<i>Staphylococcus aureus</i> virulence gene studies : a comparative microarray based approach

The development and application of a partial composite S. aureus virulence-associated gene micro array is described. Epidemic, pandemic and sporadic lineages of healthcare associated(HA-) and community-associated (CA-) S. aureus were compared. The clonal population structure was supported but further evidence for large-scale recombination events was obtained. Phage structural genes linked with the CA phenotype were identified and in silico analysis revealed these to be correlated with phage serogroup. CA strains generally carried a PVL-associated phage either of the A or Fb serogroup, whilst the HA strains predominantly carried sero group B phage. It is proposed that carriage of PVL associated phage rather than the specific pvl genes is correlated with the CA phenotype.These findings further support the role of the accessory genome in shaping the epidemiology of S. aureus.The microarray was used to study gene expression in isogenic strains differing by a deletion in the agr locus. Microarray analysis revealed significant differences between the levels of expression of several genes of the normal and mutant strains. However, RNAIII levels in the non-mutant strain were found to be cell density independent, indicating that the expected quorum sensing mechanism was not functional.Expression profiles of cells grown under biofilm simulating conditions were compared to their planktonic counterparts. Biofilm cells displayed a typical expression profile that was different from both the actively growing planktonic exponential cells and the planktonic stationary cells. The strongest feature of the biofilm state was high level expression of the haemolysin genes. This model therefore is amenable to exploitation in studies designed to improve our understanding of the mechanisms underlining biofilm survival and regulation after long periods of growth

Clinical evaluation of a loop-mediated amplification kit for diagnosis of imported malaria.

BACKGROUND: Diagnosis of malaria relies on parasite detection by microscopy or antigen detection; both fail to detect low-density infections. New tests providing rapid, sensitive diagnosis with minimal need for training would enhance both malaria diagnosis and malaria control activities. We determined the diagnostic accuracy of a new loop-mediated amplification (LAMP) kit in febrile returned travelers. METHODS: The kit was evaluated in sequential blood samples from returned travelers sent for pathogen testing to a specialist parasitology laboratory. Microscopy was performed, and then malaria LAMP was performed using Plasmodium genus and Plasmodium falciparum-specific tests in parallel. Nested polymerase chain reaction (PCR) was performed on all samples as the reference standard. Primary outcome measures for diagnostic accuracy were sensitivity and specificity of LAMP results, compared with those of nested PCR. RESULTS: A total of 705 samples were tested in the primary analysis. Sensitivity and specificity were 98.4% and 98.1%, respectively, for the LAMP P. falciparum primers and 97.0% and 99.2%, respectively, for the Plasmodium genus primers. Post hoc repeat PCR analysis of all 15 tests with discrepant results resolved 4 results in favor of LAMP, suggesting that the primary analysis had underestimated diagnostic accuracy. CONCLUSIONS: Malaria LAMP had a diagnostic accuracy similar to that of nested PCR, with a greatly reduced time to result, and was superior to expert microscopy

Research in Somalia: Opportunities for cooperation

Research cooperation between Somalia and Sweden began in 1982, but was interrupted in the early 1990s due to the civil war. As Somalia gradually starts the process of institution-building and shifting towards a federal system, the Swedish government is considering whether and in what form to re-establish its support for domestic research capabilities. This report for the Swedish International Development Cooperation Agency (Sida) and in partnership with the Somali Institute for Development Research and Analysis (SIDRA) investigates opportunities for research cooperation in Somalia. The study was organised around three guiding questions: What are the key enabling factors and barriers to research performance and academic freedom at universities in Somalia today? What are the current ongoing initiatives termed, defined or categorised as "research" support or cooperation to and in Somalia? What are the different opportunities and modalities for support to and organisation of research cooperation in Somalia