Unique evidence of fluid alteration in the Kakowa (L6) ordinary chondrite.

Meteorites preserve evidence of processes on their parent bodies, including alteration, metamorphism, and shock events. Here we show that the Kakowa (L6) ordinary chondrite (OC) preserves both shock-melt veins and pockets of detrital grains from a brecciated and altered object, including corundum, albite, silica, fayalite, forsterite, and margarite in a Pb- and Fe-rich matrix. Preservation of the observed mineralogy and texture requires a sequence of at least two impacts: first, a high-velocity collision formed the shock melt veins containing the high-pressure minerals ringwoodite, wadsleyite, majorite, and albitic jadeite; later, a low-velocity impact formed fractures and filled them with the detrital material. Oxygen and Pb isotope ratios suggest an OC origin for these detrital minerals. Although fluid alteration is common in carbonaceous chondrites, the discovery of margarite with an OC oxygen isotopic signature is novel. Kakowa extends both the impact and alteration history of L6 ordinary chondrites in general.

Heating events in the nascent solar system recorded by rare earth element isotopic fractionation in refractory inclusions.

Equilibrium condensation of solar gas is often invoked to explain the abundance of refractory elements in planets and meteorites. This is partly motivated, by the observation that the depletions in both the least and most refractory rare earth elements (REEs) in meteoritic group II calcium-aluminum-rich inclusions (CAIs) can be reproduced by thermodynamic models of solar nebula condensation. We measured the isotopic compositions of Ce, Nd, Sm, Eu, Gd, Dy, Er, and Yb in eight CAIs to test this scenario. Contrary to expectation for equilibrium condensation, we find light isotope enrichment for the most refractory REEs and more subdued isotopic variations for the least refractory REEs. This suggests that group II CAIs formed by a two-stage process involving fast evaporation of preexisting materials, followed by near-equilibrium recondensation. The calculated time scales are consistent with heating in events akin to FU Orionis- or EX Lupi-type outbursts of eruptive pre-main-sequence stars.

Evidence of presolar SiC in the Allende Curious Marie calcium aluminum rich inclusion.

Calcium aluminum rich inclusions (CAIs) are one of the first solids to have condensed in the solar nebula, while presolar grains formed in various evolved stellar environments. It is generally accepted that CAIs formed close to the Sun at temperatures above 1500 K, where presolar grains could not survive, and were then transported to other regions of the nebula where the accretion of planetesimals took place. In this context, a commonly held view is that presolar grains are found solely in the fine-grained rims surrounding chondrules and in the low-temperature fine-grained matrix that binds the various meteoritic components together. Here we demonstrate, based on noble gas isotopic signatures, that presolar SiC have been incorporated into fine-grained CAIs in the Allende carbonaceous chondrite at the time of their formation, and have survived parent body processing. This finding provides new clues on the conditions in the nascent solar system at the condensation of first solids.

New genotyping method discovers sustained nosocomial Pseudomonas aeruginosa outbreak in an intensive care burn unit.

BACKGROUND: Pseudomonas aeruginosa is a leading cause of healthcare-associated infections in the intensive care unit (ICU). AIM: To investigate an unexplained increase in the incidence of P. aeruginosa recovered from clinical samples in the ICU over a two-year period. METHODS: After unsuccessful epidemiological investigation by conventional tools, P. aeruginosa clinical isolates of all patients hospitalized between January 2010 and July 2012 were typed by a novel double-locus sequence typing (DLST) method and compared to environmental isolates recovered during the investigation period. FINDINGS: In total, 509 clinical isolates from 218 patients and 91 environmental isolates were typed. Thirty-five different genotypic clusters were found in 154 out of 218 patients (71%). The largest cluster, DLST 1-18, included 23 patients who were mostly hospitalized during overlapping periods in the burn unit. Genotype DLST 1-18 was also recovered from floor traps, shower trolleys and the shower mattress in the hydrotherapy rooms, suggesting environmental contamination of the burn unit as the source of the outbreak. After implementation of appropriate infection control measures, this genotype was recovered only once in a clinical sample from a burned patient and twice in the environment, but never thereafter during a 12-month follow-up period. CONCLUSION: The use of a novel DLST method allowed the genotyping of a large number of clinical and environmental isolates, leading to the identification of the environmental source of a large unrecognized outbreak in the burn unit. Eradication of the outbreak was confirmed after implementation of a continuous epidemiological surveillance of P. aeruginosa clones in the ICU.

Common skin infection due to Panton-Valentine leucocidin-producing Staphylococcus aureus strains in asylum seekers from Eritrea: a genome-based investigation of a suspected outbreak.

Since late 2014, multiple cases of abscesses and boils due to methicillin-susceptible Staphylococcus aureus (MSSA) expressing the Panton-Valentine leucocidin (PVL) were observed in Eritrean asylum seekers in Lausanne, Switzerland. Strains isolated from infected Eritrean and non-Eritrean patients were compared by whole genome sequencing to determine whether these numerous cases result from an outbreak. The genome of S. aureus PVL-producing strains were sequenced and compared. Clinical and epidemiological characteristics of patients infected by PVL-producing strains were investigated. This work reports 15 cases of infections due to PVL-producing strains affecting mostly asylum seekers (n = 10), people working with refugees and/or exposed to Africans (n = 3). Most infections were due to closely related strains of CC152 (n = 8) and CC15 (n = 3), two distantly related (>34 000 core single nucleotide polymorphisms) clonal complexes. An epidemiological link between the 15 cases could be ruled out by whole genome sequencing (33 to 172 core single nucleotide polymorphisms between the different strains of a given complex). Altogether, these results reflect the probable high incidence of CC15 and CC152 PVL-producing strains in eastern Africa. Clinicians facing unusual skin infections in African refugees (or in any person returning from this region of high endemicity) should consider S. aureus PVL-producer before suspecting rare infections such as leishmaniasis or rickettsiosis. Clinicians should also remember that PVL are frequently expressed by MSSA in some regions of the world and that antibiotics that are efficient on toxin expression, such as clindamycin, represent the best therapeutic option.

Added value of molecular assay Xpert MTB/RIF compared to sputum smear microscopy to assess the risk of tuberculosis transmission in a low-prevalence country.

Airborne precautions are required at hospital admission for patients with suspected pulmonary tuberculosis. The isolation is maintained until 3 serially collected sputum smears are acid-fast bacilli negative, a time- and labor-intensive method with limited sensitivity and specificity, which has a great impact on patient flow management. We evaluated the possibility of replacing the result of microscopy by the semiquantitative result of the molecular point-of-care test Xpert MTB/RIF to assess patients' transmission risk to quickly guide airborne isolation decisions in low-endemic countries. The performance of the Xpert MTB/RIF, used as a first-line test, was compared to the results of microscopy for specimens (n=242) collected from May 2010 to December 2014 in Lausanne, Switzerland. The sensitivity and specificity of Xpert MTB/RIF were 91.5% (65/71) and 99.6% (170/171), respectively, vs. 64.8% (46/71) and 94.2% (161/171) for microscopy. Samples with negative Xpert MTB/RIF were all smear negative for Mycobacterium tuberculosis (negative predictive value, 100%). The semiquantitative results of Xpert MTB/RIF-high, medium, low or very low-were found to correlate with acid-fast bacilli detection: positive predictive value of 100% (6/6), 96.5% (27/28), 52.2% (12/23) and 11.1% (1/9) respectively. Finally, when including clinical criteria, we identified 11 smear-negative but Xpert MTB/RIF-positive patients with a significant transmission potential. In conclusion, our data support the introduction of an Xpert MTB/RIF-based strategy as a replacement of smear microscopy for a faster and more accurate management of tuberculosis patients' transmission risk in a low-prevalence country.

Impact of round-the-clock CSF Gram stain on empirical therapy for suspected central nervous system infections.

The impact of round-the-clock cerebrospinal fluid (CSF) Gram stain on overnight empirical therapy for suspected central nervous system (CNS) infections was investigated. All consecutive overnight CSF Gram stains between 2006 and 2011 were included. The impact of a positive or a negative test on empirical therapy was evaluated and compared to other clinical and biological indications based on institutional guidelines. Bacterial CNS infection was documented in 51/241 suspected cases. Overnight CSF Gram stain was positive in 24/51. Upon validation, there were two false-positive and one false-negative results. The sensitivity and specificity were 41 and 99 %, respectively. All patients but one had other indications for empirical therapy than Gram stain alone. Upon obtaining the Gram result, empirical therapy was modified in 7/24, including the addition of an appropriate agent (1), addition of unnecessary agents (3) and simplification of unnecessary combination therapy (3/11). Among 74 cases with a negative CSF Gram stain and without formal indication for empirical therapy, antibiotics were withheld in only 29. Round-the-clock CSF Gram stain had a low impact on overnight empirical therapy for suspected CNS infections and was associated with several misinterpretation errors. Clinicians showed little confidence in CSF direct examination for simplifying or withholding therapy before definite microbiological results.

[Clostridium difficile infections: update on new European recommendations]. / Colite à Clostridium difficile: nouvelles recommandations de prise en charge.

Clostridium difficile infections: update on new European recommandations While metronidazole and vancomycin have been the only drug options to date for the treatment of C. difficile infection, new therapeutic approaches with promising results have recently emerged for the treatment of the first episode and relapses. Fidaxomicin is a new macrocyclic antibiotic more active against C. difficile and with a narrow spectrum allowing preservation of the intestinal microbiota. While having the same efficacy as vancomycin for the treatment of the first episode, this agent is associated with a lower rate of relapse. The highest relapse-free cure rate is achieved through fecal microbiota transplantation, which should be considered for patients with multiple relapses.

Mandatory infectious diseases consultation for MRSA bacteremia is associated with reduced mortality.

OBJECTIVES: Although infectious disease (ID) consultation has been associated with lower mortality in Staphylococcus aureus bloodstream infections, it is still not mandatory in many centers. This study aimed at assessing the impact of ID consultation on diagnostic and therapeutic management of methicillin-resistant S. aureus (MRSA) bacteremia. METHODS: Retrospective cohort study of all patients with MRSA bacteremia from 2001 to 2010. ID consultations were obtained on request between 2001 and 2006 and became mandatory since 2007. RESULTS: 156 episodes of MRSA bacteremia were included, mostly from central venous catheter (32%) and skin and soft tissue (19%) infections. ID consultation coverage was 58% between 2001 and 2006 and 91% between 2007 and 2010. ID consultation was associated with more echocardiography (59% vs. 26%, p < 0.01), vancomycin trough level measurements (99% vs. 77%, p < 0.01), follow-up blood cultures (71% vs. 50%, p = 0.05), deep-seated infections (43% vs. 16%, p < 0.01), more frequent infection source control (83% vs. 57%, p = 0.03), a longer duration of MRSA-active therapy (median and IQR: 17 days, 13-30, vs. 12, 3-14, p < 0.01) and a 20% reduction in 7-day, 30-day and in-hospital mortality. CONCLUSIONS: ID consultation was associated with a better management of patients with MRSA bacteremia and a reduced mortality.

Nonoccupational HIV post-exposure prophylaxis: a 10-year retrospective analysis.

BACKGROUND: We conducted a retrospective analysis of administration of nonoccupational HIV post-exposure prophylaxis (nPEP) in a single centre where tracing and testing of the source of exposure were carried out systematically over a 10-year period. METHODS: Files of all nPEP requests between 1998 and 2007 were reviewed. Characteristics of the exposed and source patients, the type of exposure, and clinical and serological outcomes were analysed. RESULTS: nPEP requests increased by 850% over 10 years. Among 910 events, 58% were heterosexual exposures, 15% homosexual exposures, 6% sexual assaults and 20% nonsexual exposures. In 208 events (23%), the source was reported to be HIV positive. In the remaining cases, active source tracing enabled 298 HIV tests to be performed (42%) and identified 11 HIV infections (3.7%). nPEP was able to be avoided or interrupted in 31% of 910 events when the source tested negative. Of 710 patients who started nPEP, 396 (56%) reported side effects, among whom 39 (5%) had to interrupt treatment. There were two HIV seroconversions, and neither was attributed to nPEP failure. CONCLUSIONS: nPEP requests increased over time. HIV testing of the source person avoided nPEP in 31% of events and was therefore paramount in the management of potential HIV exposures. Furthermore, it allowed active screening of populations potentially at risk for undiagnosed HIV infection, as shown by the increased HIV prevalence in these groups (3.7%) compared with a prevalence of 0.3% in Switzerland as a whole.

Studying the relationship between low back pain and working postures among those who stand and those who sit most of the working day.

A relationship between low back pain (LBP) and prolonged standing or prolonged sitting at work has not been clearly shown, despite its biological plausibility. Because sitting and standing postures vary as to duration and freedom to alternate postures, and standing postures vary as to mobility, associations between specific working postures and LBP were explored using multiple logistic regression. Associations between work factors and self-reported LBP during the previous 12 months that interfered with usual activities were examined among 4493 standing workers and 3237 sitting workers interviewed in the 1998 Quebec Health and Social Survey; 24.5% reported significant LBP. Since the same conditions can correspond to different physiological demands for sitting compared with standing workers, analyses were performed separately for the two groups. Standing without freedom to sit was associated with LBP. Different occupational physical and psychosocial factors were associated with LBP in sitting compared with standing populations.

Standing, sitting and associated working conditions in the Quebec population in 1998.

Working posture is an important determinant of musculoskeletal and vascular health. Knowledge of the context and type of postures is necessary in order to examine their associations with health-related outcomes. This study describes self-reported usual working postures in a population and their associations with other working conditions and demographic variables. The 1998 Quebec Health and Social Survey is a population-based survey of 11,986 private households in the province of Quebec. It contained a self-administered questionnaire, including an extensive occupational health section. The analyses in this study were limited to respondents with paid employment who had at least 6 months seniority in their current job, comprising 9,425 subjects. The overall prevalence of usual work in a standing posture is 58%; it is more common among men, workers under 25 years, those in the two lowest educational quintiles and those with incomes under 20,000 Canadian dollars. Only one person in six who works standing reports being able to sit at will. Women and men differ in the types of usual standing and sitting postures at work. Those who work standing and/or who work in more constrained postures are more likely to be exposed to other physical work demands, such as handling heavy loads, repetitive work, forceful exertion and low job decision latitude. The association between decision latitude and constrained postures is an important link between psychosocial and physical stressors in the workplace. In epidemiological studies, exposure covariation and interactions should be considered in the generation and interpretation of the associations between work postures and musculoskeletal disorders.

Influence of bacille Calmette-Guérin vaccination on size of tuberculin skin test reaction: to what size?

BACKGROUND: Previous bacillus Calmette-Guerin (BCG) vaccination can confound the results of a tuberculin skin test (TST). We sought to determine a cutoff diameter of TST induration beyond which the influence of BCG vaccination was negligible in evaluating potential Mycobacterium tuberculosis infection in a population of health care workers with a high vaccination rate and low incidence of tuberculosis. METHODS: From 1991 through 1998, all new employees at the University Hospital of Lausanne, Switzerland, underwent a 2-step TST at entry visit. We also gathered information on demographic characteristics, along with factors commonly associated with tuberculin positivity, including previous BCG vaccination, history of latent M. tuberculosis infection, and predictors for M. tuberculosis infection. RESULTS: Among the 5117 investigated subjects, we found that influence of BCG vaccination on TST results varied across categories of age (likelihood ratio test, 0.0001). Prior BCG vaccination had a strong influence on skin test results of

From epidemiological surveillance to European integration.

Between March and June 1999, 442 000 Kosovar refugees arrived in Albania. The national surveillance system was unprepared for this and an emergency communicable disease surveillance system was set up to detect and control potential outbreaks among the ref

Sex as a variable can be a surrogate for some working conditions: factors associated with sickness absence.

More than twice as many workdays are lost to illness than for personal or family reasons. We examine possible workplace determinants of sickness absence among French workers in the food processing industry. These workers are exposed to a variety of environmental and organizational constraints: cold, uncomfortable postures, assembly-line work, and irregular schedules. In 1987-1988, a medical examination and questionnaire were administered to 558 men and 790 women as part of a study of 17 poultry slaughterhouses and 6 canning factories. Women's and men's working conditions were very different, and their sickness absences for musculoskeletal and respiratory illnesses were related to some of their specific working conditions: cold exposure, ill-adapted work stations, and problems with their supervisors and co-workers. If male and female workers were combined into a single analysis that adjusted for sex, many of the associations operant for a single sex could no longer be seen.

Perimenstrual symptoms and working conditions among hospital workers in Quebec.

Perimenstrual symptoms are among the most common disorders of women. Seven perimenstrual symptoms were related to working conditions among 539 hospital workers in a retrospective cohort questionnaire study, as part of a larger examination of health problems and working conditions of Quebec hospital workers. Only 8% of women had experienced no symptoms of discomfort associated with their last menstrual period. Lower abdominal pain, the most common symptom (58% prevalence), was associated with lifting weights (usually patients) in a logistic regression adjusted for parity and contraceptive use. Back pain, leg pain, swelling, and headache were associated with indicators of time pressure and fast work speed. Back pain during menstruation was experienced by 44% of workers. Studies of the prevalence and etiology of back pain, a common occupational health problem among hospital workers, may be confused if perimenstrual back pain is not taken into account. Similar reservations hold for the results on other perimenstrual symptoms that are also likely to occur outside the perimenstrual period, such as leg pain, irritability, and headache.