Growth of MRSA and Pseudomonas aeruginosa in a fine-celled foam model containing sessile commensal skin bacteria

Sessile cultures of the skin bacteria Staphylococcus saprophyticus and Corynebacterium xerosis were grown using novel fine-celled foam substrata to test the outcome of challenge by methicillin-resistant Staphylococcus aureus or Pseudomonas aeruginosa under three growth medium regimens (simulated sweat, simulated serum or simulated sweat substituted with simulated serum during the microbial challenge). S. saprophyticus and C. xerosis significantly limited MRSA and P. aeruginosa immigration respectively, under the simulated sweat and serum medium regimes. Under the substitution medium regime however, MRSA and P. aeruginosa integrated into pre-established biofilms to a significantly greater extent, attaining cell densities similar to the axenic controls. The outcome of challenge was influenced by the medium composition and test organism but could not be predicted based on planktonic competition assays or growth dynamics. Interactions between skin and wound isolates could be modelled using the fine-celled foam-based system. This model could be used to further investigate interactions and also in preclinical studies of antimicrobial wound care regimens

Dysregulation of visual motion inhibition in major depression

Individuals with depression show depleted concentrations of the inhibitory neurotransmitter GABA in occipital (visual) cortex, predicting weakened inhibition within their visual systems. Yet, visual inhibition in depression remains largely unexplored. To fill this gap, we examined the inhibitory process of centersurround suppression (CSS) of visual motion in depressed individuals. Perceptual performance in discriminating the direction of motion was measured as a function of stimulus presentation time and contrast in depressed individuals (n¼27) and controls (n¼22). CSS was operationalized as the accuracy difference between conditions using large (7.5°) and small (1.5°) grating stimuli. Both depressed and control participants displayed the expected advantage in accuracy for small stimuli at high contrast. A significant interaction emerged between subject group, contrast level and presentation time, indicating that alterations of CSS in depression were modulated by stimulus conditions. At high contrast, depressed individuals showed significantly greater CSS than controls at the 66 ms presentation time (where the effect peaked in both groups). The results' specificity and dependence on stimulus features such as contrast, size and presentation time suggest that they arise from changes in early visual processing, and are not the results of a generalized deficit or cognitive bias.Accepted versio

Attenuated Virulence and Biofilm Formation in Staphylococcus aureus following Sublethal Exposure to Triclosan

Sub-effective exposure of Staphylococcus aureus to the biocide triclosan can reportedly induce a small colony variant (SCV) phenotype in Staphylococcus aureus. S. aureus SCVs are characterised by slow growth rates, reduced pigmentation and lowered antimicrobial susceptibility. Whilst they may exhibit enhanced intracellular survival, there are conflicting reports regarding their pathogenicity. The current study reports the characteristics of a SCV-like strain of S. aureus, created by repeated passage on sub-lethal triclosan concentrations. S. aureus ATCC 6538 (P0) was serially exposed ten times to concentration gradients of triclosan to generate strain P10. This strain was then further passaged ten times on triclosan-free medium (designated x10). The minimum inhibitory and bactericidal concentrations of triclosan for P0, P10 and x10 were determined and growth rates measured in biofilm and planktonic culture. Haemolysin, DNAse and coagulase activities were measured and virulence determined using a Galleria mellonella pathogenicity model. Strain P10 exhibited decreased susceptibility to triclosan and characteristics of a SCV phenotype, including considerably reduced growth rate and the formation of pinpoint colonies. However, this strain also had delayed coagulase production, impaired haemolysis (p<0.01), was defective in biofilm formation and DNAase activity, and displayed significantly attenuated virulence. Colony size, haemolysis, coagulase activity and virulence were only partially restored in strain x10, whereas planktonic growth rate was fully restored. However, x10 was at least as defective in biofilm formation and DNAse production as P10. These data suggest that although repeated exposure to triclosan may result in a SCV-like phenotype, this is not necessarily associated with increased virulence, and adapted bacteria may exhibit other functional deficiencies

The Experiences of People Who Quit Khat and the Health Care Professionals Who Support them

Background: This study aimed to explore the barriers and enablers to quitting khat from the perspective of users and the barriers and enablers to supporting users to quit from the healthcare professional (HCP) perspective. Methods: A qualitative study using semi-structured interviews and the Theoretical Domains Framework (TDF) to collect and analyse data. Results: Overall 10 khat users and 3 professionals were interviewed. Beliefs about the consequences of continued use facilitated user’s decisions to quit. Social influences were a barrier and enabler. For professionals, the social influence of other colleagues and working together was key in enabling them to support clients. Social / professional role and identity was also an important enabler, as professionals saw supporting users to quit as an integral part of their role. A range of behaviour change techniques was identified as potential ways in which quit attempts could be more successful, from the user and professionals perspective. Conclusions: The study reveals the complexity of khat chewing and quitting from the perspective of khat users, such as the varied influence of family and friends. It also identifies the many barriers and enablers that professionals experience when supporting individuals to quit, such as working with other professionals. There is little evidence for the effectiveness of current quit khat services or little information outlining how they were developed. Current services would benefit from evaluating the effectiveness of the interventions using established methodology. Recommendations for practice in the field of substance misuse have been identified

Optimization of Advertising Resources over Time: A Strategic Analysis

AMS subject classification: 90B60, 90B50, 90A80.Strategic behaviour has long been a crucial issue for modern corporations. To maximize potential profits and market share, firms are more than willing to invest in sales promotion to boost long term manufacturing output. Knowing that the sales of the firm not only respond to own advertising budgets, but also depend upon rivals’ advertising strategies, oligopolistic firms form part, therefore of a continuous race with reference to non-price competition. Efficient use of investment resources is crucial for business operations and long term strategic success. This paper aims to investigate the key issue of optimization of strategic advertising outlays. By using mathematical modelling techniques, strategic linkages between rival companies are identified and advertising impacts explained. Since advertising influences can persist through time, our discussion extends to explore this fundamental point by constructing a more advanced model to examine into the problems of optimization over time. Empirical data is used to test the predictive power of these models and assess relative efficiencies. All in all, this paper intends to highlight the importance of continuous strategic advertising investment and consequently provides comprehensive insights into the impact of modern advertising functions over time

Autofluorescence imaging – a useful adjunct in imaging macular trauma

Autofluorescence imaging is a rapid, noninvasive technique, with several applications becoming slowly integrated into ophthalmic clinical practice. We describe its use as a valuable tool for predicting the function of the retinal pigment epithelium following damage from blunt ocular trauma

Are diabetes self-management programmes for the general diabetes population effective for people with severe mental illness?: a systematic review.

Background: Diabetes self-management education programmes are effective in improving health outcomes in the general population with diabetes. However, it is not known if these programmes include people who also have a severe mental illness (SMI) and, if so, what their outcomes are. The aim of this review was to examine if evaluations of diabetes self-management education programmes included people with SMI, and if so, whether the interventions were beneficial for this population. Methods: The inclusion criteria for this systematic review, defined by PICOS criteria, were: Population - Adults with type 2 diabetes; Intervention - self-management education programme; Comparator – another active intervention or usual care; Outcomes of interest – inclusion of people with SMI and the clinical, behavioural and psychosocial outcomes in this population; Study design - randomised controlled trials. The following bibliographic databases were searched from January 2004 to April 2018: Cochrane Library, Medline, Embase, PsychINFO, Allied and Complimentary Medicine Database, Health Technology Assessment, NHS Economic Evaluations Database and CINAHL. Data were extracted on study characteristics, inclusion and exclusion criteria, participant and intervention characteristics, number of participants with SMI, and outcomes for people with SMI, if reported. Authors were contacted by email for missing data. Results: A total of 410 trials were included. At least 42% of trials did not recruit any participants with SMI. Only nine confirmed inclusion of participants with SMI, of which six provided data on the number recruited. These six trials recruited a total of 1009 participants, of whom 31 (3.1%) had SMI. It was not possible to assess intervention effectiveness for people with SMI as none of the trials reported outcomes for these participants. Conclusions: This systematic review confirms that people with SMI are often excluded from trials of diabetes self-management education, resulting in a lack of an evidence base on which to base treatment paths for this vulnerable population. It cannot be assumed that programmes developed for the general diabetes population meet the needs of people with SMI. Future research needs to examine if and how these programmes could be adapted for people with SMI or if new programmes are required

Lactobacillus rhamnosus GG inhibits the toxic effects of Staphylococcus aureus on epidermal keratinocytes

Few studies have evaluated the potential benefits of the topical application of probiotic bacteria or material derived from them. We have investigated whether a probiotic bacterium, Lactobacillus rhamnosus GG, can inhibit Staphylococcus aureus infection of human primary keratinocytes in culture. When primary human keratinocytes were exposed to S. aureus, only 25% of the keratinocytes remained viable following 24 h of incubation. However, in the presence of 10(8) CFU/ml of live L. rhamnosus GG, the viability of the infected keratinocytes increased to 57% (P = 0.01). L. rhamnosus GG lysates and spent culture fluid also provided significant protection to keratinocytes, with 65% (P = 0.006) and 57% (P = 0.01) of cells, respectively, being viable following 24 h of incubation. Keratinocyte survival was significantly enhanced regardless of whether the probiotic was applied in the viable form or as cell lysates 2 h before or simultaneously with (P = 0.005) or 12 h after (P = 0.01) S. aureus infection. However, spent culture fluid was protective only if added before or simultaneously with S. aureus. With respect to mechanism, both L. rhamnosus GG lysate and spent culture fluid apparently inhibited adherence of S. aureus to keratinocytes by competitive exclusion, but only viable bacteria or the lysate could displace S. aureus (P = 0.04 and 0.01, respectively). Furthermore, growth of S. aureus was inhibited by either live bacteria or lysate but not spent culture fluid. Together, these data suggest at least two separate activities involved in the protective effects of L. rhamnosus GG against S. aureus, growth inhibition and reduction of bacterial adhesion