Long-term Azithromycin Treatment Research Articles

Sputum bacterial load and bacterial composition correlate with lung function and are altered by long-term azithromycin treatment in children with HIV-associated chronic lung disease

BackgroundLong-term azithromycin (AZM) treatment reduces the frequency of acute respiratory exacerbation in children and adolescents with HIV-associated chronic lung disease (HCLD). However, the impact of this treatment on the respiratory bacteriome is unknown.MethodAfrican children with HCLD (defined as forced expiratory volume in 1 s z-score (FEV1z) less than − 1.0 with no reversibility) were enrolled in a placebo-controlled trial of once-weekly AZM given for 48-weeks (BREATHE trial). Sputum samples were collected at baseline, 48 weeks (end of treatment) and 72 weeks (6 months post-intervention in participants who reached this timepoint before trial conclusion). Sputum bacterial load and bacteriome profiles were determined using 16S rRNA gene qPCR and V4 region amplicon sequencing, respectively. The primary outcomes were within-participant and within-arm (AZM vs placebo) changes in the sputum bacteriome measured across baseline, 48 weeks and 72 weeks. Associations between clinical or socio-demographic factors and bacteriome profiles were also assessed using linear regression.ResultsIn total, 347 participants (median age: 15.3 years, interquartile range [12.7–17.7]) were enrolled and randomised to AZM (173) or placebo (174). After 48 weeks, participants in the AZM arm had reduced sputum bacterial load vs placebo arm (16S rRNA copies/µl in log10, mean difference and 95% confidence interval [CI] of AZM vs placebo − 0.54 [− 0.71; − 0.36]). Shannon alpha diversity remained stable in the AZM arm but declined in the placebo arm between baseline and 48 weeks (3.03 vs. 2.80, p = 0.04, Wilcoxon paired test). Bacterial community structure changed in the AZM arm at 48 weeks compared with baseline (PERMANOVA test p = 0.003) but resolved at 72 weeks. The relative abundances of genera previously associated with HCLD decreased in the AZM arm at 48 weeks compared with baseline, including Haemophilus (17.9% vs. 25.8%, p < 0.05, ANCOM ω = 32) and Moraxella (1% vs. 1.9%, p < 0.05, ANCOM ω = 47). This reduction was sustained at 72 weeks relative to baseline. Lung function (FEV1z) was negatively associated with bacterial load (coefficient, [CI]: − 0.09 [− 0.16; − 0.02]) and positively associated with Shannon diversity (0.19 [0.12; 0.27]). The relative abundance of Neisseria (coefficient, [standard error]: (2.85, [0.7], q = 0.01), and Haemophilus (− 6.1, [1.2], q < 0.001) were positively and negatively associated with FEV1z, respectively. An increase in the relative abundance of Streptococcus from baseline to 48 weeks was associated with improvement in FEV1z (3.2 [1.11], q = 0.01) whilst an increase in Moraxella was associated with decline in FEV1z (-2.74 [0.74], q = 0.002).ConclusionsAZM treatment preserved sputum bacterial diversity and reduced the relative abundances of the HCLD-associated genera Haemophilus and Moraxella. These bacteriological effects were associated with improvement in lung function and may account for reduced respiratory exacerbations associated with AZM treatment of children with HCLD.7vbprNKyGgPWNKm5AZ24DEVideo

Genetic Adaptation and Acquisition of Macrolide Resistance in Haemophilus spp. during Persistent Respiratory Tract Colonization in Chronic Obstructive Pulmonary Disease (COPD) Patients Receiving Long-Term Azithromycin Treatment.

Patients with chronic obstructive pulmonary disease (COPD) benefit from the immunomodulatory effect of azithromycin, but long-term administration may alter colonizing bacteria. Our goal was to identify changes in Haemophilus influenzae and Haemophilus parainfluenzae during azithromycin treatment. Fifteen patients were followed while receiving prolonged azithromycin treatment (Hospital Universitari de Bellvitge, Spain). Four patients (P02, P08, P11, and P13) were persistently colonized by H. influenzae for at least 3 months and two (P04 and P11) by H. parainfluenzae. Isolates from these patients (53 H. influenzae and 18 H. parainfluenzae) were included to identify, by whole-genome sequencing, antimicrobial resistance changes and genetic variation accumulated during persistent colonization. All persistent lineages isolated before treatment were azithromycin-susceptible but developed resistance within the first months, apart from those belonging to P02, who discontinued the treatment. H. influenzae isolates from P08-ST107 acquired mutations in 23S rRNA, and those from P11-ST2480 and P13-ST165 had changes in L4 and L22. In H. parainfluenzae, P04 persistent isolates acquired changes in rlmC, and P11 carried genes encoding MefE/MsrD efflux pumps in an integrative conjugative element, which was also identified in H. influenzae P11-ST147. Other genetic variation occurred in genes associated with cell wall and inorganic ion metabolism. Persistent H. influenzae strains all showed changes in licA and hgpB genes. Other genes (lex1, lic3A, hgpC, and fadL) had variation in multiple lineages. Furthermore, persistent strains showed loss, acquisition, or genetic changes in prophage-associated regions. Long-term azithromycin therapy results in macrolide resistance, as well as genetic changes that likely favor bacterial adaptation during persistent respiratory colonization. IMPORTANCE The immunomodulatory properties of azithromycin reduce the frequency of exacerbations and improve the quality of life of COPD patients. However, long-term administration may alter the respiratory microbiota, such as Haemophilus influenzae, an opportunistic respiratory colonizing bacteria that play an important role in exacerbations. This study contributes to a better understanding of COPD progression by characterizing the clinical evolution of H. influenzae in a cohort of patients with prolonged azithromycin treatment. The emergence of macrolide resistance during the first months, combined with the role of Haemophilus parainfluenzae as a reservoir and source of resistance dissemination, is a cause for concern that may lead to therapeutic failure. Furthermore, genetic variations in cell wall and inorganic ion metabolism coding genes likely favor bacterial adaptation to host selective pressures. Therefore, the bacterial pathoadaptive evolution in these severe COPD patients raise our awareness of the possible spread of macrolide resistance and selection of host-adapted clones.

Sputum TNF markers are increased in neutrophilic and severe asthma and are reduced by azithromycin treatment.

The AMAZES randomized controlled trial demonstrated that long-term low-dose azithromycin treatment reduces exacerbations of poorly controlled asthma, but the therapeutic mechanisms remain unclear. Dysregulation of the inflammatory tumour necrosis factor (TNF) pathway is implicated in asthma and could be suppressed by azithromycin. We aimed to determine the inflammatory and clinical associations of soluble TNF signalling proteins (TNF receptors [TNFR] 1 and 2, TNF) in sputum and serum, and to test the effect of 48weeks of azithromycin vs placebo on TNF markers. Sputum supernatant and serum TNFR1, TNFR2 (n=142; 75 azithromycin-treated, 67 placebo-treated) and TNF (n=48; 22 azithromycin-treated, 26 placebo-treated) were measured by ELISA in an AMAZES trial sub-population at baseline and end of treatment. Baseline levels were compared between sputum inflammatory phenotypes, severe/non-severe asthma and frequent/non-frequent exacerbators. Effect of azithromycin on markers was tested using linear mixed models. Baseline sputum TNFR1 and TNFR2 were significantly increased in neutrophilic vs non-neutrophilic asthma phenotypes, while serum markers did not differ. Sputum TNFR1 and TNFR2 were increased in severe asthma and correlated with poorer lung function, worse asthma control and increasing age. Serum TNFR1 was also increased in severe asthma. Sputum and serum TNFR2 were increased in frequent exacerbators. Azithromycin treatment significantly reduced sputum TNFR2 and TNF relative to placebo, specifically in non-eosinophilic participants. We demonstrate dysregulation of TNF markers, particularly in the airways, that relates to clinically important phenotypes of asthma including neutrophilic and severe asthma. Suppression of dysregulated TNF signalling by azithromycin could contribute to its therapeutic mechanism.

Favorable Response to Long-Term Azithromycin Therapy in Bronchiectasis Patients with Chronic Airflow Obstruction Compared to Chronic Obstructive Pulmonary Disease Patients without Bronchiectasis.

PurposeLong-term macrolide treatment is recommended for patients with chronic obstructive pulmonary disease (COPD) with frequent exacerbations. Bronchiectasis is a common comorbid condition in patients with COPD, for which long-term azithromycin is effective in preventing exacerbation. This study aimed to compare the effect of long-term azithromycin between bronchiectasis patients with chronic airflow obstruction (CAO) and COPD patients without bronchiectasis.Patients and MethodsPatients with CAO who received azithromycin for more than 12 weeks were retrospectively identified at a single referral hospital. CAO was defined as a post-bronchodilator forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) <0.7, and bronchiectasis was determined using computed tomography. The development of exacerbation and symptom improvement were compared between bronchiectasis patients with CAO and COPD patients without bronchiectasis.ResultsA total of 59 patients (43 in bronchiectasis with CAO group vs 16 in COPD without bronchiectasis group) were included in this study. Compared to COPD patients without bronchiectasis, those in bronchiectasis with CAO group were younger, more likely to be female, and never smokers. There was no difference in the previous exacerbation history or FEV1 between the two groups. The median duration of azithromycin treatment was 15 months (interquartile range, 8–25 months). At the 12-month follow-up, the development of ≥2 moderate or ≥1 severe exacerbations was significantly lower in bronchiectasis with CAO group than in COPD without bronchiectasis group (46.5% vs 87.5%, P = 0.005). The proportion of patients with symptom improvement determined by the COPD assessment test score was also significantly higher in bronchiectasis with CAO group than COPD without bronchiectasis group at the 12-month follow-up (68.2% vs 16.7%, P = 0.004).ConclusionBronchiectasis patients with CAO could benefit more from long-term azithromycin treatment than COPD patients without bronchiectasis.

Isolation of and risk factors for airway infection with Pseudomonas aeruginosa in patients with non-cystic fibrosis bronchiectasis.

ABSTRACTObjective:To identify microorganisms in sputum samples of patients with stable non-cystic fibrosis bronchiectasis and to determine risk factors related to the isolation of Pseudomonas aeruginosa (PA) in those patients. Methods:Consecutive patients were recruited from a tertiary hospital outpatient clinic in the city of Fortaleza, Brazil. The patients were submitted to spirometry, six-minute walk test, HRCT, and sputum collection. Data on serum fibrinogen levels, disease severity, sputum color, and history of azithromycin treatment were collected. Results:The study included 112 patients, and females predominated (68%). The mean age was 51.6 ± 17.4 years. Most patients presented with mild-to-moderate disease (83%). The mean six-minute walk distance was 468.8 ± 87.9 m. Mean FEV1 and FVC, in % of predicted values, were 60.4 ± 21.8% and 69.9 ± 18.5%, respectively. The mean serum fibrinogen level was 396.1 ± 76.3 mg/dL. PA was isolated in 47 patients, other potentially pathogenic microorganisms (PPMs) were isolated in 31 patients, and non-PPMs were isolated in 34 patients. Purulent sputum was identified in 77 patients (68%). The patients with PA, when compared with those without it, presented with more severe disease, higher serum fibrinogen levels, and lower FVC%. In addition, purulent sputum and long-term azithromycin treatment were more common in those with PA. The multivariate regression analysis showed that the independent factors associated with PA were serum fibrinogen level > 400 mg/dL (OR = 3.0; 95% CI: 1.1-7.7) and purulent sputum (OR = 4.3; 95% CI: 1.6-11.3). Conclusions:In our sample, the prevalence of PA in sputum was 42%. Sputum color and inflammatory markers were able to predict the isolation of PA, emphasizing the importance of routine sputum monitoring.

Neutrophil Extracellular Traps are Increased in Severe Bronchiectasis and Reduced by Long-Term Azithromycin Treatment

Background: Bronchiectasis is predominantly a neutrophilic inflammatory disease. There are no established therapies that directly target neutrophilic inflammation because of a lack of understanding of the underlying mechanisms leading to severe disease. Neutrophil extracellular trap (NET) formation is a mode of host defence that has been implicated in multiple inflammatory diseases. Methods: We conducted a series of UK and international studies to investigate the role of NETs in disease severity and treatment response in bronchiectasis. Nano LC/MS-MS was used to identify proteomic markers associated with disease severity, defined using the bronchiectasis severity index (BSI) (n=40). These were validated in two cohorts (n=175 and n=275) using a validated immunoassay to measure NETs. 20 patients with acute exacerbations of bronchiectasis were treated with intravenous antibiotics for 14 days and proteomics used to identify proteins associated with treatment response. Two studies of long-term macrolide treatment, one in bronchiectasis and a post-hoc analysis of the AMAZES trial in asthma, investigated the effect of macrolide treatment on NETs. Findings: 96 proteins were differentially expressed in sputum between severe and mild bronchiectasis. The most abundant and most discriminating were proteins known to be NET proteins. This was validated in two observational cohorts where sputum NETs were associated with BSI, quality of life, lung function, future risk of hospital admissions and mortality. Antibiotic treatment in 20 patients was associated with 23 significantly down-regulated and 16 up-regulated proteins, with the “neutrophil degranulation” pathway being most strongly implicated in response. Patients with Pseudomonas aeruginosa infection had a blunted proteomic and clinical response to treatment. Treatment with low dose azithromycin was associated with a significant reduction in NETs in sputum over 12 months in both bronchiectasis and asthma. Interpretation: NETs are identified as a key marker of disease severity and treatment response in bronchiectasis. Funding: Supported by the Scottish Government Chief Scientist Office (Senior Clinical Fellowship to JDC) and British Lung Foundation through the BLF Chair of Respiratory Research. Supported by the European Bronchiectasis Network (EMBARC), a European Respiratory Society Clinical Research Collaboration. Declaration of Interests: None to declare Ethics Approval Statement: The studies were approved by local research ethics committees and patients provided informed consent.

Antistreptococcal interventions for guttate and chronic plaque psoriasis.

Antistreptococcal interventions for guttate and chronic plaque psoriasis.

Oral administration of azithromycin ameliorates trypanosomosis in Trypanosoma congolense-infected mice.

Animal trypanosomosis is a devastating parasitic disease that is of economic importance to livestock production. The infection includes animal African trypanosomosis, surra, and dourine. The treatment is based solely on few compounds that were discovered decades ago and which are associated with severe toxicity. Furthermore, it is likely that the parasite has developed resistance towards them. Thus, there is an urgent need for new, accessible, and less toxic drugs. Azithromycin is an antibiotic with documented efficacy against Toxoplasma, Babesia, and Plasmodium. The current study investigated its effects against animal trypanosomes. An in vitro system was used to determine the trypanocidal effects of azithromycin against Trypanosoma congolense, Trypanosoma brucei brucei, and Trypanosoma evansi, and cytotoxicity in Madin-Darby bovine kidney (MDBK) and NIH 3T3 cells. Furthermore, the trypanocidal effects of azithromycin were investigated in T. congolense-infected mice. In vitro, azithromycin had an IC50 of 0.19±0.17; 3.69±2.26; 1.81±1.82μg/mL against T. congolense, T. b. brucei, and T. evansi, respectively. No cytotoxic effects were observed in MDBK and NIH 3T3 cells. The efficacy of orally administered azithromycin was investigated in short-term and long-term treatment protocols. Although the short-term treatment protocol showed no curative effects, the survival rate of the mice was significantly prolonged (p<0.001) in comparison to the control group. The long-term treatment yielded satisfying curative effects with doses of 300 and 400mg/kg achieving 80 and 100% survival, respectively. In conclusion, long-term oral azithromycin treatment has trypanocidal effects against T. congolense.

Long-term azithromycin ameliorates not only airway inflammation but also remodeling in a murine model of chronic asthma

We investigated the effect of long-term treatment with azithromycin on the pathogenesis of chronic asthma with airway remodeling. Six-week-old-BALB/c mice were sensitized with ovalbumin (OVA) combined with lipopolysaccharide (LPS) for 1 month, then challenged with OVA for 3 months. Azithromycin at 75 mg/kg was administered via oral gavage five times a week during the challenge period. Inflammatory cells, T helper 2 cytokines in bronchoalveolar lavage fluid (BAL) fluid, and airway hyperresponsiveness (AHR) were measured. Parameters related to airway remodeling were evaluated. The levels of neutrophil elastase, Interleukin (IL)-8, and BRP-39 (human homologue YKL-40) were assessed. The expression of MAPK and NF-κB signaling were investigated. Long-term treatment with azithromycin improved AHR and airway inflammation compared with the OVA and the OVA/LPS groups. The concentrations of IL-5 and IL-13 in the OVA/LPS group decreased significantly after azithromycin administration. The levels of neutrophil elastase and IL-8, as surrogate markers of neutrophil activation, were reduced in the azithromycin group compared with the OVA/LPS group. Goblet cell hyperplasia and the smooth muscle thickening of airway remodeling were attenuated after azithromycin treatment. The expression of MAPK/NF-kappaB signal and the level of BRP-39 in the lung decreased remarkably in the OVA/LPS with azithromycin-treated group. This study suggests that in a murine model of chronic asthma, long-term azithromycin treatment ameliorates not only airway inflammation but also airway remodeling by influencing on neutrophilc-related mediators, BRP-39 and MAPK/NF-κB signal pathways. Macrolide therapy might be an effective adjuvant therapy in a chronic, severe asthma with remodeling airway.

Clinical features of post-infectious bronchiolitis obliterans in children undergoing long-term azithromycin treatment.

The aim of the present study was to outline any predisposing factors and clinical and radiological features of post-infectious bronchiolitis obliterans (PIBO) in pediatric patients, and to determine the effect of long-term azithromycin treatment on these factors. In total, 16 cases of children with PIBO were retrospectively reviewed. Adenovirus and Mycoplasma pneumoniae were the most common etiological agents (12/16) in the children with PIBO. The patients presented with persistent dyspnea, a chronic cough, sputum production and wheezing following the initial lung infection. Chest X-rays indicated pulmonary overinflation and patchy ground-glass opacity. In addition, high-resolution computed tomography (HRCT) scans revealed patchy ground-glass opacity, bronchiectasis, bronchial wall thickening and mosaic perfusion in all 16 cases. A unilateral hyperlucent lung was observed in two cases. All the patients underwent treatment with low-dose azithromycin and prednisone. Follow-up examinations of the 16 cases, varying in duration between 7 and 31 months, showed that the disease condition had improved in 10 cases. However, no significant improvements were identified from the HRCT scans or were observed in the patient condition in the additional six cases. The diagnosis of BO is primarily based on a typical clinical presentation and HRCT observations. Therefore, a typical clinical history and patchy ground-glass opacity features on HRCT scans are screening indices that predict BO development. Steroids are the cornerstone of BO treatment; however, long-term azithromycin treatment can improve the condition of the patients. In summary, PIBO is a disease with a high morbidity rate and should be treated by a multidisciplinary team. Patients should receive follow-up examination for an extended period. Patchy ground-glass opacity features on HRCT scans indicate that clinical suspicion of BO is necessary in children with persistent and severe wheezing.

Characterization of Staphylococcus aureus Strains Isolated from Czech Cystic Fibrosis Patients: High Rate of Ribosomal Mutation Conferring Resistance to MLS(B) Antibiotics as a Result of Long-Term and Low-Dose Azithromycin Treatment.

Staphylococcus aureus is one of the most frequent pathogens infecting the respiratory tract of patients with cystic fibrosis (CF). This study was the first to examine S. aureus isolates from CF patients in the Czech Republic. Among 100 S. aureus isolates from 92 of 107 observed patients, we found a high prevalence of resistance to macrolide-lincosamide-streptogramin B (MLS(B)) antibiotics (56%). More than half of the resistant strains (29 of 56) carried a mutation in the MLS(B) target site. The emergence of MLS(B) resistance and mutations conferring resistance to MLS(B) antibiotics was associated with azithromycin treatment (p=0.000000184 and p=0.000681, respectively). Methicillin resistance was only detected in 3% of isolates and the rate of resistance to other antibiotics did not exceed 12%. The prevalence of small-colony variant (SCV) strains was relatively low (9%) and eight of nine isolates with the SCV phenotype were thymidine dependent. The study population of S. aureus was heterogeneous in structure and both the most prevalent community-associated and hospital-acquired clonal lineages were represented. Of the virulence genes, enterotoxin genes seg (n=52), sei (n=49), and sec (n=16) were the most frequently detected among the isolates. The PVL genes (lukS-PV and lukF-PV) have not been revealed in any of the isolates.

Antistreptococcal interventions for guttate and chronic plaque psoriasis

Antistreptococcal interventions for guttate and chronic plaque psoriasis

Meta-Analysis of the Adverse Effects of Long-Term Azithromycin Use in Patients with Chronic Lung Diseases

The adverse effects of azithromycin on the treatment of patients with chronic lung diseases (CLD) were evaluated in the present study. MEDLINE and other databases were searched for relevant articles published until August 2013. Randomized controlled trials that enrolled patients with chronic lung diseases who received long-term azithromycin treatment were selected, and data on microbiological studies and azithromycin-related adverse events were abstracted from articles and analyzed. Six studies were included in the meta-analysis. The risk of bacterial resistance in patients receiving long-term azithromycin treatment was increased 2.7-fold (risk ratio [RR], 2.69 [95% confidence interval {95% CI}, 1.249, 5.211]) compared with the risk in patients receiving placebo treatment. On the other hand, the risk of bacterial colonization decreased in patients receiving azithromycin treatment (RR, 0.551 [95% CI, 0.460, 0.658]). Patients receiving long-term azithromycin therapy were at risk of increased impairment of hearing (RR, 1.168 [95% CI, 1.030, 1.325]). This analysis provides evidence supporting the idea that bacterial resistance can develop with long-term azithromycin treatment. Besides the increasingly recognized anti-inflammatory role of azithromycin used in treating chronic lung diseases, we should be aware of the potential for adverse events with its long-term use.

Effect of Azithromycin Maintenance Treatment on Infectious Exacerbations Among Patients With Non–Cystic Fibrosis Bronchiectasis

Macrolide antibiotics have been shown beneficial in cystic fibrosis (CF) and diffuse panbronchiolitis, and earlier findings also suggest a benefit in non-CF bronchiectasis. To determine the efficacy of macrolide maintenance treatment for adults with non-CF bronchiectasis. The BAT (Bronchiectasis and Long-term Azithromycin Treatment) study, a randomized, double-blind, placebo-controlled trial conducted between April 2008 and September 2010 in 14 hospitals in The Netherlands among 83 outpatients with non-CF bronchiectasis and 3 or more lower respiratory tract infections in the preceding year. Azithromycin (250 mg daily) or placebo for 12 months. Number of infectious exacerbations during 12 months of treatment. Secondary end points included lung function, sputum bacteriology, inflammatory markers, adverse effects, symptom scores, and quality of life. Forty-three participants (52%) received azithromycin and 40 (48%) received placebo and were included in the modified intention-to-treat analysis. At end of study, the median number of exacerbations in the azithromycin group was 0 (interquartile range [IQR], 0-1), compared with 2 (IQR, 1-3) in the placebo group (P < .001). Thirty-two (80%) placebo-treated vs 20 (46%) azithromycin-treated individuals had at least 1 exacerbation (hazard ratio, 0.29 [95% CI, 0.16-0.51]). In a mixed-model analysis, change in forced expiratory volume in the first second of expiration (percent of predicted) over time differed between groups (F1,78.8 = 4.085, P = .047), with an increase of 1.03% per 3 months in the azithromycin group and a decrease of 0.10% per 3 months in the placebo group. Gastrointestinal adverse effects occurred in 40% of patients in the azithromycin group and in 5% in the placebo group (relative risk, 7.44 [95% CI, 0.97-56.88] for abdominal pain and 8.36 [95% CI, 1.10-63.15] for diarrhea) but without need for discontinuation of study treatment. A macrolide resistance rate of 88% was noted in azithromycin-treated individuals, compared with 26% in the placebo group. Among adults with non-CF bronchiectasis, the daily use of azithromycin for 12 months compared with placebo resulted in a lower rate of infectious exacerbations. This could result in better quality of life and might influence survival, although effects on antibiotic resistance need to be considered. clinicaltrials.gov Identifier: NCT00415350.

Recycling of Peptidyl-tRNAs by Peptidyl-tRNA Hydrolase Counteracts Azithromycin-Mediated Effects on Pseudomonas aeruginosa

Acute and chronic infections caused by the opportunistic pathogen Pseudomonas aeruginosa pose a serious threat to human health worldwide, and its increasing resistance to antibiotics requires alternative treatments that are more effective than available strategies. Clinical studies have clearly demonstrated that cystic fibrosis (CF) patients with chronic P. aeruginosa infections benefit from long-term low-dose azithromycin (AZM) treatment. Immunomodulating activity, the impact of AZM on the expression of quorum-sensing-dependent virulence factors, type three secretion, and motility in P. aeruginosa seem to contribute to the therapeutic response. However, to date, the molecular mechanisms underlying these AZM effects have remained elusive. Our data indicate that the AZM-mediated phenotype is caused by a depletion of the intracellular pools of tRNAs available for protein synthesis. Overexpression of the P. aeruginosa peptidyl-tRNA hydrolase, which recycles the tRNA from peptidyl-tRNA drop-off during translation, counteracted the effects of AZM on stationary-phase cell killing, cytotoxicity, and the production of rhamnolipids and partially restored swarming motility. Intriguingly, the exchange of a rare for a frequent codon in rhlR also explicitly diminished the AZM-mediated decreased production of rhamnolipids. These results indicate that depletion of the tRNA pools by AZM seems to affect the translation of genes that use rare aminoacyl-tRNA isoacceptors to a great extent and might explain the selective activity of AZM on the P. aeruginosa proteome and possibly also on the protein expression profiles of other bacterial pathogens.

Long-term azithromycin therapy for bronchiolitis obliterans syndrome: Divide and conquer?

Azithromycin may reverse or halt the decline of pulmonary function (FEV(1)) in bronchiolitis obliterans syndrome (BOS). In this study we investigated the effects of long-term azithromycin treatment in lung transplant recipients with BOS. A retrospective, observational, cohort study was performed on 107 patients with BOS (Stages 0p/1/2/3, n = 23/62/20/2), who were treated with azithromycin for 3.1 ± 1.9 years. Patients were evaluated 6.3 ± 3.8 years after transplantation and assessed for evolution of FEV(1), bronchoalveolar lavage neutrophilia and overall survival after initiation of azithromycin. Survival curves were analyzed using the log-rank test. Cox proportional hazard survival regression analysis was performed to estimate hazard ratios of clinical variables predicting outcome. FEV(1) increased ≥ 10% after 3 to 6 months of treatment in 40% of patients, of whom 33% later redeveloped BOS. FEV(1) further declined in 78% and stabilized in 22% of the remaining non-responders. Pre-treatment neutrophilia was higher in responders: 29.3% (9.3% to 69.7%) vs 11.5% (2.9% to 43.8%) (p = 0.025), in whom it significantly decreased to 4.2% (1.8% to 17.6%) (p = 0.041) after 3 to 6 months of azithromycin. Responders demonstrated better survival compared with non-responders (p = 0.050), with 6 and 21 patients, respectively, dying during follow-up (p = 0.027). Multivariate analysis identified initial azithromycin response and earlier post-transplant initiation of azithromycin to be protective for both BOS progression/relapse (hazard ratio [HR] = 0.12 [95% confidence interval 0.05 to 0.28], p < 0.0001; and HR = 0.98 [95% confidence interval 0.97 to 0.98], p < 0.0001, respectively) and retransplantation/death during follow-up (HR 0.10 [95% confidence interval 0.02 to 0.48], p = 0.004; and HR 0.96 [95% confidence interval 0.95 to 0.98], p < 0.0001, respectively). Long-term azithromycin benefits pulmonary function and survival in BOS, particularly in patients with increased lavage neutrophilia.

Long-term azithromycin use in patients with chronic obstructive pulmonary disease and tracheostomy

Patients with Chronic Obstructive Pulmonary Disease (COPD) and tracheostomy are at high risk for exacerbations and hospitalizations. Macrolide treatment has shown to reduce exacerbations in moderate-to-severe COPD. To evaluate the safety and the efficacy of long-term azithromycin use in outpatients with severe COPD and tracheostomy. A multicenter, randomized, uncontrolled, pilot trial evaluating the safety and the efficacy of azithromycin 500 mg three day-a-week for 6 months (AZI) vs. standard of care (SC) in severe COPD outpatients with tracheostomy. Patients were monitored for six months of treatment plus six months of follow up. The primary outcome was the reduction in the number of exacerbations and hospitalizations. A total of 22 patients was randomized (11 to SC and 11 to AZI). Patients in AZI had a significant lower cumulative number of exacerbations after the first 3 months of treatment when compared to patients in SC (p = 0.001), as well as hospitalizations (p = 0.02). Kaplan-Meier survival curves for time to first exacerbation showed a significant reduction in AZI of the rates of first exacerbation when compared to SC (log rank test = 12.14, p < 0.001), as well as to first hospitalization (log-rank = 4.09, p = 0.04). Azithromycin significantly improved the quality of life in comparison to SC. No serious adverse events in the AZI group were reported. Long-term azithromycin treatment seems to be safe and effective in severe COPD outpatients with tracheostomy in reducing exacerbations, hospitalizations, as well as in improving quality of life.

Lung Transplantation: The Role of Azithromycin in the Management of Patients with Bronchiolitis Obliterans Syndrome

Bronchiolitis obliterans syndrome (BOS) is the leading cause of death in lung transplant recipients (LTR). BOS is thought to result from chronic immunologic/inflammatory insults leading to peri-bronchiolar leukocyte infiltration, with a subsequent exuberant tissue re-modelling and fibro-obliteration of the luminal space of the allograft airways. Diagnosis is based on functional criteria and severity is graded on the degree of Forced Expiratory Volume in 1 second (FEV1) impairment. Current strategies to improve pulmonary function once BOS is established have demonstrated little or no impact on disease progression and re-transplantation remains the only therapeutic option. Among the alternative treatments which have been attempted in the last few years, long-term azithromycin treatment seems to be the most promising therapeutic device for BOS treatment. Azithromycin is a macrolide antibiotic, endowed with a broad spectrum of anti-inflammatory/immunomodulatory activities. Long-term oral azithromycin therapy can significantly improve FEV1 in about 42% of patients with established BOS. Moreover, reduced neutrophilia, chemokine release and bacterial exacerbations have been demonstrated. These observations suggest that the drug can down-regulate pulmonary inflammation, even if the precise underlying mechanisms still need to be determined.

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

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. 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. 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. 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.