147 research outputs found
Serratia marcescens outbreak in a neonatal intensive care unit: crucial role of implementing hand hygiene among external consultants.
BACKGROUND: Serratia marcescens represents an important pathogen involved in hospital acquired infections. Outbreaks are frequently reported and are difficult to eradicate. The aim of this study is to describe an outbreak of Serratia marcescens occurred from May to November 2012 in a neonatal intensive care unit, to discuss the control measures adopted, addressing the role of molecular biology in routine investigations during the outbreak. METHODS: After an outbreak of Serratia marcescens involving 14 neonates, all admitted patients were screened for rectal and ocular carriage every two weeks. Extensive environmental sampling procedure and hand sampling of the staff were performed. Antimicrobial susceptibility pattern and molecular analysis of isolates were carried out. Effective hand hygiene measures involving all the external consultants has been implemented. Colonized and infected babies were cohorted. Dedicated staff was established to care for the colonized or infected babies. RESULTS: During the surveillance, 65 newborns were sampled obtaining 297 ocular and rectal swabs in five times. Thirty-four Serratia marcescens isolates were collected: 11 out of 34 strains were isolated from eyes, being the remaining 23 isolated from rectal swabs. Two patients presented symptomatic conjunctivitis. Environmental and hand sampling resulted negative. During the fifth sampling procedure no colonized or infected patients have been identified. Two different clones have been identified. CONCLUSIONS: Ocular and rectal colonization played an important role in spread of infections. Implementation of infection control measures, involving also external specialists, allowed to control a serious Serratia marcescens outbreak in a neonatal intensive care unit
Central-line associated bloodstream infections in a tertiary care children's University hospital: a prospective study
BACKGROUND: The central-line associated bloodstream infections (CLABSI) are the most common healthcare-associated infections in childhood. Despite the international data available on healthcare-associated infections in selected groups of patients, there is a lack of large and good quality studies. The present survey is the first prospective study monitoring for 6 months the occurrence of central-line associated bloodstream infections in all departments of an Italian tertiary care children’s university hospital. METHODS: The study involved all children aged less than 18 years admitted to Meyer Children’s University Hospital, Florence, Italy who had a central line access between the October 15(th), 2014 and the April 14(th), 2015. CLABSI were defined according to the Center for Disease Control and Prevention criteria. CLABSI incidence rates with 95% confidence limits were calculated and stratified for the study variables. For each factor the relative risk and 95% confidence intervals were evaluated. Statistical analysis was performed using the statistical software SPSS for Windows, version 22.0 (SPSS Inc., Chicago, IL), p < 0.05 was considered statistically significant. RESULTS: CLABSI rate was 3.73/1000 (95% CI: 2.54–5.28) central line-days. A higher CLABSI incidence was seen with female gender (p = 0.045) and underlying medical conditions (excepting prematurity, surgical diseases and malignancy) (p = 0.06). In our study 5 infections, were caused by extended-spectrum β-lactamase producing organisms and in one case by carbapenem-resistant Klebsiella pneumoniae. CONCLUSIONS: Our study confirms the spreading of multi-resistant pathogens as causes of healthcare associated infections in children. An increased incidence rate of CLABSI in our study was related to underlying medical conditions. Pediatric studies focusing on healthcare infections in this type of patients should be done in order to deepen our understanding on associated risk factors and possible intervention areas
Measurement of the cosmic ray spectrum above eV using inclined events detected with the Pierre Auger Observatory
A measurement of the cosmic-ray spectrum for energies exceeding
eV is presented, which is based on the analysis of showers
with zenith angles greater than detected with the Pierre Auger
Observatory between 1 January 2004 and 31 December 2013. The measured spectrum
confirms a flux suppression at the highest energies. Above
eV, the "ankle", the flux can be described by a power law with
index followed by
a smooth suppression region. For the energy () at which the
spectral flux has fallen to one-half of its extrapolated value in the absence
of suppression, we find
eV.Comment: Replaced with published version. Added journal reference and DO
Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory
The Auger Engineering Radio Array (AERA) is part of the Pierre Auger
Observatory and is used to detect the radio emission of cosmic-ray air showers.
These observations are compared to the data of the surface detector stations of
the Observatory, which provide well-calibrated information on the cosmic-ray
energies and arrival directions. The response of the radio stations in the 30
to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of
the incoming electric field. For the latter, the energy deposit per area is
determined from the radio pulses at each observer position and is interpolated
using a two-dimensional function that takes into account signal asymmetries due
to interference between the geomagnetic and charge-excess emission components.
The spatial integral over the signal distribution gives a direct measurement of
the energy transferred from the primary cosmic ray into radio emission in the
AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air
shower arriving perpendicularly to the geomagnetic field. This radiation energy
-- corrected for geometrical effects -- is used as a cosmic-ray energy
estimator. Performing an absolute energy calibration against the
surface-detector information, we observe that this radio-energy estimator
scales quadratically with the cosmic-ray energy as expected for coherent
emission. We find an energy resolution of the radio reconstruction of 22% for
the data set and 17% for a high-quality subset containing only events with at
least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO
Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy
We measure the energy emitted by extensive air showers in the form of radio
emission in the frequency range from 30 to 80 MHz. Exploiting the accurate
energy scale of the Pierre Auger Observatory, we obtain a radiation energy of
15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV
arriving perpendicularly to a geomagnetic field of 0.24 G, scaling
quadratically with the cosmic-ray energy. A comparison with predictions from
state-of-the-art first-principle calculations shows agreement with our
measurement. The radiation energy provides direct access to the calorimetric
energy in the electromagnetic cascade of extensive air showers. Comparison with
our result thus allows the direct calibration of any cosmic-ray radio detector
against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI.
Supplemental material in the ancillary file
Combined fit to the spectrum and composition data measured by the Pierre Auger Observatory including magnetic horizon effects
The measurements by the Pierre Auger Observatory of the energy spectrum and mass composition of cosmic rays can be interpreted assuming the presence of two extragalactic source populations, one dominating the flux at energies above a few EeV and the other below. To fit the data ignoring magnetic field effects, the high-energy population needs to accelerate a mixture of nuclei with very hard spectra, at odds with the approximate E shape expected from diffusive shock acceleration. The presence of turbulent extragalactic magnetic fields in the region between the closest sources and the Earth can significantly modify the observed CR spectrum with respect to that emitted by the sources, reducing the flux of low-rigidity particles that reach the Earth. We here take into account this magnetic horizon effect in the combined fit of the spectrum and shower depth distributions, exploring the possibility that a spectrum for the high-energy population sources with a shape closer to E be able to explain the observations
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