Is current initial empirical antibiotherapy appropriate to treat bloodstream infections in short-duration chemo-induced febrile neutropenia?

INTRODUCTION: Fever of unknown origin is by far the most common diagnosis in low-risk febrile neutropenic patients undergoing chemotherapy. The current empirical regimen combines amoxicillin-clavulanic acid and fluoroquinolones in low-risk neutropenic patients. The aim of this study was to assess the appropriateness of antibiotherapy and the outcome of bloodstream infections (BSI) in patients with expected neutropenia of short duration. METHODS: This 2-year monocentric retrospective study included all consecutive neutropenic febrile adult patients with expected duration of neutropenia ≤ 7 days. They were classified into low- and high-risk groups for complications using the MASCC index. Appropriateness of initial empirical antibiotic regimen was assessed for each BSI. Multivariate analysis was performed to identify factors associated with mortality. RESULTS: Over the study period, 189 febrile episodes with positive blood cultures in neutropenic patients were reported, of which 44 occurred during expected duration of neutropenia ≤ 7 days. Patients were classified as high-risk (n = 27) and low-risk (n = 17). Gram-negative bacteria BSI represented 57% of cases, including only two multidrug-resistant bacteria in high-risk patients. Initial empirical antibiotherapy was appropriate in 86% of cases, and inappropriate in the event of coagulase-negative Staphylococcus BSI (14%), although the outcome was always favorable. In low-risk patients, no deaths and only 12% of severe complications were reported, contrasting with mortality and complication rates of 48% (p < 0.001) and 63% in high-risk patients (p < 0.001), respectively. CONCLUSIONS: Outcome of BSI is favorable in low-risk febrile neutropenic patients, even with inappropriate empirical initial antibiotic regimen for coagulase-negative Staphylococcus BSI. Initial in-hospital assessment and close monitoring of these patients are however mandatory.

Complex Microbial Communities Drive Iron and Sulfur Cycling in Arctic Fjord Sediments.

Glacial retreat is changing biogeochemical cycling in the Arctic, where glacial runoff contributes iron for oceanic shelf primary production. We hypothesize that in Svalbard fjords, microbes catalyze intense iron and sulfur cycling in low-organic-matter sediments. This is because low organic matter limits sulfide generation, allowing iron mobility to the water column instead of precipitation as iron monosulfides. In this study, we tested this with high-depth-resolution 16S rRNA gene libraries in the upper 20 cm at two sites in Van Keulenfjorden, Svalbard. At the site closer to the glaciers, iron-reducing Desulfuromonadales, iron-oxidizing Gallionella and Mariprofundus, and sulfur-oxidizing Thiotrichales and Epsilonproteobacteria were abundant above a 12-cm depth. Below this depth, the relative abundances of sequences for sulfate-reducing Desulfobacteraceae and Desulfobulbaceae increased. At the outer station, the switch from iron-cycling clades to sulfate reducers occurred at shallower depths (∼5 cm), corresponding to higher sulfate reduction rates. Relatively labile organic matter (shown by δ13C and C/N ratios) was more abundant at this outer site, and ordination analysis suggested that this affected microbial community structure in surface sediments. Network analysis revealed more correlations between predicted iron- and sulfur-cycling taxa and with uncultured clades proximal to the glacier. Together, these results suggest that complex microbial communities catalyze redox cycling of iron and sulfur, especially closer to the glacier, where sulfate reduction is limited due to low availability of organic matter. Diminished sulfate reduction in upper sediments enables iron to flux into the overlying water, where it may be transported to the shelf.IMPORTANCE Glacial runoff is a key source of iron for primary production in the Arctic. In the fjords of the Svalbard archipelago, glacial retreat is predicted to stimulate phytoplankton blooms that were previously restricted to outer margins. Decreased sediment delivery and enhanced primary production have been hypothesized to alter sediment biogeochemistry, wherein any free reduced iron that could potentially be delivered to the shelf will instead become buried with sulfide generated through microbial sulfate reduction. We support this hypothesis with sequencing data that showed increases in the relative abundance of sulfate reducing taxa and sulfate reduction rates with increasing distance from the glaciers in Van Keulenfjorden, Svalbard. Community structure was driven by organic geochemistry, suggesting that enhanced input of organic material will stimulate sulfate reduction in interior fjord sediments as glaciers continue to recede.

Relevance of omental pericellular adipose tissue collagen in the pathophysiology of human abdominal obesity and related cardiometabolic risk.

BACKGROUND: Adipose tissue fibrosis is a relatively new notion and its relationship with visceral obesity and cardiometabolic alterations remains unclear, particularly in moderate obesity. OBJECTIVE: Our objective was to examine if total and pericellular collagen accumulation are relevant for the pathophysiology of visceral obesity and related cardiometabolic risk. SUBJECTS AND METHODS: Surgical omental (OM) and subcutaneous (SC) fat samples were obtained in 56 women (age: 47.2±5.8 years; body mass index (BMI): 27.1±4.4 kg/m2). Body composition and fat distribution were measured by dual-energy X-ray absorptiometry and computed tomography, respectively. Total and pericellular collagen were measured using picrosirius red staining. CD68+ cells (total macrophages) and CD163+ cells (M2-macrophages) were identified using immunohistochemistry. RESULTS: We found that only pericellular collagen percentage, especially in OM fat, was associated with higher BMI, body fat mass and adipose tissue areas as well as lower radiologic attenuation of visceral adipose tissue and altered cardiometabolic risk variables. Strong correlations between peri-adipocyte collagen percentage and total or M2-macrophage percentages were observed in both depots. Total collagen percentage in either compartment was not related to adiposity, fat distribution or cardiometabolic risk. CONCLUSIONS: As opposed to whole tissue-based assessments of adipose tissue fibrosis, collagen deposition around the adipocyte, especially in the OM fat compartment is related to total and regional adiposity as well as altered cardiometabolic risk profile.

First case report of a human sepsis involving a recently identified anaerobic agent: Bacteroides faecis.

Up until now, Bacteroides faecis, a Gram-negative, anaerobic, non-motile, nonsporeforming rod has been principally described as a commensal microbe isolated from the feces of healthy adults. We report the first case of human Bacteroides faecis sepsis after removal of suspected post-colonic ischemia colonized epicardic electrodes. Electrodes and blood cultures both grew Gram-negative anaerobic rods but usual phenotypic methods and 16S rARN gene sequencing failed to ensure its species identification. B. faecis was finally identified using hsp60 gene sequencing. Because this species is not well-known and is difficult to identify, it may have been overlooked or misidentified in previous studies.

Fluorescent riboswitch-controlled biosensors for the genome scale analysis of metabolic pathways.

Fluorescent detection in cells has been tremendously developed over the years and now benefits from a large array of reporters that can provide sensitive and specific detection in real time. However, the intracellular monitoring of metabolite levels still poses great challenges due to the often complex nature of detected metabolites. Here, we provide a systematic analysis of thiamin pyrophosphate (TPP) metabolism in Escherichia coli by using a TPP-sensing riboswitch that controls the expression of the fluorescent gfp reporter. By comparing different combinations of reporter fusions and TPP-sensing riboswitches, we determine key elements that are associated with strong TPP-dependent sensing. Furthermore, by using the Keio collection as a proxy for growth conditions differing in TPP levels, we perform a high-throughput screen analysis using high-density solid agar plates. Our study reveals several genes whose deletion leads to increased or decreased TPP levels. The approach developed here could be applicable to other riboswitches and reporter genes, thus representing a framework onto which further development could lead to highly sophisticated detection platforms allowing metabolic screens and identification of orphan riboswitches.

E. coli-mediated gut inflammation in genetically predisposed Crohn's disease patients.

Many advances have been made in the understanding of Crohn's disease (CD) pathogenesis over the last decade. In CD patients abnormal ileal bacterial colonization could be linked to inappropriate innate immune responses to invasive bacteria. Adherent and invasive Escherichia coli strains have been isolated from CD patients and are able to adhere to and to invade intestinal epithelial cells and to induce colitis in transgenic mice expressing the human CEACAM6 molecule. In this review, we report recent advances concerning the involvement of adherent-invasive E. coli in the aetiology of CD and analyze how they can initiate inflammation of the gut mucosa in individuals with genetic predisposition.

Effects of forage quantity and access-time restriction on feeding behaviour, feed efficiency, nutritional status, and dairy performance of dairy cows fed indoors.

Optimising feed is a key challenge for dairy livestock systems, as forage stock shortages are increasingly frequent and feed is the biggest operating cost. The aim of this experiment was to evaluate the effects of reducing forage quantity and access time on dairy performance and animal nutritional status during indoor feeding. Twenty-seven Montbéliarde and Holstein cows were randomly allocated to three groups of nine cows balanced by breed, parity, days in milk, and milk yield. The three groups were given 3.9 kg DM/day of second-cut hay and 4.5 kg/day of concentrate and either i) ad libitum access to first-cut hay (Ad Libitum group; AL), ii) 10.5 kg/day of first-cut hay (Quantity-restricted group; QR), or iii) 10.5 kg/day of first-cut hay but with access time restricted to only 2 h in the morning and 2 h in the afternoon (Quantity-and-Time-restricted group; QTR). Milk yield, composition and coagulation properties, cow nutritional status (weight, body condition score, blood metabolites) and cow activities were recorded. The AL group ingested 10 % more feed than the QR group and 16 % more feed than the QTR group. Organic matter digestibility was lower in the AL group than in the QR and QTR groups whereas feed efficiency did not differ. Milk yield was not significantly different among the three groups. Compared to the QR and QTR groups, the AL group had significantly higher milk fat (35.9 vs 32.9 and 32.8 g/kg of milk) and milk protein content (29.5 vs 27.7 and 28.5 g/kg of milk). QR and QTR cows mobilised their body fat, resulting in a lower final body condition score, and tended to have a lower blood non-esterified fatty acid concentration than the AL group. QTR cows showed greater body fat mobilisation, but their final corrected BW was not different from AL cows. Access-time restriction did not impact fat and protein content but led to decreased casein, lactose contents and casein-to-whey protein ratio. The forage savings achieved through this feed management practice could prove economically substantial when forage prices increase. This practice can be of interest in grassland systems to overcome certain climatic hazards without having to resort to purchases or to increase the farm's forage autonomy.

Strategies for keeping dairy cows and calves together - a cross-sectional survey study.

Although it is still most common to rear dairy calves separately from adult cattle, the interest in prolonged contact between dairy calves and lactating cows during early life is increasing. Previous research has documented positive effects of cow-calf contact (CCC) on for example early calf growth and udder health of suckled cows, but also negative effects such as increased separation distress and reduced weight gains after weaning. The aim of this study was to use information from European farms with prolonged cow-calf contact to identify innovative solutions to common challenges for CCC farms. Commercial dairy farms that kept calves with adult lactating cows for seven days or more after birth were invited to participate, and interviews were performed with 104 farmers from six countries. During interviews, information about farm management, calf rearing, farmers' perception of animal health on their farm, and farmers' drivers and barriers for implementing CCC were collected. We found that CCC was practised in a large variety of housing and management systems, and that calves could be reared together with their dam, with foster cows, or using a combination of the two. The contact period varied considerably (7-305 days) between farms and about 25% of the farms manually milk fed the calves during parts of the milk feeding period. Daily contact time varied between farms, from 30 minutes per day to permanent contact except at milking. Behaviours indicative of separation distress, most commonly vocalisation in cows and calves, were reported by 87% of the farmers. Strategies to alleviate separation distress, for example simultaneous gradual weaning and separation, were used on some farms. Building constraints were most often mentioned as a barrier for implementing CCC. Our findings suggest that CCC is practised in a variety of commonly used husbandry systems. Reported challenges were primarily related to weaning and separation, and to building constraints; these aspects should be areas of future research.

[Improvement of severe and intravenous immunoglobulin-dependent multifocal motor neuropathy with conduction block after long-term rituximab]. / Amélioration d'un cas de neuropathie motrice multifocale avec blocs de conduction sévère, dépendant des immunoglobulines intraveineuses, après adjonction de rituximab au long cours.

INTRODUCTION: Some patients suffering from multifocal motor neuropathy with conduction blocks (MMNCB) are still disabled after treatment with intravenous immunoglobulin (IVIg). CASE REPORT: We report the benefits of a combination of rituximab (RTX) and IVIg in the case of a 72-year-old man with MMNCB. DISCUSSION: Despite an IVIg treatment, the patient had severe motor weakness of the four limbs which limited daily living activity. Azathioprine, mycophenolate mofetyl and cyclophosphamid did not improve the patient's status. Adjunction of rituximab to IVIg therapy increased muscle strength measured on MRC sum score and reduced disability evaluated on ONLS (Overall Neuropathy Limitation Scale) score in the long term (37 months). In spite of the improvement of his neurological status, the patient remained dependent on IVIg. CONCLUSION: RTX could be proposed as a long-term complementary treatment for some severe cases of IVIg-dependent NMMBC. These results must be confirmed in a randomized controlled study.

Investigation of reaction force magnitude and orientation during supine thoracic thrust manipulation applied to intervertebral and costovertebral regions.

BACKGROUND: Spinal manipulative techniques are commonly used in manual therapies but quantified descriptive and reliability data are lacking considering supine thoracic thrust manipulation. OBJECTIVES: The purpose of this study is to explore and compare kinetic parameters during supine thoracic thrust manipulation performed at two different thoracic regions. Intra-rater task repeatability and influence of practitioners were estimated. DESIGN: Exploratory and agreement study. METHODS: Kinetic parameters were assessed by examining reaction force magnitude and orientation (on the basis of the zenithal angle) using force platforms. Manipulative procedure (consisting in the application of 3 preloads followed by one thrust adjustment) at both intervertebral and costovertebral region was performed by different practitioners at three sessions. Application of thrust was allowed for experienced practitioners only. Preload force, peak force magnitude and vector force orientation were compared between anatomical sites, sessions and practitioners, and bias with limit of agreement were estimated. RESULTS: Repeatability analysis showed that practitioners achieved similar preload and peak force independent of the session, with comparable force orientation. Differences between practitioners were observed for preload and peak force but not regarding the zenithal angle during the thrust phase. CONCLUSIONS: The present study is the first that explores kinetic parameters for supine thoracic thrust manipulation applied on two different regions of the thorax. Results confirm consistency of performance among practitioners for supine manipulative techniques at intervertebral and costovertebral region. While task repeatability was confirmed, several differences were observed between practitioners. Further investigations would examine velocity, acceleration and potential neurophysiological effect of such manipulative technique.

Association between EZH2 expression, silencing of tumor suppressors and disease outcome in solid tumors.

EZH2, the main catalytic component of the Polycomb Repressive Complex 2 (PRC2) is apparently upregulated in most solid tumors. Furthermore its expression generally associates with poor prognosis. It was proposed that this correlation reflects a causal event, EZH2 mediating the silencing of key tumor suppressor loci. In contrast, we recently showed that EZH2 is dispensable for solid tumor development and that its elevated expression reflects the abnormally high proliferation rate of cancer cells. Here, we investigate the functional association between EZH2 expression and silencing of key tumor suppressor loci and further illustrate the confounding effect of proliferation on EZH2's association to outcome.

Ion excitation in a linear quadrupole ion trap with an added octopole field.

Modeling of ion motion and experimental investigations of ion excitation in a linear quadrupole trap with a 4% added octopole field are described. The results are compared with those obtained with a conventional round rod set. Motion in the effective potential of the rod set can explain many of the observed phenomena. The frequencies of ion oscillation in the x and y directions shift with amplitude in opposite directions as the amplitudes of oscillation increase. Excitation profiles for ion fragmentation become asymmetric and in some cases show bistable behavior where the amplitude of oscillation suddenly jumps between high and low values with very small changes in excitation frequency. Experiments show these effects. Ions are injected into a linear trap, stored, isolated, excited for MS/MS, and then mass analyzed in a time-of-flight mass analyzer. Frequency shifts between the x and y motions are observed, and in some cases asymmetric excitation profiles and bistable behavior are observed. Higher MS/MS efficiencies are expected when an octopole field is added. MS/MS efficiencies (N(2) collision gas) have been measured for a conventional quadrupole rod set and a linear ion trap with a 4% added octopole field. Efficiencies are chemical compound dependent, but when an octopole field is added, efficiencies can be substantially higher than with a conventional rod set, particularly at pressures of 1.4 x 10(-4) torr or less.

Methane sources in arctic thermokarst lake sediments on the North Slope of Alaska.

The permafrost on the North Slope of Alaska is densely populated by shallow lakes that result from thermokarst erosion. These lakes release methane (CH4 ) derived from a combination of ancient thermogenic pools and contemporary biogenic production. Despite the potential importance of CH4 as a greenhouse gas, the contribution of biogenic CH4 production in arctic thermokarst lakes in Alaska is not currently well understood. To further advance our knowledge of CH4 dynamics in these lakes, we focused our study on (i) the potential for microbial CH4 production in lake sediments, (ii) the role of sediment geochemistry in controlling biogenic CH4 production, and (iii) the temperature dependence of this process. Sediment cores were collected from one site in Siqlukaq Lake and two sites in Sukok Lake in late October to early November. Analyses of pore water geochemistry, sedimentary organic matter and lipid biomarkers, stable carbon isotopes, results from CH4 production experiments, and copy number of a methanogenic pathway-specific gene (mcrA) indicated the existence of different sources of CH4 in each of the lakes chosen for the study. Analysis of this integrated data set revealed that there is biological CH4 production in Siqlukaq at moderate levels, while the very low levels of CH4 detected in Sukok had a mixed origin, with little to no biological CH4 production. Furthermore, methanogenic archaea exhibited temperature-dependent use of in situ substrates for methanogenesis, and the amount of CH4 produced was directly related to the amount of labile organic matter in the sediments. This study constitutes an important first step in better understanding the actual contribution of biogenic CH4 from thermokarst lakes on the coastal plain of Alaska to the current CH4 budgets.

Antiandrogenic effect of spirolactones: mechanism of action.

Spirolactones are aldosterone antagonists which inhibit the binding of aldosterone to the renal mineralocorticoid receptor. These molecules also possess an antiandrogenic effect which could be due, among other possibilities, to a peripheral antagonism of androgens. This hypothesis has been tested in the present study. From in vivo experiments, spironolactone K+ canrenoate appear to inhibit the binding of [3H]5alpha-dihydrotestosterone [3H]DHT to the cytosolic and nuclear receptor of the rat ventral prostate. The doses used are in the same range as those used for demonstrating the antimineralocorticoid effect of these molecules. In vitro incubations and in vitro displacement studies show that spironolactone and K+ canrenoate are respectively about 20 and 100 times less effective than DHT in displacing 50 percent of 5 times 10- minus 10 M [3H]DHT from its receptor. Spirolactones are also able to compete with [3H]DHT for the specific 8 S cytosolic receptor. Neither spironolactone nor K+ canrenoate decreases prostatic 5alpha-reductase activity, even at a concentration as high as 10- minus 5 M. It seems likely that spirolactones, besides their action on testosterone biosynthesis, exert their antiandrogenic activity via a peripheral androgen antagonism.

Mechanism of action of a new antialdosterone compound, prorenone.

Two new aldosterone antagonists, K-prorenoate [potassium 3(17 beta-hydroxy-6 beta, 7 beta-methylen-3-oxo-4-androsten-17 alpha-yl)propionate] and prorenone [3(17 beta-hydroxy-6 beta, 7 beta-methylen-3-oxo-4-androsten-17 alpha-yl) propionic acid gamma-lactone], its lactonic form, were studied in rat kidney using in vitro systems. Study of [3H]prorenone binding by a recently developed computer method indicated a high affinity, low capacity class of sites which are, seemingly, mineralocorticoid receptors. In competition experiments performed on [3H]aldosterone- and [3H]dexamethasone-binding sites, prorenone appeared to be a good competitor for mineralocorticoid-binding sites and a poor competitor for glucocorticoid-binding sites. The specificity of this molecule was further confirmed by its poor ability to displace [3H]dihydrotestosterone from rat prostate androgenic receptors compared to spironolactone [3-(3-oxo-7 alpha-acetylthio-17 beta-hydroxy-4-androsten-17 alpha-yl) propionic acid gamma-lactone]. In the same experiments, K-prorenoate demonstrated a very low affinity for the two types of receptors. The behavior of [3H]prorenone cytosolic complex was also studied in kidney mince experiments, which showed that the [3H]prorenone complex was not able to translocate into the nucleus. Prorenone inhibited the binding of [3H]aldosterone to the receptor and, consequently, the nuclear binding of aldosterone was not observed.

In vitro and in vivo inhibition of the 2 active sites of ACE by omapatrilat, a vasopeptidase inhibitor.

The vasopeptidase inhibitor omapatrilat inhibits both neutral endopeptidase and angiotensin-converting enzyme (ACE). The in vitro and in vivo inhibitory potency of omapatrilat and the specific ACE inhibitor fosinopril toward the 2 active sites of ACE (called N- and C-domains) was investigated with the use of 3 substrates: angiotensin I, which is equally cleaved by the 2 ACE domains; hippuryl-histidyl-leucine, specific synthetic substrate of the C-domain in high- salt conditions; and a newly synthesized specific substrate of the N-domain designed by acetylating the lysine residue of AcSDKP. In vitro, omapatrilat was 5 times more potent than fosinoprilat in inhibiting angiotensin I hydrolysis. Omapatrilat inhibited similarly both N- and C-domain hydrolysis, whereas fosinoprilat was slightly more specific for the N-domain. The in vivo selective inhibitory potency of single oral doses of 10 mg omapatrilat and 20 mg fosinopril were investigated in a double-blind, placebo-controlled, cross-over study in 9 mildly sodium-depleted normotensive subjects. In accordance with the in vitro results, fosinopril appeared to be more specific for the N-domain than the C-domain in vivo, since plasma and urine AcSDKP concentrations were significantly higher than those observed with omapatrilat. This study shows that it is possible to assess separately in vitro and in vivo the selectivity of ACE or ACE/neutral endopeptidase inhibitors. A differential selectivity may explain some peculiar properties observed with some ACE inhibitors.

N-domain selectivity of angiotensin I-converting enzyme as assessed by structure-function studies of its highly selective substrate, N-acetyl-seryl-aspartyl-lysyl-proline.

The physiological functions of angiotensin I-converting enzyme (ACE) are not limited to its cardiovascular role. ACE constantly degrades N-acetyl-seryl-aspartyl-lysyl-proline (AcSDKP), a natural circulating regulator of the hematopoietic stem cell proliferation, and thereby may be involved in hematopoietic stem cell regulation. AcSDKP is hydrolyzed 50-fold faster by the N-domain active site compared to the C-domain active site. The aim of the present study was to investigate which aminoacid residues from AcSDKP are required to ensure N-domain specificity. Several peptides were designed by progressively increasing the length of the peptidic chain from a tripeptide to a pentapeptide. Kinetic studies of the wild-type ACE and of the two ACE mutants containing a single active domain (N- or C-domain) were performed using Bz (benzoyl) Asp-Lys-Pro, benzoyl-glycyl (Bz-Gly)-Asp-Lys-Pro, and Bz-Gly-Ser-Asp-Lys-Pro (with its intermediate product Bz-Gly-Ser-Asp) as substrates. The unexpected importance of an aspartic acid in the P1 position was discovered, as well as the interaction of the P2 and P3 positions in the substrate to increase or decrease N-domain specificity. Substrates longer than five residues may involve interdependence between subsites. Finally, the discovery of highly specific and novel N-domain substrates cannot be predicted from single subsite mapping, but may require other approaches such as combinatorial peptide libraries.