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

Mupirocin Ointment Effect on Polyposis Recurrence After Sinus Surgery

Introduction

Staphylococcus aureus is an identified pathogen involved in the recurrence of symptoms in patients with chronic rhinosinusitis with nasal polyps. We investigated the effectiveness of a topical ointment of mupirocin applied in the nasal vestibule in lessening symptom recurrence and improving the efficiency of functional endoscopic sinus surgery.

Materials and Methods

Patients with chronic rhinosinusitis, nasal polyps, and a positive nostril culture for Staphylococcus aureus were included in a clinical trial. The right nostril was determined as the intervention group (applying mupirocin ointment) and the left as the control group (applying vitamin A ointment). Lund-Mackay radiological scores and Lund-Kennedy endoscopic scores were examined at the time of diagnosis and six months later.

Results

Among 60 patients with chronic rhinosinusitis with nasal polyps, 91.6% were positive for nostril Staphylococcus aureus. Comparing the average of the diagnostic radiological and endoscopic scores with the follow-up values in both groups indicated a significant improvement after surgery (P-value=0.001, 0.001). However, there was no significant difference in the radiological and endoscopic score improvements between the study and control groups (P-value > 0.56, 0.74).

Conclusion

Nasal mupirocin administration following endoscopic sinus surgery cannot significantly prevent symptom recurrence in chronic rhinosinusitis with nasal polyps.

A large-volume low-pressure nasal irrigation delivers drug into the nasal cavity? An in vivo study

The nasal administration route emerged as an interesting route in systemic and brain drug delivery, and different modalities of nasal delivery are available. The nasal irrigation is one of them, but there is a lack of studies investigating the distribution of a large-volume irrigation. The main aim of this study was to assess the deposition of radiolabeled saline in the nasal cavities and paranasal sinuses following nasal irrigation by imaging. Five healthy males volunteered to perform large-volume low-pressure nasal irrigation, with a douching device containing 50 mL of radiolabeled isotonic saline. Participants underwent a scintigraphy immediately after. Both the nasal cavities and maxillary sinuses were systematically reached by the solution during nasal irrigation. The sinuses set in a lower position during nasal irrigation showed a tendency to be more irrigated than the sinuses set in a higher position (7.67% vs 22.72%; p = 0.086). Moreover, substantial inter- and intraindividual heterogeneity regarding solution deposition was observed. Large-volume low-pressure nasal irrigation is a good modality to reach the maxillary sinuses as well as the nasal cavities. In order to ensure adequate reaching of both nasal cavities and paranasal sinuses, nasal irrigation should be performed bilaterally.

The intra-host evolutionary landscape and pathoadaptation of persistent Staphylococcus aureus in chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a common chronic sinonasal mucosal inflammation associated with Staphylococcus aureus biofilm and relapsing infections. This study aimed to determine rates of S. aureus persistence and pathoadaptation in CRS patients by investigating the genomic relatedness and antibiotic resistance/tolerance in longitudinally collected S. aureus clinical isolates. A total of 68 S. aureus paired isolates (34 pairs) were sourced from 34 CRS patients at least 6 months apart. Isolates were grown into 48 h biofilms and tested for tolerance to antibiotics. A hybrid sequencing strategy was used to obtain high-quality reference-grade assemblies of all isolates. Single nucleotide variants (SNV) divergence in the core genome and sequence type clustering were used to analyse the relatedness of the isolate pairs. Single nucleotide and structural genome variations, plasmid similarity, and plasmid copy numbers between pairs were examined. Our analysis revealed that 41 % (14/34 pairs) of S. aureus isolates were persistent, while 59 % (20/34 pairs) were non-persistent. Persistent isolates showed episode-specific mutational changes over time with a bias towards events in genes involved in adhesion to the host and mobile genetic elements such as plasmids, prophages, and insertion sequences. Furthermore, a significant increase in the copy number of conserved plasmids of persistent strains was observed. This was accompanied by a significant increase in biofilm tolerance against all tested antibiotics, which was linked to a significant increase in biofilm biomass over time, indicating a potential biofilm pathoadaptive process in persistent isolates. In conclusion, our study provides important insights into the mutational changes during S. aureus persistence in CRS patients highlighting potential pathoadaptive mechanisms in S. aureus persistent isolates culminating in increased biofilm biomass.

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.

Low pH nasal rinse solution enhances mupirocin antimicrobial efficacy

Background: Chronic rhinosinusitis (CRS) is a common condition negatively impacting a patient’s quality of life. It has been hypothesized that bacterial biofilms are involved in the pathogenesis of CRS due to their persistence and difficulty to eradicate with conventional antibiotic therapy. Hence, the topical delivery of antibiotics via nasal rinse solution has gained a lot of attention due to the ability to deliver higher local concentrations, with less systemic absorption and side effects. This study investigates the efficacy of mupirocin dissolved in the 3 most commonly used sinus rinses in Australia Neilmed (isotonic saline), Flo Sinus Care (sodium chloride, sodium bicarbonate, potassium chloride, glucose anhydrous and calcium lactate and Pentahydrate) and FloCRS (sodium chloride, potassium chloride and xylitol). Methods: Planktonic and biofilm cultures of S. aureus (ATCC25923, 2 methicillin-resistant S. aureus (MRSA) (C222 and C263), and 2 methicillin-susceptible S. aureus (MSSS) (C311 and C349) clinical isolates) were treated with mupirocin dissolved in three sinus rinses (Neilmed, Flo Sinus Care and FloCRS with different pH). To establish whether pH was a significant factor in determining antibiotic activity, experiments with Flo CRS were performed both at pH 5.64 and elevated pH 7.7. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined for planktonic cells. The biofilm biomass and metabolic activity were assessed by using crystal violet assay and alamarBlue assay respectively. Results: The combination of mupirocin in low pH (pH 5.64) sinus rinse (FloCRS) had the highest efficacy in reducing the growth of S. aureus in both the planktonic and biofilm forms. Mupirocin diluted in FloCRS (pH 5.64) showed a significantly higher reduction in both biomass and metabolic activity than that was observed when mupirocin was diluted in Neilmed, Flo Sinus Care or FloCRS (pH 7.7). Conclusion: The choice of irrigant solution for topical mupirocin delivery appears to be important for antimicrobial activity. The delivery of mupirocin via low pH FloCRS could be useful in eliminating S. aureus biofilms present on the sinus mucosa of patients with CRS.

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.

Antibiotics Affect ROS Production and Fibroblast Migration in an In-vitro Model of Sinonasal Wound Healing

Introduction: Antibiotics are often administered to patients perioperatively and have been shown to affect ROS production of nasal cells in vitro, but their effect in the setting of active wound healing remains unclear. Reactive oxygen species (ROS) are known to play a significant role in wound healing. This study analyzed a broad array of antibiotics used after sinus surgery to assess their effect on wound healing and ROS production in vitro. It was hypothesized that ROS production would be affected by these antibiotics and there would be a negative relationship between ROS activity and cell migration speed. Methods: Monolayers of primary human nasal epithelial cells (HNEC) and primary fibroblasts were disrupted with a linear wound, treated with 10 different antibiotics or a ROS inhibitor and observed over 36 h in a controlled environment using confocal microscopy. ROS activity and migration speed of the wound edge were measured at regular intervals. The relationship between the two parameters was analyzed using mixed linear modeling. Results: Performing a linear scratch over the cell monolayers produced an immediate increase in ROS production of ~35% compared to unscratched controls in both cell types. Incubation with mitoquinone and the oxazolidinone antibiotic linezolid inhibited ROS activity in both fibroblasts and HNEC in association with slowed fibroblast cell migration (p < 0.05). Fibroblast cell migration was also reduced in the presence of clarithromycin and mupirocin (p < 0.05). A significant correlation was seen between ROS suppression and cell migration rate in fibroblasts for mitoquinone and all antibiotics except for azithromycin and doxycycline, where no clear relationship was seen. Treatments that slowed fibroblast cell migration compared to untreated controls showed a significant correlation with ROS suppression (p < 0.05). Conclusion: Increased ROS production in freshly wounded HNEC and fibroblast cell monolayers was suppressed in the presence of antibiotics, in correlation with reduced fibroblast cell migration. In contrast, HNEC cell migration was not significantly affected by any of the antibiotics tested. This differential effect of antibiotics on fibroblast and HNEC migration might have clinical relevance by reducing adhesion formation without affecting epithelial healing in the postoperative setting.

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.

Mupirocin: applications and production

Mupirocin is an antibiotic from monocarboxylic acid class used as antibacterial agent against methicillin-resistant Staphylococcus aureus (MRSA) and can be obtained as a mixture of four pseudomonic acids by Pseudomonas fluorescens biosynthesis. Nowadays improving antibiotics occupies an important place in the pharmaceutical industry as more and more resistant microorganisms are developing. Mupirocin is used to control the MRSA outbreaks, for infections of soft tissue or skin and for nasal decolonization. Due to its wide use without prescription, the microorganism's resistance to Mupirocin increased from up to 81%, thus becoming imperative its control or improvement. As the biotechnological production of Mupirocin has not been previously reviewed, in the present paper we summarize some consideration on the biochemical process for the production of pseudomonic acids (submerged fermentation and product recovery). Different strains of Pseudomonas, different culture medium and different conditions for the fermentation were analysed related to the antibiotics yield and the product recovery step is analysed in relation to the final purity. However, many challenges have to be overcome in order to obtain pseudomonic acid new versions with better properties related to antibacterial activity.

Chronic rhinosinusitis: Endotypes, biomarkers, and treatment response

It is increasingly recognized that chronic rhinosinusitis (CRS) comprises a spectrum of different diseases with distinct clinical presentations and pathogenic mechanisms. Defining the distinct phenotypes and endotypes of CRS affects prognosis and, most importantly, is necessary as the basis for making therapeutic decisions. The need for individualized definitions of pathogenic mechanisms before initiating therapy extends to virtually all therapeutic considerations. This is clearly crucial with antibiotics, where, barring an influence from their off-target anti-inflammatory pharmacologic effects, an understanding of the role of the individual biome predicts likelihood of therapeutic benefit. However, this need for identifying individual phenotypes and endotypes also extends to the agent that is currently considered the mainstay of treatment of CRS, specifically glucocorticoids. As with asthma, it is recognized that a large minority of patients with CRS have a steroid-resistant phenotype, identification of which will preclude use of these agents with their potential side effects. Identification of endotypes is also becoming increasingly imperative because targeted biotherapeutic agents, such as anti-IgE and anti-cytokine antibodies, are becoming available. These agents are likely to benefit patients in whom the targeted mediator is not only expressed but demonstrably driving a central mechanism in that patient. In summary, the treatment of CRS is at an exciting crossroad. On the positive side, numerous therapeutics are in development that seem likely to have a positive effect in our patients with this condition. The challenge is that these therapies will require targeted individualized treatments based on identifying subjects with the relevant endotype.

Can phage therapy solve the problem of recalcitrant chronic rhinosinusitis?

Chronic rhinosinusitis (CRS) affects 5-15% of the global population. In some patients, the infectious exacerbations of the disease are recalcitrant to medical treatment and surgery. These cases are probably associated with the presence of bacterial biofilms. Bacteriophage (phage) therapy seems to be a promising antibiofilm strategy. The efficacy of phage therapy in sinonasal infections has been demonstrated both in vitro and in animal models. In the past, phage preparations were also administered to humans with CRS with favorable outcomes and no significant side effects. Very recently, the safety and efficacy of phage therapy in otolaryngological infections has been demonstrated in pioneer Phase I/II clinical trials. This review addresses the potential of phage therapy to treat CRS. We also discuss issues that require further research.