Human nasal challenge with Streptococcus pneumoniae is immunising in the absence of carriage.

Infectious challenge of the human nasal mucosa elicits immune responses that determine the fate of the host-bacterial interaction; leading either to clearance, colonisation and/or disease. Persistent antigenic exposure from pneumococcal colonisation can induce both humoral and cellular defences that are protective against carriage and disease. We challenged healthy adults intra-nasally with live 23F or 6B Streptococcus pneumoniae in two sequential cohorts and collected nasal wash, bronchoalveolar lavage (BAL) and blood before and 6 weeks after challenge. We hypothesised that both cohorts would successfully become colonised but this did not occur except for one volunteer. The effect of bacterial challenge without colonisation in healthy adults has not been previously assessed. We measured the antigen-specific humoral and cellular immune responses in challenged but not colonised volunteers by ELISA and Flow Cytometry. Antigen-specific responses were seen in each compartment both before and after bacterial challenge for both cohorts. Antigen-specific IgG and IgA levels were significantly elevated in nasal wash 6 weeks after challenge compared to baseline. Immunoglobulin responses to pneumococci were directed towards various protein targets but not capsular polysaccharide. 23F but not 6B challenge elevated IgG anti-PspA in BAL. Serum immunoglobulins did not increase in response to challenge. In neither challenge cohort was there any alteration in the frequencies of TNF, IL-17 or IFNγ producing CD4 T cells before or after challenge in BAL or blood. We show that simple, low dose mucosal exposure with pneumococci may immunise mucosal surfaces by augmenting anti-protein immunoglobulin responses; but not capsular or cellular responses. We hypothesise that mucosal exposure alone may not replicate the systemic immunising effect of experimental or natural carriage in humans.

Problem-based learning (PBL): getting the most out of your students - their roles and responsibilities: AMEE Guide No. 84.

This Guide discusses the considerable literature on the merits or shortcomings of Problem-based learning (PBL), and the factors that promote or inhibit it, when seen through the eyes of the student. It seems to be the case that PBL works best when students and faculty understand the various factors that influence learning and are aware of their roles; this Guide deals with each of the main issues in turn. One of the most important concepts to recognise is that students and Faculty share the responsibility for learning and there are several factors that can influence its success. They include student motivation for PBL and the various ways in which they respond to being immersed in the process. As faculty, we also need to consider the way in which the learning environment supports the students develop the habit of life-long learning, and the skills and attitudes that will help them become competent reflective practitioners. Each of these elements place responsibilities upon the student, but also upon the Faculty and learning community they are joining. Although all of the authors work in a European setting, where PBL is used extensively as a learning strategy in many medical schools, the lessons learned we suggest, apply more widely, and several of the important factors apply to any form of curriculum. This Guide follows on from a previous review in the AMEE Guides in Medical education series, which provided an overview of PBL and attempts to emphasise the key role that students have in mastering their subject through PBL. This should render the business of being a student a little less mystifying, and help faculty to see how they can help their students acquire the independence and mastery that they will need.

Tablet versus paper marking in assessment: feedback matters.

BACKGROUND: The Objective Structured Clinical Examination (OSCE) is a cornerstone in healthcare assessment. As a potential tool for providing learner-centred feedback on a large scale, the use of tablet devices has been proposed for the recording of OSCE marks, moving away from the traditional, paper-based checklist. METHODS: Examiner-recorded comments were collated from successive first year formative and summative OSCE examinations, with paper-based checklists used in 2012 and iPad-based checklists used in 2013. A total of 558 and 498 examiner-candidate interactions took place in the January OSCE examinations, and 1402 and 1344 for the May OSCE examination for 2012 and 2013 respectively. Examiner comments were analyzed for quantity and quality. A tool was developed and validated to assess the quality of the comments left by examiners for use as feedback (Kappa = 0.625). RESULTS: A direct comparison of paper-based checklists and iPad-recorded examinations showed an increase in the quantity of comments left from 41 to 51 % (+ 10 %). Furthermore, there was an increase in the number of comments left for students deemed 'borderline': + 22 %. In terms of the quality of the comments for feedback, there was a significant improvement (p < 0.001) between comments left in written-recorded and iPad-recorded examinations. CONCLUSIONS: iPad-marked examinations resulted in a greater quantity and quality of examiner comment for use as feedback, particularly for students performing less well, enabling tutors to direct further learning for these students.