Anti-inflammatory activity of clarithromycin in adults with chronically inflamed sinus mucosa

Immunologic effect and clinical impact of erythromycin in septic patients: A randomized clinical trial

To investigate the potential regulatory effect of erythromycin added to standard care in septic patients on sepsis biomarkers and clinical outcome. It was a single-blind randomized trial including critical septic patients. The primary endpoint was the change in the TNF/IL-10 ratio between days 0 and 6. Changes in other biomarkers, vasopressor use, and 28-day mortality were secondary endpoints. One hundred and ten patients were examined (erythromycin group, n = 55 versus placebo group, n = 55). Clinical features of the groups were well matched. Erythromycin addition had no beneficial effects on the TNF/IL-10 ratio or mortality (51% vs. 47%, p = 0.62). Both groups' serum TNF/IL-10 ratios did not significantly rise (from 0.48 [0.34-1.18] to 0.59 [0.21-1.10] vs. 0.65 [0.25-1.14] to 0.93 [0.24-1.88] in the erythromycin and placebo groups, respectively; p values = 0.86 and 0.12). Serum Procalcitonin (PCT) and CRP dropped considerably in the Erythromycin group, whereas only PCT showed a drop in the placebo group. On day 6, the non-survivors' serum TNF/IL-10 ratio was lower than that of the survivors (0.55 [0.17-1.04] vs 1.08 [0.4-2.28], p = 0.029). Neither the pro/anti-inflammatory imbalance nor the mortality were impacted by the addition of erythromycin to standard care in septic patients (ClinicalTrials.gov ID: NCT04665089 (11/12/2020)).

Immunomodulatory Effects of Macrolides Considering Evidence from Human and Veterinary Medicine

Macrolide antimicrobial agents have been in clinical use for more than 60 years in both human and veterinary medicine. The discovery of the non-antimicrobial properties of macrolides and the effect of immunomodulation of the inflammatory response has benefited patients with chronic airway diseases and impacted morbidity and mortality. This review examines the evidence of antimicrobial and non-antimicrobial properties of macrolides in human and veterinary medicine with a focus toward veterinary macrolides but including important and relevant evidence from the human literature. The complete story for these complex and important molecules is continuing to be written.

Pleiotropic effects of antibiotics on T cell metabolism and T cell-mediated immunity

T cells orchestrate adaptive and innate immune responses against pathogens and transformed cells. However, T cells are also the main adaptive effector cells that mediate allergic and autoimmune reactions. Within the last few years, it has become abundantly clear that activation, differentiation, effector function, and environmental adaptation of T cells is closely linked to their energy metabolism. Beyond the provision of energy equivalents, metabolic pathways in T cells generate building blocks required for clonal expansion. Furthermore, metabolic intermediates directly serve as a source for epigenetic gene regulation by histone and DNA modification mechanisms. To date, several antibiotics were demonstrated to modulate the metabolism of T cells especially by altering mitochondrial function. Here, we set out to systematically review current evidence about how beta-lactam antibiotics, macrolides, fluoroquinolones, tetracyclines, oxazolidinones, nitroimidazoles, and amphenicols alter the metabolism and effector functions of CD4+ T helper cell populations and CD8+ T cells in vitro and in vivo. Based on this evidence, we have developed an overview on how the use of these antibiotics may be beneficial or detrimental in T cell-mediated physiological and pathogenic immune responses, such as allergic and autoimmune diseases, by altering the metabolism of different T cell populations.

[Efficacy of clarithromycin in the adjuvant treatment of chronic periodontitis: a Meta-analysis]

OBJECTIVE

To evaluate the clinical efficacy of clarithromycin (CLM) in the adjuvant treatment of chronic periodontitis systematically, obtain reasonable conclusions through evidence-based medicine, and provide guidance for clinical rational drug use.

METHODS

Literature about CLM in the adjuvant treatment of chronic periodontitis was searched in CNKI, VIP, Wanfang, Chinese Biomedical Literature Database, PubMed, ScienceDirect, and Embase databases from inception to February 2019 using a computer. Meta-analysis was performed on the homogeneous study using RevMan 5.3 software after two independent reviewers screened the literature, evaluated the quality of the study, extracted the data, and evaluated the risk of bias in the included studies.

RESULTS

Six randomized controlled trials were included in 316 subjects. The meta-analysis showed that compared with the scaling and root planning (SRP) group, the probing depth (PD) was reduced in patients with CLM and SRP [MD=-1.00, 95%CI (-1.55, -0.45), P=0.000 04]. Clinical attachment loss was obtained [MD=-0.03, 95%CI (0.43, 0.65), P<0.000 01], and the difference between the groups was statistically significant. The modified sulcus bleeding index (mSBI) was reduced [MD=-0.01, 95%CI (-0.14, 0.19), P=0.66]. No significant difference was observed between the groups, but the decrease in mSBI was more significant in CLM combined with SRP group.

CONCLUSIONS

CLM combined with subgingival SRP can achieve remarkable results in treating chronic periodontitist.

Algorithm for Management of the Refractive Aerosinusitis Patient

Introduction

For some career military aviators, their ability to continue on flight status is limited by the pressure and pain of aerosinusitis, which is present only while in the flying environment. Failure to treat their disease process can mean the end of their flying careers and the loss of valuable assets trained with taxpayer dollars. Because some medications commonly used in treatment of sinus diseases are not allowed in aviation, this presents a unique problem for their medical management. Surgical treatment must be aimed at treating to symptom relief and not solely disease mitigation. One alternative is operating "beyond the scope of disease" present during a one-atmosphere clinic visit.

Materials and Methods

A case series of nine career aviators with aerosinusitis treated at one academic military Otolaryngology department in a tertiary care facility. Results from a treatment algorithm that balances symptomatology and staged surgical intervention are reviewed. The primary endpoint was return to flight duty.

Results

For patients treated according to this algorithm, the mean time to return to flight duty was 3.8 mo, requiring an average of 1.2 surgeries. To date, 100% of career aviators have returned to flight duty using this method.

Conclusion

Refractory aerosinusitis represents a potentially career-ending medical condition for the aviator and lost training costs to the taxpayers. Using the treatment algorithm presented, 100% of aviators were able to return to flight duty; a savings of millions of dollars for taxpayers. Future work will focus on modifications to the surgical techniques to reduce the extent of surgery while maintaining satisfactory results. Additional study should be undertaken to assess generalizability of these results in the broader aviation community.

The Immunomodulatory Effects of Macrolides-A Systematic Review of the Underlying Mechanisms

Background

The mechanisms underlying the non-antimicrobial immunomodulatory properties of macrolides are not well understood.

Objectives

To systematically review the evidence for the immunomodulatory properties of macrolides in humans and to describe the underlying mechanism and extent of their influence on the innate and adaptive immune system.

Methods

A systematic literature search was done in MEDLINE using the OVID interface from 1946 to December 2016 according to the preferred reporting items for systematic reviews and meta-analysis (PRISMA). Original articles investigating the influence of four macrolides (azithromycin, clarithromycin, erythromycin, and roxithromycin) on immunological markers in humans were included.

Results

We identified 22 randomized, controlled trials, 16 prospective cohort studies, and 8 case–control studies investigating 47 different immunological markers (186 measurements) in 1,834 participants. The most frequently reported outcomes were a decrease in the number of neutrophils, and the concentrations of neutrophil elastase, interleukin (IL)-8, IL-6, IL-1beta, tumor necrosis factor (TNF)-alpha, eosinophilic cationic protein, and matrix metalloproteinase 9. Inhibition of neutrophil function was reported more frequently than eosinophil function. A decrease in T helper (Th) 2 cells cytokines (IL-4, IL-5, IL-6) was reported more frequently than a decrease in Th1 cytokines (IL-2, INF-gamma).

Conclusion

Macrolides influence a broad range of immunological mechanisms resulting in immunomodulatory effects. To optimize the treatment of chronic inflammatory diseases by macrolides, further studies are necessary, particularly comparing different macrolides and dose effect relationships.

Effects of six-week clarithromycin therapy in corticosteroid-dependent asthma: A randomized, double-blind, placebo-controlled pilot study

BACKGROUND

Although corticosteroids such as prednisone are efficacious for the treatment of severe asthma, chronic administration of oral corticosteroid therapy is associated with significant adverse effects. Previous studies have shown that clarithromycin is effective in reducing bronchial hyperresponsiveness and allergen-induced bronchoconstriction. However, the effect of long-term clarithromycin therapy in patients with prednisone-dependent asthma is uncertain.

OBJECTIVE

This study was conducted to determine the effects of oral clarithromycin on prednisone daily dosage, pulmonary function, quality of life (QOL), and asthmatic symptoms in patients with corticosteroid-dependent asthma.

METHODS

This 14-week, prospective, randomized, double-blind, placebo-controlled pilot study was conducted at Pulmonary Associates (Phoenix, Arizona) and the University of Illinois at Chicago Medical Center (Chicago, Illinois). Patients aged 18 to 75 years with an established diagnosis of asthma and who had been receiving ≥5 mg/d of prednisone for the preceding 6 months were enrolled. After a 4-week data-collection period, patients received clarithromycin 500 mg BID for 6 weeks, followed by a 4-week follow-up period. The effects of clarithromycin therapy on prednisone dosage requirements, pulmonary function (as assessed using spirometry), QOL, and asthmatic symptoms (nocturnal asthma, shortness of breath, chest discomfort, wheezing, and cough) were assessed.

RESULTS

Fourteen patients (9 men, 5 women; mean [SD] age, 62 [13] years) completed the study and were included in the final analysis. One patient withdrew from the study due to clarithromycin-related nausea. After 6 weeks of clarithromycin therapy, patients were able to tolerate a significant reduction in mean (SD) prednisone dosage from baseline (30% [18%]; P- 0.020). Pulmonary function, QOL, and asthmatic symptoms did not significantly worsen despite reduction in prednisone dose. All patients who completed the study tolerated clarithromycin therapy.

CONCLUSIONS

In this pilot study of patients with corticosteroid-dependent asthma, 6-week clarithromycin 500 mg BID was clinically effective in allowing a reduction in prednisone dosage, without worsening pulmonary function, QOL, or asthmatic symptoms. In addition, clarithromycin was well tolerated, with only 1 patient discontinuing therapy due to treatment-related nausea.

Clarithromycin (Biaxin®) extended-release tablet: a therapeutic review

Clarithromycin (Biaxin) extended-release tablets, an advanced generation macrolide, were recently introduced into the USA for the treatment of acute exacerbations of chronic bronchitis, community-acquired pneumonia and acute maxillary sinusitis. The reformulation is intended to improve both patient compliance and tolerability. The extended-release tablets allow convenient once-daily dosing (1000 mg). The extended-release formulation has been shown to be equivalent to the immediate-release formulation concerning area under the plasma concentration time curve. In comparative clinical trials for acute exacerbations of chronic bronchitis, community-acquired pneumonia and acute maxillary sinusitis, clarithromycin extended-release tablets were equivalent to the immediate-release formulation concerning clinical efficacy and bacterial eradication, with improved gastrointestinal tolerability. Similar efficacy and gastrointestinal tolerability results were demonstrated in a recent comparative study of clarithromycin extended-release formulation and amoxicillin-clavulanate in patients with acute exacerbations of chronic bronchitis. Clarithromycin extended-release 1000 mg daily has also been shown to be equivalent to levofloxacin 500 mg daily for the treatment of community-acquired pneumonia in a recent study. The macrolide class of antimicrobials, including clarithromycin extended-release, continues to be a safe and efficacious choice for the out-patient management of community-acquired bacterial respiratory tract infections.

Clarithromycin Extended-Release Tablet

Clarithromycin is an orally active, advanced-generation macrolide that has been reformulated as an extended-release tablet (Biaxin) XL Filmtab allowing convenient once-daily administration. The reformulation is intended to improve patient compliance and the tolerability of the drug. Although maximum plasma clarithromycin concentrations are lower and reached later with the extended-release tablets than with the immediate-release tablets, the two formulations are bioequivalent with respect to the area under the plasma concentration-time curve. Bioequivalence is also achieved between the formulations for the microbiologically active metabolite, 14-hydroxy-clarithromycin. Two randomized trials in patients with acute exacerbations of chronic bronchitis (AECB) showed that a 7-day course of clarithromycin extended-release 1000 mg once daily produced clinical cure rates of 83% and 85% and bacteriologic cure rates of 86% and 92% at the test-of-cure study visit. Similar rates of cure were achieved with a 7-day course of twice-daily clarithromycin immediate-release and with a 10-day course of twice-daily amoxicillin/clavulanic acid.A 7-day course of clarithromycin extended-release 1000 mg once daily produced clinical and bacteriologic cure rates of 88% and 86%, respectively, in patients with community-acquired pneumonia (CAP). Similar cure rates were achieved in recipients of once-daily levofloxacin in the same trial. In patients with acute maxillary sinusitis, a 14-day course of either once-daily clarithromycin extended-release or twice-daily clarithromycin immediate-release produced statistically equivalent clinical cure rates of 85% and 79%, respectively. Both treatment groups achieved similar rates of radiographic success and resolution of sinusitis. Recent results indicate that clarithromycin extended-release 500 mg once daily for 5 days is also effective in the treatment of patients with streptococcal pharyngitis/tonsillitis and in the treatment of AECB. The most frequently reported drug-related events with clarithromycin extended-release were abnormal taste (7% incidence), diarrhea (6%) and nausea (3%). Most adverse drug reactions were of a mild and transient nature. In comparative clinical trials, clarithromycin extended-release had an improved gastrointestinal tolerability profile compared with the immediate-release formulation. In addition, clarithromycin extended-release was better tolerated than amoxicillin/clavulanic acid and as well tolerated as levofloxacin. Further studies are required to assess the cost-effectiveness ratio of clarithromycin relative to comparator antibacterial agents.

CONCLUSION

Clarithromycin extended-release is an effective treatment for AECB, CAP, acute maxillary sinusitis, and pharyngitis (although not approved for the latter in the US), and is administered in a convenient dosage regimen that has the potential to encourage good compliance. The reformulation modulates clarithromycin absorption kinetics thereby improving tolerability. Therefore, clarithromycin extended-release provides a useful option for the treatment of specific respiratory tract infections.

Managing upper respiratory tract complications of primary ciliary dyskinesia in children

PURPOSE OF REVIEW

Primary ciliary dyskinesia (PCD) is a rare and heterogeneous disease that is often misdiagnosed or diagnosed late with more advanced sequelae. PCD primarily effects the respiratory tract, yet most research focuses on the lower respiratory tract manifestations, most of which is derived from research on cystic fibrosis. Little is known about the management of the upper respiratory tract sequelae of PCD. This review summarizes the available evidence for the management of otologic and sinonasal manifestations of PCD.

RECENT FINDINGS

The natural history of otitis media with effusion and hearing loss in PCD appears to fluctuate into adulthood and does not resolve by the age of 9 years, regardless of treatment, as previously assumed. Ventilation tube insertion improves hearing in PCD, but may lead to a higher rate of otorrhoea when compared with the general population. Sinonasal disease in PCD is poorly studied; however, it appears that patients with chronic rhinosinusitis (CRS) may benefit from long-term macrolide therapy and endoscopic sinus surgery (ESS) in recalcitrant disease. Therapies targeted at improving mucociliary clearance have not been tested specifically in PCD. Pharmacogenetic therapy is currently under investigation to target the primary defect in PCD.

SUMMARY

Otologic sequeale in PCD should undergo lifelong evaluation and monitoring and ventilation tube insertion should be considered to avoid complications of chronic hearing loss. Sinonasal disease benefits from macrolide therapy and ESS. Randomized controlled trials of treatment efficacy of the upper respiratory tract manifestations of PCD are lacking.

Antimicrobials and chronic rhinosinusitis with or without polyposis in adults: an evidenced-based review with recommendations

BACKGROUND

Chronic rhinosinusitis (CRS) is characterized by inflammation of the mucosa of the nose and paranasal sinuses. The role of bacterial or fungal infection in CRS is unclear, yet antimicrobials are commonly prescribed for this condition. Published guidelines offer little direction regarding antibiotic strategies for CRS. The purpose of this article is to provide an evidence-based approach to the use of antibacterial and antifungal antibiotics in the management of CRS.

METHODS

A systematic review of the literature was performed following recommendations of the Clinical Practice Guideline Manual, Conference on Guideline Standardization (COGS), and the Appraisal of Guidelines and Research Evaluation (AGREE). Inclusion criteria were: age ≥18 years old, chronic rhinosinusitis with or without polyps, antibiotic treatment as the experimental group, and clearly defined primary clinical endpoint. Studies involving patients with cystic fibrosis or acute invasive fungal sinusitis were excluded.

RESULTS

The review identified and evaluated the literature on 8 classes of antimicrobials for CRS: oral antibacterial antibiotics ≤3 weeks, oral antibacterial antibiotics >3 weeks, macrolide antibiotics, intravenous antibacterial antibiotics, topical antibacterial antibiotics, oral antifungals, intravenous antifungals, and topical antifungals.

CONCLUSION

Based on the available evidence, oral antibacterial antibiotics and prolonged macrolide antibiotics are considered therapeutic options in the treatment of CRS while the use of topical antibacterial antibiotics, intravenous antibacterial antibiotics and oral, topical, or intravenous antifungals would be recommended against. These evidence-based recommendations should not necessarily be applied to all patients with CRS and are not intended to supersede clinical judgment based on individual patient circumstances.

Mechanisms of action and clinical application of macrolides as immunomodulatory medications

Macrolides have diverse biological activities and an ability to modulate inflammation and immunity in eukaryotes without affecting homeostatic immunity. These properties have led to their long-term use in treating neutrophil-dominated inflammation in diffuse panbronchiolitis, bronchiectasis, rhinosinusitis, and cystic fibrosis. These immunomodulatory activities appear to be polymodal, but evidence suggests that many of these effects are due to inhibition of extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation and nuclear factor kappa B (NF-kappaB) activation. Macrolides accumulate within cells, suggesting that they may associate with receptors or carriers responsible for the regulation of cell cycle and immunity. A concern is that long-term use of macrolides increases the emergence of antimicrobial resistance. Nonantimicrobial macrolides are now in development as potential immunomodulatory therapies.

Anti-inflammatory effects of macrolides: applications in chronic rhinosinusitis

The anti-inflammatory effects of macrolides are significant. The clinical impact on diffuse panbronchiolitis (DPB) has improved 10-year survival from 12% to more than 90% for these patients. The immunomodulatory activity of macrolides has been a source of mechanistic research as well as clinical research in non-DPB inflammatory airway disease. Suppression of neutrophilic inflammation of the airways has been demonstrated as the most robust immunomodulatory response from 14- and 15-membered ring macrolides. The inhibition of transcription factors, mainly nuclear factor-kB and activator protein 1, from alterations in intracellular cell signaling drives this mechanism. The suppression of interleukin-8 to a range of endogenous and exogenous challenges characterizes the alterations to cytokine production. The inflammatory mechanisms of chronic rhinosinusitis (CRS) have been a major non-DPB focus. Macrolides have been trialed in more than 14 prospective trials and are the focus of numerous research projects. Evidence for a strong clinical effect in CRS is mounting, but results may be tempered by researchers' inability to characterize the disease process. Eosinophilic dominated CRS is unlikely to respond, based on current research understanding and data from clinical trials. This article discusses the current concepts of macrolides and their application in the management of CRS.

Comprehensive surgical management of the aerosinusitis patient

PURPOSE OF REVIEW

Provide a comprehensive overview of the pathophysiology and surgical management strategies of sinus barotrauma with attention to recent advancements in endoscopic surgical technique.

RECENT FINDINGS

New endoscopic frontal sinus surgery techniques have been shown to be highly effective with rhinosinusitis management, but these techniques have not been evaluated with sinus barotrauma management.

SUMMARY

We discuss the surgical goals and expectations with sinus barotrauma and contrast these to those with chronic rhinosinusitis (CRS). Sinus barotrauma surgery requires anatomic patency of involved sinuses whereas CRS patients are satisfied with a lack of symptoms from any residual mucosal disease.

Effects of long-term clarithromycin treatment on lavage-fluid markers of inflammation in chronic rhinosinusitis

Macrolides can be clinically effective in chronic rhinosinusitis (CRS). However, little is known about how these drugs affect pathophysiological features of CRS in vivo. In the present study, patients with CRS were subjected to long-term treatment with clarithromycin. Nasal lavages with and without histamine (40 and 400 microg ml(-1)) were carried out prior to and late into the treatment period. Histamine was included as a tool to produce plasma exudation, a process known to move free cellular products from the mucosal tissue into the airway lumen thereby enriching nasal surface liquids with such products. Interleukin-8 (IL-8), myeloperoxidase (MPO), eosinophil cationic protein (ECP), alpha(2)-macroglobulin and fucose were monitored as indices of pro-inflammatory cytokine production, neutrophil and eosinophil granulocyte activities, plasma exudation and mucinous secretion, respectively. Clarithromycin reduced the lavage fluid levels of IL-8 at the low-dose histamine observation (P<0.001). There was a trend towards reduced MPO by the treatment, whereas ECP was significantly reduced at the low-dose histamine observation (P<0.05). alpha(2)-Macroglobulin was reduced by clarithromycin (saline lavages) (P = 0.05), whereas fucose was unaffected. The exudative responsiveness to high-dose histamine was significantly reduced by the treatment (P<0.05). Furthermore, significantly lower levels of fucose were observed at the low-dose histamine observation (P<0.01). We conclude that long-term clarithromycin treatment likely exerts an anti-inflammatory effect in CRS.

Effect of clarithromycin on cytokines and chemokines in children with an acute exacerbation of recurrent wheezing: a double-blind, randomized, placebo-controlled trial

BACKGROUND

Clarithromycin is postulated to possess immunomodulatory properties in addition to its antimicrobial activity.

OBJECTIVE

To evaluate the effect of clarithromycin on serum and nasopharyngeal cytokine and chemokine concentrations in children with an acute exacerbation of recurrent wheezing.

METHODS

Children with a history of recurrent wheezing or asthma and who presented with an acute exacerbation of wheezing were enrolled in a double-blind, randomized trial of clarithromycin vs placebo. Concentrations of tumor necrosis factor alpha (TNF-alpha), interferon-gamma (IFN-gamma), interleukin-1beta (IL-1beta), IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, granulocyte-macrophage colony-stimulating factor, RANTES, eotaxin, macrophage inflammatory protein 1alpha, macrophage inflammatory protein 1beta, and monocyte chemoattractant protein 1 were measured in serum and/or nasopharyngeal aspirates before, during, and after therapy. Mycoplasma pneumoniae and Chlamydophila pneumoniae infection were evaluated for by polymerase chain reaction and serologic testing.

RESULTS

Nasopharyngeal concentrations of TNF-alpha, IL-1beta, and IL-10 were significantly and persistently lower in children treated with clarithromycin compared with placebo. There tended to be a greater effect of clarithromycin on nasopharyngeal cytokine concentrations in patients with evidence of M. pneumoniae or C. pneumoniae infection. No significant differences were detected in serum cytokines for children treated with clarithromycin compared with placebo.

CONCLUSION

Clarithromycin therapy reduces mucosal TNF-alpha, IL-1beta, and IL-10 concentrations in children with an acute exacerbation of recurrent wheezing.

Chlamydophila pneumoniae in chronic rhinosinusitis

CONCLUSIONS

The intracellular bacterium Chlamydophila pneumoniae (Cp) was infrequently found in nasopharynx and lacking in biopsies from the middle turbinate in chronic rhinosinusitis (CRS) patients. Compared with healthy controls, patients suffering from CRS had significantly higher and more prevalent antibody titers to Cp. However, an association between CRS and Cp could not be established.

OBJECTIVES

To study the prevalence of Cp in CRS patients and in healthy controls to determine if an association exists between Cp and CRS.

MATERIALS AND METHODS

PCR against Cp was run on middle turbinate biopsies and on throat and nasopharyngeal swabs from 25 CRS patients and from 10 healthy controls. Serum samples were tested for Cp-specific antibodies by the microimmunofluorescence method. Patients that tested positive for Cp or had high antibody titers were treated with antibiotics.

RESULTS

Cp was found in nasopharyngeal samples from two patients but from none of the controls. Neither patients nor controls had Cp in biopsies from the middle turbinate. Antibody titers against Cp were significantly higher and more prevalent in patients than in controls. Seventeen patients were treated with antibiotics but only four of them recovered from sinusitis symptoms during the 2-year follow-up.

Macrolide immunomodulatory effects and symptom resolution in acute exacerbation of chronic bronchitis and acute maxillary sinusitis: a focus on clarithromycin

Bacterial respiratory tract infections are common in the primary care setting and patients often seek the assistance of a healthcare professional in order to achieve resolution of their symptoms. Antibiotic agents that offer rapid symptom relief, in addition to excellent bacteriological and clinical cure, are highly desired. Macrolides have proven to be highly effective in treating acute bacterial exacerbations of chronic bronchitis and acute maxillary sinusitis. In addition, immunomodulatory effects that may contribute to symptom resolution have been reported. This article reviews current literature on symptom resolution in acute bacterial exacerbations of chronic bronchitis and acute maxillary sinusitis, with a focus on clarithromycin, and explores the potential mechanisms that may contribute to this action.

Value of short-course antimicrobial therapy in acute bacterial rhinosinusitis

Traditional approaches to antimicrobial management of acute bacterial rhinosinusitis (ABRS) focus on courses of therapy of at least 10 days duration. The rationale for this length of therapy originated from studies in tonsillopharyngitis. Short-course antibiotic therapy for ABRS with 3-5 days of azithromycin has proved equally effective. Potential added benefits of short-course therapy include improved compliance, fewer adverse events as well as reduced risk of treatment failure, bacterial resistance and cost. Single-dose therapy is now possible with a novel microsphere formulation of azithromycin, which permits administration of a higher 2.0 g oral dose. This has proved as effective and well tolerated as 10 days levofioxacin 500 mg/day in patients with uncomplicated ABRS. High single-dose therapy has the potential to maximize adherence to prescribed therapy and thus to help in the battle to control rising antibiotic resistance among respiratory pathogens.

Anti-inflammatory effects of macrolide antibiotics in the treatment of chronic rhinosinusitis

Apart from their obvious antibiotic effects, the macrolides have some potentially useful immunomodulatory properties. Which pathway dominates the clinical effect is debatable. Favoring the anti-inflammatory effects are the substantial in vitro data and serum concentrations well below minimal inhibitory concentrations for several pathogens. Furthermore, tissue reparative effects are seen in diffuse panbronchiolitis regardless of the presence of P. aeruginosa, a pathogen not sensitive to macrolide antibiotics. Clinical studies support the view that prolonged treatment is likely to be beneficial in most patients who have CRS. The evidence concerning CRS is still weak because placebo-controlled trials are missing. One should remember, however, the general lack of placebo-controlled trials even in the "more established" medical management of CRS. The concern for an increasing incidence of macrolide-resistant bacterial strains must be taken seriously. Therefore the authors advocate repeated nasal cultures during macrolide therapy. It is hoped that the future will bring larger, prospective, randomized, controlled trials that will investigate the efficacy and safety of macrolides in CRS.

Treatment of chronic rhinosinusitis with low-dose, long-term macrolide antibiotics: an evolving paradigm

The 14-membered and 15-membered ring macrolide antibiotics express immunomodulatory effects in chronic respiratory disorders in humans that are distinct from their antimicrobial properties. These drugs downregulate the excessive immune and inflammatory responses observed in these conditions while promoting tissue repair. To this end, chronic rhinosinusitis is characterized by mucosal inflammation of nasal and sinus mucosa for more than 3 months and accounts for significant health care resource allocation due to difficulties in treatment. Clinical efficacy of macrolide antibiotics as biologic response modifiers in patients with chronic rhinosinusitis is suggested by compelling basic research and small, uncontrolled clinical studies. Hence, long-term, prospective double-blind placebo-controlled clinical studies are indicated to establish the utility of these drugs in the treatment of patients with chronic rhinosinusitis.

Macrolides in cystic fibrosis

Macrolide antibiotics have been licensed since the 1950s and have an important role in the treatment of a diverse range of infectious diseases. Macrolide antibiotics have antibacterial activity against gram-positive bacteria, some gram-negative bacteria and intracellular pathogens. The spectrum of antibacterial activity combined with excellent intracellular and tissue penetration has led to the extensive use of this class of drugs in respiratory disease. Macrolide antibiotics also have demonstrated anti-inflammatory properties in various in vitro and in vivo model systems. Novel antimicrobial and anti-inflammatory properties of macrolide may result in clinical benefits, particularly in conditions where the infectious agent is inherently resistant to macrolides. Three randomized control trials have demonstrated improved lung function in patients treated with the macrolide antibiotic, azithromycin. Azithromycin was generally well tolerated and resulted in reduction in the inflammatory response which may be due to an immunomodulatory role. Short term studies (three to six months) have not demonstrated the development of increased bacterial resistance or the emergence of new pathogens following azithromycin.

Effects of clarithromycin on inflammatory cell mediator release and survival

BACKGROUND

Clarithromycin exhibits anti-inflammatory as well as antimicrobial activity, leading to decreased symptoms of asthma and chronic sinusitis. The mode of anti-inflammatory effects of clarithromycin on inflammatory cells is not well understood. We hypothesized that clarithromycin inhibits inflammatory cell mediator release and survival.

METHODS

We investigated the effects of this drug on survival and mediator release from mast cells, eosinophils and neutrophils.

RESULTS

Human eosinophil and neutrophil respiratory burst was inhibited by up to 54% after 1-2 h pretreatment with 100 microg/ml clarithromycin. Similar doses of erythromycin did not affect respiratory burst responses in these cells. Clarithromycin at doses of up to 100 microg/ml had no effect on granule-derived mediators released from mast cells and neutrophils. However, we found that clarithromycin (100 microg/ml) induced cell death in mast cells and eosinophils after 16-48 h incubation.

CONCLUSION

Clarithromycin inhibited inflammatory cell mediator release and survival, which may enhance its ability to reduce the symptoms of chronic sinusitis and asthma.

Clinical implications of the immunomodulatory effects of macrolides on sinusitis

This article reviews the treatment of chronic sinusitis with macrolides. Chronic sinusitis is often the result of bacterial infections that lead to chronic inflammation with thickening of the sinus mucosa and hypersecretion of mucus. In addition to their anti-infective properties, some macrolides possess immunomodulatory effects. These macrolides have been used successfully to treat diffuse panbronchiolitis, a progressive inflammatory lung disease, and may be useful for treatment of asthma, chronic bronchitis, chronic sinusitis, cystic fibrosis, and bronchiectasis. The clinical benefits of macrolides in patients with chronic sinusitis include decreased nasal secretions and postnasal drip, with improvement in nasal obstruction. In vivo and in vitro studies show that some macrolides affect neutrophil chemotaxis and infiltration, inflammatory cytokine production, mucus production, and the transportability of airway secretions. These findings indicate that macrolides are promising agents for treating chronic inflammation of the airways.

The Effect of Clarithromycin on Inflammatory Markers in Chronic Obstructive Pulmonary Disease: Preliminary Data

BACKGROUND:

Clarithromycin is an antimicrobial agent that can be used for treatment of chronic obstructive pulmonary disease (COPD) exacerbations with bronchodilator therapy. However, it has also been shown that clarithromycin has antiinflammatory effects by the inhibition of cytokine production.

OBJECTIVE:

To evaluate the antiinflammatory effect of clarithromycin on serum and sputum interleukin-8 (IL-8), tumor necrosis factor-α (TNF-α), and leukotriene B4 levels in patients with COPD.

METHODS:

Thirty men with mild to moderate COPD were enrolled in this prospective, single-center, double-blind, placebo-controlled study. None of the patients was receiving systemic or inhaled corticosteroids during the study. Subjects received either clarithromycin or placebo for 14 days. Before and after this treatment period, spirometric tests and arterial blood gas analysis were performed, blood was drawn for measurement of serum inflammatory markers, and sputum was induced.

RESULTS:

There were no statistically significant differences in baseline clinical or laboratory parameters between the groups. After the treatment, the induced sputum total cell counts, and IL-8 and TNF-α levels decreased significantly in the clarithromycin group compared with pretreatment levels (mean ± SD IL-8 1606 ± 367.3 vs 882 ± 143.6 pg/mL, p = 0.001; TNF-α 638.2 ± 287.5 vs 390 ± 235 pg/mL, p = 0.001). Similarly, decreases in serum inflammatory markers were found in the clarithromycin group while there was no significant change in the placebo group.

CONCLUSIONS:

This study demonstrated that the decrease in IL-8 and TNF-α levels might be related to the antiinflammatory effect of clarithromycin. Thus, we suggest that the use of clarithromycin in COPD exacerbations may either treat the infection or help control the inflammation. Future studies are needed to determine the clinical significance of these findings.

Chronic rhinosinusitis: management for optimal outcomes

Chronic rhinosinusitis is characterized by nasal purulence accompanied by malaise, postnasal drip and nasal dryness or crusting. It is a condition that is very difficult to treat and can be very disabling to the patients. A clinical diagnosis is based on history and evaluation with endoscopy, and computerized tomographic scanning. The etiology of chronic rhinosinusitis is multifactorial and comprises a vicious cycle of pathophysiological, anatomical, and constitutive factors. Predisposing factors include ciliary impairment, allergy, nasal polyposis, and immune deficiency. Treatment is aimed at reducing mucosal inflammation and swelling, controlling infection, and restoring aeration of the nasal and sinus mucosa. The choice of treatment is influenced by many factors including past medication, duration of symptoms and the presence of allergy/nasal polyps. Pharmacologic treatment, with local or systemic corticosteroids such as mometasone furoate, fluticasone propionate, beclometasone dipropionate or oral prednisolone coupled with nasal lavage with isotonic saline solutions are the cornerstones of disease management. Systemic antibiotics including amoxicillin/clavulanic acid, ciprofloxacin, clarithromycin, and trimethoprim/sulfamethoxazole (cotrimoxazole) are often administered to patients with chronic sinusitis and underlying bacterial infection. In patients with underlying allergy, additional treatment with antihistamines should be considered. Aeration of the sinuses may temporarily be improved with local nasal decongestants such as oxymetazoline. If symptoms persist after aggressive medical treatment, surgery should be considered. Surgery should be functional and involve widening the natural drainage openings of the sinuses and preserving the ciliated epithelium as much as possible. In the case of nasal polyposis surgery is more aggressive involving removal of the diseased polypous mucosa. It is recommended that medical treatment should be continued post sinus surgery.

Clarithromycin in 2003: sustained efficacy and safety in an era of rising antibiotic resistance

Data from surveillance studies show increasing prevalence of respiratory pathogens resistant to commonly used antibiotics. Thus, a Medline search was conducted to identify studies of clarithromycin, especially those addressing macrolide resistance. Changing trends of in vitro susceptibility have not affected clinical efficacy with clarithromycin. Over the last 12 years, clarithromycin study results have shown consistent rates of clinical cure and bacteriological eradication, which are similar to those observed with comparator agents. The incidence of clarithromycin treatment failure in patients infected with Streptococcus pneumoniae is substantially less than that predicted by macrolide resistance rates from surveillance programmes. In summary, despite widespread use since its introduction, clarithromycin remains active both in vitro and in vivo against clinically relevant respiratory tract pathogens.

Chronic rhinosinusitis and eosinophils: do macrolides have an effect?

PURPOSE OF REVIEW

Long-term, low-dose macrolide therapy is effective in the treatment of chronic airway inflammation. It is believed that macrolide antibiotics produce this benefit through an antiinflammatory effect that is separate from their antibiotic effect. Eosinophils are key mediators in the inflammation seen in chronic rhinosinusitis. This review discusses the effect of macrolides on eosinophilic inflammation.

RECENT FINDINGS

In vitro studies recently have suggested that macrolides increase eosinophil apoptosis and reduce production of eosinophil chemotactic cytokines and adhesion molecules. In vivo studies have shown a reduction in eosinophil count and activity in asthma and chronic rhinosinusitis. Clinical response to macrolide treatment is thought to be less likely in patients with atopy.

SUMMARY

In contrast to the evidence supporting the effect of macrolides on neutrophilic inflammation, there are limited data to suggest an influence on eosinophilic inflammation. For this reason, patients with prominent eosinophilic inflammation may in the future be identified as being less likely to respond to treatment. Further in vitro and clinical studies are required to investigate this subject.

Macrolides for the treatment of chronic sinusitis, asthma, and COPD

In addition to their well-known antimicrobial activity, macrolides possess immunomodulatory properties that may confer beneficial effects to patients with respiratory diseases associated with chronic inflammation. These properties include attenuation of inflammatory responses in the lung, mucoregulatory properties, and effects on bronchial responsiveness. Macrolides increase mucociliary clearance, improve sinusitis symptoms, and decrease nasal secretions and polyp size in patients with sinusitis. They also have been shown to modify the inflammatory response associated with chronic sinusitis. In patients with asthma, macrolides have been reported to reduce airway hyperresponsiveness and improve pulmonary function, and have historically been selected for their "steroid-sparing" effect. Preliminary data from studies of patients with COPD have shown improvements in symptom scores and FEV(1) after macrolide treatment. As biological response modifiers, macrolides have the potential to improve the outcomes of patients with inflammatory airway diseases. Large scale, placebo-controlled clinical trials designed to assess long-term efficacy and safety in these diseases are warranted.

Intravenous antibiotics for chronic rhinosinusitis: are they effective?

PURPOSE OF REVIEW

Antibiotics have been used commonly in chronic rhinosinusitis, often because chronic rhinosinusitis has features of a prolonged bacterial sinusitis, including abnormal CT findings and positive bacterial cultures. The advent of peripherally inserted central catheters has enabled outpatient parenteral antibiotic therapy to become a convenient means of delivering potent antibiotics for various conditions when oral antibiotics may not be effective or appropriate. Chronic rhinosinusitis has been included as a condition that may benefit from outpatient parenteral antibiotic therapy; however, there are few studies that document its success and, furthermore, chronic rhinosinusitis may not always be an infectious process.

RECENT FINDINGS

Three recent uncontrolled retrospective studies examined outpatient parenteral antibiotic therapy in chronic rhinosinusitis. In one series outpatient parenteral antibiotic therapy was used as an adjunct to sinus surgery, in another it was used as an alternative to sinus surgery in the pediatric population, and in the third it was used as temporary resolution for adult patients who had failed other therapies including sinus surgery. Short-term success rates were reported in the range of 29 to 89%, but relapse rates were as high as 89%. Complication rates in theses studies ranged from 14 to 26%, including medication reactions and intravenous line problems.

SUMMARY

The role of outpatient parenteral antibiotic therapy in the treatment of chronic rhinosinusitis has not been universally established. Although outpatient parenteral antibiotic therapy may have a role in avoiding sinus surgery in select pediatric populations, the contribution to a lasting resolution in adult patients is less clear and there are possible complications. Recognizing subsets of chronic rhinosinusitis patients for whom outpatient parenteral antibiotic therapy is appropriate will be the challenge for the future.

Chlamydia pneumoniae and atherosclerosis -- what we know and what we don't

The clinical manifestations of atherosclerosis include coronary artery disease (CAD), stroke, abdominal aortic aneurysm and peripheral vascular disease. World-wide, CAD and stroke are the leading causes of death and disability. The recognition of atherosclerosis as an inflammatory disease in its genesis, progression and ultimate clinical manifestations has created an interesting area of vascular research. Apart from those well-known traditional risk factors for atherosclerosis, novel and potentially treatable atherosclerotic risk factors such as homocysteine (an amino acid derived from the metabolism of dietary methionine that induces vascular endothelial dysfunction) and infections have emerged. In fact, the century-old 'infectious' hypothesis of atherosclerosis has implicated a number of micro-organisms that may act as contributing inflammatory stimuli. Although cytomegalovirus, Helicobacter pylori and Chlamydia pneumoniae are the three micro-organisms most extensively studied, this review will focus on C. pneumoniae. Collaborative efforts from many disciplines have resulted in the accumulation of evidence from seroepidemiological, pathological, animal model, immunological and antibiotic intervention studies, linking C. pneumoniae with atherosclerosis. Seroepidemiological observations provide circumstantial evidence, which is weak in most prospective studies. Pathological studies have demonstrated the preferential existence of C. pneumoniae in atherosclerotic plaque tissues, while animal model experiments have shown the induction of atherosclerosis by C. pneumoniae. Finally, immunological processes whereby C. pneumoniae could participate in key atherogenic and atherothrombotic events have also been identified. Although benefits of the secondary prevention of atherosclerosis have been demonstrated in some antibiotic intervention studies, a number of negative studies have also emerged. The results of the ongoing large prospective human antibiotic intervention trials may help to finally establish if there is a causal link between C. pneumoniae infection and atherosclerosis.