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Biomedical subjects

P G Murphy

Publications and source records attributed to P G Murphy.

At least 19 recordsLinked to original sources
PubMed2005

Microbial ecology of the cystic fibrosis lung: does microflora type influence microbial loading?

This study aims to examine the association between the numbers of culturable microbial species forming the microflora of the lung in patients with cystic fibrosis (CF) and microbial loading (i.e., type[s] versus numbers). Additionally, it examines qualitative combinations of the microflora present in a large adult CF centre (n=138) in order to ascertain ecological relationships between the taxa present. The culturable microflora of sputum from 34 adults patients with CF are enumerated using a spread plate technique on non-selective agar, and the microflora identified phenotypically employing the API 20NE scheme. Microbiological examination of the 34 adult patients demonstrated that their sputum contained between one and three taxa, with a mean cell density of 8.25 +/- 0.85 log colony-forming units (cfu)/g sputum and a range of 5.91-9.74 log cfu/g sputum. Most colonising patterns demonstrated only Gram-negative infection (22/34), followed by a mixed Gram-positive/Gram-negative infection pattern (10/34). Only 2/34 patients had a single Gram-positive infection. Most patients (53%) were colonised by only one organism, with 38% of patients colonised by two organisms, and the remainder (4%) colonised with three organisms. There was no statistical difference (P>0.05) between microbial cell density and the number of taxa present (i.e., the greater number of taxa present in sputum did not produce a higher cell density). However, there was a significantly higher cell density (log 0.59 cfu/g sputum) noted for those patients who had only Gram-negative infection, compared to those who had a mixed Gram-negative/Gram-positive infection pattern (P=0.02). Relatively little is known about the ecological interactions that exist between the microflora in the CF lung. Further work is required to explore these interactions in order to aid understanding of the succession and dominance of Gram-negatives in chronic chest infections. Ultimately, a greater understanding of such interactions may allow the opportunity to manipulate the ecology of the lung to control otherwise problematic pathogens

Adult↗
PubMed2004

Brainstem death testing in the UK--time for reappraisal?

BACKGROUND: A diagnosis of brainstem death in the UK is based on clinical assessment rather than technical investigations, but is considered rigorous enough to be legally synonymous with death. METHODS: A questionnaire in five sections concerning clinician details, initiation of support, criteria for testing, conduct of the tests, and the process of organ donation, was sent to all members of the Neuroanaesthesia Society. RESULTS: The survey reveals evidence of failure to apply existing guidelines accurately and a wide variation in practice where the recommendations are not specific. CONCLUSIONS: In an era of scrutiny of medical process, it is timely to consider whether the current guidelines should be revisited. Clarification of the approach to biochemical derangement, and the role of confirmatory tests when the residual effect of sedative agents cannot be excluded, are two areas worthy of debate.

Brain Death↗
PubMed2004

Lessons from a pre-season influenza outbreak in a day school.

An outbreak of an upper respiratory tract illness at a secondary school, which led to the hospitalisation of 23 cases, occurred in Ireland at the beginning of September 2003. Medical and laboratory examinations, initially for suspected meningitis, were carried out on the hospitalised cases and bacterial meningitis was ruled out. One hundred and seventy-nine students and teachers were interviewed and a retrospective cohort study was conducted among the sixth year students. One hundred and seven respondents met the case definition, but no associations were found between the environmental exposures investigated and illness. As it was before the expected influenza season, initial samples were not tested for influenza, but one month later the new influenza A/Fujian/411/2002 (H3N2)-like strain was confirmed and implicated in the outbreak. It was the first reported outbreak of influenza in Europe in the 2003 'winter' season and it demonstrated the need for vigilance for early and unexpected occurrence of influenza. It also provided valuable lessons for laboratory and epidemiological investigation and management of pre-season influenza.

Absenteeism↗
PubMed2003

Novel employment of lactate dehydrogenase release from porcine aortic endothelial cells (PAEC) as a quantitative marker of cytotoxic activity in thermophilic Campylobacter spp. from human faecal isolates, poultry and environmental sources.

The aim of this study was to employ a novel cytotoxicity assay based on primary porcine aortic endothelial cells in combination with a lactate dehydrogenase release assay to quantitatively determine differences in cytotoxin production between Campylobacter jejuni, C. coli, C. lari and urease-positive thermophilic campylobacters (UPTC), isolated from human faeces, animals and environmental sources. Campylobacter isolates totalling 34 and comprising of C. jejuni (n = 24) C. coli (n = 5) and UPTC (n = 4) and C. lari (n = 1) were analysed. The cytotoxic response ranged from 32.15 to 64.47% and 33.08 to 59.41%, for C. jejuni from chicken and human isolates, respectively and there was no statistically significant difference (P > 0.05) in cytotoxic response between C. jejuni isolated from humans and chicken isolates (50.78% versus 50.55% cytotoxicity, respectively). However, there was a difference in response between C. jejuni and C. coli isolated from chickens (50.78% versus 33.22% cytotoxicity, respectively). The greatest cytotoxic response was obtained with the UPTC group of organisms examined (n = 4 isolates) (mean cytotoxic response = 57.11% cytotoxicity. Employment of this cytotoxin assay may help identify virulent strains in poultry that could potentially proceed to cause clinical problems for humans and thus intervention measures targeted at the reduction or elimination of such specific strains, may be sought.

Animals↗
PubMed2003

Haemophilus segnis: a rare cause of endocarditis.

This report presents a case of endocarditis due to Haemophilus segnis, which represents a speciation difficulty for the routine laboratory. In this study, a molecular approach provided speciation, which was confirmed phenotypically by a reference laboratory. The use of molecular genotypic analysis is an additional strategy in the investigation of endocarditis. It has applications not only in isolate identification but also in primary detection of infection, particularly in patients whose blood is culture negative by conventional methodologies.

Base Sequence↗
PubMed2001

A rapid molecular assay for the detection of antibiotic resistance determinants in causal agents of infective endocarditis.

AIMS: To develop and employ a PCR amplification system, directly from clinical specimens, for the rapid molecular detection of common antimicrobial resistance genes for streptococci, staphylococci and enterococci organisms causing infective endocarditis (IE). METHODS AND RESULTS: Eleven antibiotic resistance genes were targeted by PCR along with four identification-related loci. Blood culture and heart valve material from staphylococcal endocarditis patients were directly examined for methicillin resistance. PCR conditions were optimized for the following antibiotic resistance loci: staphylococci (mecA, aacA-aphD), streptococci (PBP 1A, PBP 2B, gyrB, parE) and enterococci (vanA, vanB, vanC-1, vanC-2, aacA-aphD, aphA3). The presence of methicillin resistance was confirmed in one of the eight IE patients examined. CONCLUSION: This study presents a PCR amplification system for the detection of antibiotic resistance genes. Detection of such genes may indicate susceptibility of the causal agents of IE to commonly prescribed antimicrobial agents. SIGNIFICANCE AND IMPACT OF THE STUDY: Rapid detection of antibiotic resistant organisms may reduce the use of inappropriate antibiotic agents or enable the use of the most appropriate combinations of antibiotics, other than those that would normally be prescribed empirically for IE. Such a method may be particularly valuable in cases of culture-negative endocarditis. Detection of antibiotic resistance genes by molecular-based techniques, namely PCR, will allow more directed antibiotic therapy and may also provide opportunities for earlier identification of resistant organisms.

Drug Resistance, Microbial↗
PubMed2001

Improved cultural detection of Burkholderia cepacia from sputum in patients with cystic fibrosis.

AIMS: To evaluate the sensitivity and specificity of two selective media for the isolation of Burkholderia cepacia from sputum specimens in patients with cystic fibrosis (CF). METHODS: In total, 149 expectorated sputum specimens from 113 patients with CF (32 cepacia colonised patients and 81 non-cepacia colonised patients) attending three CF centres were examined for the presence of B cepacia on two selective media: (1) MAST selective agar, a commercially available selective medium widely used in the UK and (2) BCSA (B cepacia selective agar), a new medium recently described, which is used predominantly in North America. RESULTS: Burkholderia cepacia was isolated from 53 of 149 (35.6%) specimens examined, representing 32 of 113 (28.3%) patients, using both the MAST and BCSA media. Growth was most rapid on BCSA with all (53 of 53) isolates detectable after 48 hours, compared with 50 of the 53 isolates on MAST agar, with the remaining three isolates detectable at five days. Twenty eight contaminants were identified on MAST agar and 13 on BCSA agar; mainly Alcaligenes xylosoxidans and yeast on MAST agar and Flavobacterium indologenes on BCSA medium. BCSA was equivalent to MAST agar in its ability to isolate B cepacia from patients with CF with a history of B cepacia infection. CONCLUSIONS: The increased selectivity and reduced time to detection of BCSA makes it an attractive alternative to MAST. However, its present limited commercial availability in the UK may delay its use in routine diagnostic laboratories because of complications with media preparation and quality control.

Adult↗
PubMed2001

Occurrence of Burkholderia cepacia in foods and waters: clinical implications for patients with cystic fibrosis.

Two hundred forty-eight retail "ready-to-eat" foodstuffs in eight food categories and 134 waters categorized into nine types were analyzed for the presence of the Burkholderia cepacia complex of organisms. Of these, 14 of 26 (53.8%) samples of raw unpasteurized bovine milk were positive for this organism. Consumption of raw unpasteurized milk may therefore act as a potential source of infection with this organism, which is of particular concern for patients with cystic fibrosis, where colonization and infection with this organism can lead to a fatal necrotizing pneumonia and premature death. In addition to the associated risk of infection from fecal pathogens, patients with cystic fibrosis should therefore avoid the consumption of raw unpasteurized milk to minimize the risk of becoming infected with this organism.

Animals↗