Login to your account

Username *
Password *
Remember Me

Blog With Right Sidebar

Deletion and acquisition of genomic content during early stage adaptation of Pseudomonas aeruginosa to a human host environment.

Related Articles

Deletion and acquisition of genomic content during early stage adaptation of Pseudomonas aeruginosa to a human host environment.

Environ Microbiol. 2012 Aug;14(8):2200-11

Authors: Rau MH, Marvig RL, Ehrlich GD, Molin S, Jelsbak L

Abstract
Adaptation of bacterial pathogens to a permanently host-associated lifestyle by means of deletion or acquisition of genetic material is usually examined through comparison of present-day isolates to a distant theoretical ancestor. This limits the resolution of the adaptation process. We conducted a retrospective study of the dissemination of the P. aeruginosa DK2 clone type among patients suffering from cystic fibrosis, sequencing the genomes of 45 isolates collected from 16 individuals over 35 years. Analysis of the genomes provides a high-resolution examination of the dynamics and mechanisms of the change in genetic content during the early stage of host adaptation by this P. aeruginosa strain as it adapts to the cystic fibrosis (CF) lung of several patients. Considerable genome reduction is detected predominantly through the deletion of large genomic regions, and up to 8% of the genome is deleted in one isolate. Compared with in vitro estimates the resulting average deletion rates are 12- to 36-fold higher. Deletions occur through both illegitimate and homologous recombination, but they are not IS element mediated as previously reported for early stage host adaptation. Uptake of novel DNA sequences during infection is limited as only one prophage region was putatively inserted in one isolate, demonstrating that early host adaptation is characterized by the reduction of genomic repertoire rather than acquisition of novel functions. Finally, we also describe the complete genome of this highly adapted pathogenic strain of P. aeruginosa to strengthen the genetic basis, which serves to help our understanding of microbial evolution in a natural environment.

PMID: 22672046 [PubMed - in process]

Symptoms, but not a biomarker response to inhaled corticosteroids, predict asthma in preschool children with recurrent wheeze.

Related Articles

Symptoms, but not a biomarker response to inhaled corticosteroids, predict asthma in preschool children with recurrent wheeze.

Mediators Inflamm. 2012;2012:162571

Authors: Klaassen EM, van Kant KD, Jöbsis Q, Høvig ST, van Schayck CP, Rijkers GT, Dompeling E

Abstract
Background. A reliable asthma diagnosis is challenging in preschool wheezing children. As inhaled corticosteroids (ICS) are more effective in asthmatics than in children with transient wheeze, an ICS response might be helpful in early asthma diagnosis. Methods. 175 children (aged two-four years) with recurrent wheeze received 200 μg Beclomethasone extra-fine daily for eight weeks. Changes in Exhaled Breath Condensate (EBC) biomarkers (pH, interleukin (IL)-1α, IL-2, IL-4, IL-5, IL-10, IFN-γ, sICAM, and CCL-11), Fractional exhaled Nitric Oxide (FeNO), airway resistance, and symptoms were assessed. At six years of age a child was diagnosed as transient wheezer or asthmatic. Adjusted logistic regression analysis was performed with multiple testing correction. Results. 106 transient wheezers and 64 asthmatics were analysed at six years of age. Neither changes in EBC biomarkers, nor FeNO, airway resistance, or symptoms during ICS trial at preschool age were related to asthma diagnosis at six years of age. However, asthmatics had more airway symptoms before the start of the ICS trial than transient wheezers (P < 0.01). Discussion. Although symptom score in preschool wheezing children at baseline was associated with asthma at six years of age, EBC biomarkers, airway resistance, or symptom response to ICS at preschool age could not predict asthma diagnosis at six years of age.

PMID: 23304059 [PubMed - in process]

[Clinical value of bronchoalveolar lavage].

Related Articles

[Clinical value of bronchoalveolar lavage].

Rev Med Suisse. 2012 Nov 21;8(363):2212-4, 2216-8

Authors: Pasche A, Braunschweig R, Fitting JW, Nicod LP

Abstract
Bronchoalveolar lavage (BAL) is a minimally invasive procedure used to characterize the status of the alveolar space. Standardization of the procedure and the analysis of samples taken is essential for their proper interpretation. In nonresolving or ventilator-associated pneumonia, BAL contributes to the detection of resistant pathogens and noninfectious etiologies. In immunocompromised hosts with radiological infiltrates, BAL should be performed early during work-up since outcome is significantly modified in this population group. In cases of interstitial lung disease, BAL can exclude infectious or neoplastic causes. Associated with a clinical and radiological evaluation, it provides valuables additional diagnostic information.

PMID: 23240296 [PubMed - indexed for MEDLINE]

Endotoxin markers in bronchoalveolar lavage fluid of patients with interstitial lung diseases.

Related Articles

Endotoxin markers in bronchoalveolar lavage fluid of patients with interstitial lung diseases.

Multidiscip Respir Med. 2012 Dec 22;7(1):54

Authors: Szponar BA, Larsson L, Domaga A-Kulawik J

Abstract
ABSTRACT: BACKGROUND: Exposure to inhaled endotoxins (lipopolysaccharides, LPS) of Gram-negative bacteria commonly found in indoor environments and assessed in secondary tobacco smoke, has been associated with airway inflammation and asthma exacerbation. The bronchoalveolar lavage fluid (BALf) from patients with interstitial lung diseases (sarcoidosis, lung fibrosis, smoking-related ILD, eosinophilic disorders) was analyzed for the markers of lipopolysaccharide (LPS, endotoxin). METHODS: BALf was obtained from patients with diffuse lung diseases: idiopathic pulmonary fibrosis (n = 42), sarcoidosis (n = 22), smoking-related-ILD (n = 11) and eosinophilic disorders (n = 8). Total cell count and differential cell count were performed. In addition, samples were analyzed for 3-hydroxy fatty acids (3-OHFAs) of 10--18 carbon chain lengths, as markers of LPS, by gas chromatography-tandem mass spectrometry. RESULTS: The highest LPS concentration was found in patients with eosinophilic disorders and the lowest in patients with sarcoidosis (p< 0.05) followed by the lung fibrosis and the sr-ILD patients. The difference between LPS in BALf with extremely high eosinophil proportion (> 25 %) and those with lower proportion was also significant (p = 0.014). A significant correlation was found between LPS and eosinophils, but not between LPS and lymphocytes, neutrophils, or macrophages count. CONCLUSIONS: A positive relationship of LPS and eosinophilic pulmonary disorders may be linked to a persistent eosinophil activation mediated by Th2 pathway: chronic endotoxin exposure would intensify Th2 pathway resulting in fibrosis and, at the same time, eosinophil stimulation, and hence in eosinophilic pulmonary disorders.

PMID: 23259971 [PubMed - as supplied by publisher]

The evolving pharmacotherapy of pulmonary fibrosis.

Related Articles

The evolving pharmacotherapy of pulmonary fibrosis.

Expert Opin Pharmacother. 2013 Jan;14(1):79-89

Authors: Lota HK, Wells AU

Abstract
Introduction: Novel compounds targeting various aspects of fibrogenesis have been developed consequent to the increasing knowledge of the pathogenetic mechanisms of the interstitial lung diseases (ILDs). The authors review the evolution of treatment approaches in the ILDs, informed by recent placebo-controlled trials, and discuss current clinical trials in which emerging pathogenetic mechanisms are targeted as novel therapeutic agents. Areas covered: In idiopathic pulmonary fibrosis (IPF), recent randomised, placebo-controlled trials have tested the efficacy of new therapies, and although primary end points have not been met in most, treatment effects have been observed. The demonstration of harmful effects from widely used IPF therapies has been equally important. Pirfenidone and nintedanib are emerging agents that exert pleiotropic effects, reflective of the multiple mechanistic pathways of IPF. Treatment may necessitate a similarly multifaceted approach using combination regimens of antifibrotic and antioxidant agents in order to be effective. In other ILDs, including systemic sclerosis, other connective tissue diseases and pulmonary sarcoidosis, the inflammatory/fibrotic model remains appropriate. Studies in systemic sclerosis have provided 'proof of concept' data for immunosuppressive therapy in the prevention of disease progression but there is a continuing need for controlled clinical trials in the more prevalent ILDs. Expert opinion: In IPF, significant treatment effects have been reported with pirfenidone, nintedanib and N-acetylcysteine. Combinations of these pleiotropic agents, along with future monotherapies, in 'oncological regimens' may hold the key to more effective IPF treatment. In disorders other than IPF, there is an ongoing need for the controlled evaluation of traditional anti-inflammatory and immunosuppressive therapies. 'Cohort enrichment' (the selective recruitment of patients most likely to progress) holds the key to the identification of worthwhile treatment benefits.

PMID: 23265249 [PubMed - in process]

Search