The detection and identification of microorganisms circulating in the bloodstream of patients is arguably one of the most important functions of the clinical microbiology laboratory. Effective ...implementation of this function requires careful consideration of specimen collection and processing, culture techniques, result reporting, and, perhaps most importantly, result interpretation by the physician. The purpose of this review is to provide a synopsis of the current state of the art for each of these areas, with the intention of providing adequate information to enable clinical laboratory personnel and physicians to critically evaluate and, if required, improve their current blood culture practices.
Despite widespread use of antibiotics, few studies have measured their effects on the burden or diversity of bacteria in the mammalian intestine. We developed an oral antibiotic treatment protocol ...and characterized its effects on murine intestinal bacterial communities and immune cell homeostasis. Antibiotic administration resulted in a 10-fold reduction in the amount of intestinal bacteria present and sequencing of 16S rDNA segments revealed significant temporal and spatial effects on luminal and mucosal-associated communities including reductions in luminal Firmicutes and mucosal-associated Lactobacillus species, and persistence of bacteria belonging to the Bacteroidetes and Proteobacteria phyla. Concurrently, antibiotic administration resulted in reduced RELM beta production, and reduced production of interferon-gamma and interleukin-17A by mucosal CD4(+) T lymphocytes. This comprehensive temporal and spatial metagenomic analyses will provide a resource and framework to test the influence of bacterial communities in murine models of human disease.
The next generation magnetic spectrometer in space, AMS-100, is designed to have a geometrical acceptance of 100 m 2 sr and to be operated for at least ten years at the Sun–Earth Lagrange Point 2. ...Compared to existing experiments, it will improve the sensitivity for the observation of new phenomena in cosmic rays, and in particular in cosmic antimatter, by at least a factor of 1000. The magnet design is based on high temperature superconductor tapes, which allow the construction of a thin solenoid with a homogeneous magnetic field of 1 Tesla inside. The inner volume is instrumented with a silicon tracker reaching a maximum detectable rigidity of 100 TV and a calorimeter system that is 70 radiation lengths deep, equivalent to four nuclear interaction lengths, which extends the energy reach for cosmic-ray nuclei up to the PeV scale, i.e. beyond the cosmic-ray knee. Covering most of the sky continuously, AMS-100 will detect high-energy gamma-rays in the calorimeter system and by pair conversion in the thin solenoid, reconstructed with excellent angular resolution in the silicon tracker.
Physicians should understand the performance characteristics of evolving laboratory tests used to diagnose Clostridium difficile infection if they are to correctly integrate test results with ...clinical information and formulate an appropriate therapeutic intervention for patients with antibiotic-associated diarrhea.
We present prototype modules for a tracking detector consisting of multiple layers of 0.25
mm diameter scintillating fibers that are read out by linear arrays of silicon photomultipliers. The module ...production process is described and measurements of the key properties for both the fibers and the readout devices are shown. Five modules have been subjected to a 12
GeV/
c proton/pion testbeam at CERN. A spatial resolution of
50
μ
m
and light yields exceeding 20 detected photons per minimum ionizing particle have been achieved, at a tracking efficiency of more than 98.5%. Possible techniques for further improvement of the spatial resolution are discussed.
Summary
Colonization of the human small intestine by Vibrio cholerae requires the type 4 toxin co‐regulated pilus (TCP). Genes encoding the structure and biogenesis functions of TCP are organized ...within an operon located on the Vibrio Pathogenicity Island (VPI). In an effort to elucidate the functions of proteins involved in TCP biogenesis, in frame deletions of all of the genes within the tcp operon coding for putative pilus biogenesis proteins have been constructed and the resulting mutants characterized with respect to the assembly and function of TCP. As a result of this analysis, we have identified the product of one of these genes, tcpF, as a novel secreted colonization factor. Chromosomal deletion of tcpF yields a mutant that retains in vitro phenotypes associated with the assembly of functional TCP yet is severely attenuated for colonization of the infant mouse intestine. Furthermore, we have determined that the mechanism by which TcpF is translocated across the bacterial outer membrane requires the TCP biogenesis machinery and is independent of the type II extracellular protein secretion (EPS) system. These results suggest a dual role for the TCP biogenesis apparatus in V. cholerae pathogenesis and a novel mechanism of intestinal colonization mediated by a soluble factor.
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