Sarah J. Pitt

Antimicrobial properties of mucus from the brown garden snail Helix aspersa

Abstract Research into naturally occurring antimicrobial substances has yielded effective treatments. One area of interest is peptides and proteins produced by invertebrates as part of their defence system, including the contents of mollusc mucus. Mucus produced by the African giant land snail, Achatina fulica has been reported to contain two proteins with broad-spectrum antibacterial activity. Mucus from the brown garden snail, Helix aspersa, appears to have skin regeneration properties. This study sought to investigate the antimicrobial properties of H. aspersa mucus. Mucus was collected from H. aspersa snails, diluted in phosphate-buffered saline (PBS), with the supernatant tested against a wide range of organisms in a disc-diffusion antimicrobial assay. This was followed with comparative experiments involving A. fulica, including bacteriophage assays. Mucus from both species of snail was passed through a series of protein size separation columns in order to determine the approximate size of the antimicrobial substance. Electrophoresis was also carried out on the H. aspersa mucus. Results indicated that H. aspersa mucus had a strong antibacterial effect against several strains of Pseudomonas aeruginosa and a weak effect against Staphylococcus aureus. Mucus from A. fulica also inhibited the growth of S. aureus, but the broad spectrum of activity reported by other workers was not observed. Antimicrobial activity was not caused by bacteriophage. Size separation experiments indicated that the antimicrobial substance(s) in H. aspersa were between 30 and 100 kDa. Electrophoresis revealed two proteins in this region (30–40 kDa and 50–60 kDa). These do not correspond with antimicrobial proteins previously reported in A. fulica. This study found one or more novel antimicrobial agents in H. aspersa mucus, with a strong effect against P. aeruginosa.

The value of computer based formative assessment in undergraduate biological science teaching

Abstract The impact of introducing computer-based self-assessment quizzes on examination performance was monitored in 5 modules delivered to undergraduate students in the first, second, and final years at university over a 2–3 year period. The patterns of usage were also monitored to determine the extent to which the quizzes were used and whether there were differences between the students at different stages of their education. Overall, all groups used the CBA package in broadly similar ways, although year 1 students were least likely to access their quiz. Most students used the quizzes during normal ‘office hours’ between Monday and Friday, but up to 22% of use occurred in the evenings and 3–20% at weekends. Most log-on events were recorded in the weeks immediately prior to an examination. There was a positive relationship between the introduction of the quizzes and mean examination mark; in particular, increases in the proportion of students obtaining good (>60%) marks were observed. The results suggest that the provision of computer-based self-assessment quizzes is helpful to students and that the opportunity to access them at any time is appreciated. At present, it appears that the more motivated individuals are assisted most by the quizzes. Integration of formative CBA into a programme of learning appears to be beneficial, particularly when used in conjunction with other forms of formative assessment.

Diagnostic virology and patient care: from vaguely interesting to vitally important

Abstract The existence of pathogenic viruses was inferred by experiments at the turn of the twentieth century. Key developments in detection of viruses, including electron microscopy and monolayer cell culture, were made in the middle of that century. However, in terms of patient care, the results from the virology laboratory often arrived the patient was ‘better or dead’. The advent of molecular techniques, particularly polymerase chain reaction and more recently whole genome sequencing made timely and accurate diagnosis of viral infections feasible. A range of approaches have been taken to identify and characterise new viruses. Vaccines against viruses have made it possible to eliminate two pathogenic mammalian viruses altogether, with several others close to eradication. The role of biomedical scientists working in diagnostic virology is more relevant to patient care than ever.

The contribution of hand drying in prevention of transmission of microorganisms: Comparison of the efficacy of three hand drying methods in the removal and distribution of microorganisms

Background: Hand hygiene is a key tool in infection control. While methods of hand washing have been widely researched, there have been fewer studies investigating the effectiveness of available ways to dry hands in public areas. Aims: This study compared the efficacy of using paper towels (PT), warm air dryers (WAD) and jet air dryers (JAD) after hand washing in terms of microbiological effectiveness and potential for dispersal of pathogens. Methods: Microbial flora on palms and fingertips of 30 subjects were sampled on nutrient agar plates before washing hands and after drying with PTs, WADs and JADs. Total colony forming units (cfus) were recorded. Walls in the vicinity of a PT dispenser, WAD and JAD in female and male washrooms were sampled for the presence of viable microorganisms. Results: Mean cfu significantly reduced after drying with PTs (palms t= 2.67, p <0.05; fingertips t=4.44, p<0.01) significantly increased after using WADs (palms t=3.11, p<0.01; fingertips t=2.06, p<0.05), but there was no difference with JAD (palms t= 1.85, p>0.05; fingertips t=0.97, p>0.05). Some dispersal of organisms was detected on the washroom walls, with the least distribution around PT dispensers and unusual opportunistic pathogens isolated from the JAD units. Discussion: PTs are more effective at drying hands than WADs and JADs, they are more likely to be used appropriately and lead to minimal dispersal of microorganisms from wet hands.

Clinical Microbiology for Diagnostic Laboratory Scientists

This book is intended for post‐registration and post‐graduate level scientists who are developing careers in diagnostic clinical microbiology. It is suitable for those who are working in hospital laboratories while studying for advanced qualifications, as well as full‐time MSc students. The aim is to prompt readers to make connections between the clinical symptoms, pathogenesis of infections and the approaches used in laboratory diagnosis. This is not a comprehensive account of all aspects of clinical microbiology, but a consideration of a range of infections caused by selected pathogenic bacteria, viruses, fungi, protozoa and helminths. The idea is to use these examples to illustrate clinical and diagnostic issues, to stimulate critical appraisal of p idence and to encourage problem‐solving in the clinical laboratory context.

Biomedical scientist training officers' evaluation of integrated (co-terminus) Applied Biomedical Science BSc programmes: a multicentre study.

Abstract The introduction of the Institute of Biomedical Science (IBMS) portfolio for pre-registration training in 2003 allowed universities to develop integrated (co-terminus) biomedical science BSc programmes. Students undertake structured placements within clinical pathology laboratories as part of their degree. The clinical training and professional development of students is undertaken by training officers (TOs), who are experienced Health Professions Council (HPC)-registered biomedical scientists and usually also members of the IBMS. This study aims to evaluate TOs’ perceptions of these integrated degrees as a means of delivering pre-registration training for biomedical scientists. A questionnaire to collect quantitative data and be completed anonymously was sent to TOs, via staff at participating universities. Items considered TOs’ perceptions in four categories: how well students fitted into the laboratory team, their professional and scientific development, the impact of delivering integrated degrees on service delivery, and the commitment to training students. Surveys took place in 2007, 2008 and 2009 and involved TOs taking students from 10, 14 and 17 universities each year, respectively. The response rates to the survey were 60% in 2007, 34% in 2008 and 12% in 2009. Participants were representative in terms of age, gender and pathology discipline and had a broad range of experience with students. The overall mean score for TOs perceptions was 3.38 in 2007 which increased significantly to 3.99 in 2009 (Kruskall Wallis test χ2 = 21.13, P<0.01). Mean scores in three of the four categories were positive in 2007, although the impact on service delivery was perceived negatively. In all areas, means were significantly greater in 2009. The results indicate that TOs view the integrated degrees favourably and are happy with the scientific and professional development of students. Although designing training sessions suitable for undergraduates took extra work initially, TOs are committed to delivering the training.