related to the microbiology of tonsils particularly to the presence of biofilms. In conclusion, evidence of biofilms in tonsils in correlation with the demonstrated clinical symptoms explains the recalcitrant nature of tonsillar diseases and highlights the importance of biofilm's early detection and prevention towards better therapeutic management of biofilm-related infections.

Complementary and integrative treatments: rhinosinusitis

Rhinosinusitis is characterized by inflammation of the mucosa involving the paranasal sinuses and the nasal cavity and is one of the most common health care problems, with significant impairment of quality of life. There is a growing amount of interest in the use of complementary and integrative medicine for the treatment of rhinosinusitis. This article focuses on an integrative approach to rhinosinusitis.

Role of adenoid biofilm in chronic otitis media with effusion in children

To study the extent of surface adenoid biofilm and to evaluate its role in the pathogenesis of chronic otitis media with effusion (COME) in children. The study was carried out on 100 children between 3 and 14 years of age, who were divided into two groups. The first group (50 children) had otitis media with effusion associated with adenoid hypertrophy, whereas the second group (50 children) had adenoid hypertrophy without middle ear effusion. Adenoidectomy with ventilation tube insertion was done for group 1 cases, whereas, only Adenoidectomy was done for group 2 cases. Microbiological study, Scanning electron microscope and multiplex- PCR were done for suspected adenoid biofilms and specimens from middle ear effusion. Adenoids removed from children with COME had higher grade biofilm formation (74 %) than the second group (42 %). No correlation was found between adenoid size and biofilm formation. Culture of adenoid tissue in group 1 patients was positive in 52 % of cases compared to 96 % by PCR, while in group 2 culture of adenoid tissue was positive in 38 % compared to 48 % by PCR. Culture of middle ear fluid was positive in 32 % of cases only compared to 80 % by PCR. A positive correlation was found between results of bacterial biofilm visualized by SEM and bacteria detected and identified by PCR technique. On the other hand, no correlation was found between results of bacterial biofilm visualized by SEM and bacteria detected by culture. The size of the adenoid is not the main determinant factor in OME pathogenesis but the degree of bacterial colonization is much more important. Adenoids in COME may act as a reservoir of chronic infection rather than causing mechanical Eustachian obstruction. Higher grade biofilm formation was found in cases with middle ear effusion than those with adenoid hypertrophy only. These findings support the hypothesis that there would be an association between adenoidal biofilm formation and COME. This study focused on the value of PCR in detecting pathogens in the adenoid and middle ear specimens although the bacterial culture would be negative.

The effect of antimicrobial photodynamic therapy on human ciliated respiratory mucosa

BACKGROUND

Chronic recurrent sinusitis (CRS) is one of the most common chronic conditions in the United States. There is a significant subpopulation of CRS patients who remain resistant to cure despite rigorous treatment regimens including surgery, allergy therapy, and prolonged antibiotic therapy. Antimicrobial photodynamic therapy (aPDT) is a noninvasive nonantibiotic broad spectrum antimicrobial treatment. Our previous in vitro studies demonstrated that aPDT reduced CRS polymicrobial biofilm and planktonic bacteria and fungi by > 99.9% after a single treatment. Prior to human treatment however, aPDT treatment must be demonstrated to not result in histologic damage to the sinus ciliated respiratory epithelium. The objective of this study was to demonstrate the safety of aPDT treatment on a living human ciliated respiratory mucosal model (EpiAirway).

METHODS

A study of aPDT treatment of EpiAirway was performed. Treatment groups included a nontreatment control, laser light alone, photosensitizer alone, and therapeutic photosensitizer and light combination (aPDT). At completion of treatment, the EpiAirway tissue was fixed in 10% formalin, paraffin-embedded, sectioned, H&E stained and mounted. All samples were blinded and microscopically examined by a human pathologist to assess any effect of aPDT on the tissue, cilia, or mucosal glands. The results were correlated with the treatment parameters.

RESULTS

The EpiAirway histologic study demonstrated no histologic alteration of the respiratory cilia or mucosal epithelium in any of the treatment groups.

CONCLUSIONS

aPDT is a safe treatment for CRS resulting in no histologic alteration of human ciliated respiratory mucosa as is found in the human sinuses.

Molecular basis of tobacco-induced bacterial biofilms: an in vitro study

OBJECTIVE

To evaluate changes in the expression of biofilm-related genes when exposed to tobacco smoke and oxidative stress.

STUDY DESIGN

Experimental, in vitro. Setting Laboratories of Rhinology and Microbiology, University of Pennsylvania.

SUBJECTS AND METHODS

Bacterial biofilm mass was measured using crystal violet staining and measurement of the optical density. Biofilm-related genes of the Pseudomonas aeruginosa PAO1 strain (pilF, flgK, lasI, lasB, rhlA, and algC) were studied following repetitive exposure to exogenous tobacco smoke and hydrogen peroxide. This was done using a reporter plasmid.

RESULTS

After 1 exposure to smoke, there was no change in biofilm formation. However, after 2 and 3 exposures, the biofilm formed had an increased mass (P < .05). With respect to oxidative stress in the form of H(2)O(2), bacterial cultures demonstrated a dose- and time-dependent induction of biofilm formation compared with control conditions. Gene expression following repetitive smoke exposure demonstrated an increase in expression of pilF, flgK, algC, and lasI genes (P < .05); a decrease in rhlA (P < .05); and no significant change in the lasB gene (P = 0.1). Gene expression following H(2)O(2) exposure demonstrated an increase in pilF (P < .05), whereas the other genes failed to demonstrate a statistical change.

CONCLUSIONS

Repetitive tobacco smoke exposure leads to molecular changes in biofilm-related genes, and exposure to oxidative stress in the form of H(2)O(2) induces biofilm growth in PAO1. This could represent adaptative changes due to oxidative stress or chemically mediated through any of the several chemicals encountered in tobacco smoke and may explain increased biofilm formation in microbes isolated from smokers.

Efficacy of NVC-422 against Staphylococcus aureus biofilms in a sheep biofilm model of sinusitis

BACKGROUND

Bacterial biofilms are a major obstacle in management of recalcitrant chronic rhinosinusitis. NVC-422 is a potent, fast-acting, broad-spectrum, nonantibiotic, antimicrobial with a new mechanism of action effective against biofilm bacteria in in vitro conditions. The aim of this study was to investigate the safety and efficacy of NVC-422 as local antibiofilm treatment in a sheep model of rhinosinusitis.

METHODS

After accessing and occluding frontal sinus ostia in 24 merino sheep via staged endoscopic procedures, S. aureus clinical isolate was instilled in frontal sinuses. Following biofilm formation, ostial obstruction was removed and sinuses irrigated with 0.1% and 0.5% NVC-422 in 5 mM acetate isotonic saline at pH 4.0. Sheep were monitored for adverse effects and euthanized 24 hours after treatment. Frontal sinuses were assessed for infection and changes in mucosa after the treatment. S. aureus biofilms were identified with Baclight-confocal scanning microscopy protocol and the biofilm biomass assayed by applying the COMSTAT2 program to recorded image stacks.

RESULTS

After 2 irrigations with 0.1% NVC-422, S. aureus biofilm biomass was reduced when compared to control sinuses (p = 0.0001), though this effect was variable in samples. NVC-422 0.5% solution irrigations reduced biofilm even more significantly and consistently over all samples (p < 0.0001). NVC-422 0.5% was also more effective than 0.1% NVC-422, vehicle control, and normal saline sinus irrigations in reducing biofilm biomass (p < 0.05 for all subgroups). No adverse events were observed in sheep after sinus irrigations with 0.1% and 0.5% NVC-422 solutions.

CONCLUSION

NVC-422 is an effective topical agent against S. aureus biofilms, with dose-dependent efficacy in this animal model of biofilm-associated sinusitis.

Prevalence of Biofilms and Their Response to Medical Treatment in Chronic Rhinosinusitis without Polyps

Objective. The aim of this study was to investigate the prevalence of biofilms and the effects of medical treatment modalities in chronic rhinosinusitis (CRS) patients without nasal polyps.

Study Design. Randomized controlled trial.

Settings. Tertiary referral hospital.

Subjects and Methods. The authors randomly divided 32 adult patients with CRS without nasal polyps into 2 groups. In the first group (n = 16), oral clarithromycin was administered 500 mg/bid for 2 weeks and then 250 mg/d for the following 6 weeks. In the second group (n = 16), an 8-week course of 200-mcg/d topical mometasone furoate was added to the clarithromycin regimen, identical to the first group. The pre- and posttreatment nasal tissue samples were evaluated by scanning electron microscopy for biofilm prevalence and graded from 0 to 3 according to density and extension.

Results. Biofilms were detected in 24 of 32 patients (75%) before the treatment (grades 1-3). Biofilms were detected in 14 of 32 patients (43.8%) after the treatment (grades 1-2). When each group was evaluated independently, there was a significant improvement after the treatment in both groups I and II. When the biofilm grades of group I were compared to those of group II, there was no significant difference both in the pre- and posttreatment evaluation.

Conclusion. The prevalence of biofilms in CRS without polyps was 75% in our study. Regression of biofilms to 43% was observed under medical treatment. Adding nasal steroids to macrolides gave no further benefit.

Antimicrobial photodynamic therapy treatment of chronic recurrent sinusitis biofilms

BACKGROUND

Chronic recurrent sinusitis (CRS) is an inflammatory disease of the facial sinuses and nasal passages that is defined as lasting longer than 12 weeks or occurring more than 4 times per year with symptoms usually lasting more than 20 days. The National Institute for Health Statistics estimates that CRS is one of the most common chronic conditions in the United States, affecting an estimated 37 million Americans. The potential etiologies of CRS include bacteria, viruses, allergies, fungi, superantigens, and microbial biofilms. In clinical practice there is a significant subpopulation of patients with CRS who remain resistant to cure despite rigorous treatment regimens including surgery, allergy therapy, and prolonged antibiotic therapy. The reason for treatment failure is thought to be related to the destruction of the sinus mucociliary defense by the chronic sinus infection resulting in the development of secondary antibiotic-resistant microbial colonization of the sinuses and biofilm formation. Antimicrobial photodynamic therapy (aPDT) is a nonantibiotic broad-spectrum antimicrobial treatment that has been demonstrated to eradicate antibiotic-resistant bacteria and biofilms. The objective of this study was to demonstrate the effectiveness of a noninvasive aPDT treatment method of eradicating antibiotic resistant biofilms/microorganisms known to cause CRS in an in vitro model.

METHODS

Antibiotic-resistant planktonic bacteria and fungi and polymicrobial biofilms of Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus (MRSA) were grown on silastic sheets and treated with a methylene blue photosensitizer and 670 nm non-thermal-activating light. Cultures of the planktonic microorganisms and biofilms were obtained before and after light treatment to determine efficacy of planktonic bacteria and biofilm reduction.

RESULTS

The in vitro CRS planktonic microorganism and biofilm study demonstrated that aPDT reduced the CRS polymicrobial biofilm by >99.9% after a single treatment.

CONCLUSION

aPDT can effectively treat CRS polymicrobial antibiotic-resistant bacteria, fungi, and biofilms in vivo. Human clinical studies are currently planned to assess the safety and efficacy of this treatment for CRS.

Pathophysiology of Chronic Rhinosinusitis with Nasal Polyp

Background

Chronic rhinosinusitis (CRS) is a common inflammatory condition of the paranasal sinuses and nasal passages. CRS with nasal polyp (CRSwNP) is a subtype of CRS, and the pathogenesis of CRSwNP remains largely unclear.

Methods

This article reviews the literature regarding the pathophysiology of CRSwNP.

Results

Evidence suggests that altered innate immunity, adaptive immunity, tissue remodeling, and/or effects of microorganisms may play a role in the development of CRSwNP. Aberrant arachidonic acid metabolism may also contribute to the pathogenesis of CRSwNP in patients with aspirin-exacerbated respiratory disease.

Conclusion

There have been significant advances in the understanding pathophysiology of CRSwNP. Additional research is needed to elucidate these mechanisms and to determine their relative importance in the pathogenesis of CRSwNP.

The role of hepatocyte growth factor/c-Met in chronic rhinosinusitis with nasal polyps

BACKGROUND

Hepatocyte growth factor (HGF) is a growth factor thought to attenuate Th2-driven eosinophilic airway inflammatory responses. Increased expression of HGF and its receptor c-Met in nasal polyps suggests a role in disease pathogenesis. The effect of HGF on human sinonasal epithelial cell (SNEC) responses to Th2 inflammatory cytokines in chronic rhinosinusitis with nasal polyps (CRSwNP) has not been explored.

METHODS

SNECs isolated from patients with CRSwNP and control subjects were grown in cell culture at the air-liquid interface. The Th2 cytokine IL-13 was applied for 24 hours in the presence or absence of HGF. Eotaxin-3 and c-Met expression was assessed using real-time PCR, immunohistochemistry, and flow cytometry.

RESULTS

SNECs obtained from both CRSwNP and control subjects showed markedly increased expression of eotaxin-3 after exposure to IL-13. HGF significantly blocked IL-13-induced expression of eotaxin-3 in control SNECs, but not in SNECs derived from CRSwNP subjects.

CONCLUSION

SNECs are active participants in sinonasal mucosal immunity, expressing inflammatory mediators in response to potential pathogens and endogenous cytokines. Although Th2 cytokines can elicit expression of proeosinophilic mediators by SNECs, HGF appears to have a down-regulating effect on this response. In patients with CRSwNP, SNECs are resistant to this attenuation, showing continued IL-13-induced eotaxin-3 expression despite HGF treatment. Abnormalities in the regulation of epithelial cell responses to endogenous cytokines and growth factors may contribute to the persistent eosinophilic inflammatory state in CRSwNP.

Tobacco smoke mediated induction of sinonasal microbial biofilms

Cigarette smokers and those exposed to second hand smoke are more susceptible to life threatening infection than non-smokers. While much is known about the devastating effect tobacco exposure has on the human body, less is known about the effect of tobacco smoke on the commensal and commonly found pathogenic bacteria of the human respiratory tract, or human respiratory tract microbiome. Chronic rhinosinusitis (CRS) is a common medical complaint, affecting 16% of the US population with an estimated aggregated cost of $6 billion annually. Epidemiologic studies demonstrate a correlation between tobacco smoke exposure and rhinosinusitis. Although a common cause of CRS has not been defined, bacterial presence within the nasal and paranasal sinuses is assumed to be contributory. Here we demonstrate that repetitive tobacco smoke exposure induces biofilm formation in a diverse set of bacteria isolated from the sinonasal cavities of patients with CRS. Additionally, bacteria isolated from patients with tobacco smoke exposure demonstrate robust in vitro biofilm formation when challenged with tobacco smoke compared to those isolated from smoke naïve patients. Lastly, bacteria from smoke exposed patients can revert to a non-biofilm phenotype when grown in the absence of tobacco smoke. These observations support the hypothesis that tobacco exposure induces sinonasal biofilm formation, thereby contributing to the conversion of a transient and medically treatable infection to a persistent and therapeutically recalcitrant condition.

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.

Biofilms

Bacterial biofilms are 3-dimensional aggregates of bacteria that have been shown to play a major role in many chronic infections. Evidence is growing that bacterial biofilms may play a role in certain cases of recalcitrant chronic sinusitis that do not respond to traditional medical and surgical therapies. Novel therapies may have clinical applications to prevent and destabilize biofilms. Future research will determine if topical antimicrobials, surfactants, and other adjuvant therapies can be used to treat biofilm-associated chronic rhinosinusitis.

Treatment-recalcitrant chronic rhinosinusitis with polyps is associated with altered epithelial cell expression of interleukin-33

BACKGROUND

Abnormalities in host mucosal immunity exist in chronic rhinosinusitis with nasal polyps (CRSwNPs), but it is unclear whether this is a cause or an effect of the eosinophilic inflammation and frequent microbial colonization that characterizes the disease. Sinonasal epithelial cells (SNECs) are critical participants in healthy antimicrobial innate immune defense. They also can promote Th2 inflammation with various mediators, including interleukin (IL)-33, which induces T helper cells to produce Th2 cytokines.

METHODS

CRSwNP SNECs were obtained during sinus surgery and stored. Patients were subsequently classified as either treatment responsive or treatment recalcitrant, based on long-term outcomes of medical and surgical therapy. Epithelial cells from these patients were grown in air-liquid interface (ALI) culture and treated with IL-13, as well as the bacteria-associated molecule, CpG. Expression of IL-33 mRNA was determined by real-time polymerase chain reaction.

RESULTS

Recalcitrant CRSwNP epithelial cells had increased baseline expression of IL-33 compared with responsive CRSwNPs, which was further increased by 24-hour exposure to CpG. Treatment-responsive epithelial cells were not induced by CpG to express IL-33. Prolonged treatment with IL-13 during differentiation at the ALI diminished the baseline expression of IL-33 and prevented the subsequent induction of IL-33 by CpG.

CONCLUSION

Mucosal innate immunity likely plays an important role in CRSwNP pathogenesis. A definitive link between infectious triggers and the development of Th2 inflammation has been elusive. We have found constitutive IL-33 expression by SNECs in recalcitrant CRSwNPs, which can be further induced by a bacteria-associated molecular pattern. Dysregulated epithelial cell immune interactions between host and environment may contribute to Th2 inflammation in CRSwNPs.

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.

The future of early disease detection? Applications of electronic nose technology in otolaryngology

INTRODUCTION

Recent advances in electronic nose technology, and successful clinical applications, are facilitating the development of new methods for rapid, bedside diagnosis of disease. There is a real clinical need for such new diagnostic tools in otolaryngology.

MATERIALS AND METHODS

We present a critical review of recent advances in electronic nose technology and current applications in otolaryngology.

RESULTS

The literature reports evidence of accurate diagnosis of common otolaryngological conditions such as sinusitis (acute and chronic), chronic suppurative otitis media, otitis externa and nasal vestibulitis. A significant recent development is the successful identification of biofilm-producing versus non-biofilm-producing pseudomonas and staphylococcus species.

CONCLUSION

Electronic nose technology holds significant potential for enabling rapid, non-invasive, bedside diagnosis of otolaryngological disease.

Diagnosis and management of chronic rhinosinusitis in adults

Chronic rhinosinusitis (CRS) is characterized by mucosal inflammation affecting both the nasal cavity and paranasal sinuses; its causes are potentially numerous, disparate, and frequently overlapping. The more common conditions that are associated with CRS are perennial allergic and nonallergic rhinitis, nasal polyps, and anatomical mechanical obstruction (septum/turbinate issues). Other less common etiologies include inflammation (eg, from superantigens), fungal sinusitis or bacterial sinusitis with or without associated biofilm formation, gastroesophageal reflux, smoke and other environmental exposures, immune deficiencies, genetics, and aspirin-exacerbated respiratory disease. A diagnosis of CRS is strongly suggested by a history of symptoms (eg, congestion and/or fullness; nasal obstruction, blockage, discharge, and/or purulence; discolored postnasal discharge; hyposmia/anosmia; facial pain and/or pressure) and their duration for > 3 months. A definitive diagnosis requires physical evidence of mucosal swelling or discharge appreciated during physical examination coupled with CT imaging if inflammation does not involve the middle meatus or ethmoid bulla. Multivariant causation makes the diagnosis of CRS and selection of treatment complex. Furthermore, various types of health care providers including ear, nose, and throat (ENT) specialists, allergists, primary care physicians, and pulmonologists treat CRS, and each is likely to have a different approach. A structured approach to the diagnosis and management of CRS can help streamline and standardize care no matter where patients present for evaluation and treatment. A 2008 Working Group on CRS in Adults, supported by the American Academy of Otolaryngic Allergy (AAOA), developed a series of algorithms for the differential diagnosis and treatment of CRS in adults, based on the evolving understanding of CRS as an inflammatory disease. The algorithms presented in this paper address an approach for all CRS patients as well as approaches for those with nasal polyps, edema observed on nasal endoscopy, purulence observed on nasal endoscopy, an abnormal history and physical examination, and an abnormal history and normal physical examination.

[Bacteriological study of ethmoid specimens from patients with nasal polyposis after ethmoidal surgery]

OBJECTIVE

To compare the bacteriological and clinical findings in ethmoid specimens from patients with nasal polyposis after radical ethmoidal surgery.

PATIENTS AND METHODS

From June to November 2008, 60 patients were prospectively included. For each patient, two samples for each ethmoidal cavity were taken. Aerobic and anaerobic bacterial cultures and fungal cultures were processed and the antibiotic susceptibility was evaluated for each isolated bacterial strain.

RESULTS

Pathogenic bacteria were isolated in 48 patients (80%) including predominantly Staphylococcus aureus (60%) or a Gram-negative bacterium. The microorganisms were nearly all susceptible to antibiotics, including the aminoglycosides. No correlation between the presence of pathogenic bacteria and the clinical status of the patients was found.

CONCLUSION

In this study, a great number of patients was colonized with pathogenic bacteria. However, the presence of pathogenic bacteria was not correlated with the clinical status of the patients.

Biofilms in chronic rhinosinusitis: a review

BACKGROUND

Bacterial biofilms consist of a complex, organized community of bacteria that anchor to both biotic and abiotic surfaces. They are composed of layers of embedded, live bacteria within extruded exopolymeric matrix. This configuration allows for evasion of host defenses and decreased susceptibility to antibiotic therapy while maintaining the ability to deliberately release planktonic bacteria, resulting in recurrent acute infections. Thus, bacterial biofilms were hypothesized to contribute to the progression and persistence of chronic rhinosinusitis.

METHODS

This review summarizes several of the seminal papers supporting this hypothesis.

RESULTS

Multiple reports using various imaging modalities have demonstrated the presence of biofilms in sinonasal mucosa of patients with chronic rhinosinusitis. More recently, several studies have correlated the presence of biofilms with poor clinical outcomes in the disease process. Early therapeutic interventions have generated mixed results.

CONCLUSIONS

Bacterial biofilms appear to contribute to the progression of chronic rhinosinusitis in a subset of patients, although substantial effort toward therapeutic intervention is still necessary.

Current issues in the management of sinonasal methicillin-resistant Staphylococcus aureus

PURPOSE OF REVIEW

Staphylococcus aureus is an important pathogen, contributing to both pediatric and adult infections in the USA. In recent years, methicillin-resistant Staphylococcus aureus (MRSA) has become a source of public fear and outcry. In this article, we review facts and fiction of sinonasal MRSA.

RECENT FINDINGS

Although the exact role of bacteria in chronic rhinosinusitis continues to be debated, the role of MRSA in these patients is even less apparent. When MRSA is involved, there are few to guide treatment. Oral, parenteral, and topical antibiotics are all used in the treatment of sinonasal MRSA. MRSA eradication has been advocated by some; however, there are few data to support the efficacy of eradication. Current treatment regimens by the authors are reviewed.

SUMMARY

There is much that is not known about the role of MRSA in sinonasal infection, and the impact of sinonasal MRSA on the health quality of the community also remains undefined. Treatment outlines are presented; however, with the current state of data, these treatment preferences lack a solid, evidence-based foundation that is favored. Future studies will lay the foundation for more rigorously supported treatment algorithms.

Are bulb syringe irrigators a potential source of bacterial contamination in chronic rhinosinusitis?

BACKGROUND

The purpose of this study was to determine if bulb syringe irrigators are a potential source for bacterial contamination in patients with chronic rhinosinusitis.

METHODS

Standard 3-oz bulb syringe irrigators (n = 24) were each flushed with the following solutions twice daily: A (n = 8), sterile isotonic saline; B (n = 8), prepared hypertonic saline (3 tsp table salt/L of sterile water); and C (n = 8), prepared baking soda/saline (1 tsp table salt + 1 tsp baking soda/L of commercial sterile water). Syringes were stored on a residential bathroom counter, and two from each group were harvested for culture weekly for 4 weeks.

RESULTS

There was no growth from syringes irrigated with any of the three solutions after the first 7 days of irrigation. After the entire 4-week study period, potential pathogens were recovered from 6/8 (75%) bulbs from group A, 0/8 bulbs from group B, and 1/8 bulbs (12.5%) from group C. All positive cultures revealed growth by 1-2 days postinoculation (p = 0.002). The organism recovered from syringes in group A was Pseudomonas fluorescens in all six specimens. The one positive culture in group C represented a single colony of Gram-positive cocci.

CONCLUSION

Under realistic conditions, bulb syringes are susceptible to contamination with potential bacterial pathogens, particularly when using unbuffered isotonic saline.

Th2 cytokines associated with chronic rhinosinusitis with polyps down-regulate the antimicrobial immune function of human sinonasal epithelial cells

BACKGROUND

Chronic rhinosinusitis with nasal polyps (CRSwNPs) is a disorder characterized by persistent eosinophilic Th2 inflammation and frequent sinonasal microbial colonization. It has been postulated that an abnormal mucosal immune response underlies disease pathogenesis. The relationship between Th2 inflammatory cytokines and the innate immune function of sinonasal epithelial cells (SNECs) has not been explored.

METHODS

Human SNECs (HSNECs) isolated from control subjects and patients with CRS were assessed for expression of antimicrobial innate immune genes and proinflammatory cytokine genes by real-time polymerase chain reaction, ELISA, and flow cytometry. A model of the Th2 inflammatory environment was created by exposure of primary HSNEC to the Th2 cytokine interleukin (IL)-4 or IL-13 for 36 hours, with subsequent assessment of innate immune gene expression.

RESULTS

HSNEC obtained from CRSwNP patients displayed decreased expression of multiple antimicrobial innate immune markers, including toll-like receptor 9, human beta-defensin 2, and surfactant protein A. Baseline expression of these genes by normal and CRS HSNEC in culture is significantly down-regulated after incubation with IL-4 or IL-13.

CONCLUSION

Expression of multiple innate immune genes by HSNEC is reduced in CRSwNP. One mechanism appears to be a direct effect of the leukocyte-derived Th2 cytokines present in the sinonasal mucosa in CRSwNP. Impaired mucosal innate immunity may contribute to microbial colonization and abnormal immune responses associated with CRSwNP.

Biofilms and their role in otorhinolaryngological disease

OBJECTIVE

To describe the pathophysiology of biofilm communities and their role in otorhinolaryngological disease, with reference to the published literature.

DESIGN

Review of relevant literature, using Medline and the combined search terms 'biofilms' and 'otorhinolaryngology', and also various related keywords such as 'tonsil' and 'adenoid'.

RESULTS

Description of biofilm pathophysiology and of published reports of biofilms in otorhinolaryngological disease.

CONCLUSION

Virtually all microbes live in biofilm communities. Within these communities, the microbes assume differing specialised roles which confer survival advantages on the community. These communities cause chronic and device-associated infections. Within the specialist field of otorhinolaryngology, biofilms have been shown to play a role in many infections, including: chronic otitis media, cholesteatoma, chronic tonsillitis, chronic sinusitis, and infections of tracheostomies, endotracheal tubes and cochlear implants.

A sheep model for the study of biofilms in rhinosinusitis

BACKGROUND

Bacterial biofllms have been shown in chronic diseases such as cystic fibrosis, cholesteatoma, and otitis media with effusion. Recently, their detection on the mucosal tissue of sinusitis patients has implicated them in the pathogenesis of this condition. We present an animal model using sheep experimentally infected with Staphylococcus aureus to study the possible association between biofilm and sinusitis.

METHODS

Twenty-four sheep underwent bilateral endoscopic sinus surgery to identify their frontal ostia. The frontal sinuses were treated in one of the following ways according to preoperative randomization: (1) ostium left patent, (2) ostium left patent and bacteria instilled, (3) ostium occluded, or (4) ostium occluded and bacteria instilled. The frontal mucosa was harvested at day 7 and examined for biofilm presence using confocal scanning laser microscopy (CSLM) as well as scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

RESULTS

All three modalities showed different rates of biofilm detection. Three-dimensional structures that could be interpreted as biofilms were documented in 86% (n = 36) of the sinuses analyzed using SEM. These structures were seen in all four study groups. The detection rate using the other two modalities was much lower with CSLM, showing biofilms in 48% (n = 20) and TEM in only 29% (n = 12) of the sinuses analyzed. Unlike SEM, these two modalities only detected bacterial biofilms in sinuses randomized to bacterial instillation.

CONCLUSION

The demonstration of bacterial biofilms in this animal model of sinusitis further supports the hypotheses that biofilms may play a role in the pathogenesis of this condition. There is an obvious discrepancy in the sensitivity and specificity of biofilm detection using the three modalities mentioned. CSLM appears to be the most objective technique. The inherent flaws, sampling error, and subjectivity involved in SEM and TEM make these less reliable in documenting biofilm existence.

Biofilms in ear, nose, and throat infections: how important are they?

BACKGROUND

Biofilms present a new challenging concept in sustaining chronic, common antibiotic-resistant ear, nose, and throat (ENT) infections. They are communities of sessile bacteria embedded in a matrix of extracellular polymeric substances of their own synthesis that adhere to a foreign body or a mucosal surface with impaired host defense. The aim of this paper is to review the literature on ENT diseases that can be attributed to biofilm formation and to discuss options for future treatment.

MATERIALS AND METHODS

Literature review from Medline and database sources. Electronic links and related books were also included.

STUDY SELECTION

Controlled clinical trials, animal models, ex vivo models, laboratory studies, retrospective studies, and systematic reviews.

DATA SYNTHESIS

Biofilm formation is a dynamic five-step process guided by interbacterial communicating systems. Bacteria in biofilms express different genes and have markedly different phenotypes from their planktonic counterparts. Detachment of cells, production of endotoxin, increased resistance to the host immune system, and provision of a niche for the generation of resistant organisms are biofilm processes that could initiate the infection process. Effective prevention and management strategies include interruption of quorum sensing, inhibition of related genes, disruption of the protective extrapolymer matrix, macrolides (clarithromycin and erythromycin), and mechanical debridement of the biofilm-bearing tissues. With regard to medical indwelling devices, surface treatment of fluoroplastic grommets and redesign of cochlear implants could minimize initial microbial colonization.

CONCLUSION

As the role of biofilms in human infection becomes better defined, ENT surgeons should be prepared to deal with their unique and tenacious nature.