“The aim of this study was to identify and characterize 97
methicillin-resistant Staphylococcus aureus (MRSA) isolates. Two conventional multiplex PCR assays, a real-time PCR assay and two PCR-based genotyping techniques including the spa- and hypervariable www.selleckchem.com/products/ly2835219.html region (HVR)-typing methods were used to identify and characterize 97 MRSA strains isolated between April 2006 to September 2007 from the Steve Biko Academic Hospital. All MRSA isolates were positive for 16S rRNA gene, 99% were positive for the mecA gene and 4% positive for the Panton-Valentine leukocidin (PVL) gene. Staphylococcal cassette chromosome mec (SCCmec) typing showed 67% of isolates were SCCmec II [health-care-associated SNX-5422 datasheet MRSA (HA-MRSA)], 14% were SCCmec III (HA-MRSA) and 4% were SCCmec IVd [community-associated MRSA (CA-MRSA)]. These CA-MRSA isolates showed a prevalence of 100% for the PVL gene. Using spa typing, three distinct clusters could be identified while HVR typing revealed six different clusters. CA-MRSA isolates were clustered together using spa and HVR typing.
This study showed the prevalence of the CA-MRSA strains, PVL genes, the SCCmec types and the clonality of the MRSA strains. The high prevalence of the PVL gene in CA-MRSA isolates already residing in intensive care units was alarming and indicated the emergence of new MRSA lineages with a particular fitness for community and hospital transmission.”
profile of visible whispering gallery modes (WGM) from a single microdisk based on silicon nanocrystals (Si-nc) and SiO2 superlattices was observed. Using thermal evaporation, the active layer, which consists of 30 pairs of similar to 3 nm thick Si-ncs and similar to 4 nm thick SiO2 layer, was fabricated on Si substrate. Si-ncs with diameters of 3 nm, which are well defined by SiOx layer thickness, were formed by high temperature annealing at 1100 degrees C for 60 min under N-2 GNS-1480 datasheet environment. After standard photolithography and dry etching procedure, a microdisk with 8.8 mu m diameter on a silicon pedestal was successfully obtained. We calculated the expected radial profiles of the WGMs by solving the Maxwell equations using appropriate boundary conditions. Comparison with finite-difference time-domain (FDTD) simulation depicts similar radial profiles of the WGMs. Using a confocal microphotoluminescence setup, light emission from the top of a single disk was analyzed depending on the detection position. Thanks to the birefringence of nature of Si-nc/SiO2 superlattices, well-isolated sharp TE mode WGMs could be detected from the top, without using polarizers. Irrelative to detection position, broad Si-nc background luminescence is consistently found. And as the detection point was moved from the center to the outside of the disk, WGMs fields were strongly decreased especially for the detection at the outside.