Understanding MRSA clonal competition within a UK hospital; the possible importance of density dependence

Background Methicillin resistant Staphylococcus aureus (MRSA) bacteria cause serious, often healthcare-associated infections and are frequently highly resistant to diverse antibiotics. Multiple MRSA clonal complexes (CCs) have evolved independently and countries have different prevalent CCs. It is unclear when and why the dominant CC in a region may switch. Methods We developed a mathematical deterministic model of MRSA CC competing for limited resource. The model distinguishes ‘standard MRSA’ and multidrug resistant sub-populations within each CC, allowing for resistance loss and transfer between same CC bacteria. We first analysed how dynamics of this system depend on growth-rate and resistance-potential differences between CCs, and on their resistance gene accumulation. We then fit the model to capture the longitudinal CC dynamics observed at a single UK hospital, which exemplified the UK-wide switch from mainly CC30 to mainly CC22. Results We find that within a CC, gain and loss of resistance can allow for co-existence of sensitive and resistant sub-populations. Due to more efficient transfer of resistance at higher CC density, more drug resistance can accumulate in the population of a more prevalent CC. We show how this process of density dependent competition, together with prevalence disruption, could explain the relatively sudden switch from mainly CC30 to mainly CC22 in the UK hospital setting. Alternatively, the observed hospital dynamics could be reproduced by assuming that multidrug resistant CC22 evolved only around 2004. Conclusions We showed how higher prevalence may advantage a CC by allowing it to acquire antimicrobial resistances more easily. Due to this density dependence in competition, dominance in an area can depend on historic contingencies; the MRSA CC that happened to be first could stay dominant because of its high prevalence advantage. This then could help explain the stability, despite frequent stochastic introductions across borders, of geographic differences in MRSA CC

Sympatric Speciation: When Is It Possible in Bacteria?

This study investigated a potential auditory illusion in duration perception induced by rhythmic temporal contexts. Listeners with or without musical training performed a duration discrimination task for a silent period in a rhythmic auditory sequence. The critical temporal interval was presented either within a perceptual group or between two perceptual groups. We report the just-noticeable difference (difference limen, DL) for temporal intervals and the point of subjective equality (PSE) derived from individual psychometric functions based on performance of a two-alternative forced choice task. In musically untrained individuals, equal temporal intervals were perceived as significantly longer when presented between perceptual groups than within a perceptual group (109.25% versus 102.5% of the standard duration). Only the perceived duration of the between-group interval was significantly longer than its objective duration. Musically trained individuals did not show this effect. However, in both musically trained and untrained individuals, the relative difference limens for discriminating the comparison interval from the standard interval were larger in the between-groups condition than in the within-group condition (7.3% vs. 5.6% of the standard duration). Thus, rhythmic grouping affected sensitivity to duration changes in all listeners, with duration differences being harder to detect at boundaries of rhythm groups than within rhythm groups. Our results show for the first time that temporal Gestalt induces auditory duration illusions in typical listeners, but that musical experts are not susceptible to this effect of rhythmic grouping.Ellison Medical FoundationSwiss National Science Foundation (PA00P1_131448/1

Preparing isiXhosa home language teachers for the 21st century classroom: Student teachers' experiences, challenges and reflections

The aim of the article is to identify the gaps between theory and practice in pre-service teacher training with special reference to the teaching of isiXhosa as a home language in the Further Education and Training (FET) phase (Grades 10–12) in some Western Cape high schools. The article is based on data that was collected from Postgraduate Certificate in Education (PGCE) students taking isiXhosa (home language) as one of their teaching method subjects as part of their pre-service training. The data were collected by means of an open-ended questionnaire, semi-structured interviews and an analysis of student teachers’ reflective journals. The article provides an analysis of PGCE students’ experiences and reflections on the teaching of isiXhosa as a home language in schools. It argues that if there is a gap between theory underpinning initial pre-service training and actual practice in schools, there will be no significant improvement in the teaching of isiXhosa as a home language. It concludes by proposing ways of improving both pre-service and in-service teacher education practice to develop African languages as academic or intellectual languages at school level

Communication about genetic testing with breast and ovarian cancer patients: a scoping review

© 2018, The Author(s). Genetic testing of patients with cancer is increasingly offered to guide management, resulting in a growing need for oncology health professionals to communicate genetics information and facilitate informed decision-making in a short time frame. This scoping review aimed to map and synthesise what is known about health professionals’ communication about genetic testing for hereditary breast and ovarian cancer with cancer patients. Four databases were systematically searched using a recognised scoping review method. Areas and types of research were mapped and a narrative synthesis of the findings was undertaken. Twenty-nine papers from 25 studies were included. Studies were identified about (i) information needs, (ii) process and content of genetic counselling, (iii) cognitive and emotional impact, including risk perception and recall, understanding and interpretation of genetic test results, and anxiety and distress, (iv) patients’ experiences, (v) communication shortly after diagnosis and (vi) alternatives to face-to-face genetic counselling. Patients’ need for cancer-focused, personalised information is not always met by genetic counselling. Genetic counselling tends to focus on biomedical information at the expense of psychological support. For most patients, knowledge is increased and anxiety is not raised by pre-test communication. However, some patients experience anxiety and distress when results are disclosed, particularly those tested shortly after diagnosis who are unprepared or unsupported. For many patients, pre-test communication by methods other than face-to-face genetic counselling is acceptable. Research is needed to identify patients who may benefit from genetic counselling and support and to investigate communication about hereditary breast and ovarian cancer by oncology health professionals

Social entrepreneurs in challenging places: A Delphi study of experiences and perspectives

Social Enterprises have grown in number and scope in response to reductions in state-provided welfare and increasing ambition to improve social conditions. While a range of issues have been identified in the literature as affecting the ability of Social Enterprises to successfully conduct their activities, there is currently a dearth of research into the relative influence of these factors. This study explores and ranks the challenges faced by social entrepreneurs in South Wales. Based on a Delphi study with 21 social entrepreneurs, government policy-developers and scholars, it presents a hierarchy of 14 factors, useful instruments for informing social entrepreneurs and policy-makers about the way social enterprises are managed, and how national and local policy should be developed. As part of this, the study also identifies four novel factors that affect the sustainability of social enterprises: ‘Professionalisation of Marketing’, ‘Perception of Validity’, ‘Leadership’ and ‘Situatedness’

Cooperation and virulence in acute Pseudomonas aeruginosa infections

BACKGROUND: Efficient host exploitation by parasites is frequently likely to depend on cooperative behaviour. Under these conditions, mixed-strain infections are predicted to show lower virulence (host mortality) than are single-clone infections, due to competition favouring non-contributing social 'cheats' whose presence will reduce within-host growth. We tested this hypothesis using the cooperative production of iron-scavenging siderophores by the pathogenic bacterium Pseudomonas aeruginosa in an insect host. RESULTS: We found that infection by siderophore-producing bacteria (cooperators) results in more rapid host death than does infection by non-producers (cheats), and that mixtures of both result in intermediate levels of virulence. Within-host bacterial growth rates exhibited the same pattern. Crucially, cheats were more successful in mixed infections compared with single-clone infections, while the opposite was true of cooperators. CONCLUSION: These data demonstrate that mixed clone infections can favour the evolution of social cheats, and thus decrease virulence when parasite growth is dependent on cooperative behaviours

Beneficial immune modulatory effects of a specific nutritional combination in a murine model for cancer cachexia

The majority of patients with advanced cancer are recognised by impaired immune competence influenced by several factors, including the type and stage of the tumour and the presence of cachexia. Recently, a specific nutritional combination containing fish oil, specific oligosaccharide mixture, high protein content and leucine has been developed aimed to support the immune system of cancer patients in order to reduce the frequency and severity of (infectious) complications. In a recently modified animal model cachexia is induced by inoculation of C26 tumour cells in mice. In a pre-cachectic state, no effect was observed on contact hypersensitivity, a validated in vivo method to measure Th1-mediated immune function, after adding the individual nutritional ingredients to the diet of tumour-bearing mice. However, the complete mixture resulted in significantly improved Th1 immunity. Moreover, in a cachectic state, the complete mixture reduced plasma levels of pro-inflammatory cytokines and beneficially affected ex vivo immune function. Accordingly, the combination of the nutritional ingredients is required to obtain a synergistic effect, leading to a reduced inflammatory state and improved immune competence. From this, it can be concluded that the specific nutritional combination has potential as immune-supporting nutritional intervention to reduce the risk of (infectious) complications in cancer patients

Go4it; study design of a randomised controlled trial and economic evaluation of a multidisciplinary group intervention for obese adolescents for prevention of diabetes mellitus type 2

<p>Abstract</p> <p>Background</p> <p>In the Netherlands, the first adolescents with diabetes mellitus type 2 as a result of obesity have recently been diagnosed. Therefore, it is very important that programs aiming at the prevention of type 2 diabetes of obese adolescents are developed and evaluated.</p> <p>Methods</p> <p>Go4it is a multidisciplinary group treatment that focuses on: 1) increasing awareness of the current dietary and physical activity behaviour (i.e. energy balance behaviour), 2) improving diet, 3) decreasing sedentary behaviour, 4) increasing levels of physical activity, and 5) coping with difficult situations. Go4it consists of 7 sessions with an interval of 2–3 weeks.</p> <p>The effectiveness of the multidisciplinary group treatment compared with usual care (i.e. referral to a dietician) was evaluated in a randomised controlled trial. We examined effects on BMI(sds), body composition, energy expenditure, glucose tolerance and insulin resistance (primary outcome measure), as well as dietary and physical activity behaviour and quality of life. An economic evaluation from a societal perspective was conducted alongside the randomised trial to evaluate the cost-effectiveness of the multidisciplinary treatment program vs. usual care.</p> <p>Discussion</p> <p>In this paper we described a multidisciplinary treatment program (Go4it) for obese adolescents and the design of a randomised controlled trial and economic evaluation to evaluate its effectiveness and cost-effectiveness.</p> <p>Trial registration</p> <p>Netherlands Trial Register (ISRCTN27626398).</p