The use of typing methods and infection prevention measures to control a bullous impetigo outbreak on a neonatal ward

<p>Abstract</p> <p>Background</p> <p>We describe an outbreak of Bullous Impetigo (BI), caused by a (methicillin susceptible, fusidic acid resistant) <it>Staphylococcus aureus</it> (SA) strain, <it>spa-</it>type t408, at the neonatal and gynaecology ward of the Jeroen Bosch hospital in the Netherlands, from March-November 2011.</p> <p>Methods</p> <p>We performed an outbreak investigation with revision of the hygienic protocols, MSSA colonization surveillance and environmental sampling for MSSA including detailed typing of <it>SA</it> isolates. <it>Spa</it> typing was performed to discriminate between the SA isolates. In addition, Raman-typing was performed on all t408 isolates.</p> <p>Results</p> <p>Nineteen cases of BI were confirmed by SA positive cultures. A cluster of nine neonates and three health care workers (HCW) with <it>SA</it> t408 was detected. These strains were MecA^-, PVL^-, Exfoliative Toxin (ET)A^-, ETB⁺, ETAD^-, fusidic acid-resistant and methicillin susceptible. Eight out of nine neonates and two out of three HCW t408 strains yielded a similar Raman type. Positive t408 HCW were treated and infection control procedures were reinforced. These measures stopped the outbreak.</p> <p>Conclusions</p> <p>We conclude that treatment of patients and HCW carrying a predominant SA t408, and re-implementing and emphasising hygienic measures were effective to control the outbreak of SA t408 among neonates.</p

Terahertz modulation of the Faraday rotation by laser pulses via the optical Kerr effect

The magneto-optical Faraday effect played a crucial role in the elucidation of the electromagnetic nature of light. Today it is powerful means to probe magnetism and the basic operational principle of magneto-optical modulators. Understanding the mechanisms allowing for modulation of the magneto-optical response at terahertz frequencies may have far-reaching consequences for photonics, ultrafast optomagnetism and magnonics, as well as for future development of ultrafast Faraday modulators. Here we suggest a conceptually new approach for an ultrafast tunable magneto-optical modulation with the help of counter-propagating laser pulses. Using terbium gallium garnet (Tb3Ga5O12) we demonstrate the feasibility of such magneto-optical modulation with a frequency up to 1.1 THz, which is continuously tunable by means of an external magnetic field. Besides the novel concept for ultrafast magneto-optical polarization modulation, our findings reveal the importance of accounting for propagation effects in the interpretation of pump–probe magneto-optical experiments

cDNA cloning and expression of Brassica napus enoyl-acyl carrier protein reductase in Escherichia coli

The onset of storage lipid biosynthesis during seed development in the oilseed crop Brassica napus (rape seed) coincides with a drastic qualitative and quantitative change in fatty acid composition. During this phase of storage lipid biosynthesis, the enzyme activities of the individual components of the fatty acid synthase system increase rapidly. We describe a rapid and simple purification procedure for the plastid-localized NADH-dependent enoyl-acyl carrier protein reductase from developing B. napus seed, based on its affinity towards the acyl carrier protein (ACP). The purified protein was N-terminally sequenced and used to raise a potent antibody preparation. Immuno-screening of a seed-specific lambda gt11 cDNA expression library resulted in the isolation of enoyl-ACP reductase cDNA clones. DNA sequence analysis of an apparently full-length cDNA clone revealed that the enoyl-ACP reductase mRNA is translated into a precursor protein with a putative 73 amino acid leader sequence which is removed during the translocation of the protein through the plastid membrane. Expression studies in Escherichia coli demonstrated that the full-length cDNA clone encodes the authentic B. napus NADH-dependent enoyl-ACP reductase. Characterization of the enoyl-ACP reductase genes by Southern blotting shows that the allo-tetraploid B. napus contains two pairs of related enoyl-ACP reductase genes derived from the two distinct genes found in both its ancestors, Brassica oleracea and B. campestris. Northern blot analysis of enoyl-ACP reductase mRNA steady-state levels during seed development suggests that the increase in enzyme activity during the phase of storage lipid accumulation is regulated at the level of gene expression