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Biomedical subjects

J Stuart Elborn

Publications and source records attributed to J Stuart Elborn.

27 records · Page 2Linked to original sources
PubMed2004

Epidemiology of Burkholderia cepacia complex species recovered from cystic fibrosis patients: issues related to patient segregation.

Studies of the prevalence of Burkholderia cepacia complex species amongst cystic fibrosis (CF) patients in different geographical regions, and the association between cross-infection and putative transmissibility markers, will further our understanding of these organisms and help to address infection-control issues. In this study, B. cepacia complex isolates from CF patients in different regions of Europe were analysed. Isolates were examined for B. cepacia complex species and putative transmissibility markers [cable pilin subunit gene (cblA) and the B. cepacia epidemic strain marker (BCESM)]. Sporadic and cross-infective strains were identified by random amplification of polymorphic DNA (RAPD). In total, 79% of patients were infected with Burkholderia cenocepacia (genomovar III), 18% with Burkholderia multivorans (genomovar II) and less than 5% of patients with B. cepacia (genomovar I), Burkholderia stabilis (genomovar IV) or Burkholderia vietnamiensis (genomovar V). The cblA and BCESM transmissibility markers were only detected in strains of B. cenocepacia. The BCESM was a more sensitive marker for transmissible B. cenocepacia strains than cblA, although sporadic B. cenocepacia strains containing the BCESM, but lacking cblA, were also observed. Furthermore, clusters of cross-infection with transmissibility marker-negative strains of B. multivorans were identified. In conclusion, B. cenocepacia was the greatest cause of cross-infection, and the most widely distributed B. cepacia complex species, within these CF populations. However, cross-infection was not exclusive to B. cenocepacia and cblA and the BCESM were not absolute markers for transmissible B. cenocepacia, or other B. cepacia complex strains. It is therefore suggested that CF centres cohort patients based on the presence or absence of B. cepacia complex infection and not on the basis of transmissibility marker-positive B. cenocepacia as previously suggested.

Bacterial Typing Techniques↗
PubMed2003

Development of a diagnostic PCR assay that targets a heat-shock protein gene (groES) for detection of Pseudomonas spp. in cystic fibrosis patients.

Laboratory detection of Pseudomonas spp., in particular Pseudomonas aeruginosa, remains an important assay in the management of patients with cystic fibrosis (CF). As the groES and groEL genes of P. aeruginosa have now been cloned and their nucleotide sequences determined, the aim of this study was to develop a novel PCR assay for the detection of Pseudomonas spp. from patients with CF by employing conserved primer regions of the groE heat-shock protein domain gene. A PCR assay was designed that targeted a 536 bp region of the groE gene to detect Pseudomonas spp. PCR amplification of genomic DNA from extracted organisms generated an amplicon of the expected size (approx. 536 bp) for all P. aeruginosa (n = 60), Pseudomonas putida, Pseudomonas fluorescens and Pseudomonas stutzeri isolates examined, but did not produce a positive amplicon for several other genera and species that are commonly isolated from the sputum of CF patients. RFLP analysis of the amplicons of all P. aeruginosa isolates demonstrated a single RFLP type that consisted of three bands at approximately 80, 190 and 250 bp; direct sequencing of the amplicons demonstrated the presence of a single sequence type, indicating the highly conserved nature of this region. In addition, the assay successfully produced a positive signal from primary non-selective plates of three known P. aeruginosa culture-positive CF patients, but was unable to generate a signal in a further six CF patients who had no history of infection with P. aeruginosa or other Pseudomonas spp. This assay is recommended to detect the presence of Pseudomonas spp., including P. aeruginosa, from primary culture plates that originate from laboratory analysis of CF patients' sputum, particularly at review, in those patients with no previous history of Pseudomonas infection or those who appear to be transiently colonized by this organism. Employment of such molecular methodologies, in conjunction with routine clinical sputum cultures, may provide improved information on the microbial status of CF patients, which will aid clinicians in both optimum patient management in terms of antibiotic regimes and CF centre infection-control practices.

Adolescent↗
PubMed2002

Improved molecular detection of Burkholderia cepacia genomovar III and Burkholderia multivorans directly from sputum of patients with cystic fibrosis.

Optimum detection of the Burkholderia cepacia complex (BCC) from sputum of patients with cystic fibrosis (CF) is essential in preventing patient-to-patient transmission of this organism. The aim of this study was to develop an improved PCR assay with reference to sensitivity for the direct detection of BCC organisms from CF sputum employing the recA locus. The sensitivity results of three recA PCR assays were compared using various combinations of previously published primers. These included (i) a single-round approach using the primer set BCR1/BCR2, yielding a 1036-bp product, (ii) a single-round approach using the primer set BCR1/Mr, yielding a 465-bp product, and (iii) a semi-nested PCR (SN-PCR) approach using the primer set BCR1/BCR2 followed by BCR1/Mr. The sensitivity of these assays were determined by spiking B. cepacia-free sputum with known numbers of four strains of BCC, namely, genomovar II [B. multivorans] (C1576), genomovar IIIa (C5424, C6433) and genomovar IIIb (C1394). Following optimization, the chosen assay was performed on 14 patients. Employment of the single-round assay with BCR1/BCR2 was the least sensitive with a detection threshold of 10(7) cfu/g sputum for GIIIa and GIIIb, and 10(8) cfu/g sputum for GII. Sensitivity was improved by targeting the smaller amplification region of the recA locus (465 bp) employing the BCR1/Mr primer pair, in combination with a single-round approach, whereby the detection threshold was improved by 1 log for each genomovar. Employment of the semi-nested assay demonstrated optimum sensitivity, whereby the detection threshold increased to 10(1) and 10(2) cfu/g sputum for genomovar IIIa/IIIb and genomovar II, respectively. Subsequent genomovar characterisation can be performed by sequencing of the PCR amplicon without the need for culture which may be beneficial in patients in the initial stages of colonisation or who are transiently colonised and who may be culture-negative for BCC.

Adult↗
PubMed2002

Improved molecular identification of Thermoactinomyces spp. associated with mushroom worker's lung by 16S rDNA sequence typing.

Mushroom worker's lung (MWL) is a hypersensitivity pneumonitis or allergic alveolitis caused by a type III IgG-mediated immunopathogenic inflammatory reaction in the host due to the inhalation of several thermophilic organisms, including Thermoactinomyces spp. It is difficult to distinguish phenotypically the eight species of this genus; therefore, this study sought to develop an improved molecular means of identifying Thermoactinomyces spp. associated with MWL by partial 16S rDNA PCR amplification and direct sequencing. Hypervariable regions within the 16S rRNA gene, which could be employed as signature sequences of the eight individual species, were identified and employed with highly conserved flanking primers to allow initial PCR amplification, before direct DNA sequencing of the 16S rDNA amplicons. A novel 24-mer 16S rDNA oligonucleotide upstream primer was designed from in silico alignments of all Thermoactinomyces spp. and was employed in combination with downstream (reverse) 16S rDNA primers. This permitted the successful identification of all four isolates associated with mushroom workers' lung. The method may be useful in the identification of Thermoactinomyces spp. associated with allergic alveolitis or pneumonitis associated with occupational exposure in agricultural and horticultural environments.

Agricultural Workers' Diseases↗
PubMed2002

Comparison of sputum induction using high-output and low-output ultrasonic nebulizers in normal subjects and patients with COPD.

STUDY OBJECTIVE: s: Induced sputum is used to investigate pulmonary diseases. Low-output ultrasonic nebulizers have become available and have potential advantages over high-output nebulizers. We hypothesized that a low-output nebulizer would give comparable results to a high-output nebulizer, with an acceptable safety profile. DESIGN: Randomized, crossover study. SETTING: University teaching hospital. PARTICIPANTS: Ten normal subjects and 10 patients with COPD. INTERVENTIONS: Participants attended for sputum induction on two occasions in random order using low-output and high-output nebulizers. MEASUREMENTS AND RESULTS: Lung function and oxygen saturation were measured during sputum induction, and tolerability of the procedure was assessed. Cell counts, interleukin 8, and neutrophil elastase were measured in sputum. Use of the high-output nebulizer resulted in a greater FEV(1) (mean +/- SEM, 0.29 +/- 0.04 L vs 0.21 +/- 0.04 L; p = 0.04) and percentage drop in FEV(1) (25.8 +/- 2.6% vs 19.5 +/- 2.9%, respectively; p = 0.02) compared with the low-output nebulizer in patients with COPD. There was a shorter tolerated nebulization time with the high-output nebulizer compared with the low-output nebulizer: 12.7 +/- 2.0 min vs 16.5 +/- 1.8 min, respectively (p = 0.02). Modified Borg scores were lower with the low-output nebulizer than the high-output nebulizer in normal subjects: median, 0 (interquartile range [IQR], 0 to 1) vs median, 1.5 (IQR, 0 to 2), respectively (p = 0.05). There were no differences in cell counts and soluble markers of inflammation. CONCLUSIONS: The low-output ultrasonic nebulizer is comparable to high-output nebulizer for cellular and soluble markers of inflammation, results in a smaller reduction in FEV(1), is better tolerated, and is a suitable tool for investigating airway inflammation in patients with COPD.

Adult↗
PubMedDate not supplied

Airway clearance in bronchiectasis: a randomized crossover trial of active cycle of breathing techniques versus Acapella.

BACKGROUND: The efficacy of a new airway clearance device (Acapella) has not been previously investigated. Active cycle of breathing techniques (ACBT) is the standard airway clearance technique used in patients with bronchiectasis. OBJECTIVE: The objective of this study was to compare the efficacy of ACBT with Acapella as methods of airway clearance in adults with stable, productive bronchiectasis. METHODS: Twenty patients (7 males), age 58 +/- 11 years (mean +/- SD), FEV1 64 +/- 22% predicted with stable (change of not greater than FEV1 10% predicted during 3 months prior to study), productive (history of expectoration of half an egg cup sputum/day) bronchiectasis attended the respiratory clinic on 3 days. Day 1: 40-min training session on ACBT and Acapella. Days 2 and 3: 30-min treatment session of either ACBT or Acapella. Treatment order was determined by a concealed randomization procedure. The following outcomes were measured before and after treatment spirometry, SpO2 and breathlessness by an independent assessor who was blinded to treatment order. Weight of sputum (during treatment plus 30 min after treatment), number of coughs and patient preference were also recorded. RESULTS: No significant differences were found at baseline indicating that patients were stable. No significant differences were found between weight of sputum expectorated with ACBT treatment and weight of sputum expectorated with Acapella treatment--mean difference 0.54 g (95% CI -0.39 to 1.46). A greater proportion of patients preferred Acapella (14/20). CONCLUSION: Acapella is as effective a method of airway clearance as ACBT and may offer a user-friendly alternative to ACBT for patients with bronchiectasis.

Airway Obstruction↗