133 research outputs found
Characterization of the Prophage Repertoire of African Salmonella Typhimurium ST313 Reveals High Levels of Spontaneous Induction of Novel Phage BTP1
In the past 30 years,Salmonella bloodstream infections have become a significant health problem in sub-Saharan Africa and are responsible for the deaths of anestimated 390,000 people each year. The disease is predominantly caused by a recently described sequence type of SalmonellaTyphimurium: ST313, which has a distinctive set of prophage sequences. We have thoroughly characterized the ST313-associated prophages both genetically and experimentally. ST313 representative strain D23580 contains five full-length prophages: BTP1, Gifsy-2D23580, ST64BD23580, Gifsy-1D23580,and BTP5. We show that commonS.Typhimurium prophages Gifsy-2, Gifsy-1, andST64B are inactivated in ST313 by mutations. Prophage BTP1 was found to be a functional novel phage, and the first isolate of the proposed new species “Salmonellavirus BTP1”, belonging to the P22virusgenus. Surprisingly,∼109BTP1 virus particlesperml were detected in the supernatant of non-induced, stationary-phase culturesof strain D23580, representing the highest spontaneously induced phage titer so farreported for a bacterial prophage. High spontaneous induction is shown to be anintrinsic property of prophage BTP1, and indicates the phage-mediated lysis of around0.2% of the lysogenic population. The fact that BTP1 is highly conserved in ST313 poses interesting questions about the potential fitness costs and benefits of novel prophagesin epidemicS.Typhimurium ST313
Isolation and characterisation of bacteriophages with activity against invasive non-typhoidal Salmonella causing blood-stream infection in Malawi
In recent years, novel lineages of invasive non-typhoidal Salmonella (iNTS) serovars Typhimurium and Enteritidis have been identified in patients with bloodstream infection in sub-Saharan Africa. Here, we isolated and characterised 32 phages capable of infecting S. Typhimurium and S. Enteritidis, from water sources in Malawi and the UK. The phages were classified in three major phylogenetic clusters that were geographically distributed. In terms of host range, Cluster 1 phages were able to infect all bacterial hosts tested, whereas Clusters 2 and 3 had a more restricted profile. Cluster 3 contained two sub-clusters, and 3.b contained the most novel isolates. This study represents the first exploration of the potential for phages to target the lineages of Salmonella that are responsible for bloodstream infections in sub-Saharan Africa
Sequential Acquisition of T Cells and Antibodies to Nontyphoidal Salmonella in Malawian Children
Background
Salmonella Typhimurium (STm) remain a prominent cause of bacteremia in sub-Saharan Africa. Complement-fixing antibodies to STm develop by 2 years of age. We hypothesized that STm-specific CD4+ T cells develop alongside this process.
Methods
Eighty healthy Malawian children aged 0–60 months were recruited. STm-specific CD4+ T cells producing interferon γ, tumor necrosis factor α, and interleukin 2 were quantified using intracellular cytokine staining. Antibodies to STm were measured by serum bactericidal activity (SBA) assay, and anti-STm immunoglobulin G antibodies by enzyme-linked immunosorbent assay.
Results
Between 2006 and 2011, STm bacteremias were detected in 449 children <5 years old. STm-specific CD4+ T cells were acquired in infancy, peaked at 14 months, and then declined. STm-specific SBA was detectable in newborns, declined in the first 8 months, and then increased to a peak at age 35 months. Acquisition of SBA correlated with acquisition of anti–STm–lipopolysaccharide (LPS) immunoglobulin G (r = 0.329 [95% confidence interval, .552–.062]; P = .01) but not anti–STm–outer membrane protein or anti–STm-flagellar protein (FliC).
Conclusions
Acquisition of STm-specific CD4+ T cells in early childhood is consistent with early exposure to STm or cross-reactive protein antigens priming this T-cell development. STm-specific CD4+ T cells seem insufficient to protect against invasive nontyphoidal Salmonella disease, but sequential acquisition of SBA to STm LPS is associated with a decline in its incidence
The Reframing of Methodology: Revisiting a PhD Study
The paper draws on a PhD study to explore some methodological dilemmas associated with the execution of qualitative research when framed within positivist study design. The PhD was linked to an externally funded research project which evaluated the implementation of a custody-based intervention in the secure estate. While the PhD was conceived as a qualitative study, informed by interpretivist methodology and associated epistemology, the wider funded study was informed by positivist tradition and used a quantitative method. This led to dilemmas of both practical and methodological nature. The author revisits her study's methodological position to review issues raised by the research design and suggests an alternative proposal informed methodologically by critical realism which may better serve the study's interests. In doing so, the paper suggests how revisiting previous research may assist us in gaining methodological understanding and allow us to reframe our future endeavours to more useful end
Febrile Illness Evaluation in a Broad Range of Endemicities (FIEBRE): protocol for a multisite prospective observational study of the causes of fever in Africa and Asia.
INTRODUCTION NlmCategory: BACKGROUND content:
Fever commonly leads to healthcare seeking and hospital
admission in sub-Saharan Africa and Asia. There is only limited
guidance for clinicians managing non-malarial fevers, which
often results in inappropriate treatment for patients.
Furthermore, there is little evidence for estimates of disease
burden, or to guide empirical therapy, control measures,
resource allocation, prioritisation of clinical diagnostics or
antimicrobial stewardship. The Febrile Illness Evaluation in a
Broad Range of Endemicities (FIEBRE) study seeks to address
these information gaps. - Label: METHODS AND ANALYSIS
NlmCategory: UNASSIGNED content: FIEBRE investigates febrile
illness in paediatric and adult outpatients and inpatients using
standardised clinical, laboratory and social science protocols
over a minimum 12-month period at five sites in sub-Saharan
Africa and Southeastern and Southern Asia. Patients presenting
with fever are enrolled and provide clinical data, pharyngeal
swabs and a venous blood sample; selected participants also
provide a urine sample. Laboratory assessments target infections
that are treatable and/or preventable. Selected point-of-care
tests, as well as blood and urine cultures and antimicrobial
susceptibility testing, are performed on site. On day 28,
patients provide a second venous blood sample for serology and
information on clinical outcome. Further diagnostic assays are
performed at international reference laboratories. Blood and
pharyngeal samples from matched community controls enable
calculation of AFs, and surveys of treatment seeking allow
estimation of the incidence of common infections. Additional
assays detect markers that may differentiate bacterial from
non-bacterial causes of illness and/or prognosticate illness
severity. Social science research on antimicrobial use will
inform future recommendations for fever case management.
Residual samples from participants are stored for future use. -
Label: ETHICS AND DISSEMINATION NlmCategory: UNASSIGNED content:
Ethics approval was obtained from all relevant institutional and
national committees; written informed consent is obtained from
all participants or parents/guardians. Final results will be
shared with participating communities, and in open-access
journals and other scientific fora. Study documents are
available online (https://doi.org/10.17037/PUBS.04652739)
A Study of Characteristics of work of the school teacher for every place of work -What should be know with the staff of mental health support?-
学校教師の仕事は非常に複雑で難しく、教師は非常に多忙である。そのため、教師のメンタルヘルスは次第に悪化し、休職者も増える傾向である。ところが精神科医やカウンセラーなどの教師を支援する立場にある専門家の中には、「教師の仕事は楽である」という誤解をしているものもいる。それでは十分な支援ができるはずもない。筆者は、支援にあたる者が、教師の業務の特性や学校組織の特徴を知りことが重要であると考えた。そこで小学校、中学校、高等学校ごとに、その職場の特性や人間関係の特徴を列記し、不調の背景要因を整理した。The school teachers' works are very complicated and difficult, and most of teachers are very busy. Therefore, the state of teachers' mental health is in a very bad tendency. However, among the specialists in the position which supports teachers, such as a psychiatrist and counselor, there are those who have misunderstanding, saying "A teacher's work is easy". The writer thought it important that a psychiatrist and counselor got to know the characteristic of a teacher's work and culture peculiar to school. So, in thia paper, the writer summarized the characteristic of the work for every elementary school, junior high school, and high school, and described the factor to which a school teacher becomes out of condition mentally
Bacterial Meningitis in Malawian Adults, Adolescents, and Children During the Era of Antiretroviral Scale-up and Haemophilus influenzae Type b Vaccination, 2000-2012
Background
We documented bacterial meningitis trends among adults and children presenting to a large teaching hospital in Malawi during introduction of Haemophilus influenzae type b (Hib) vaccination and the rollout of antiretroviral therapy (ART).
Methods
We analyzed data from 51 000 consecutive cerebrospinal fluid (CSF) samples obtained from adults, adolescents, and children with suspected meningitis admitted to the Queen Elizabeth Central Hospital, Blantyre, Malawi, between 2000 and 2012.
Results
There was a significant decline in the total number of CSF isolates over 12 years (incident rate ratio [IRR], 0.93; 95% CI, .92–.94; P < .001). This decline was entirely in children aged <5 years (IRR, 0.87; 95% CI, .85–.88; P < .001) and coincided with the introduction of Hib vaccination. The number of adult isolates has remained unchanged (IRR, 0.99; 95% CI, .97–1.0; P = .135) despite rapid scale-up of ART provision. In children aged <5 years, Streptococcus pneumoniae, nontyphoidal salmonellae (NTS), and Hib were the most frequently isolated pathogens, and have declined over this time period. Streptococcus pneumoniae was the most frequently isolated pathogen in older children and adults. Estimated incidence of bacterial meningitis in 2012 was 20 per 100 000 cases in children aged <14 years, 6 per 100 000 adolescents, and 10 per 100 000 adults.
Conclusions
Rates of bacterial meningitis have declined in children, but not adults, coinciding with the introduction of Hib vaccination. The highly successful rollout of ART has not yet resulted in a reduction in the incidence in adults where the burden remains high. Long-term surveillance of bacterial meningitis outside of the epidemic “meningitis belt” in Africa is essential
Typhoid Fever and Invasive Nontyphoid Salmonellosis, Malawi and South Africa
To determine the prevalence of invasive nontyphoid salmonellosis and typhoid fever in Malawi and South Africa, we compared case frequency and patient age distribution. Invasive nontyphoid salmonellosis showed a clear bimodal age distribution; the infection developed in women at a younger age than in men. Case frequency for typhoid fever was lower than for salmonellosis
Young people's uses of celebrity: Class, gender and 'improper' celebrity
This is an Author's Accepted Manuscript of an article published in Discourse: Studies in the Cultural
Politics of Education, 34(1), 2013, copyright Taylor & Francis, available online at:
http://www.tandfonline.com/10.1080/01596306.2012.698865.In this article, we explore the question of how celebrity operates in young people's everyday lives, thus contributing to the urgent need to address celebrity's social function. Drawing on data from three studies in England on young people's perspectives on their educational and work futures, we show how celebrity operates as a classed and gendered discursive device within young people's identity work. We illustrate how young people draw upon class and gender distinctions that circulate within celebrity discourses (proper/improper, deserving/undeserving, talented/talentless and respectable/tacky) as they construct their own identities in relation to notions of work, aspiration and achievement. We argue that these distinctions operate as part of neoliberal demands to produce oneself as a ‘subject of value’. However, some participants produced readings that show ambivalence and even resistance to these dominant discourses. Young people's responses to celebrity are shown to relate to their own class and gender position.The Arts and Humanities Research Council, the British Academy, the
Economic and Social Research Council, and the UK Resource Centre for
Women in Science Engineering and Technology
Cryo-EM structure and molecular dynamics analysis of the fluoroquinolone resistant mutant of the AcrB transporter from salmonella
Salmonella is an important genus of Gram-negative pathogens, treatment of which has become problematic due to increases in antimicrobial resistance. This is partly attributable to the overexpression of tripartite efflux pumps, particularly the constitutively expressed AcrAB-TolC. Despite its clinical importance, the structure of the Salmonella AcrB transporter remained unknown to-date, with much of our structural understanding coming from the Escherichia coli orthologue. Here, by taking advantage of the styrene maleic acid (SMA) technology to isolate membrane proteins with closely associated lipids, we report the very first experimental structure of Salmonella AcrB transporter. Furthermore, this novel structure provides additional insight into mechanisms of drug efflux as it bears the mutation (G288D), originating from a clinical isolate of Salmonella Typhimurium presenting an increased resistance to fluoroquinolones. Experimental data are complemented by state-of-the-art molecular dynamics (MD) simulations on both the wild type and G288D variant of Salmonella AcrB. Together, these reveal several important differences with respect to the E. coli protein, providing insights into the role of the G288D mutation in increasing drug efflux and extending our understanding of the mechanisms underlying antibiotic resistance
- …