1,720,968 research outputs found
Automation of MLST using third-generation liquid-handling technology
No full textThe molecular characterization of bacterial pathogens of clinical significance is increasingly important. Methods, such as multilocus sequence typing (MLST), allow bacterial strains to be characterized during case clusters, for antibiotic-resistant strains to be monitored, and for the impact of new vaccines to be assessed. Our laboratory performs MLST on Neisseria meningitidis, Streptococcus pneumonaie, Haemophilus influenzae, and Staphylococcus aureus. We have developed high-throughput automated methods to allow MLST to be performed in a time scale useful in a clinical setting. Here we describe the automation of MLST on a third-generation liquid-handling robot.<br/
Pseudomonas aeruginosa outbreaks in the neonatal intensive care unit - a systematic review of risk factors and environmental sources
No full textPseudomonas aeruginosa is a Gram-negative bacterium commonly occurring in soil and water. It is an opportunistic pathogen and an important cause of healthcare-associated infections, particularly among infants in neonatal intensive care units (NICUs). Several reports regarding outbreaks of P. aeruginosa in NICUs have been published. MEDLINE and EMBASE databases were searched using the MeSH terms [Pseudomonas aeruginosa], [Outbreak OR Infection OR bacteraemia, OR sepsis OR disease] and [Neonat* OR baby OR babies OR newborn*]. Fifteen studies describing a total of 414 infants colonized or infected with P. aeruginosa were reviewed. The mean percentage of infections occurring in the populations that had been colonized by the organism (calculated as n(infected)/n(infected)+n(colonized)) was 22%. Environmental sampling was performed in 14 studies, nine of which detected P. aeruginosa. The risk factors identified were antimicrobial drug use and the number of days of antimicrobial therapy prescribed before positive blood culture, exposure to particular healthcare workers (HCW), transfusion of blood products, and intravenous delivery of nutrients/electrolytes. Exposure to umbilical venous catheters was associated with bloodstream infections. Increasing age and use of artificial fingernails were risk factors for colonization of hands of HCWs. Low birth weight pre-term infants were at greater risk of mortality from P. aeruginosa infection than older infants
Whole genome sequencing of carriage and disease isolates of Streptococcus pneumoniae serotype 22F reveals lineage specific divergence and niche adaptation
No full textDistribution of carried pneumococcal clones in UK children following the introduction of the 7-valent pneumococcal conjugate vaccine: a 3-year cross-sectional population based analysis
No full textThe success of Streptococcus pneumoniae (pneumococcus) in both colonisation and disease is associated with the increased prevalence of genetic clones expressing virulence factors that assist host invasion. We studied the distribution of pneumococcal clones in paediatric carriage as part of an ongoing longitudinal study of pneumococcal carriage in children less than 5 years of age. Across three years, 87 different sequence types (STs) were found amongst 310 pneumococci. A decline in PCV-7 related STs was observed during the study period. STs 62, 199, 433 and 1692 increased after the implementation of PCV-7 and were related to increases in serotypes 11A, 19A, 22F, and to serotype 6C, respectively. Overall, a strong correlation was observed between ST and serotype. Thirteen STs contained multiple serotypes and 74 STs were associated with only one serotype. On-going molecular epidemiological surveillance of pneumococcal carriage is warranted during the implementation of pneumococcal conjugate vaccines
Potential impact of conjugate vaccine on the incidence of invasive pneumococcal disease among children in Scotland
No full textWe sought to determine the potential impact of seven-valent pneumococcal conjugate vaccine on the incidence of invasive pneumococcal disease (IPD) among children in Scotland. Invasive pneumococci from blood and cerebrospinal fluid, isolated between 2000 and 2004 from all children aged less than 5 years in Scotland, were characterized by serotyping. Using reported efficacy data of the seven-valent pneumococcal conjugate vaccine (PCV7) along with likely coverage rates, we made an estimation of the potential impact on the incidence of IPD among children in Scotland. A total of 217 pneumococci were characterized into 22 different serogroups/types, the most common, in rank order, being 14, 19F, 6B, 18C, 23F, 9V, 4, 1, 19A, and 6A. Estimated serotype coverage for PCV7 was 76.5% in those aged less than 5 years of age but increased to 88.9% for those aged 1 year. By using serotype coverage and estimates of vaccine efficacy and uptake, the potential impact of the vaccine for those greater than 2 months of age, but less than 5 years, was estimated as 67.3%, leading to an average of 29 preventable cases per year. The introduction of PCV7 into the childhood immunization schedule would reduce the burden of pneumococcal disease in children, and the incidence would be particularly reduced in those children aged 1 year. Additional benefits may be gained in adults through herd protection. Continued surveillance of IPD is required before, during, and after the introduction of PCV7
Comparative genomics of carriage and disease isolates of Streptococcus pneumoniae serotype 22F reveals lineage specific divergence and niche adaptation
Full text linkStreptococcus pneumoniaeis a major cause of meningitis, sepsis and pneumonia worldwide. Pneumococcal conjugate vaccines (PCV) have been part of the UK's childhood immunisation programme since 2006 and have significantly reduced the incidence of disease due to vaccine efficacy in reducing carriage in the population. Here we isolated two clones of 22F (an emerging serotype of clinical concern, multilocus sequence types (MLST) 433 and 698) and conducted comparative genomic analysis on four isolates, paired by ST with one of each pair being derived from carriage and the other disease (sepsis). The most compelling observation was of non-synonymous mutations inpgdA, encoding peptidoglycanN-acetylglucosamine deacetylase A, which were found in the carriage isolates of both ST433 and 698. Deacetylation of pneumococcal peptidoglycan is known to enable resistance to lysozyme upon invasion. Whilst no other clear genotypic signatures related to disease or carriage could be determined, additional intriguing comparisons between the two STs were possible. These include the presence of an intact prophage, in addition to numerous additional phage insertions, within the carriage isolate of ST433. Contrasting gene repertoires related to virulence and colonisation, including: bacteriocins, lantibiotics, and toxin-antitoxin systems, were also observed
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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