An evaluation of food as a potential source for clostridium difficile acquisition in hospitalized patients

OBJECTIVETo determine whetherClostridium difficileis present in the food of hospitalized patients and to estimate the risk of subsequent colonization associated withC. difficilein food.METHODSThis was a prospective cohort study of inpatients at a university-affiliated tertiary care center, May 9, 2011–July 12, 2012. Enrolled patients submitted a portion of food from each meal. Patient stool specimens and/or rectal swabs were collected at enrollment, every 3 days thereafter, and at discharge, and were cultured forC. difficile. Clinical data were reviewed for evidence of infection due toC. difficile.A stochastic, discrete event model was developed to predict exposure toC. difficilefrom food, and the estimated number of new colonization events from food exposures per 1,000 admissions was determined.RESULTSA total of 149 patients were enrolled and 910 food specimens were obtained. Two food specimens from 2 patients were positive forC. difficile(0.2% of food samples; 1.3% of patients). Neither of the 2 patients was colonized at baseline withC. difficile. Discharge colonization status was available for 1 of the 2 patients and was negative. Neither was diagnosed withC. difficileinfection while hospitalized or during the year before or after study enrollment. Stochastic modeling indicated contaminated hospital food would be responsible for less than 1 newly colonized patient per 1,000 hospital admissions.CONCLUSIONSThe recovery ofC. difficilefrom the food of hospitalized patients was rare. Modeling suggests hospital food is unlikely to be a source ofC. difficileacquisition.Infect Control Hosp Epidemiol2016;1401–1407</jats:sec

Prevalence of qacA/B genes and mupirocin resistance among methicillin-resistant Staphylococcus aureus (MRSA) isolates in the setting of chlorhexidine bathing without mupirocin

OBJECTIVE: We aimed to determine the frequency of qacA/B chlorhexidine tolerance genes and high-level mupirocin resistance among MRSA isolates before and after the introduction of a chlorhexidine (CHG) daily bathing intervention in a surgical intensive care unit (SICU). DESIGN: Retrospective cohort study (2005–2012) SETTING: A large tertiary-care center PATIENTS: Patients admitted to SICU who had MRSA surveillance cultures of the anterior nares METHODS: A random sample of banked MRSA anterior nares isolates recovered during (2005) and after (2006–2012) implementation of a daily CHG bathing protocol was examined for qacA/B genes and high-level mupirocin resistance. Staphylococcal cassette chromosome mec (SCCmec) typing was also performed. RESULTS: Of the 504 randomly selected isolates (63 per year), 36 (7.1%) were qacA/B positive ( + ) and 35 (6.9%) were mupirocin resistant. Of these, 184 (36.5%) isolates were SCCmec type IV. There was a significant trend for increasing qacA/B (P= .02; highest prevalence, 16.9% in 2009 and 2010) and SCCmec type IV (P< .001; highest prevalence, 52.4% in 2012) during the study period. qacA/B( + ) MRSA isolates were more likely to be mupirocin resistant (9 of 36 [25%] qacA/B( + ) vs 26 of 468 [5.6%] qacA/B(−); P= .003). CONCLUSIONS: A long-term, daily CHG bathing protocol was associated with a change in the frequency of qacA/B genes in MRSA isolates recovered from the anterior nares over an 8-year period. This change in the frequency of qacA/B genes is most likely due to patients in those years being exposed in prior admissions. Future studies need to further evaluate the implications of universal CHG daily bathing on MRSA qacA/B genes among hospitalized patients

Randomized controlled trial to determine the impact of probiotic administration on colonization with multidrug-resistant organisms in critically ill patients

This was a randomized controlled pilot study of Lactobacillus rhamnosus GG versus standard of care to prevent gastrointestinal multidrug-resistant organism (MDRO) colonization in ICU patients. Seventy subjects were included in analyses. There were no significant differences in acquisition or loss of any MDROs (p>0.05). There were no probiotic-associated adverse events

Saharan dust aerosol over the central Mediterranean Sea: PM₁₀ chemical composition and concentration versus optical columnar measurements

This study aims to determine the mineral contribution to PM₁₀ in the central Mediterranean Sea, based on 7 yr of daily PM₁₀ samplings made on the island of Lampedusa (35.5° N, 12.6° E). <br><br> The chemical composition of the PM₁₀ samples was determined by ion chromatography for the main ions, and, on selected samples, by particle-induced X-ray emission (PIXE) for the total content of crustal markers. Aerosol optical depth measurements were carried out in parallel to the PM₁₀ sampling. <br><br> The average PM₁₀ concentration at Lampedusa over the period June 2004–December 2010 is 31.5 μg m⁻³, with low interannual variability. The annual means are below the EU annual standard for PM₁₀, but 9.9% of the total number of daily data exceeds the daily threshold value established by the European Commission for PM (50 μg m⁻³, European Community, EC/30/1999). <br><br> The Saharan dust contribution to PM₁₀ was derived by calculating the contribution of Al, Si, Fe, Ti, non-sea-salt (nss) Ca, nssNa, and nssK oxides in samples in which PIXE data were available. Cases in which crustal content exceeded the 75th percentile of the crustal oxide content distribution were identified as elevated dust events. Using this threshold, we obtained 175 events. Fifty-five elevated dust events (31.6%) displayed PM₁₀ higher than 50 μg m⁻³, with dust contributing by 33% on average. <br><br> The crustal contribution to PM₁₀ has an annual average value of 5.42 μg m⁻³, and reaches a value as high as 67.9 μg m⁻³ (corresponding to 49% of PM₁₀) during an intense Saharan dust event. <br><br> The crustal content estimated from a single tracer, such as Al or Ca, is in good agreement with the one calculated as the sum of the metal oxides. Conversely, larger crustal contents are derived by applying the EU guidelines for demonstration and subtraction of exceedances in PM₁₀ levels due to high background of natural aerosol. The crustal aerosol amount and contribution to PM₁₀ showed a very small seasonal dependence; conversely, the dust columnar burden displays an evident annual cycle, with a strong summer maximum (monthly average aerosol optical depth at 500 nm up to 0.28 in June–August). We found that 71.3% of the dust events identified from optical properties over the atmospheric column display a high dust content at the ground level. Conversely, the remaining 28.7% of cases present a negligible or small impact on the surface aerosol composition due to the transport processes over the Mediterranean Sea, where dust frequently travels above the marine boundary layer, especially in summer. <br><br> Based on backward trajectories, two regions, one in Algeria–Tunisia, and one in Libya, are identified as main source areas for intense dust episodes occurring mainly in autumn and winter. Data on the bulk composition of mineral aerosol arising from these two source areas are scarce; results on characteristic ratios between elements show somewhat higher values of Ca / Al and (Ca + Mg) / Fe (2.5 ± 1.0, and 4.7 ± 2.0, respectively) for Algeria–Tunisia than for Libyan origin (Ca / Al = 1.9 ± 0.7 and (Ca + Mg) / Fe = 3.3 ± 1.1)

Inflammatory cytokines compromise programmed cell death-1 (PD-1)-mediated T cell suppression in inflammatory arthritis through up-regulation of soluble PD-1

The programmed cell death 1 (PD-1) receptor plays a major role in regulating T cell activation. Our aim was to determine how inflammation influences PD-1-mediated T cell suppression. Flow cytometry analysis of rheumatoid arthritis (RA) and psoriatic arthritis (PsA) synovial fluid (SF) mononuclear cells showed an increase in the percentage of PD-1(+) cells within the CD4(+) and CD8(+) T cell compartment compared to paired peripheral blood (PB). Upon in-vitro T cell receptor (TCR) stimulation of healthy control (HC) CD4(+) T cells in the presence of plate-bound PD-L1fc chimera, significantly decreased proliferation and interferon (IFN)-γ secretion was observed. In contrast, CD4(+) T cells from RA and PsA PB and SF appeared resistant to such PD-1-mediated inhibition. Addition of the proinflammatory cytokines tumour necrosis factor (TNF)α, interleukin (IL)-6 and IL-1β, which were increased in RA and PsA SF compared to osteoarthritis (OA) SF, consistently abrogated PD-1-mediated suppression in HC CD4(+) T cell cultures. This effect was reversed by inhibitors of these cytokines. Soluble PD-1 (sPD-1) levels were increased in cell culture supernatants from TNFα and IL-6-stimulated cultures compared to untreated controls, and also in RA and PsA, but not in OA, serum and SF. Functionally, addition of sPD-1fc counteracted PD-1-mediated suppression of HC CD4(+) T cells, and increased T cell proliferation in HC CD4(+) T cell/monocyte co-cultures. These in-vitro findings indicate that CD4(+) T cells from patients with RA and PsA show increased resistance to PD-1-mediated suppression, which may be explained in part by the presence of soluble PD-1 in the inflammatory environment.</p

Freshening rather than warming drives trematode transmission from periwinkles to mussels

In the Western Baltic Sea, climate change is happening at much faster rate than in most other seas and organisms are additionally exposed to a steep and variable salinity gradient. Climate change has previously been shown to affect parasite transmission in other marine ecosystems, yet little is known about potential effects of warming and desalination on parasite–host interactions. In laboratory experiments, we determined the combined effects of projected seawater warming and freshening on the emergence, activity, survival, and infectivity of cercariae (free-swimming infectious stage) of the trematode Himasthla elongata (Mehlis 1831), shed from its first intermediate host, the periwinkle Littorina littorea (Linnaeus 1758), in the Baltic Sea. We also assessed the susceptibility of the second intermediate host, the mussel Mytilus edulis Linnaeus, 1758, to cercarial infections. Generally, salinity was the main driver, particularly of cercarial activity, infectivity, and mussel susceptibility to infection. At the lowest salinity (13), cercariae were 50% less active compared to the highest salinity (19). Infection success and host susceptibility followed a similar pattern, with 47% and 43% less metacercariae (encysted stage) present at salinity 13 than at salinity 19, respectively. In contrast, effects of simulated warming were found only for cercarial survival, with cercarial longevity being higher at 19 than at 23&nbsp;°C. No significant interactions between temperature and salinity were found. In contrast to the literature, the results suggest that a climate change-driven freshening (partly also warming) may lead to a general decline of marine trematodes, with possible beneficial effects for the involved hosts

The relationship between cortical lesions and periventricular NAWM abnormalities suggests a shared mechanism of injury in primary-progressive MS.

In subjects with multiple sclerosis (MS), pathology is more frequent near the inner and outer surfaces of the brain. Here, we sought to explore if in subjects with primary progressive MS (PPMS) cortical lesion load is selectively associated with the severity of periventricular normal appearing white matter (NAWM) damage, as assessed with diffusion weighted imaging. To this aim, twenty-four subjects with PPMS and twenty healthy controls were included in the study. Using diffusion data, skeletonized mean diffusivity (MD) NAWM maps were computed excluding WM lesions and a 2 mm-thick peri-lesional rim. The supra-tentorial voxels between 2 and 6 mm of distance from the lateral ventricles were included in the periventricular NAWM mask while the voxels between 6 and 10 mm from the lateral ventricles were included in the deep NAWM mask; mean MD values were then computed separately for these two masks. Lastly, cortical lesions were assessed on phase-sensitive inversion recovery (PSIR) images and cortical thickness was quantified on volumetric T1 images. Our main result was the observation in the PPMS group of a significant correlation between periventricular NAWM MD values and cortical lesion load, with a greater cortical lesion burden being associated with more abnormal periventricular NAWM MD. Conversely, there was no correlation between cortical lesion load and deep NAWM MD values or periventricular WM lesions. Our data thus suggest that a common - and relatively selective - factor plays a role in the development of both cortical lesion and periventricular NAWM abnormalities in PPMS

A long-term time series of global and diffuse photosynthetically active radiation in the Mediterranean: interannual variability and cloud effects

Abstract. Measurements of global and diffuse photosynthetically active radiation (PAR) have been carried out on the island of Lampedusa, in the central Mediterranean Sea, since 2002. PAR is derived from observations made with multi-filter rotating shadowband radiometers (MFRSRs) by comparison with a freshly calibrated PAR sensor and by relying on the on-site Langley plots. In this way, a long-term calibrated record covering the period 2002–2016 is obtained and is presented in this work. The monthly mean global PAR peaks in June, with about 160 W m−2, while the diffuse PAR reaches 60 W m−2 in spring or summer. The global PAR displays a clear annual cycle with a semi amplitude of about 52 W m−2. The diffuse PAR annual cycle has a semi amplitude of about 12 W m−2. A simple method to retrieve the cloud-free PAR global and diffuse irradiances in days characterized by partly cloudy conditions has been implemented and applied to the dataset. This method allows retrieval of the cloud-free evolution of PAR and calculation of the cloud radiative effect, CRE, for downwelling PAR. The cloud-free monthly mean global PAR reaches 175 W m−2 in summer, while the diffuse PAR peaks at about 40 W m−2. The cloud radiative effect, CRE, on global and diffuse PAR is calculated as the difference between all-sky and cloud-free measurements. The annual average CRE is about −14.7 W m−2 for the global PAR and +8.1 W m−2 for the diffuse PAR. The smallest CRE is observed in July, due to the high cloud-free condition frequency. Maxima (negative for the global, and positive for the diffuse component) occur in March–April and in October, due to the combination of elevated PAR irradiances and high occurrence of cloudy conditions. Summer clouds appear to be characterized by a low frequency of occurrence, low altitude, and low optical thickness, possibly linked to the peculiar marine boundary layer structure. These properties also contribute to produce small radiative effects on PAR in summer. The cloud radiative effect has been deseasonalized to remove the influence of annual irradiance variations. The monthly mean normalized CRE for global PAR can be well represented by a multi-linear regression with respect to monthly cloud fraction, cloud top pressure, and cloud optical thickness, as determined from satellite MODIS observations. The behaviour of the normalized CRE for diffuse PAR can not be satisfactorily described by a simple multi-linear model with respect to the cloud properties, due to its non-linear dependency, in particular on the cloud optical depth. The analysis suggests that about 77 % of the global PAR interannual variability may be ascribed to cloud variability in winter