In situ identification of Gram-negative bacteria in human lungs using a topical fluorescent peptide targeting lipid A.

Respiratory infections in mechanically ventilated patients caused by Gram-negative bacteria are a major cause of morbidity. Rapid and unequivocal determination of the presence, localization, and abundance of bacteria is critical for positive resolution of the infections and could be used for patient stratification and for monitoring treatment efficacy. Here, we developed an in situ approach to visualize Gram-negative bacterial species and cellular infiltrates in distal human lungs in real time.

Garlic revisited: antimicrobial activity of allicin-containing garlic extracts against Burkholderia cepacia complex.

The antimicrobial activities of garlic and other plant alliums are primarily based on allicin, a thiosulphinate present in crushed garlic bulbs. We set out to determine if pure allicin and aqueous garlic extracts (AGE) exhibit antimicrobial properties against the Burkholderia cepacia complex (Bcc), the major bacterial phytopathogen for alliums and an intrinsically multiresistant and life-threatening human pathogen. We prepared an AGE from commercial garlic bulbs and used HPLC to quantify the amount of allicin therein using an aqueous allicin standard (AAS).

Cathelicidin host defence peptide augments clearance of pulmonary Pseudomonas aeruginosa infection by its influence on neutrophil function in vivo.

Cathelicidins are multifunctional cationic host-defence peptides (CHDP; also known as antimicrobial peptides) and an important component of innate host defence against infection. In addition to microbicidal potential, these peptides have properties with the capacity to modulate inflammation and immunity. However, the extent to which such properties play a significant role during infection in vivo has remained unclear.

Mannose-binding lectin deficiency and disease severity in non-cystic fibrosis bronchiectasis: a prospective study.

Background: Mannose-binding lectin (MBL) is a key component of innate immunity. MBL deficiency is common (10-30% of the general population depending on the definition used) and has been associated with disease progression in cystic fibrosis. We aimed to assess the effect of MBL deficiency on disease severity in non-cystic fibrosis bronchiectasis.

Draft Genome Sequence of a Stable Mucoid Strain of Pseudomonas aeruginosa PAO581 with a mucA25 Mutation.

A mutation in the mucA gene, which encodes a negative regulator of alginate production in Pseudomonas aeruginosa, is the main mechanism underlying the conversion to mucoidy in clinical isolates from patients with cystic fibrosis (CF). Here, we announce the draft genome sequence of the stable alginate-overproducing mucoid strain P. aeruginosa PAO581 with a mucA25 mutation, a derivative from the nonmucoid strains P.

Vitamin-D deficiency is associated with chronic bacterial colonisation and disease severity in bronchiectasis.

Introduction: Vitamin-D deficiency has been linked to an increased risk of respiratory infections. The objective of this study was to determine the frequency and clinical importance of vitamin-D deficiency in patients with bronchiectasis.

Methods: 25-hydroxyvitamin-D was measured by immunoassay in 402 stable patients with bronchiectasis.

Short- and long-term antibiotic treatment reduces airway and systemic inflammation in non-cystic fibrosis bronchiectasis.

Rationale: The vicious cycle hypothesis of bronchiectasis argues that bacterial colonization leads to airway inflammation and progressive lung damage. The logical extension of this hypothesis is that acute or chronic antibiotic therapy should improve airway inflammation and clinical outcome. There are little data to support this hypothesis in patients with non-cystic fibrosis (CF) bronchiectasis.

Pseudomonas aeruginosa bacteraemia in an adult with cystic fibrosis and acute appendicitis.

Despite their high bacterial load, bacteraemia is rare in patients with cystic fibrosis (CF). We report an adult with CF who developed Pseudomonas aeruginosa bacteraemia during an episode of acute appendicitis. The Pseudomonas aeruginosa isolated from the blood culture was confirmed by molecular typing to be the same transmissible strain responsible for the patient's chronic pulmonary infection.

A randomized controlled trial of nebulized gentamicin in non-cystic fibrosis bronchiectasis.

Rationale: Bronchiectasis is a chronic debilitating disease with few evidence-based long-term treatments.

Objectives: A randomized controlled trial assessing the efficacy of nebulized gentamicin therapy over 1 year in patients with non-cystic fibrosis bronchiectasis.

Methods: Sixty-five patients were randomized to either twice-daily nebulized gentamicin, 80 mg, or nebulized 0.

The human cathelicidin LL-37 preferentially promotes apoptosis of infected airway epithelium.

Cationic host defense peptides are key, evolutionarily conserved components of the innate immune system. The human cathelicidin LL-37 is an important cationic host defense peptide up-regulated in infection and inflammation, specifically in the human lung, and was shown to enhance the pulmonary clearance of the opportunistic pathogen Pseudomonas aeruginosa in vivo by as yet undefined mechanisms. In addition to its direct microbicidal potential, LL-37 can modulate inflammation and immune mechanisms in host defense against infection, including the capacity to modulate cell death pathways.

Clinical outcome for cystic fibrosis patients infected with transmissible pseudomonas aeruginosa: an 8-year prospective study.

Background: Although there is now compelling evidence for cross-infection by strains of Pseudomonas aeruginosa at some specialist (cystic fibrosis [CF]) centers, the clinical impact of infection by transmissible strains is unclear.

Methods: In an 8-year prospective study, we compared the clinical outcome of two groups of patients with CF infected by transmissible (n = 28) and sporadic strains (n = 52) of P aeruginosa.

Results: There were no differences between the two groups in survival, annual changes in spirometry, or BMI.

Subdivision of the bacterioferritin comigratory protein family of bacterial peroxiredoxins based on catalytic activity.

Peroxiredoxins are ubiquitous proteins that catalyze the reduction of hydroperoxides, thus conferring resistance to oxidative stress. Using high-resolution mass spectrometry, we recently reclassified one such peroxiredoxin, bacterioferritin comigratory protein (BCP) of Escherichia coli, as an atypical 2-Cys peroxiredoxin that functions through the formation of an intramolecular disulfide bond between the active and resolving cysteine. An engineered E.

Diagnostic importance of pulmonary interleukin-1beta and interleukin-8 in ventilator-associated pneumonia.

Background: Ventilator-associated pneumonia (VAP) is the most commonly fatal nosocomial infection. Clinical diagnosis of VAP remains notoriously inaccurate. The hypothesis was tested that significantly augmented inflammatory markers distinguish VAP from conditions closely mimicking VAP.

Efficient production of human beta-defensin 2 (HBD2) in Escherichia coli.

Human beta-defensin 2 (HBD2) has been shown to interact with pathogenic bacteria and components of the mammalian innate and adaptive immune response. We describe a quick and reliable method for the production of HBD2 in Escherichia coli. HBD2 was expressed as an insoluble fusion, chemically cleaved and oxidised to give a single, folded HBD2 beta-isoform.

Trappin-2 promotes early clearance of Pseudomonas aeruginosa through CD14-dependent macrophage activation and neutrophil recruitment.

Microaspiration of Pseudomonas aeruginosa contributes to the pathogenesis of nosocomial pneumonia. Trappin-2 is a host defense peptide that assists with the clearance of P. aeruginosa through undefined mechanisms.

The genome of Burkholderia cenocepacia J2315, an epidemic pathogen of cystic fibrosis patients.

Bacterial infections of the lungs of cystic fibrosis (CF) patients cause major complications in the treatment of this common genetic disease. Burkholderia cenocepacia infection is particularly problematic since this organism has high levels of antibiotic resistance, making it difficult to eradicate; the resulting chronic infections are associated with severe declines in lung function and increased mortality rates. B.

Chemical and biological features of Burkholderia cepacia complex lipopolysaccharides.

The Burkholderia cepacia complex comprises 10 closely related Gram-negative organisms all of which appear capable of causing disease in humans. These organisms appear of particular relevance to patients with cystic fibrosis. Lipopolysaccharide (LPS) is an important virulence determinant in Gram-negative pathogens.

The changing epidemiology of Burkholderia species infection at an adult cystic fibrosis centre.

Background: This study reviews the impact of changing infection control practices at the Manchester Adult Cystic Fibrosis Centre (MACFC) upon the epidemiology of Burkholderia species infections.

Methods: We reviewed strain and genomovar typing of all available Burkholderia isolates at our centre between 1983-2006.

Results: The incidence/prevalence of infection with Burkholderia species between 1983-1990 was below 5%/9% each year.

Analysis and separation of residues important for the chemoattractant and antimicrobial activities of beta-defensin 3.

beta-Defensins are important in mammalian immunity displaying both antimicrobial and chemoattractant activities. Three canonical disulfide intramolecular bonds are believed to be dispensable for antimicrobial activity but essential for chemoattractant ability. However, here we show that HBD3 (human beta-defensin 3) alkylated with iodoactemide and devoid of any disulfide bonds is still a potent chemoattractant.

Evolving epidemiology of Pseudomonas aeruginosa and the Burkholderia cepacia complex in cystic fibrosis lung infection.

The morbidity and mortality of patients with cystic fibrosis (CF) is primarily determined by chronic and debilitating lung infections caused by a surprisingly narrow spectrum of bacterial pathogens. Pseudomonas aeruginosa is by far the most prevalent life-threatening CF pathogen. In the absence of aggressive early therapy, it infects the majority of adult patients and determines long-term survival.

Environmental Burkholderia cepacia complex isolates in human infections.

Members of the Burkholderia cepacia complex (Bcc), found in many environments, are associated with clinical infections. Examining diverse species and strains from different environments with multilocus sequence typing, we identified > 20% of 381 clinical isolates as indistinguishable from those in the environment. This finding links the natural environment with the emergence of many Bcc infections.

Covalent dimer species of beta-defensin Defr1 display potent antimicrobial activity against multidrug-resistant bacterial pathogens.

Beta defensins comprise a family of cationic, cysteine-rich antimicrobial peptides, predominantly expressed at epithelial surfaces. Previously we identified a unique five-cysteine defensin-related peptide (Defr1) that, when synthesized, is a mixture of dimeric isoforms and exhibits potent antimicrobial activity against Escherichia coli and Pseudomonas aeruginosa. Here we report that Defr1 displays antimicrobial activity against an extended panel of multidrug-resistant nosocomial pathogens for which antimicrobial treatment is limited or nonexistent.

A putative gene cluster for aminoarabinose biosynthesis is essential for Burkholderia cenocepacia viability.

Using a conditional mutagenesis strategy we demonstrate here that a gene cluster encoding putative aminoarabinose (Ara4N) biosynthesis enzymes is essential for the viability of Burkholderia cenocepacia. Loss of viability is associated with dramatic changes in bacterial cell morphology and ultrastructure, increased permeability to propidium iodide, and sensitivity to sodium dodecyl sulfate, suggesting a general cell envelope defect caused by the lack of Ara4N.