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

Safety of Antibiotic Irrigations for Acute Exacerbations of Chronic Rhinosinusitis in Patients with Identical Drug Allergies or Adverse Reactions: A Pilot Study

Objectives: The use of topical antibiotics in the treatment of acute exacerbation of chronic rhinosinusitis (AECRS) represents a viable option prior to initiation of parenteral antibiotics when no oral antibiotic alternatives are available due to patient allergy or adverse reactions. The main objectives of this pilot study were to determine the safety and efficacy of antibiotic irrigations in the treatment of AECRS in patients with documented adverse reactions to the oral form of the drug. Methods: A retrospective review was performed of patients diagnosed with AECRS treated with antibiotic irrigations. Inclusion criteria included a documented allergy or adverse event to the systemic form of the same antibiotic. Patient demographics, medical history, prior sinus surgery, nasal endoscopy findings, and microbiology results were obtained. Side effects to the antibiotic irrigations were recorded. Results: Six patients met the inclusion criteria resulting in 7 treated cases of AECRS. Four patients with adverse effects to oral trimethoprim/sulfamethoxazole (TMP/SMZ) received TMP/SMZ irrigations, and 1 patient with an adverse reaction to oral ciprofloxacin was treated with ciprofloxacin irrigations. One patient with adverse effects to both oral TMP/SMZ and levofloxacin was treated with TMP/SMZ and levofloxacin irrigations, respectively during 2 separate AECRS episodes. Following treatment, 1 case (14.3%) resulted in complete resolution of infection, 1 (14.3%) had partial improvement, and 5 (71.4%) had minimal to no endoscopic improvement at the subsequent clinic visit. There were no adverse reactions to antibiotic irrigations among the entire cohort. Conclusions: Currently, no prior study has examined whether adverse reactions to a systemic antibiotic also occur when the medication is delivered topically via sinonasal irrigations. Our findings suggest that topical administration of antibiotics may be a safe alternative for patients with adverse effects to the systemic form.

Endoscopic outcomes in patients with AERD treated with topical antibiotics and intranasal corticosteroids

Background

Identifying effective therapy for recalcitrant chronic rhinosinusitis with nasal polyposis (CRSwNP) is a major challenge; and subtypes such as aspirin-exacerbated respiratory disease (AERD) are even more difficult to treat. Evidence on topical antibiotics use in (CRSwNP) is lacking. Current consensus guidelines recommend against its routine use, but recent reviews show some benefit when managing recalcitrant disease after endoscopic sinus surgery (ESS).

Objective

Evaluate the effect of culture-directed topical antibiotics on sinonasal outcomes in AERD patients with a positive perioperative sinonasal bacterial culture who have undergone ESS.

Methods

A retrospective cohort study of AERD patients with positive sinonasal culture, who underwent ESS from 2016 to 2021 was performed. Forty-four patients were identified and stratified based on their postoperative medical treatment. Twenty-six underwent postoperative intranasal corticosteroids (INCS) alone, while eighteen underwent INCS plus a 4-weeks treatment with topical antibiotics. SNOT-22 and Lund-Kennedy score (LKS) were assessed preoperatively and at 4-weeks and 4-6 months after ESS.

Results

A statistically significant improvement in the 4-weeks and 4-6 months postoperative SNOT-22 and LKS were noted within both groups (p<0.05). However, only a statistically significant difference was found in the 4-weeks postoperative LKS when comparing between treatment groups (p=0.01). Our linear regression model demonstrated a relationship between the use of combined therapy with INCS and topical antibiotics and the LKS 4-weeks post ESS (p=0.015).

Conclusion

In AERD patients with a confirmed sinus infection, the combination of culture-directed topical antibiotics and intranasal corticosteroid irrigations in the postoperative period can provide a short-term improvement in endoscopic scores.

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.

Sinonasal Stent Coated with Slow-Release Varnish of Chlorhexidine Has Sustained Protection against Bacterial Biofilm Growth in the Sinonasal Cavity: An In Vitro Study

The aim of the study was to develop a sustained-release varnish (SRV) containing chlorhexidine (CHX) for sinonasal stents (SNS) to reduce bacterial growth and biofilm formation in the sinonasal cavity. Segments of SNS were coated with SRV-CHX or SRV-placebo and exposed daily to bacterial cultures of Staphylococcus aureus subsp. aureus ATCC 25923 or Pseudomonas aeruginosa ATCC HER-1018 (PAO1). Anti-bacterial effects were assessed by disc diffusion assay and planktonic-based activity assay. Biofilm formation on the coated stents was visualized by confocal laser scanning microscopy (CLSM) and high-resolution scanning electron microscopy (HR-SEM). The metabolic activity of the biofilms was determined using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) method. Disc diffusion assay showed that SRV-CHX-coated SNS segments inhibited bacterial growth of S. aureussubsp. aureus ATCC 25923 for 26 days and P. aeruginosa ATCC HER-1018 for 19 days. CHX was released from coated SNS segments in a pH 6 medium up to 30 days, resulting in growth inhibition of S. aureussubsp. aureus ATCC 25923 for 22 days and P. aeruginosa ATCC HER-1018 for 24 days. The MTT assay showed a reduction of biofilm growth on the coated SNS by 69% for S. aureussubsp. aureus ATCC 25923 and 40% for P. aeruginosa ATCC HER-1018 compared to the placebo stent after repeated exposure to planktonic growing bacteria. CLSM and HR-SEM showed a significant reduction of biofilm formation on the SRV-CHX-coated SNS segments. Coating of SNS with SRV-CHX maintains a sustained delivery of CHX, providing an inhibitory effect on the bacterial growth of S. aureussubsp. aureus ATCC 25923 and P. aeruginosa ATCC HER-1018 for approximately 3 weeks.

International consensus statement on allergy and rhinology: rhinosinusitis 2021

I.

EXECUTIVE SUMMARY

BACKGROUND: The 5 years since the publication of the first International Consensus Statement on Allergy and Rhinology: Rhinosinusitis (ICAR-RS) has witnessed foundational progress in our understanding and treatment of rhinologic disease. These advances are reflected within the more than 40 new topics covered within the ICAR-RS-2021 as well as updates to the original 140 topics. This executive summary consolidates the evidence-based findings of the document.

METHODS

ICAR-RS presents over 180 topics in the forms of evidence-based reviews with recommendations (EBRRs), evidence-based reviews, and literature reviews. The highest grade structured recommendations of the EBRR sections are summarized in this executive summary.

RESULTS

ICAR-RS-2021 covers 22 topics regarding the medical management of RS, which are grade A/B and are presented in the executive summary. Additionally, 4 topics regarding the surgical management of RS are grade A/B and are presented in the executive summary. Finally, a comprehensive evidence-based management algorithm is provided.

CONCLUSION

This ICAR-RS-2021 executive summary provides a compilation of the evidence-based recommendations for medical and surgical treatment of the most common forms of RS.

Current Perspective on Nasal Delivery Systems for Chronic Rhinosinusitis

Chronic rhinosinusitis is an upper respiratory disease during which topical drug treatment via the nasal cavity is the most actively utilized therapeutic strategy. In addition to steroids, antibiotics, and antifungal agents, which are widely used in clinical practice, research on novel topical agents to improve the bacterial biofilm or mucociliary clearance remains ongoing. Moreover, owing to the complex structure of the nasal cavity, the effects of nasal drug delivery vary depending on factors related to delivery fluid dynamics, including device, volume, and compounds. In this article, we review methods and compounds that have been applied to chronic rhinosinusitis management and introduce recent advances and future perspectives in nasal drug delivery for upper respiratory diseases.

Preoperative Nasal Swab Culture: Is It Beneficial in Preventing Postoperative Infection in Complicated Septorhinoplasty?

BACKGROUND

Surgical-site infection following complicated septorhinoplasty may result in serious complications. Therefore, efforts to prevent surgical-site infections after complicated septorhinoplasty are important. The purpose of this study was to analyze the microbiological profile of preoperative nasal swab cultures and to evaluate the effect of antibiotic prophylaxis and topical antibiotic decolonization according to the antibiotic sensitivity results of surgical-site infections in complicated septorhinoplasty.

METHODS

This 10-year cohort study included the data on 437 consecutive patients who underwent complicated septorhinoplasty. The patients were categorized into three cohorts based on the time of preoperative nasal swab culture collection. Patients in cohort 1 did not undergo nasal swab cultures and received empirical antibiotics. Patients in cohort 2 underwent only one preoperative nasal swab culture and received microorganism-sensitive antibiotics. Patients in cohort 3 underwent repeated nasal swab cultures. The antibiotics were changed when microorganisms resistant to the empirical antibiotics were isolated. Microbiological data and the rates of surgical-site infection and inflammation were compared among the three cohorts.

RESULTS

Methicillin-sensitive Staphylococcus aureus was the most commonly isolated microorganism. In cohort 1, two (5 percent) and two (5 percent) patients experienced surgical-site infections and inflammation, respectively. In cohort 2, two (3 percent) and three (4 percent) patients experienced surgical-site infections and inflammation, respectively. In cohort 3, one (0.3 percent) and one (0.3 percent) patient experienced surgical-site infection and inflammation, respectively.

CONCLUSION

The present study demonstrated that preoperative screening using repeated nasal swab cultures, followed by appropriate antibiotic prophylaxis and topical antibiotic decolonization, may reduce surgical-site infection in complicated septorhinoplasty.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

Topical antibiotic therapy in chronic rhinosinusitis: an update

BACKGROUND

Topical antibiotic therapies have been investigated for their use in chronic rhinosinusitis (CRS). However, society guidelines and evidence-based medicine reviews have recommended against the use of topical antibiotic therapy based on randomized controlled trials (RCTs). The purpose of this article is to review recent clinical research published since the aforementioned guidelines were published.

METHODS

A structured literature review was performed on clinical studies published in the last 5 years investigating the use of topical antibiotic therapies.

RESULTS

One double-blinded, randomized controlled trial (DB-RCT) supported the use of tobramycin using a vibrating aerosolizer; 1 non-blinded non-randomized controlled prospective trial lent support to use of topical ofloxacin for its anti-biofilm properties; and 1 meta-analysis found mupirocin irrigations to be beneficial in the short term. One Cochrane Review was unable to make a recommendation as no trial met the inclusion criteria. An additional systematic review found limited evidence to support the use of topical antibiotics with the exception of mupirocin irrigations that may be considered in Staphylococcus aureus infections. Two retrospective studies found that topical antibiotics change bacterial cultures of the sinuses.

CONCLUSION

There is additional evidence to support continuing investigation of topical antibiotic therapies. Further, larger RCTs are required to establish the efficacy of topical antibiotic therapies.

Targeting the Bacterial Protective Armour; Challenges and Novel Strategies in the Treatment of Microbial Biofilm

Infectious disease caused by pathogenic bacteria continues to be the primary challenge to humanity. Antimicrobial resistance and microbial biofilm formation in part, lead to treatment failures. The formation of biofilms by nosocomial pathogens such as Staphylococcus aureus (S. aureus), Pseudomonas aeruginosa (P. aeruginosa), and Klebsiella pneumoniae (K. pneumoniae) on medical devices and on the surfaces of infected sites bring additional hurdles to existing therapies. In this review, we discuss the challenges encountered by conventional treatment strategies in the clinic. We also provide updates on current on-going research related to the development of novel anti-biofilm technologies. We intend for this review to provide understanding to readers on the current problem in health-care settings and propose new ideas for new intervention strategies to reduce the burden related to microbial infections.

Understanding the Role of Biofilms and Superantigens in Chronic Rhinosinusitis

PURPOSE OF REVIEW

This review explores recent discoveries in our understanding of how biofilms and superantigens contribute to the pathogenesis of chronic rhinosinusitis (CRS). It also examines clinical implications and novel treatment approaches for biofilm associated CRS.

RECENT FINDINGS

While the role of biofilms in CRS has been studied for 14 years, research interest has now turned toward elucidating new methods of biofilm detection, microbial diversity, and novel treatment approaches. Recent studies on biofilm superantigens aim to clarify the immunological mechanisms of upper airway inflammation, particularly the type-2 response seen in nasal polyposis.

SUMMARY

Biofilms are a topic of research interest for their role in the pathogenesis of chronic rhinosinusitis, particularly when they elute superantigens. New studies on this topic focus on the molecular and cellular mechanisms at play.

The effects of nasal irrigation with various solutions after endoscopic sinus surgery: systematic review and meta-analysis

Background

Nasal irrigation is commonly performed in patients with chronic rhinosinusitis after functional endoscopic sinus surgery. This study systematically assessed the clinical efficacy of nasal irrigation from the medical literature.

Methods

The PubMed, Embase and Cochrane Central Register of Controlled Trials databases were searched using a comprehensive strategy, limited to English-language articles, published from October 1971 to March 2017, and comprising human subjects.

Results

A total of 824 trials were identified, 5 of which, involving 331 participants, were included in this systematic review. After selection, only three trials were eligible for inclusion in a meta-analysis. Nasal irrigation using normal saline and various solutions was found to be effective in reducing symptom scores and endoscopic scores for chronic rhinosinusitis patients after functional endoscopic sinus surgery. Comparison of outcome measures, such as eosinophil count reduction, revealed that various solutions are more effective than normal saline alone; however, no statistical significance was found in terms of reduced symptom or endoscopic scores.

Conclusion

Based on the current limited evidence, nasal irrigation is an effective therapy for chronic rhinosinusitis patients after functional endoscopic sinus surgery. However, when comparing various solutions with normal saline, no significant difference was found in symptom scores or endoscopic scores.

Topical therapy for refractory rhinosinusitis caused by methicillin-resistant Staphylococcus aureus: First report in a prospective series

OBJECTIVE

The incidence of refractory chronic rhinosinusitis (CRS) associated with methicillin-resistant Staphylococcus aureus (MRSA) is rising and remains a therapeutic challenge. The goal of this study is to demonstrate the efficacy of a non-invasive topical therapy against MRSA in these patients.

METHODS

Seventeen patients with refractory CRS caused by MRSA were treated with a topical therapy protocol. Treatment consisted of weekly endoscopic sinus debridement followed by intra-sinus installation of a hydroxyl-ethylcellulose gel that releases mometasone and a culture-directed antibiotic for a period of 6 weeks, along with daily nasal nebulization of mometasone with the same antibiotic and saline rinses. Clinical outcome was assessed using the Lund-Kennedy (LK) symptom and endoscopic appearance scores. Sinus mucosal tissue was homogenized and cultured, and microbial biofilm burden was assessed based on colony forming units (CFUs) counts.

RESULTS

Rhinotopic therapy resulted in clearance of MRSA in 13 of 16 patients (81.2%). Treated patients also demonstrated significant improvement clinically as measured by the LK scores. In addition, a significant decrease in mucosal CFUs was observed post-therapy.

CONCLUSION

Our findings demonstrate that topical therapy is an effective method for treating MRSA-associated refractory CRS.

Intranasal Delivery of Topically-Acting Levofloxacin to Rats: a Proof-of-Concept Pharmacokinetic Study

PURPOSE

To evaluate the potential of levofloxacin intranasal administration as a promising alternative approach to treat local infections such as chronic rhinosinusitis, by delivering drug concentrations directly to the site of infection.

METHODS

Drug concentrations were measured in plasma, olfactory bulb and nasal mucosa of anterior (ANM) and posterior regions after intranasal (0.24 mg/kg) and intravenous (10 mg/kg) administration to rats, and pharmacokinetic parameters were compared between routes. For intranasal administration a thermoreversible in-situ gel was used.

RESULTS

Plasma and olfactory bulb exposure to levofloxacin was minimal following intranasal dose, preventing systemic and central nervous system adverse effects. Levofloxacin concentration-time profile in ANM revealed higher concentrations during the first 60 min of the study following intranasal administration than the corresponding ones obtained after intravenous administration. A rapid and continuous decay of levofloxacin concentration in this nasal region was observed after intranasal delivery, resulting in much lower values at the last sampling time-points.

CONCLUSION

The higher dose-normalized concentrations and pharmacokinetic exposure parameters of levofloxacin in ANM after intranasal administration, demonstrates that intranasal delivery of the formulated gel is, by itself, advantageous for delivering levofloxacin to biophase and thus an attractive approach in management of chronic rhinosinusitis.

Hyaluronate effect on bacterial biofilm in ENT district infections: a review

Bacterial resistance is a growing phenomenon which led the scientific community to search for new therapeutic targets, such as biofilm. A bacterial biofilm is a surface-associated agglomerate of microorganisms embedded in a self-produced extracellular polymeric matrix made of polysaccharides, nucleic acids, and proteins. Scientific literature offers several reports on a biofilm's role in infections regarding various body districts. The presence of a bacterial biofilm is responsible for poor efficacy of antibiotic therapies along with bacterial infections in ear, nose, and throat (ENT) districts such as the oral cavity, ear, nasal cavities, and nasal sinuses. In particular, bacterial biofilms are associated with recalcitrant and symptomatically more severe forms of chronic rhinosinusitis. As of today, there are no therapeutic options for the eradication of bacterial biofilm in ENT districts. Hyaluronic acid is a glycosaminoglycan composed of glucuronic acid and N-acetylglucosamine disaccharide units. Its efficacy in treating rhinosinusitis, whether or not associated with polyposis, is well documented, as well as results from its effects on mucociliary clearance, free radical production and mucosal repair. This review's aim is to evaluate the role of bacterial biofilms and the action exerted on it by hyaluronic acid in ENT pathology, with particular attention to the rhinosinusal district. In conclusion, this paper underlines how the efficacy of hyaluronate as an anti-bacterial biofilm agent is well demonstrated by in vitro studies; it is, however, only preliminarily demonstrated by clinical studies.

Antibiotic treatment of biofilm infections

Bacterial biofilms are associated with a wide range of infections, from those related to exogenous devices, such as catheters or prosthetic joints, to chronic tissue infections such as those occurring in the lungs of cystic fibrosis patients. Biofilms are recalcitrant to antibiotic treatment due to multiple tolerance mechanisms (phenotypic resistance). This causes persistence of biofilm infections in spite of antibiotic exposure which predisposes to antibiotic resistance development (genetic resistance). Understanding the interplay between phenotypic and genetic resistance mechanisms acting on biofilms, as well as appreciating the diversity of environmental conditions of biofilm infections which influence the effect of antibiotics are required in order to optimize the antibiotic treatment of biofilm infections. Here, we review the current knowledge on phenotypic and genetic resistance in biofilms and describe the potential strategies for the antibiotic treatment of biofilm infections. Of note is the optimization of PK/PD parameters in biofilms, high-dose topical treatments, combined and sequential/alternate therapies or the use antibiotic adjuvants.

Mupirocin in the Treatment of Staphylococcal Infections in Chronic Rhinosinusitis: A Meta-Analysis

Background

Saline irrigation of the nasal cavity is a classic and effective treatment for acute or chronic rhinosinusitis. Topical antibiotics such as mupirocin have been widely used for recalcitrant chronic rhinosinusitis. Therefore, the purpose of this study was to evaluate the effect of saline irrigation using mupirocin.

Methods

A systematic literature review and meta-analysis of mupirocin saline irrigation were performed using EMBASE, MEDLINE, and Cochrane library through December 2015. Data were analyzed with R 3.2.2 software. A random effects model was used because of the diversity of included studies. Sensitivity analysis of particular tested groups and single proportion tests were also performed. The main outcome measure was residual staphylococcal infection, as confirmed by culture or PCR.

Results

Two RCTs, two prospective studies and two retrospective studies were included. A random effects model meta-analysis of the pooled data identified a relative risk of residual infection of 0.13 (95% CI: 0.06–0.26, p<0.05) with low heterogeneity (I² = 0%). The proportion of residual staphylococcal infections after 1 month was 0.08 (95% CI: 0.04–0.16). However, this proportion increased to 0.53 at 6 months (95% CI: 0.27–0.78).

Conclusions

The short-term use of mupirocin has a strongly reductive effect on staphylococcal infection in chronic rhinosinusitis. Although there is currently a lack of clear evidence, future studies with well-designed inclusion criteria and randomized controlled trials are needed to examine mupirocin’s long-term effect on chronic rhinosinusitis.

Current trends in topical therapies for chronic rhinosinusitis: update and literature review

INTRODUCTION

Chronic rhinosinusitis (CRS) affects millions of patients worldwide. The disease is multifactorial with influences including anatomic factors, immunological disturbances, and altered sinonasal microbiome. Although oral medications are effective in controlling some symptoms, they are associated with side effects and long-term use is not ideal. Thus, topical therapies have emerged as an alternative delivery method for localized, high-concentration medication with less side effects. Areas covered: This is a review of the various topical therapies available or under investigation for the management of CRS. Common medications such as saline, steroids, and antimicrobials will be discussed. Furthermore, additives including manuka honey, xylitol, surfactant, N-chlorotaurine, Dead Sea salt, and sodium hyaluronate will be addressed. Innovations in topical therapies, such as drug-eluting biomaterials and photodynamic therapy, will also be reviewed. Expert opinion: Although topical therapies provide a high dose of active substance at the site of disease, their efficacy in CRS is not clear. Topical saline and intranasal steroids appear to consistently demonstrate therapeutic benefits. However, other topical medications require further investigation to determine long-term clinical efficacy and safety. A better understanding of their effects on the sinonasal mucociliary system is needed before they become the standard of care in CRS.

Understanding Biofilms in Chronic Sinusitis

Chronic sinusitis is a burdensome disease that has substantial individual and societal impact. Although great advances in medical and surgical therapies have been made, some patients continue to have recalcitrant infections. Microbial biofilms have been implicated as a cause of recalcitrant chronic sinusitis, and recent studies have tried to better understand the pathogenesis of chronic sinusitis as it relates to microbial biofilms. Here, we provide an overview of biofilms in chronic sinusitis with emphasis on pathogenesis, treatment, and future directions. In addition, recent evidence is presented, elucidating the role of bitter taste receptors as a possible key factor leading to biofilm formation.