280 research outputs found
Clostridioides difficile Infection, Still a Long Way to Go.
Clostridioides difficile is an increasingly common pathogen both within and outside the hospital and is responsible for a large clinical spectrum from asymptomatic carriage to complicated infection associated with a high mortality. While diagnostic methods have considerably progressed over the years, the optimal diagnostic algorithm is still debated and there is no single diagnostic test that can be used as a standalone test. More importantly, the heterogeneity in diagnostic practices between centers along with the lack of robust surveillance systems in all countries and an important degree of underdiagnosis due to lack of clinical suspicion in the community, hinder a more accurate evaluation of the burden of disease. Our improved understanding of the physiopathology of CDI has allowed some significant progress in the treatment of CDI, including a broader use of fidaxomicine, the use of fecal microbiota transplantation for multiples recurrences and newer approaches including antibodies, vaccines and new molecules, already developed or in the pipeline. However, the management of CDI recurrences and severe infections remain challenging and the main question remains: how to best target these often expensive treatments to the right population. In this review we discuss current diagnostic approaches, treatment and potential prevention strategies, with a special focus on recent advances in the field as well as areas of uncertainty and unmet needs and how to address them
Multi-wavelength characterisation of z~2 clustered, dusty star forming galaxies discovered by Planck
(abridged) We report the discovery of PHz G95.5-61.6, a complex structure
detected in emission in the Planck all-sky survey that corresponds to two
over-densities of high-redshift galaxies. This is the first source from the
Planck catalogue of high-z candidates that has been completely characterised
with follow-up observations from the optical to the sub-millimetre domain.
Herschel/SPIRE observations at 250, 350 and 500 microns reveal the existence of
five sources producing a 500 microns emission excess that spatially corresponds
to the candidate proto-clusters discovered by Planck. Further observations at
CFHT in the optical bands (g and i) and in the near infrared (J, H and K_s),
plus mid infrared observations with IRAC/Spitzer (at 3.6 and 4.5 microns)
confirm that the sub-mm red excess is associated with an over-density of
colour-selected galaxies. Follow-up spectroscopy of 13 galaxies with
VLT/X-Shooter establishes the existence of two high-z structures: one at z~1.7
(three confirmed member galaxies), the other at z~2.0 (six confirmed members).
This double structure is also seen in the photometric redshift analysis of a
sample of 127 galaxies located inside a circular region of 1'-radius containing
the five Herschel/SPIRE sources, where we found a double-peaked excess of
galaxies at z~1.7 and z~2.0 with respect to the surrounding region. These
results suggest that PHz G95.5-61.6 corresponds to two accreting nodes, not
physically linked to one another, embedded in the large scale structure of the
Universe at z~2 and along the same line-of-sight. In conclusion, the data,
methods and results illustrated in this pilot project confirm that Planck data
can be used to detect the emission from clustered, dusty star forming galaxies
at high-z, and, thus, to pierce through the early growth of cluster-scale
structures.Comment: 15 pages, 13 figures. Accepted for publication in Astronomy and
Astrophysic
Frequencies and Damping rates of a 2D Deformed Trapped Bose gas above the Critical Temperature
We derive the equation of motion for the velocity fluctuations of a 2D
deformed trapped Bose gas above the critical temperature in the hydrodynamical
regime. From this equation, we calculate the eigenfrequencies for a few
low-lying excitation modes. Using the method of averages, we derive a
dispersion relation in a deformed trap that interpolates between the
collisionless and hydrodynamic regimes. We make use of this dispersion relation
to calculate the frequencies and the damping rates for monopole and quadrupole
mode in both the regimes. We also discuss the time evolution of the wave packet
width of a Bose gas in a time dependent as well as time independent trap.Comment: 13 pages, latex fil
Core genome multilocus sequence typing of Clostridioides difficile to investigate transmission in the hospital setting.
Traditional epidemiological investigations of healthcare-associated Clostridioides difficile infection (HA-CDI) are often insufficient. This study aimed to evaluate a procedure that includes secondary isolation and genomic typing of single toxigenic colonies using core genome multilocus sequence typing (cgMLST) for the investigation of C. difficile transmission.
We analyzed retrospectively all toxigenic C. difficile-positive stool samples stored at the Lausanne University Hospital over 6 consecutive months. All isolates were initially typed and classified using a modified double-locus sequence typing (DLST) method. Genome comparison of isolates with the same DLST and clustering were subsequently performed using cgMLST. The electronic administrative records of patients with CDI were investigated for spatiotemporal epidemiological links supporting hospital transmission. A comparative descriptive analysis between genomic and epidemiological data was then performed.
From January to June 2021, 86 C. difficile isolates were recovered from thawed samples of 71 patients. Thirteen different DLST types were shared by > 1 patient, and 13 were observed in single patients. A genomic cluster was defined as a set of isolates from different patients with ≤ 3 locus differences, determined by cgMLST. Seven genomic clusters were identified, among which plausible epidemiological links were identified in only 4/7 clusters.
Among clusters determined by cgMLST analysis, roughly 40% included unexplained HA-CDI acquisitions, which may be explained by unidentified epidemiological links, asymptomatic colonization, and/or shared common community reservoirs. The use of DLST, followed by whole genome sequencing analysis, is a promising and cost-effective stepwise approach for the investigation of CDI transmission in the hospital setting
Enhancement of the scissors mode of an expanding Bose-Einstein condensate
We study the time-evolution of the scissors mode of a Bose-Einstein
condensate during the ballistic expansion after release from the magnetic trap.
We show that despite the nontrivial character of the superfluid expansion, the
sinusoidal behavior of the scissor oscillations is recovered after an
asymptotic expansion, with an enhancement of the final amplitude. We
investigate this phenomenon with a condensate held in an elongated
magnetostatic potential, whose particular shape allows for the excitation of
the scissors mode.Comment: RevTeX, 5 figure
Kelvin Modes of a fast rotating Bose-Einstein Condensate
Using the concept of diffused vorticity and the formalism of rotational
hydrodynamics we calculate the eigenmodes of a harmonically trapped
Bose-Einstein condensate containing an array of quantized vortices. We predict
the occurrence of a new branch of anomalous excitations, analogous to the
Kelvin modes of the single vortex dynamics. Special attention is devoted to the
excitation of the anomalous scissors mode.Comment: 7 pages, 3 figures, submitted to Phys. Rev.
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