Phages infecting
Salmonella Typhimurium PT160 and
Campylobacter jejuni were added at a low or high (10 or 10
4) multiplicity of infection (MOI) to either low or high (<100 or 10
4
cm
−2) densities of ...host bacteria inoculated onto raw and cooked beef, and incubated at 5 and 24
°C to simulate refrigerated and room temperature storage. Counts of host bacteria were made throughout the incubation period, with phages being counted at the first and last sampling times. Host inactivation was variable and depended on the incubation conditions and food type. Significant host inactivations of the order of 2–3
log
10
cm
−2 at 5
°C and >5.9
log
10
cm
−2 at 24
°C were achieved compared to phage-free controls using the
Salmonella phage under optimal conditions (high host cell density and MOI). These results alongside those already published indicate that phages may be useful in the control for foodborne pathogens.
A number of outbreaks of Escherichia coli O157:H7 infections involving beef have been reported. Options for controlling bacterial pathogens in raw foods are limited, but one is to use bacteriophages ...(phages). We describe the isolation and characterisation of phage FAHEc1, which infects E. coli O157, and its ability to kill its host in vitro and on beef. The phage belonged to the family Myoviridae and lysed 28 of 30 E. coli O157 (:H7, :HNM and :H not specified) isolates, only one other non-O157 E. coli serotype (O162:H7), and none of the other 13 bacterial species tested. The phage did not contain stx1, stx2, eae or ehxA virulence genes as assessed by PCR. An approximate 4 log10 inactivation of E. coli O157:H7 occurred at 5 °C in the presence of phage FAHEc1 at >107 PFU/ml in broth in vitro. On thinly sliced beef pieces incubated at 37 °C, a > 2.7 log10 reduction occurred with 3.2 × 107 PFU/4 cm2 meat piece. At lower phage concentrations (103–104 PFU/4 cm2 piece) phage replication occurred on beef at 37 °C. When the phage was applied to beef pieces under conditions simulating hot boning and conventional carcass cooling, inactivation of E. coli O157:H7 of approximately 2 log10 was measured under optimal conditions with phages applied at 3.2 × 107 PFU/4 cm2 meat piece.
•A phage was isolated which infected 28 of 30 Escherichia coli O157:H7 isolates tested.•A greater than 4 log10 reduction was recorded in broth at 5 °C when host cells were incubated with the phage.•A dose-dependent reduction in host cells was caused by the phage on meat.•The phage inactivated the pathogen on typical carcass and boxed beef cooling curves.
A bacteriophage (phage) that infected strains of the species Listeria monocytogenes as well as Listeria ivanovii and Listeria welshimeri, but not Listeria grayi or Listeria innocua, was isolated from ...sheep faeces. The phage had a contractile tail and an icosohedral head indicating that it was a myovirus, and was morphologically similar to phage A511. At 30 °C, phages added at 5.2 × 107 PFU ml−1 prevented the growth in broth of L. monocytogenes present at approximately twice this concentration for 7 h, but re-growth occurred such that the concentration after 24 h incubation was similar in both control and phage-treated cultures. At the same temperature, but on the surface of vacuum-packed ready-to-eat chicken breast roll, there was an immediate 2.5 log10 CFU cm−2 reduction in pathogen concentration following addition of phages and then re-growth. However, at a temperature reflecting that at which a chilled food might be held (5°C), this re-growth was prevented over 21 days incubation. The data suggest a dose-dependent rapid reduction in pathogen concentration followed by no continued phage-mediated effect. These results, alongside other published data, indicate that a high concentration of phages per unit area is required to ensure significant inactivation of target pathogens on food surfaces.
► A newly isolated phage controlled Listeria monocytogenes under refrigeration. ► The effect was rapid and dose dependent. ► A high concentration of phages is needed for successful pathogen control. ► The high concentration used does not mean that the mechanism is lysis from without.
We present twin Van Allen Probes spacecraft observations of the effects of a solar wind shock impacting the magnetosphere on 8 October 2013. The event provides details both of the accelerating ...electric fields associated with the shock and the response of inner magnetosphere electron populations across a broad range of energies. During this period, the two Van Allen Probes observed shock effects from the vantage point of the dayside magnetosphere at radial positions of L = 3 and L = 5, at the location where shock‐induced acceleration of relativistic electrons occurs. The extended (~1 min) duration of the accelerating electric field across a broad extent of the dayside magnetosphere, coupled with energy‐dependent relativistic electron gradient drift velocities, selects a preferred range of energies (3–4 MeV) for the initial enhancement. Those electrons—whose drift velocity closely matches the azimuthal phase velocity of the shock‐induced pulse—stayed in the accelerating wave as it propagated tailward and received the largest increase in energy. Drift resonance with subsequent strong ULF waves further accentuated this range of electron energies. Phase space density and positional considerations permit the identification of the source population of the energized electrons. Observations detail the promptness (<20 min), energy range (1.5–4.5 MeV), energy increase (~500 keV), and spatial extent (L* ~3.5–4.0) of the enhancement of the relativistic electrons. Prompt acceleration by impulsive shock‐induced electric fields and subsequent ULF wave processes therefore comprises a significant mechanism for the acceleration of highly relativistic electrons deep inside the outer radiation belt as shown clearly by this event.
Key Points
Dual‐spacecraft dayside observations quantify shock‐induced effects
Drift resonance with induced electric fields accelerates 3–4 MeV electrons
Energy increase ~500 keV occurs in <20 min for 3 MeV at L*~3.8
Nesiritide is approved in the United States for early relief of dyspnea in patients with acute heart failure. Previous meta-analyses have raised questions regarding renal toxicity and the mortality ...associated with this agent.
We randomly assigned 7141 patients who were hospitalized with acute heart failure to receive either nesiritide or placebo for 24 to 168 hours in addition to standard care. Coprimary end points were the change in dyspnea at 6 and 24 hours, as measured on a 7-point Likert scale, and the composite end point of rehospitalization for heart failure or death within 30 days.
Patients randomly assigned to nesiritide, as compared with those assigned to placebo, more frequently reported markedly or moderately improved dyspnea at 6 hours (44.5% vs. 42.1%, P=0.03) and 24 hours (68.2% vs. 66.1%, P=0.007), but the prespecified level for significance (P≤0.005 for both assessments or P≤0.0025 for either) was not met. The rate of rehospitalization for heart failure or death from any cause within 30 days was 9.4% in the nesiritide group versus 10.1% in the placebo group (absolute difference, -0.7 percentage points; 95% confidence interval CI, -2.1 to 0.7; P=0.31). There were no significant differences in rates of death from any cause at 30 days (3.6% with nesiritide vs. 4.0% with placebo; absolute difference, -0.4 percentage points; 95% CI, -1.3 to 0.5) or rates of worsening renal function, defined by more than a 25% decrease in the estimated glomerular filtration rate (31.4% vs. 29.5%; odds ratio, 1.09; 95% CI, 0.98 to 1.21; P=0.11).
Nesiritide was not associated with an increase or a decrease in the rate of death and rehospitalization and had a small, nonsignificant effect on dyspnea when used in combination with other therapies. It was not associated with a worsening of renal function, but it was associated with an increase in rates of hypotension. On the basis of these results, nesiritide cannot be recommended for routine use in the broad population of patients with acute heart failure. (Funded by Scios; ClinicalTrials.gov number, NCT00475852.).
The Solar Orbiter magnetometer Horbury, T. S.; O’Brien, H.; Carrasco Blazquez, I. ...
Astronomy and astrophysics (Berlin),
10/2020, Letnik:
642
Journal Article
Recenzirano
Odprti dostop
The magnetometer instrument on the Solar Orbiter mission is designed to measure the magnetic field local to the spacecraft continuously for the entire mission duration. The need to characterise not ...only the background magnetic field but also its variations on scales from far above to well below the proton gyroscale result in challenging requirements on stability, precision, and noise, as well as magnetic and operational limitations on both the spacecraft and other instruments. The challenging vibration and thermal environment has led to significant development of the mechanical sensor design. The overall instrument design, performance, data products, and operational strategy are described.
The purpose of this study was to determine the efficacy of a peer-led illness self-management intervention called Wellness Recovery Action Planning (WRAP) by comparing it with usual care. The primary ...outcome was reduction of psychiatric symptoms, with secondary outcomes of increased hopefulness, and enhanced quality of life (QOL). A total of 519 adults with severe and persistent mental illness were recruited from outpatient community mental health settings in 6 Ohio communities and randomly assigned to the 8-week intervention or a wait-list control condition. Outcomes were assessed at end of treatment and at 6-month follow-up using an intent-to-treat mixed-effects random regression analysis. Compared to controls, at immediate postintervention and at 6-month follow-up, WRAP participants reported: (1) significantly greater reduction over time in Brief Symptom Inventory Global Symptom Severity and Positive Symptom Total, (2) significantly greater improvement over time in hopefulness as assessed by the Hope Scale total score and subscale for goal directed hopefulness, and (3) enhanced improvement over time in QOL as assessed by the World Health Organization Quality of Life-BREF environment subscale. These results indicate that peer-delivered mental illness self-management training reduces psychiatric symptoms, enhances participants' hopefulness, and improves their QOL over time. This confirms the importance of peer-led wellness management interventions, such as WRAP, as part of a group of evidence-based recovery-oriented services.
The objective of this research was to evaluate the relationship between udder health and reproductive performance in UK dairy cows. Data from 80 herds were restructured such that each unit of data ...represented a 2-d period during lactation where a cow was at risk of becoming pregnant. Multilevel discrete-time survival models were then used within a Bayesian framework to explore associations between reproductive outcomes and a variety of potential explanatory variables. Separate models were constructed using 2 different univariate binary outcomes: a cow becoming pregnant during a risk period and a cow becoming pregnant as a result of a given service. Potential explanatory variables included occurrence of clinical mastitis and a categorical representation of individual cow somatic cell count (SCC), both at a variety of timings relative to the risk period. Posterior predictions were used to assess model fit and to check model building assumptions. These demonstrated that the model represented the data well. Within-sample Monte Carlo simulation (i.e., use of the model to predict outcomes for cases within the data set, repeated over a large number of iterations) was used to illustrate results as posterior predicted relative risks. A negative association was found between reproductive performance and cases of clinical mastitis over a wide time frame relative to the risk period (from 28d before to 70d after the risk period). A similar negative association with the probability of a service leading to a pregnancy (pregnancy rate) was observed over the same time frame. Higher SCC recordings (i.e., those more likely to be associated with an intramammary infection) were also associated with decreased reproductive performance, especially where an individual cow SCC of greater than 399,000/mL was recorded in the 30d following a risk period or service. This research demonstrates that both clinical and subclinical mastitis are associated with a reduction in reproductive performance, and that this influence varies in magnitude but can be exerted over a prolonged period.
The objective of this observational study was to quantify associations between Mycobacterium avium subspecies paratuberculosis (MAP) antibody status and a variety of fertility outcomes, in UK dairy ...cattle. Longitudinal milk recording, fertility and MAP antibody enzyme-linked immunosorbent assay (ELISA) milk test data were collated retrospectively from 121,762 lactations in 78 herds. Datasets were structured into appropriate units to suit outcomes and enable temporal association between current and future MAP status, and fertility measures. Current MAP status was categorised according to most recent status within 180 days, with time-related future MAP status assigned based on MAP antibody ELISA milk test data for each cow. Multilevel multivariable logistic regression models were used to evaluate associations between MAP status and 21-day pregnancy and submission rate and conception risk. Posterior predictions and cross-validation techniques were used to assess model fit and check model building assumptions. A negative association was found between risk of insemination (Odds Ratio OR, 0.78; 95% Credible Interval CI, 0.66–0.92) and conception occurring (OR, 0.65; CI, 0.5–0.84) and transition from negative to non-negative MAP test status in the next 30–90 days. A positive association was observed between risk of insemination (OR, 1.34; CI, 1.16–1.52) and conception occurring (OR, 1.26; CI, 1.11–1.43) and transition from negative to non-negative MAP test status in the next 90–180 days. Current positive MAP test status was negatively and positively associated with insemination (OR, 0.59; CI, 0.49–0.70) and conception risk (OR, 1.12; CI, 0.96–1.30), respectively. Herd managers will have had access to test results, declaring cows with past recent or multiple positive MAP antibody ELISA results not to be bred, negatively influencing insemination risk. Overall, these results demonstrate the temporal association between a positive MAP antibody ELISA result and dairy cow fertility outcomes, with particular variability prior to a positive MAP antibody ELISA result.
•Johne’s disease (JD) antibody status was associated with dairy cow fertility.•Insemination and conception risks were increased > 90 days before positive JD status.•Insemination and conception risks were reduced 30–90 days before positive JD status.•Insemination risk remained reduced after positive JD status.
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