Erythromycin and diffuse panbronchiolitis

Vaginal Microbiome in Preterm Rupture of Membranes

There is an association between vaginal microbiota dysbiosis and preterm premature rupture of membranes (PPROM). In PPROM, reduced Lactobacillus spp abundance is linked to the emergence of high-risk vaginal microbiota, close to the time of membrane rupture. Although PPROM itself can change vaginal microbial composition, antibiotic therapy profoundly effects community structure. Erythromycin may have a beneficial effect in women deplete in Lactobacillus spp but damages a healthy microbiome by targeting Lactobacillus spp. Increased rates of chorioamnionitis and early-onset neonatal sepsis are associated with vaginal microbiota dysbiosis close to the time of delivery.

Azithromycin induces epidermal differentiation and multivesicular bodies in airway epithelia

Background

Azithromycin (Azm) is a macrolide recognized for its disease-modifying effects and reduction in exacerbation of chronic airway diseases. It is not clear whether the beneficial effects of Azm are due to its anti-microbial activity or other pharmacological actions. We have shown that Azm affects the integrity of the bronchial epithelial barrier measured by increased transepithelial electrical resistance. To better understand these effects of Azm on bronchial epithelia we have investigated global changes in gene expression.

Methods

VA10 bronchial epithelial cells were treated with Azm and cultivated in air-liquid interface conditions for up to 22 days. RNA was isolated at days 4, 10 and 22 and analyzed using high-throughput RNA sequencing. qPCR and immunostaining were used to confirm key findings from bioinformatic analyses. Detailed assessment of cellular changes was done using microscopy, followed by characterization of the lipidomic profiles of the multivesicular bodies present.

Results

Bioinformatic analysis revealed that after 10 days of treatment genes encoding effectors of sterol and cholesterol metabolism were prominent. Interestingly, expression of genes associated with epidermal barrier differentiation, KRT1, CRNN, SPINK5 and DSG1, increased significantly at day 22. Together with immunostaining, these results suggest an epidermal differentiation pattern. We also found that Azm induced the formation of multivesicular and lamellar bodies in two different airway epithelial cell lines. Lipidomic analysis revealed that Azm was entrapped in multivesicular bodies linked to different types of lipids, most notably palmitate and stearate. Furthermore, targeted analysis of lipid species showed accumulation of phosphatidylcholines, as well as ceramide derivatives.

Conclusions

Taken together, we demonstrate how Azm might confer its barrier enhancing effects, via activation of epidermal characteristics and changes to intracellular lipid dynamics. These effects of Azm could explain the unexpected clinical benefit observed during Azm-treatment of patients with various lung diseases affecting barrier function.

Electronic supplementary material

The online version of this article (10.1186/s12931-019-1101-3) contains supplementary material, which is available to authorized users.

Inflammation in cystic fibrosis: An update

Inflammation plays a critical role in cystic fibrosis (CF) lung pathology and disease progression making it an active area of research and important therapeutic target. In this review, we explore the most recent research on the major contributors to the exuberant inflammatory response seen in CF as well as potential therapeutics to combat this response. Absence of functional cystic fibrosis transmembrane conductance regulator (CFTR) alters anion transport across CF airway epithelial cells and ultimately results in dehydration of the airway surface liquid. The dehydrated airway surface liquid in combination with abnormal mucin secretion contributes to airway obstruction and subsequent infection that may serve as a trigger point for inflammation. There is also evidence to suggest that airway inflammation may be excessive and sustained relative to the infectious stimuli. Studies have shown dysregulation of both pro-inflammatory mediators such as IL-17 and pro-resolution mediators including metabolites of the eicosanoid pathway. Recently, CFTR potentiators and correctors have garnered much attention in the CF community. Although these modulators address the underlying defect in CF, their impact on downstream consequences such as inflammation are not known. Here, we review pre-clinical and clinical data on the impact of CFTR modulators on inflammation. In addition, we examine other cell types including neutrophils, macrophages, and T-lymphocytes that express CFTR and contribute to the CF inflammatory response. Finally, we address challenges in developing anti-inflammatory therapies and highlight some of the most promising anti-inflammatory drugs under development for CF.

Vaginal dysbiosis increases risk of preterm fetal membrane rupture, neonatal sepsis and is exacerbated by erythromycin

BACKGROUND

Preterm prelabour rupture of the fetal membranes (PPROM) precedes 30% of preterm births and is a risk factor for early onset neonatal sepsis. As PPROM is strongly associated with ascending vaginal infection, prophylactic antibiotics are widely used. The evolution of vaginal microbiota compositions associated with PPROM and the impact of antibiotics on bacterial compositions are unknown.

METHODS

We prospectively assessed vaginal microbiota prior to and following PPROM using MiSeq-based sequencing of 16S rRNA gene amplicons and examined the impact of erythromycin prophylaxis on bacterial load and community structures.

RESULTS

In contrast to pregnancies delivering at term, vaginal dysbiosis characterised by Lactobacillus spp. depletion was present prior to the rupture of fetal membranes in approximately a third of cases (0% vs. 27%, P = 0.026) and persisted following membrane rupture (31%, P = 0.005). Vaginal dysbiosis was exacerbated by erythromycin treatment (47%, P = 0.00009) particularly in women initially colonised by Lactobacillus spp. Lactobacillus depletion and increased relative abundance of Sneathia spp. were associated with subsequent funisitis and early onset neonatal sepsis.

CONCLUSIONS

Our data show that vaginal microbiota composition is a risk factor for subsequent PPROM and is associated with adverse short-term maternal and neonatal outcomes. This highlights vaginal microbiota as a potentially modifiable antenatal risk factor for PPROM and suggests that routine use of erythromycin for PPROM be re-examined.

New Drugs for Pediatric Asthma

Asthma is the most common chronic disease in children. As suggested by international guidelines, the main goals of asthma treatment are symptoms control and lung function preservation, through a stepwise and control-based approach. The first line therapy based on inhaled corticosteroids may fail to reach control in more than one third of patients, especially adolescents, and in these lung function and quality of life may progressively worsen. Treatment with omalizumab, the first anti-immunoglobulin E recombinant humanized monoclonal antibody, has been definitely approved in pediatric uncontrolled asthma. In this review, we discuss the mechanisms and potential roles of emerging therapies for pediatric severe asthma. Novel biologic drugs (i.e., dupilumab, mepolizumab, reslizumab, and benralizumab) seem to be promising in reducing annual exacerbation rates and steroid-use in glucocorticoid-dependent cases, but available data are few and limited to adolescents and adults. Evidences on the use of the muscarinic antagonist tiotropium as controller medication in pediatric settings are progressively growing, sustaining an application as asthma maintenance treatment in children aged >6 years and in preschool children with persistent asthmatic symptoms, but well powered trials are needed to confirm its safety and efficacy. New inhaled corticosteroids (i.e., ciclesonide and mometasone) are effective as once-daily controller therapy, but long-term studies in the different pediatric ages are needed to compare effectiveness and safety to usual treatments. At present, the role of macrolides in pediatric severe asthma is controversial and their administration is not recommended routinely, but may be considered in children with neutrophilic asthma for reducing daily oral steroids administration and improving lung function. Despite the availability of several novel therapeutic strategies for uncontrolled asthma, future trials targeted at specific pediatric age subgroups are needed to support evidences of safety and efficacy also in children.

Azithromycin Attenuates Pseudomonas-Induced Lung Inflammation by Targeting Bacterial Proteins Secreted in the Cultured Medium

Background

Pseudomonas aeruginosa airway infections are a major cause of morbidity and mortality in patients with cystic fibrosis (CF). Azithromycin improves the related clinical outcomes, but its mechanisms of action remain poorly understood. We tested the hypothesis that azithromycin downregulates P. aeruginosa-induced pro-inflammatory responses by modifying release of bacterial proteins.

Methods

We monitored inflammatory markers in lungs of CF mutant mice and their littermate controls in response to conditioned media (CM) collected from the reference P. aeruginosa PAO1 strain cultured in the presence or in the absence of azithromycin. A mass spectrometry-based proteomic approach was applied to examine whether the macrolide elicits a differential release of bacterial proteins.

Results

CM collected from azithromycin-untreated PAO1 cultures induced powerful pro-inflammatory neutrophil-dominated responses. Azithromycin attenuated the responses, mainly of macrophage chemoattractant protein-1, tumor necrosis factor-α, and interferon-γ, in CF but not in wild-type mice. Proteomic analysis showed that azithromycin upregulated an array of bacterial proteins including those associated with regulation of immune functions and with repair and resolution of inflammatory responses like the chaperone DnaK and the S-adenosylmethionine synthase, while it downregulated the extracellular heme acquisition protein HasA and the catalytic enzyme lysylendopeptidase.

Conclusion

Supernatants collected from cultures of the bacterial strain PAO1 represent a novel experimental model to trigger in vivo lung inflammatory responses that should be closer to those obtained with live bacteria, but without bacterial infection. Combined with a bactericidal effect, complex regulation of bacterial innate immune and metabolic factors released in the cultured medium by the action of the macrolide can contribute to its anti-inflammatory effects.

Management of Pulmonary Disease in Patients with Cystic Fibrosis

Cystic fibrosis is the most common, life-shortening autosomal recessive disease, affecting approximately 1 in 3400 live births in the United States. Gastrointestinal and pulmonary manifestations are most common. With the introduction of pancreatic enzyme and vitamin supplementation, lung disease accounts for the vast majority of morbidity and mortality in patients with cystic fibrosis. The lungs of cystic fibrosis patients are essentially normal at birth but demonstrate evidence of airway inflammation and infection in early infancy. A vicious cycle of inflammation, infection and obstruction ultimately leads to destruction of airways, impairment of gas exchange and death.

Current pharmacological management of pulmonary disease targets reducing airway obstruction, controlling infection and more recently, controlling inflammation. An increased recovery of unusual and highly resistant bacteria from patients with more advanced disease has been observed. Aggressive treatment of acute pulmonary exacerbations with combination antibiotic therapy for two to three weeks has shown pronounced beneficial effects. The routine use of prophylactic antistaphylococcal antibiotics is still controversial.

Although current pharmacologic treatment is symptomatic, new agents are being developed and studied that target the underlying defect in the CFTR protein. This review focuses on current pharmacologic management of pulmonary disease in patients with cystic fibrosis and the role of new agents emerging for the treatment of this disease.

Infections and Asthma

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Wheezing viral respiratory illnesses are the most common initial presentation of childhood asthma.

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Once asthma is established, viral infections, most notably rhinovirus (RV), are the most frequent trigger of severe asthma exacerbations. RV-C appears to be a particularly pathogenic virus in children with asthma.

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Evidence has recently emerged to suggest that bacterial pathogens in the lower airway may contribute to the expression of asthma. Ongoing studies are critical to our understanding of the role of the airway microbiome in asthma inception and exacerbation.

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Synergistic interactions between underlying allergy and virus infections play an important mechanistic role in asthma inception and exacerbation, and are an important therapeutic target.

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Novel therapies are needed to prevent and treat virus-induced wheezing and asthma exacerbations.

Effects of long-term use of macrolides in patients with non-cystic fibrosis bronchiectasis: a meta-analysis of randomized controlled trials

Background

The purpose of this study was to evaluate the clinical benefits and safety of the long-term use of macrolides in patients with non-cystic fibrosis (non-CF) bronchiectasis.

Methods

Embase, Pubmed, the Cochrane Library and Web of Science databases were searched from inception up to March 2014. The primary outcome was the improvement of exacerbations of bronchiectasis. Secondary endpoints included changes of microbiology, lung function, quality of life, sputum volume, adverse events and macrolide resistance.

Results

The literature search yielded 139 studies, ten of which containing 601 patients were included in this meta-analysis. Macrolides showed a statistically-significant improvement in reducing acute exacerbations per patient during follow-up treatment (RR = 0.55, 95% CI: 0.47, 0.64, P < 0.001), increasing the number of patients free from exacerbations (OR = 2.81, 95% CI: 1.85, 4.26, P < 0.001), and prolonging time to a first exacerbation (HR = 0.38, 95% CI: 0.28, 0.53, P < 0.001). Macrolides maintenance treatment was superior to control with respect to attenuating FEV1 decline (p = 0.02), improving sputum volume (p = 0.009) and SGRQ total scores (p = 0.02), but showed a higher risk of adverse events, especially diarrhea (OR = 5.36; 95% CI: 2.06, 13.98, P = 0.0006). Eradication of pathogens was improved in the macrolide group (OR = 1.76, 95% CI: 0.91, 3.41, P = 0.09), while pathogen resistance caused by macrolides dramatically increased (OR = 16.83, 95% CI: 7.26, 38.99, P < 0.001). The new appearance of a microbiologic profile or participant withdrawal due to adverse events showed no significant differences between the two groups.

Conclusion

In patients with non-CF bronchiectasis, macrolide maintenance treatment can effectively reduce frequency of exacerbations, attenuate lung function decline, decrease sputum volume, improve quality of life, but may be accompanied with increased adverse events (especially diarrhea) and pathogen resistance.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-015-0872-5) contains supplementary material, which is available to authorized users.

Is there a role for macrolides in severe asthma?

PURPOSE OF REVIEW

Severe asthma is a heterogeneous syndrome, encompassing several distinct clinical phenotypes. Different molecular and cellular pathways or endotypes determine the type of underlying airway inflammation in patients with severe asthma, which can be categorized as eosinophilic asthma (allergic and nonallergic) or noneosinophilic asthma (neutrophilic and paucigranulocytic). In this review, we discuss the potential role of macrolides in the treatment of severe asthma in adults.

RECENT FINDINGS

Maintenance treatment with low-dose macrolides such as erythromycin and azithromycin provides clinical benefit in several chronic neutrophilic airway diseases, including cystic fibrosis (CF), non-CF bronchiectasis and exacerbation-prone chronic obstructive pulmonary disease. Although several short-term studies of macrolides in mild-to-moderate asthma have failed to improve lung function, the AzIthromycin in Severe Asthma trial has demonstrated a significant reduction in the rate of exacerbations in patients with exacerbation-prone noneosinophilic severe asthma. As chronic macrolide use is associated with the risks of population antimicrobial resistance, this add-on treatment should be restricted to severe asthma patients at greatest unmet need despite optimal asthma management.

SUMMARY

Further clinical, translational and basic research is needed to better phenotype patients with severe asthma, to determine the risk-benefit ratio of macrolide maintenance treatment in neutrophilic severe asthma and to elucidate the principal mechanisms of action of macrolides.

Advantages and drawbacks of long-term macrolide use in the treatment of non-cystic fibrosis bronchiectasis

Non-cystic fibrosis (non-CF) bronchiectasis is a respiratory disease characterized by persistent airway inflammation and dilation of bronchial wall driven by various causes. Patients with bronchiectasis suffer from excessive sputum production, recurrent exacerbations, and progressive airway destruction. Major therapy for bronchiectasis is focused on breaking the "vicious cycle" of mucus stasis, infection, inflammation, and airway destruction. Growing evidences have been shown that macrolides possess immunoregulatory and anti-inflammatory functions beyond their antimicrobial effects. Macrolide antibiotics have been effectively used in the treatment of diffuse panbronchiolitis, CF and bronchiolitis obliterans syndrome. Currently a number of clinical trials were performed to assess macrolide treatment in the management of non-CF bronchiectasis. The purpose of this paper is to review the efficacy and potential risks of these recent studies on the use of macrolides in non-CF bronchiectasis.

Mitochondrial OXPHOS function is unaffected by chronic azithromycin treatment

BACKGROUND

Certain antibiotics may cause unwanted side effects due to the similarity of the mitochondrial translation system to the prokaryotic one. Children with cystic fibrosis (CF) are vulnerable to recurrent respiratory tract infections and azithromycin, a translation targeted antibiotic, is often used chronically to treat CF patients. No major clinical side effects were found with chronic treatment. However, mitochondrial function was not previously assessed. We evaluated oxidative phosphorylation (OXPHOS) in lymphocytes from children with CF receiving chronic azithromycin treatment using an improved ATP production assay.

METHOD

Enzymatic activities of respiratory chain complexes II-IV and ATP production were measured in lymphocytes.

RESULTS

Relative to controls and to CF patients without azithromycin treatment, no significant difference in mitochondrial respiratory chain complexes II-IV was detected, and ATP production with pyruvate, glutamate and succinate, did not disclose any differences between the groups.

CONCLUSION

We suggest that chronic treatment with azithromycin does not significantly affect OXPHOS function.

Complex airway disease: an approach to assessment and management

Research into new treatments for airway disease focuses on severe disease because morbidity, mortality, and health-care costs are substantial and the unmet need is greatest. One reason why outcomes are poor in these patients could be that the clinical expression of disease is heterogeneous and difficult to classify. As a result, guideline-based management algorithms fail. Additionally, difficulties with disease classification and misconceptions about the relation between different aspects of severe airway disease have hindered new drug development. A potential solution is to use a new approach to assess severe airway disease, which moves the diagnostic focus from categorisation of patients to identification and characterisation of the main drivers of disease. This approach will help rather than hinder identification of clinically important phenotypes of disease and will facilitate the development of new phenotype-specific treatment options.

Diffuse Panbronchiolitis

Diffuse panbronchiolitis (DPB) is characterized by chronic sinobronchial infection and diffuse bilateral micronodular pulmonary lesions consisting of inflammatory cells. Studies on disease etiology point to a genetic predisposition unique to Asians. Early therapy for DPB was largely symptomatic. The advent of macrolide antibiotics, including erythromycin, roxithromycin and clarithromycin, has strikingly changed disease prognosis. Low-dose, long-term macrolide therapy for DPB originated from detailed observations of response to therapy in a single patient. The bactericidal activity of macrolides, particularly erythromycin, is not a significant factor for their clinical efficacy in DPB. Firstly, irrespective of bacterial clearance, clinical improvement is observed in patients treated with erythromycin. Secondly, even in cases with bacterial superinfection with Pseudomonas aeruginosa resistant to macrolides, treatment has proved effective. Thirdly, the recommended dosage of macrolides produces peak levels in tissue that are below the minimum inhibitory concentrations for major pathogenic bacteria that colonize the airway. In the last two decades, the possible mechanism underlying the effectiveness of macrolide therapy has been extensively studied. The proposed mechanism of action includes inhibition of excessive mucus and water secretion from the airway epithelium, inhibition of neutrophil accumulation in the large airway, inhibition of lymphocyte and macrophage accumulation around the small airway, and modulation of bacterial virulence. The great success of macrolide therapy in diffuse panbronchiolitis may extend its application to the treatment of other chronic inflammatory disorders. If the anti-inflammatory activity of macrolides is independent of their bactericidal effect, new anti-inflammatory macrolides without antimicrobial activity should be developed to minimize emergence of macrolide-resistant micro-organisms.

Pathogen- and host-directed anti-inflammatory activities of macrolide antibiotics

Macrolide antibiotics possess several, beneficial, secondary properties which complement their primary antimicrobial activity. In addition to high levels of tissue penetration, which may counteract seemingly macrolide-resistant bacterial pathogens, these agents also possess anti-inflammatory properties, unrelated to their primary antimicrobial activity. Macrolides target cells of both the innate and adaptive immune systems, as well as structural cells, and are beneficial in controlling harmful inflammatory responses during acute and chronic bacterial infection. These secondary anti-inflammatory activities of macrolides appear to be particularly effective in attenuating neutrophil-mediated inflammation. This, in turn, may contribute to the usefulness of these agents in the treatment of acute and chronic inflammatory disorders of both microbial and nonmicrobial origin, predominantly of the airways. This paper is focused on the various mechanisms of macrolide-mediated anti-inflammatory activity which target both microbial pathogens and the cells of the innate and adaptive immune systems, with emphasis on their clinical relevance.

Clinical efficacy of macrolide antibiotics against genetically determined macrolide-resistant Mycoplasma pneumoniae pneumonia in paediatric patients

BACKGROUND AND OBJECTIVE

Since 2000, the prevalence of macrolide-resistant (MR) Mycoplasma pneumoniae has increased among paediatric patients in Japan. To determine the efficacy of macrolides against MR M. pneumoniae pneumonia, microbiological and clinical efficacies were compared during the antibiotic treatment.

METHODS

Samples from a total of 30 children with M. pneumoniae pneumonia, as confirmed by PCR and serology, were analyzed. Primers for domain V of 23S rRNA were used, and DNA sequences of the PCR products were compared with the sequence of an M. pneumoniae reference strain.

RESULTS

Isolates from 21 patients demonstrated point mutations, and these patients were defined as MR. The remaining nine patients, whose isolates showed no point mutations, were categorized as control (macrolide-sensitive) patients. The number of M. pneumoniae in nasopharyngeal samples from the control group decreased rapidly 48 h after initiation of macrolide treatment and showed a close relationship with clinical outcome. In contrast, the number of M. pneumoniae 48 h after initiation of macrolide treatment were significantly higher in samples from MR patients than in samples from macrolide-sensitive patients. In 15 of 21 MR patients, fever persisted for more than 48 h after the initiation of macrolide treatment. When treatment was changed to minocycline, fever disappeared within 48 h in all these MR patients. There were no differences between MR patients who demonstrated a reduction in fever and those in whom fever persisted after 48 h of macrolide treatment.

CONCLUSIONS

The microbiological and clinical efficacies of macrolides for treating patients with MR M. pneumoniae pneumonia were low. These results show that macrolides are clearly less effective in patients with MR M. pneumoniae pneumonia.

Neomacrolides in the treatment of patients with severe asthma and/or bronchiectasis: a retrospective observational study

RATIONALE

Previous studies have demonstrated that long-term low-dose macrolides are efficacious in cystic fibrosis (CF) and diffuse panbronchiolitis, two chronic neutrophilic airway diseases.

AIMS

The aims of this study were to evaluate the efficacy and safety of low-dose neomacrolides as add-on therapy in patients with severe asthma and/or bronchiectasis and to identify predictors for therapeutic response.

METHODS

In a retrospective observational cohort study, we examined 131 adult, non-CF patients with severe asthma and/or bronchiectasis, receiving low-dose neomacrolides as add-on treatment. Pulmonary function tests and symptom scores were assessed at baseline and after 3 to 8 weeks of therapy.

RESULTS

After 3-8 weeks of treatment with low-dose neomacrolides, 108 patients were available for evaluation. In asthma patients (n = 47), pulmonary function tests and symptom scores improved significantly. Responders (≥7% forced expiratory volume in one second predicted [FEV(1)%] improvement) were older (55 vs. 47 years; p = 0.042) and had a longer duration of asthma (29 vs. 9 years; p = 0.052). In patients with bronchiectasis only (n = 61), symptom scores improved significantly. Responders (≥60% symptom score improvement) were older (61 vs. 53 years; p = 0.004), more frequently male (53% vs. 27%; p = 0.043), and there was a nonsignificant trend towards higher high-resolution CT (HRCT) score for bronchiectasis in responders (6.4 vs. 4.6; p = 0.053). In multivariate logistic regression analysis, age and male gender were independent predictors for improvement in this group.

CONCLUSION

The results of this retrospective study suggest that neomacrolides may be useful as an add-on therapy in patients with severe asthma and/or bronchiectasis. Older age may predict good response in patients with severe asthma, whereas older age, male gender and a higher HRCT score for bronchiectasis may predict therapeutic response in patients with bronchiectasis only. Prospective controlled trials of neomacrolides in patients with severe asthma are needed to confirm these observations.

Evaluation and management of pulmonary disease in ataxia-telangiectasia

Ataxia-telangiectasia (A-T) is a rare autosomal recessive disorder caused by mutations in the ATM gene, resulting in faulty repair of breakages in double-stranded DNA. The clinical phenotype is complex and is characterized by neurologic abnormalities, immunodeficiencies, susceptibility to malignancies, recurrent sinopulmonary infections, and cutaneous abnormalities. Lung disease is common in patients with A-T and often progresses with age and neurological decline. Diseases of the respiratory system cause significant morbidity and are a frequent cause of death in the A-T population. Lung disease in this population is thought to exhibit features of one or more of the following phenotypes: recurrent sinopulmonary infections with bronchiectasis, interstitial lung disease, and lung disease associated with neurological abnormalities. Here, we review available evidence and present expert opinion on the diagnosis, evaluation, and management of lung disease in A-T, as discussed in a recent multidisciplinary workshop. Although more data are emerging on this unique population, many recommendations are made based on similarities to other more well-studied diseases. Gaps in current knowledge and areas for future research in the field of pulmonary disease in A-T are also outlined.

Azithromycin paradox in the treatment of cystic fibrosis airway disease

Evaluation of: Saiman L, Anstead M, Mayer-Hamblett N et al.: Effect of azithromycin on pulmonary function in patients with cystic fibrosis uninfected with Pseudomonas aeruginosa: a randomized controlled trial. JAMA 303(17), 1707–1715 (2010). Chronic airway infection and inflammation are hallmarks of cystic fibrosis (CF). Disease progression can be described as chronic inflammation punctuated by acute exacerbations with overt immunological responses. Macrolide antibiotics, which have both immunomodulatory and antibacterial activities, have been shown to be beneficial in the management of CF airway disease, although the mechanism of action is unknown. It is also unclear whether all patients, particularly those not colonized with Pseudomonas aeruginosa, benefit from this treatment. In this article, Saiman et al. examine the effects of azithromycin on lung function in pediatric and adolescent CF patients who are not colonized with P. aeruginosa. The data indicate beneficial effects of azithromycin treatment and suggest the mechanisms of action of azithromycin is at least partially independent of P. aeruginosa.

Efficacy of periprosthetic erythromycin delivery for wear debris-induced inflammation and osteolysis

OBJECTIVES

We have reported that oral erythromycin (EM) inhibits periprosthetic tissue inflammation in a group of patients with aseptic loosening. The purpose of this study was to assess the efficacy of local, periprosthetic EM delivery in a rat model.

METHODS

Uncoated Ti pins were press-fit into the right tibia of fourteen Sprague-Dawley rats following an intramedullar injection of UHMWPE (ultra high molecular weight polyethylene) particles. Revision surgeries were performed 2 months after the primary surgery. EM was applied to the Peri-Apatite™ (PA) layer of the titanium (Ti) pins. The previously implanted Ti pins were withdrawn and replaced with Ti pins coated either with (n = 7) or without (n = 7) EM. The rats were killed 1 month after "revision surgery". The EM efficacy was evaluated by (MicroCT) μCT and histology.

RESULTS

μCT analysis showed that bone volume percentage (BV/TV) was significantly higher in the EM-treated group compared to the untreated group (p < 0.05). Histological analysis showed that EM treatment inhibits UHMWPE particle-induced periprosthetic tissue inflammation compared to the untreated group.

CONCLUSION

This study demonstrated that periprosthetic EM delivery reduced periprosthetic inflammation and improved the quality of surrounding bone.

Azithromycin attenuates airway inflammation in a mouse model of viral bronchiolitis

Background

Viral bronchiolitis is the leading cause of hospitalization in young infants. It is associated with the development of childhood asthma and contributes to morbidity and mortality in the elderly. Currently no therapies effectively attenuate inflammation during the acute viral infection, or prevent the risk of post-viral asthma. We hypothesized that early treatment of a paramyxoviral bronchiolitis with azithromycin would attenuate acute and chronic airway inflammation.

Methods

Mice were inoculated with parainfluenza type 1, Sendai Virus (SeV), and treated daily with PBS or azithromycin for 7 days post-inoculation. On day 8 and 21 we assessed airway inflammation in lung tissue, and quantified immune cells and inflammatory mediators in bronchoalveolar lavage (BAL).

Results

Compared to treatment with PBS, azithromycin significantly attenuated post-viral weight loss. During the peak of acute inflammation (day 8), azithromycin decreased total leukocyte accumulation in the lung tissue and BAL, with the largest fold-reduction in BAL neutrophils. This decreased inflammation was independent of changes in viral load. Azithromycin significantly attenuated the concentration of BAL inflammatory mediators and enhanced resolution of chronic airway inflammation evident by decreased BAL inflammatory mediators on day 21.

Conclusions

In this mouse model of paramyxoviral bronchiolitis, azithromycin attenuated acute and chronic airway inflammation. These findings demonstrate anti-inflammatory effects of azithromycin that are not related to anti-viral activity. Our findings support the rationale for future prospective randomized clinical trials that will evaluate the effects of macrolides on acute viral bronchiolitis and their long-term consequences.

Cystic fibrosis

Cystic fibrosis is the most common lethal genetic disease in white populations. The outlook for patients with the disease has improved steadily over many years, largely as a result of earlier diagnosis, more aggressive therapy, and provision of care in specialised centres. Researchers now have a more complete understanding of the molecular-biological defect that underlies cystic fibrosis, which is leading to new approaches to treatment. One of these treatments, hypertonic saline, is already in use, whereas others are in advanced stages of development. We review clinical care for cystic fibrosis and discuss recent advances in the understanding of its pathogenesis, implementation of screening of neonates, and development of therapies aimed at treating the basic defect.

Azithromycin attenuates airway inflammation in a noninfectious mouse model of allergic asthma

BACKGROUND

Definitive conclusions regarding the antiinflammatory effects of macrolide antibiotics for treatment of asthma are difficult to formulate since their beneficial effects may be related to their antimicrobial action. We hypothesized that azithromycin possesses distinct antiinflammatory properties and tested this assumption in a noninfectious mouse model of allergic asthma.

METHODS

To induce allergic airway inflammation, 7-week-old BALB/cJ mice underwent intraperitoneal ovalbumin sensitization on days 0 and 7 followed by an intranasal challenge on day 14. Mice were treated with azithromycin or phosphate-buffered saline (PBS) solution on days 13 through 16. On day 17, airway inflammation was assessed by quantifying leukocytes in the airway, expression of multiple inflammatory mediators in the BAL fluid, and mucous cell metaplasia. In a separate set of experiments, azithromycin or PBS solution treatment were initiated after the ovalbumin challenge. Each experiment was repeated 3 times (a total of 9 to 11 mice in each group).

RESULTS

Compared to treatment with PBS solution, azithromycin attenuated the ovalbumin-dependent airway inflammation. We observed a decrease in total leukocytes in the lung tissue and BAL fluid. In addition, azithromycin attenuated the expression of cytokines (eg, interleukin [IL]-13 and IL-5) and chemokines (eg, CCL2, CCL3, and CCL4) in the BAL fluid and abrogated the extent of mucous cell metaplasia. Similar antiinflammatory effects were observed when azithromycin treatment was initiated after the ovalbumin challenge.

CONCLUSION

In this noninfectious mouse model of allergic asthma, azithromycin attenuated allergic airway inflammation. These findings demonstrate an antiinflammatory effect of azithromycin and suggest azithromycin may have beneficial effects in treating noninfectious airway inflammatory diseases, including asthma.

Effect of oral erythromycin therapy in patients with aseptic loosening of joint prostheses

There is currently no cure for aseptic loosening (AL) of total joint replacement (TJR) except surgical revision. The purpose of this study was to determine whether oral EM could improve the periprosthetic tissue profiles and reduce serum cytokine production in AL patients who are candidates for surgical revision. We recruited 32 AL patients. AL patients were treated with either EM (600 mg/day, n=18) or placebo (n=14) daily, started one month before surgery and ending on the day of surgery. Blood samples were obtained before EM treatment and during surgery. Periprosthetic tissues and joint fluids were collected during surgery. Our results demonstrate that oral EM reduces the inflammation of periprosthetic tissues, as manifested by the reduction of the numbers of infiltrating cells, CD68+ macrophages, RANKL+ cells, and TRAP+ cells. Remarkable decreases of TNFalpha (9.6-fold), IL-1beta (21.2-fold), and RANKL (76-fold) gene transcripts were observed in periprosthetic tissues of patients treated with oral EM. Serum levels of both TNFalpha and (to a lesser extent) IL-1beta were significantly reduced following EM treatment (p<0.05). Our results suggest that EM represents a biological cure or prevention for those patients who might need repeated revision surgeries and/or show the early signs of progressive osteolysis after TJR.

Cystic fibrosis lung disease in adult patients

As the longevity of all patients with cystic fibrosis (CF) continues to increase (median 2005 survival=36.8 years), more adult patients will be receiving their medical care from nonpediatric adult-care providers. Cystic fibrosis remains a fatal disease, with more than 80% of patients dying after the age of 18 years, and most deaths resulting from pulmonary disease. The changing epidemiology requires adult-care providers to become knowledgeable and competent in the clinical management of adults with CF. Physicians must understand the influence of specific genotype on phenotypic disease presentation and severity, the pathogenic factors determining lung disease onset and progression, the impact of comorbid disease factors such as CF-related diabetes and malnutrition upon lung disease severity, and the currently approved or standard accepted therapies used for chronic management of CF lung disease. This knowledge is critical to help alleviate morbidity and improve mortality for the rapidly expanding population of adults with CF.

Management of chronic cough

Cough that remains unexplained after basic clinical assessment is a common reason for referral to secondary care. Much of the evidence about management of isolated chronic cough is derived from case series; this evidence suggests that isolated chronic cough is usually due to asthma, gastro-oesophageal reflux disease, and upper airway conditions, and that it can be cured in most people by treatment of these conditions. However, there is increasing recognition that satisfactory control of chronic cough is not achieved in a substantial number of patients seen in secondary care. Moreover, there is a concern that perpetuation of the belief that chronic cough is solely due to the effects of comorbid conditions is inhibiting research into the pathophysiology of an abnormally heightened cough reflex, and jeopardising development of improved treatments. We advocate a change in emphasis, which makes a clear distinction between cough due to corticosteroid-responsive eosinophilic airway diseases and corticosteroid-resistant non-eosinophilic cough. We recommend that some factors with weak evidence of an association with cough are best viewed as potential aggravating factors of an intrinsic abnormality of the cough reflex, rather than the cause. We call for more research into the basic mechanisms and pharmacological control of an abnormally heightened cough reflex, and recommend ways to assess the effects of potentially antitussive treatments.

Immunomodulatory effects of erythromycin and its derivatives on human T-lymphocyte in vitro

To elucidate the immunomodulatory mechanisms of macrolides, we investigated here the effects of erythromycin (EM) and its derivatives, 1 and 2, which show no antibacterial activity, on the proliferation and the activation of the transcription factor nuclear factor-kappaB (NF-kappaB) in Jurkat T cells. MTT assay revealed that EM, 1 and 2 could inhibit T lymphocyte proliferation markedly. Flow cytometry and TUNEL analysis showed EM (30 microg/mL-100 microg/mL) and 1 (3 microg/mL-30 microg/mL) could induce T lymphocyte apoptosis, 2 (3 microg/mL-30 microg/mL) induced a cell cycle arrest in G(2)/M. RT-PCR and Western blotting analysis conformed that EM and its two derivatives could inhibit the expressions of NF-kappaB mRNA and protein. Taken together, these data suggest EM and its derivatives, 1 and 2, have immunomodulatory effect, presumably via an interaction with the NF-kappaB expression, inhibiting the proliferation of T lymphocyte, implicating an approach for the development of new drugs for treating inflammatory diseases.

Role of macrolide therapy in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a leading cause of death and disability worldwide. The Global Burden of Disease study has concluded that COPD will become the third leading cause of death worldwide by 2020, and will increase its ranking of disability-adjusted life years lost from 12th to 5th. Acute exacerbations of COPD (AECOPD) are associated with impaired quality of life and pulmonary function. More frequent or severe AECOPDs have been associated with especially markedly impaired quality of life and a greater longitudinal loss of pulmonary function. COPD and AECOPDs are characterized by an augmented inflammatory response. Macrolide antibiotics are macrocyclical lactones that provide adequate coverage for the most frequently identified pathogens in AECOPD and have been generally included in published guidelines for AECOPD management. In addition, they exert broad-ranging, immunomodulatory effects both in vitro and in vivo, as well as diverse actions that suppress microbial virulence factors. Macrolide antibiotics have been used to successfully treat a number of chronic, inflammatory lung disorders including diffuse panbronchiolitis, asthma, noncystic fibrosis associated bronchiectasis, and cystic fibrosis. Data in COPD patients have been limited and contradictory but the majority hint to a potential clinical and biological effect. Additional, prospective, controlled data are required to define any potential treatment effect, the nature of this effect, and the role of bronchiectasis, baseline colonization, and other cormorbidities.

Suppression of oxidant-induced glutathione synthesis by erythromycin in human bronchial epithelial cells

BACKGROUND

Macrolide antibiotics have anti-inflammatory effects which are utilized for the treatment of chronic inflammatory airway diseases. Recently, their anti-inflammatory effects have been proposed to be beneficial in patients with chronic obstructive pulmonary disease (COPD).

OBJECTIVES

Since the molecular mechanisms of anti-inflammatory effects are associated with inhibition of activator protein 1 (AP-1) and nuclear factor (NF)-kappaB, and both are reported to be involved in the expression of gamma-glutamylcysteine synthetase (gamma-GCS), we set out to determine if these drugs influence the oxidant-antioxidant balance in human bronchial epithelial (HBE) cells.

METHODS

16HBE cells were preincubated with erythromycin (EM) at different concentrations and times and then exposed to hydrogen peroxide (0.01 mM). Levels of interleukin (IL)-8 and glutathione (GSH), and activity of gamma-GCS and gamma-GCS heavy subunit (gamma-GCS-HS) protein production were assayed. AP-1 and NF-kappaB binding to the 5'-flanking region of IL-8 and gamma-GCS-HS genes was assessed by electrophoretic mobility-shift assay.

RESULTS

The increase in IL-8 levels and activity of AP-1 induced by H(2)O(2) were abrogated by preincubation of the cells with EM (5 mug/ml) for 36 h. We also showed that preincubation with EM for 48 h inhibited H(2)O(2)-induced GSH levels, gamma-GCS activity and expression of gamma-GCS-HS, and decreased AP-1 binding to the gamma-GCS-HS 5'-flanking region.

CONCLUSIONS

The confirmation of antioxidants maintaining enzyme suppression by EM raised concerns on whether this drug could disrupt the oxidant/ antioxidant balance during long-term use. These data provide important insights into the treatment of inflammatory lung diseases with macrolide antibiotics.

Cystic fibrosis pulmonary guidelines: chronic medications for maintenance of lung health

RATIONALE

Cystic fibrosis is a recessive genetic disease characterized by dehydration of the airway surface liquid and impaired mucociliary clearance. As a result, individuals with the disease have difficulty clearing pathogens from the lung and experience chronic pulmonary infections and inflammation. Death is usually a result of respiratory failure. Newly introduced therapies and aggressive management of the lung disease have resulted in great improvements in length and quality of life, with the result that the median expected survival age has reached 36 years. However, as the number of treatments expands, the medical regimen becomes increasingly burdensome in time, money, and health resources. Hence, it is important that treatments should be recommended on the basis of available evidence of efficacy and safety.

OBJECTIVES

The Cystic Fibrosis Foundation therefore established a committee to examine the clinical evidence for each therapy and to provide guidance for the prescription of these therapies.

METHODS

The committee members developed and refined a series of questions related to drug therapies used in the maintenance of pulmonary function. We addressed the questions in one of three ways, based on available evidence: (1) commissioned systematic review, (2) modified systematic review, or (3) summary of existing Cochrane reviews.

CONCLUSIONS

It is hoped that the guidelines provided in this article will facilitate the appropriate application of these treatments to improve and extend the lives of all individuals with cystic fibrosis.

Noneosinophilic asthma: A distinct clinical and pathologic phenotype

The use of induced sputum to assess airway inflammation in large and diverse populations with asthma has led to the recognition that significant numbers of patients do not have evidence of eosinophilic airway inflammation. The absence of a sputum eosinophilia has been noted in patients across the range of asthma severity; it has also been reported in patients presenting with an asthma exacerbation. However, whether noneosinophilic asthma represents a pathologically distinct and clinically important asthma phenotype remains unclear. In this review, we present recent evidence suggesting that noneosinophilic asthma represents a stable phenotype associated with a distinct lower airway pathology and structure. We suggest that this lower airway inflammation develops in response to etiologic factors acting through the innate immune pathway and that elements of this immune response contribute to airway dysfunction. Finally, we argue that noneosinophilic asthma is associated with clinically important differences in natural history and treatment response. We particularly highlight evidence that noneosinophilic asthma is associated with a reduced short-term and long-term response to corticosteroid therapy.

Azithromycin reduces spontaneous and induced inflammation in DeltaF508 cystic fibrosis mice

Background

Inflammation plays a critical role in lung disease development and progression in cystic fibrosis. Azithromycin is used for the treatment of cystic fibrosis lung disease, although its mechanisms of action are poorly understood. We tested the hypothesis that azithromycin modulates lung inflammation in cystic fibrosis mice.

Methods

We monitored cellular and molecular inflammatory markers in lungs of cystic fibrosis mutant mice homozygous for the ΔF508 mutation and their littermate controls, either in baseline conditions or after induction of acute inflammation by intratracheal instillation of lipopolysaccharide from Pseudomonas aeruginosa, which would be independent of interactions of bacteria with epithelial cells. The effect of azithromycin pretreatment (10 mg/kg/day) given by oral administration for 4 weeks was evaluated.

Results

In naive cystic fibrosis mice, a spontaneous lung inflammation was observed, characterized by macrophage and neutrophil infiltration, and increased intra-luminal content of the pro-inflammatory cytokine macrophage inflammatory protein-2. After induced inflammation, cystic fibrosis mice combined exaggerated cellular infiltration and lower anti-inflammatory interleukin-10 production. In cystic fibrosis mice, azithromycin attenuated cellular infiltration in both baseline and induced inflammatory condition, and inhibited cytokine (tumor necrosis factor-α and macrophage inflammatory protein-2) release in lipopolysaccharide-induced inflammation.

Conclusion

Our findings further support the concept that inflammatory responses are upregulated in cystic fibrosis. Azithromycin reduces some lung inflammation outcome measures in cystic fibrosis mice. We postulate that some of the benefits of azithromycin treatment in cystic fibrosis patients are due to modulation of lung inflammation.

Stress oxydatif et BPCO. Rôle des infections. Prévention

For the next decade, COPD will become the third cause of mortality in the world. COPD is mainly due to cigarette smoking and presents different levels of severity according to people, probably linked to environmental and genetic factors, which are not well documented. Recent publications pointed out bacterial bronchial colonization and exacerbations of infectious origin as worsening factors through a pro-inflammatory effect and oxidative stress. This should lead to a comprehensive review of anti-infectious prevention tools and to discuss the role of prophylactic antibiotherapy and antioxidants.

Clinical evaluation of macrolide-resistant Mycoplasma pneumoniae

Macrolide-resistant Mycoplasma pneumoniae (MR M. pneumoniae) has been isolated from clinical specimens in Japan since 2000. A comparative study was carried out to determine whether or not macrolides are effective in treating patients infected with MR M. pneumoniae. The clinical courses of 11 patients with MR M. pneumoniae infection (MR patients) treated with macrolides were compared with those of 26 patients with macrolide-susceptible M. pneumoniae infection (MS patients). The total febrile days and the number of febrile days during macrolide administration were longer in the MR patients than in the MS patients (median of 8 days versus median of 5 days [P = 0.019] and 3 days versus 1 day [P = 0.002], respectively). In addition, the MR patients were more likely than the MS patients to have had a change of the initially prescribed macrolide to another antimicrobial agent (63.6% versus 3.8%; odds ratio, 43.8; P < 0.001), which might reflect the pediatrician's judgment that the initially prescribed macrolide was not sufficiently effective in these patients. Despite the fact that the febrile period was prolonged in MR patients given macrolides, the fever resolved even when the initial prescription was not changed. These results show that macrolides are certainly less effective in MR patients.

Neutrophil survival-enhancing activity in sputum from patients with diffuse panbronchiolitis

Diffuse panbronchiolitis (DPB) is a life-threatening airway disease in which neutrophils persistently and massively emigrating to the airways cause progressive and irreversible tissue damage. However, the pathogenesis of the airway inflammation remains unclear. The failure of non-inflammatory removal of emigrating neutrophils due to delayed apoptosis has been proposed as a mechanism by which the neutrophilic inflammation persists. Therefore, we aimed to investigate whether an activity that delays neutrophil apoptosis is present at the inflamed sites in DPB. Neutrophils isolated from normal volunteers were cultured with sputum extracts of patients with DPB, and viability and apoptosis of neutrophil was evaluated for the culture period. Neutrophils cultured with sputum extracts for 2 and 3 days showed significantly enhanced survival compared to those with medium alone. The neutrophil survival-enhancing activity in sputum extracts was heat-labile and partially, but significantly, neutralized with anti-human GM-CSF, but not with anti-human G-CSF antibody. The enhancement of neutrophil survival was associated with an inhibition of apoptosis demonstrated by cytology, TUNEL assay and DNA fragmentation analysis. These results suggest that neutrophil apoptosis is prevented by survival-enhancing factors including GM-CSF in the airways of DPB, leading to neutrophil death by necrosis that causes further recruitment and activation of neutrophils.

Antiinflammatory Therapies for Cystic Fibrosis: Past, Present, and Future

Inflammation is a major component of the vicious cycle characterizing cystic fibrosis pulmonary disease. If untreated, this inflammatory process irreversibly damages the airways, leading to bronchiectasis and ultimately respiratory failure. Antiinflammatory drugs for cystic fibrosis lung disease appear to have beneficial effects on disease parameters. These agents include oral corticosteroids and ibuprofen, as well as azithromycin, which, in addition to its antimicrobial effects, also possesses antiinflammatory properties. Inhaled corticosteroids, colchicine, methotrexate, montelukast, pentoxifylline, nutritional supplements, and protease replacement have not had a significant impact on the disease. Therapy with oral corticosteroids, ibuprofen, and fish oil is limited by adverse effects. Azithromycin appears to be safe and effective, and is thus the most promising antiinflammatory therapy available for patients with cystic fibrosis. Pharmacologic therapy with antiinflammatory agents should be started early in the disease course, before extensive irreversible lung damage has occurred.

Improved lung function and body mass index associated with long-term use of Macrolide antibiotics

BACKGROUND

A number of studies have suggested that the non-antimicrobial actions of macrolide antibiotics may be valuable in treating patients with cystic fibrosis. The use of long-term macrolide antibiotics for the management of CF patients colonised by Pseudomonas aeruginosa and progressive pulmonary disease was introduced into our clinic in 1997. A retrospective study was undertaken to assess of the impact of this therapy.

METHODS

Twenty patients with progressive pulmonary disease (>10% fall in FEV(1) over 12 months despite optimising conventional therapy) were commenced on Azithromycin, 250 mg daily during a 21-month period. At the time of assessment they had remained on therapy for a mean of 0.9 years. Changes in lung function, weight, body mass index (BMI) and frequency of pulmonary exacerbations were assessed. A group of 20 patients with stable lung function and matched as far as possible for age and sex was identified for comparison.

RESULTS

Pulmonary function increased significantly in the Azithromycin group with FEV1% predicted increasing from a mean of 50.2-59.1% (P=0.001) while FVC% predicted increase from 64.5 to 76.1% (P=0.002). There was small but non-significant fall in lung function in the comparison group. Body mass index increased by a mean of 1.1 in the Azithromycin group but remained unchanged in the comparison group. The number of pulmonary exacerbations requiring intravenous antibiotics declined by 48.3% in macrolide treated subjects compared to the pre-treatment period (P<0.025); frequency of exacerbations in the control group was unchanged.

CONCLUSION

Long-term Azithromycin treatment in patients with progressive deterioration in lung function appears to have led to an improvement in pulmonary function, increased body mass index and decreased the frequency of pulmonary exacerbations requiring intravenous antibiotics.

Is otitis media with effusion a biofilm infection?

Recent attention has focused on the possibility that otitis media with effusion (OME) may represent a chronic infective state such as those evidenced in conditions secondary to biofilms or small colony variants. This review discusses the evidence suggesting that this may indeed be the case and explains why this may prove to be important in the future management of this condition by discussing recent advances in understanding these bacterial phenotypic variants.

Pathophysiology and management of pulmonary infections in cystic fibrosis

This comprehensive State of the Art review summarizes the current published knowledge base regarding the pathophysiology and microbiology of pulmonary disease in cystic fibrosis (CF). The molecular basis of CF lung disease including the impact of defective cystic fibrosis transmembrane regulator (CFTR) protein function on airway physiology, mucociliary clearance, and establishment of Pseudomonas aeruginosa infection is described. An extensive review of the microbiology of CF lung disease with particular reference to infection with P. aeruginosa is provided. Other pathogens commonly associated with CF lung disease including Staphylococcal aureus, Burkholderia cepacia, Stenotrophomonas maltophilia, Achromobacter xylosoxidans and atypical mycobacteria are also described. Clinical presentation and assessment of CF lung disease including diagnostic microbiology and other measures of pulmonary health are reviewed. Current recommendations for management of CF lung disease are provided. An extensive review of antipseudomonal therapies in the settings of treatment for early P. aeruginosa infection, maintenance for patients with chronic P. aeruginosa infection, and treatment of exacerbation in pulmonary symptoms, as well as antibiotic therapies for other CF respiratory pathogens, are included. In addition, the article discusses infection control policies, therapies to optimize airway clearance and reduce inflammation, and potential future therapies.

Tissue reparative effects of macrolide antibiotics in chronic inflammatory sinopulmonary diseases

It is well established that macrolide antibiotics are efficacious in treating sinopulmonary infections in humans. However, a growing body of experimental and clinical evidence indicates that they also express distinct salutary effects that promote and sustain the reparative process in the chronically inflamed upper and lower respiratory tract. Unlike the anti-infective properties, these distinct effects are manifested at lower doses, usually after a relatively prolonged period (weeks) of treatment, and in the absence of an identifiable, viable pathogen. Long-term, low-dose administration of macrolide antibiotics has been used most commonly for sinusitis, diffuse panbronchiolitis, asthma, bronchiectasis, and cystic fibrosis. It is associated with down-regulation of nonspecific host inflammatory response to injury and promotion of tissue repair. Although large-scale trials are lacking, the prolonged use of these drugs has not been associated with emergence of clinically significant bacterial resistance or immunosuppression. Long-term, low-dose administration of 14- and 15-membered ring macrolide antibiotics may represent an important adjunct in the treatment of chronic inflammatory sinopulmonary diseases in humans.

Use of modulators of airways inflammation in patients with CF

One of the hallmarks of cystic fibrosis (CF) lung disease is the presence of intense, neutrophil-dominated airway inflammation, and many researchers have focused on developing therapies to reduce inflammation in CF lung disease. Systemic corticosteroids can delay progression of lung disease, but at the cost of unacceptable side effects. Inhaled corticosteroids are widely used, but their efficacy has yet to be demonstrated in a controlled fashion. Ibuprofen has also been shown to delay disease progression, but its use has been limited by the need to obtain individual pharmacokinetics and concern about side effects. Other treatments with potential anti-inflammatory effects include pentoxifylline, leukotriene antagonists, docosahexaenoic acid, and azithromycin. Few, if any, large clinical studies of these therapies have been published, but several are presently underway. Because neutrophil elastase appears to be a key mediator of tissue damage in CF lung disease, anti-elastase compounds have also been studied, including alpha-1-protease inhibitor, secretory leukocyte protease inhibitor, and small molecule inhibitors. There have been no large-scale controlled trials of these therapies in CF. More recently, investigators have focused on cytokine modulation, using either interleukin-10 or interferon gamma. Some complementary and alternative medicine therapies may also have anti-inflammatory effects, although their clinical value has yet to be demonstrated in a rigorously-controlled fashion. In summary, numerous anti-inflammatory therapies have been applied to CF lung disease, but more large, well-controlled studies will need to be performed to determine their true clinical usefulness.

Clinical relevance of macrolide-resistant Streptococcus pneumoniae for community-acquired pneumonia

Macrolides are often the first choice for empirical treatment of community-acquired pneumonia. However, macrolide resistance among Streptococcus pneumoniae has escalated at alarming rates in North America and worldwide. Macrolide resistance among pneumococci is primarily due to genetic mutations affecting the ribosomal target site (ermAM) or active drug efflux (mefE). Prior antibiotic exposure is the major risk factor for amplification and perpetuation of resistance. Clonal spread facilitates dissemination of drug-resistant strains. Data assessing the impact of macrolide resistance on clinical outcomes are spare. Many experts believe that the clinical impact is limited. Ribosomal mutations confer high-grade resistance, whereas efflux mutations can likely be overridden in vivo. Favorable pharmacokinetics and pharmacodynamics, high concentrations at sites of infections, and additional properties of macrolides may enhance their efficacy. In this article, we discuss the prevalence of macrolide resistance among S. pneumoniae, risk factors and mechanisms responsible for resistance, therapeutic strategies, and implications for the future.