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BACKGROUND: Between September 2016 and November 2020, 17 cases of difficult-to-treat resistant Pseudomonas aeruginosa (DTR-PA) were reported in haematology patients at a tertiary referral hospital in the North of England. AIM: A retrospective case-control study was conducted to investigate the association between DTR-PA infection and clinical interventions, patient movement, antimicrobial use and comorbidities. METHODS: Cases were patients colonized or infected with the outbreak strain of DTR-PA who had been admitted to hospital prior to their positive specimen. Exposures were extracted from medical records, and cases were compared with controls using conditional logistic regression. Environmental and microbiological investigations were also conducted. FINDINGS: Seventeen cases and 51 controls were included. The final model included age [>65 years, adjusted OR (aOR) 6.85, P=0.232], sex (aOR 0.60, P=0.688), admission under the transplant team (aOR 14.27, P=0.43) and use of ciprofloxacin (aOR 102.13, P=0.030). Investigations did not indicate case-to-case transmission or a point source, although a common environmental source was highly likely. CONCLUSION: This study found that the use of fluoroquinolones is an independent risk factor for DTR-PA in haematology patients. Antimicrobial stewardship and review of fluoroquinolone prophylaxis should be considered as part of PA outbreak investigations in addition to standard infection control interventions.
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Infección Hospitalaria , Infecciones por Pseudomonas , Humanos , Anciano , Fluoroquinolonas/uso terapéutico , Estudios de Casos y Controles , Estudios Retrospectivos , Pseudomonas aeruginosa , Infección Hospitalaria/prevención & control , Farmacorresistencia Bacteriana Múltiple , Infecciones por Pseudomonas/tratamiento farmacológico , Infecciones por Pseudomonas/epidemiología , Infecciones por Pseudomonas/microbiología , Brotes de Enfermedades , Centros de Atención Terciaria , Antibacterianos/uso terapéutico , Antibacterianos/farmacologíaRESUMEN
OBJECTIVE: Public health control measures at borders have long been central to national strategies for the prevention and containment of infectious diseases. Travel was inevitably associated with the rapid global transmission of COVID-19. In the UK, public health authorities tried to reduce the risks of travel-associated spread by providing public health information at ports of entry. This study investigates risk assessment processes, decision-making and adherence to official advice among international travellers, to provide evidence for future policy on the provision of public health information to facilitate safer international travel. STUDY DESIGN: This study is a qualitative study evaluation. METHOD: International air passengers arriving at the London Heathrow Airport on scheduled flights from China and Singapore were approached for interview after consenting to contact in completed surveys. Semi-structured interviews were conducted by telephone, using two topic guides to explore views of official public health information and self-isolation. Interview transcripts were coded and analysed thematically. RESULTS: Participants regarded official advice from Public Health England as adequate at the time, despite observing differences with intervention measures implemented in their countries of departure. Most participants also described adopting precautionary measures, including self-isolation and the use of face coverings that went beyond official advice, but reported adherence to guidance on contacting health authorities was more variable. Adherence to the official guidance was informed by the perceived salience of specific transmission possibilities and containment measures assessed in relation to participants' local social and institutional environments. CONCLUSION: Analysis of study findings demonstrates that international air travellers' responses to public health advice constitute a proactive process of risk assessment and rationalised decision-making to guide preventive action. This process incorporates consideration of the current living situation, trust in information sources, correspondence with cultural logics and willingness to accept potential risk to self and significant others. Our findings concerning international passengers' understanding of, and compliance with, official advice and mitigation measures provide valuable evidence to inform future policy and generate recommendations on the presentation of public health information to facilitate safer international travel. Access to a central source of regularly updated official information would help minimise confusion between different national guidelines. Greater attention to the differentiated information needs of diverse groups in creating future public-facing guidance would help to minimise the uncertainties generated by the receipt of generic information.
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COVID-19 , Humanos , Salud Pública , SARS-CoV-2 , Viaje , Reino UnidoRESUMEN
OBJECTIVES: In the containment phase of the response to the COVID-19 outbreak, Public Health England (PHE) delivered advice to travellers arriving at major UK ports. We aimed to rapidly evaluate the impact and effectiveness of these communication materials for passengers in the early stages of the pandemic. STUDY DESIGN: The study design used is the mixed-methods evaluation. METHODS: A questionnaire survey and follow-up interviews with passengers arriving at London Heathrow Airport on scheduled flights from China and Singapore. The survey assessed passengers' knowledge of symptoms, actions to take, and attitudes towards PHE COVID-19 public health information; interviews explored their views of official public health information and self-isolation. RESULTS: One hundred and twenty-one passengers participated in the survey and 15 in follow-up interviews. Eighty three percentage of surveyed passengers correctly identified all three COVID-19 associated symptoms listed in PHE information at that time. Most could identify the recommended actions and found the advice understandable and trustworthy. Interviews revealed that passengers shared concerns about the lack of wider official action, and that passengers' knowledge had been acquired elsewhere as much from PHE. Respondents also noted their own agency in choosing to self-isolate, partially as a self-protective measure. CONCLUSION: PHE COVID-19 public health information was perceived as clear and acceptable, but we found that passengers acquired knowledge from various sources and they saw the provision of information alone on arrival as an insufficient official response. Our study provides fresh insights into the importance of taking greater account of diverse information sources and of the need for public assurance in creating public health information materials to address global health threats.
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Viaje en Avión , COVID-19/prevención & control , Información de Salud al Consumidor , Internacionalidad , Salud Pública , Adulto , Anciano , Anciano de 80 o más Años , Aeropuertos , COVID-19/epidemiología , Femenino , Conocimientos, Actitudes y Práctica en Salud , Humanos , Masculino , Persona de Mediana Edad , Investigación Cualitativa , Encuestas y Cuestionarios , Reino Unido/epidemiología , Adulto JovenRESUMEN
AIM: To describe the investigation and management of a meticillin-resistant Staphylococcus aureus (MRSA) outbreak on a neonatal intensive care unit (NICU) and the lessons learnt. METHODS: This was an outbreak report and case-control study conducted in a 40-cot NICU in a tertiary referral hospital and included all infants colonized/infected with gentamicin-resistant MRSA. INTERVENTION: Standard infection-control measures including segregation of infants, barrier precautions, enhanced cleaning, assessment of staff practice including hand hygiene, and increased MRSA screening of infants were implemented. Continued MRSA acquisitions led to screening of all NICU staff. A case-control study was performed to assess staff contact with colonized babies and inform the management of the outbreak. FINDINGS: Eight infants were colonized with MRSA (spa type t2068), one of whom subsequently developed an MRSA bacteraemia. MRSA colonization was significantly associated with lower gestational age; lower birthweight and with being a twin. Three nurses were MRSA colonized but only one nurse (45) was colonized with MRSA spa type t2068. Multivariable logistic regression analysis identified being cared for by nurse 45 as an independent risk factor for MRSA colonization. CONCLUSIONS: Lack of accurate recording of which nurses looked after which infants (and when) made identification of the risk posed by being cared for by particular nurses difficult. If this had been clearer, it may have enabled earlier identification of the colonized nurse, avoiding subsequent cases. This study highlights the benefit of using a case-control study, which showed that most nurses had no association with colonized infants.
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Portador Sano/epidemiología , Brotes de Enfermedades , Unidades de Cuidado Intensivo Neonatal , Staphylococcus aureus Resistente a Meticilina/aislamiento & purificación , Infecciones Estafilocócicas/epidemiología , Portador Sano/microbiología , Portador Sano/prevención & control , Portador Sano/transmisión , Estudios de Casos y Controles , Transmisión de Enfermedad Infecciosa/prevención & control , Femenino , Humanos , Lactante , Recién Nacido , Control de Infecciones/métodos , Masculino , Staphylococcus aureus Resistente a Meticilina/clasificación , Infecciones Estafilocócicas/microbiología , Infecciones Estafilocócicas/prevención & control , Infecciones Estafilocócicas/transmisión , Centros de Atención TerciariaRESUMEN
In semiconductors, quantum confinement can greatly enhance the interaction between band carriers (electrons and holes) and dopant atoms. One manifestation of this enhancement is the increased stability of exciton magnetic polarons in magnetically doped nanostructures. In the limit of very strong 0D confinement that is realized in colloidal semiconductor nanocrystals, a single exciton can exert an effective exchange field Bex on the embedded magnetic dopants that exceeds several tesla. Here we use the very sensitive method of resonant photoluminescence (PL) to directly measure the presence and properties of exciton magnetic polarons in colloidal Cd1-xMnxSe nanocrystals. Despite small Mn2+ concentrations (x = 0.4-1.6%), large polaron binding energies up to â¼26 meV are observed at low temperatures via the substantial Stokes shift between the pump laser and the resonant PL maximum, indicating nearly complete alignment of all Mn2+ spins by Bex. Temperature and magnetic field-dependent studies reveal that Bex ≈ 10 T in these nanocrystals, in good agreement with theoretical estimates. Further, the emission line widths provide direct insight into the statistical fluctuations of the Mn2+ spins. These resonant PL studies provide detailed insight into collective magnetic phenomena, especially in lightly doped nanocrystals where conventional techniques such as nonresonant PL or time-resolved PL provide ambiguous results.
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In the context of the increasing incidence of extended-spectrum beta-lactamase (ESBL) Escherichia coli infection, this prospective frequency-matched case-control study aimed to identify risk factors that would provide information and guidance for local clinical practice. One hundred and twelve participants were recruited: 54 cases and 58 controls. Univariate analysis indicated that isolation of an ESBL-producing E. coli in the previous 12 months and diabetes were significantly associated with the outcome. This study demonstrates the utility of service evaluation studies for producing epidemiological information to inform clinical practice.
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Complicaciones de la Diabetes/microbiología , Infecciones por Escherichia coli/microbiología , Escherichia coli/enzimología , Infecciones Urinarias/microbiología , beta-Lactamasas/metabolismo , Adulto , Anciano , Anciano de 80 o más Años , Estudios de Casos y Controles , Infecciones por Escherichia coli/epidemiología , Proteínas de Escherichia coli/metabolismo , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Factores de Riesgo , Infecciones Urinarias/epidemiología , Infecciones Urinarias/etiologíaRESUMEN
Strontium titanate (SrTiO3) is a foundational material in the emerging field of complex oxide electronics. Although its bulk electronic and optical properties are rich and have been studied for decades, SrTiO3 has recently become a renewed focus of materials research catalysed in part by the discovery of superconductivity and magnetism at interfaces between SrTiO3 and other non-magnetic oxides. Here we illustrate a new aspect to the phenomenology of magnetism in SrTiO3 by reporting the observation of an optically induced and persistent magnetization in slightly oxygen-deficient bulk SrTiO3-δ crystals using magnetic circular dichroism (MCD) spectroscopy and SQUID magnetometry. This zero-field magnetization appears below ~18 K, persists for hours below 10 K, and is tunable by means of the polarization and wavelength of sub-bandgap (400-500 nm) light. These effects occur only in crystals containing oxygen vacancies, revealing a detailed interplay between magnetism, lattice defects, and light in an archetypal complex oxide material.
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OBJECTIVE: Starting in 2013, all pediatric residents entering fellowship must be provided six educational units whose structure is to be determined by their individual career plans. We sought to determine whether (1) neonatology fellowship program directors (PDs) consistently identify certain weaknesses among incoming fellows and (2) neonatology fellowship PDs agree on the most beneficial activities in which pediatric residents should participate to improve preparation for entry into neonatology fellowships. STUDY DESIGN: We sent a 21-question survey focused on the structure and implementation of the 6-unit curriculum to all members of the Organization of Neonatology Training Program Directors. RESULTS: Sixty-seven percent of PDs responded. Seventy-five percent cited insufficient procedural skills as the primary weakness of incoming fellows. More than 80% rated additional training in clinical neonatology, including procedural and resuscitation training, as 'beneficial' or 'highly beneficial'. In contrast, fewer than 40% of PDs gave the same positive ratings to activities broadly focused on scholarship. CONCLUSIONS: The results of the survey may help guide pediatric residency programs as they undertake development of these new curricular initiatives for individual residents entering neonatology.
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Competencia Clínica , Curriculum , Internado y Residencia , Neonatología/educación , Pediatría/educación , Actitud del Personal de Salud , Recolección de Datos , Becas , Neonatología/organización & administración , Ejecutivos Médicos , Estados UnidosRESUMEN
We use terahertz pulses to induce resonant transitions between the eigenstates of optically generated exciton populations in a high-quality semiconductor quantum well sample. Monitoring the excitonic photoluminescence, we observe transient quenching of the 1s exciton emission, which we attribute to the terahertz-induced 1s-to-2p excitation. Simultaneously, a pronounced enhancement of the 2s exciton emission is observed, despite the 1s-to-2s transition being dipole forbidden. A microscopic many-body theory explains the experimental observations as a Coulomb-scattering mixing of the 2s and 2p states, yielding an effective terahertz transition between the 1s and 2s populations.
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AIM: The mammalian intestinal microflora has been shown to impact host physiology. In cattle, intestinal bacteria are also associated with faecal contamination of environmental sources and human illness via foodborne pathogens. Use of wet distillers' grains with solubles (WDGS) in cattle feed creates a gastrointestinal environment where some bacterial species are enriched. Here, we examine if a diet containing 40% WDGS results in fundamentally different microbial community structures. METHODS AND RESULTS: The 20,002 16S r-RNA gene sequences from 20 beef cattle were analysed using Sanger sequencing methods. At the genus level, Prevotella (Gram negative) and Anaerobacter (Gram positive) were the most frequently occurring bacteria in our beef cattle faecal samples. Diet-associated differences in prevalence were noted for Prevotella but not Anaerobacter. CONCLUSIONS: Diet affects community structure. Faecal communities of co-housed beef cattle are not identical. SIGNIFICANCE AND IMPACT OF THE STUDY: It is known that a diet of 40% corn-based WDGS increases the generic Escherichia coli in the faeces and enriches E. coli O157:H7. The results from the current study suggest that in addition to previously observed changes in E. coli, the entire bacterial community structure is different for animals fed 40% corn-based WDGS compared to a traditional corn-finishing diet.
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Alimentación Animal , Bacterias/aislamiento & purificación , Dieta/veterinaria , Heces/microbiología , Animales , Bacterias/genética , Bacterias/crecimiento & desarrollo , Bovinos , Grano Comestible , Escherichia coli/crecimiento & desarrollo , Escherichia coli O157/crecimiento & desarrollo , Tracto Gastrointestinal , Carne/microbiología , ARN Bacteriano/genética , ARN Ribosómico 16S/genética , Zea maysRESUMEN
An important challenge in the biomaterials field is to mimic the structure of functional tissues via cell and extracellular matrix (ECM) alignment and anisotropy. Toward this goal, silk-based scaffolds resembling bone lamellar structure were developed using a freeze-drying technique. The structure could be controlled directly by solute concentration and freezing parameters, resulting in lamellar scaffolds with regular morphology. Different post-treatments, such as methanol, water annealing and steam sterilization, were investigated to induce water stability. The resulting structures exhibited significant differences in terms of morphological integrity, structure and mechanical properties. The lamellar thicknesses were â¼2.6 µm for the methanol-treated scaffolds and â¼5.8 µm for water-annealed. These values are in the range of those reported for human lamellar bone. Human bone marrow-derived mesenchymal stem cells (hMSC) were seeded on these silk fibroin lamellar scaffolds and grown under osteogenic conditions to assess the effect of the microstructure on cell behavior. Collagen in the newly deposited ECM was found aligned along the lamellar architectures. In the case of methanol-treated lamellar structures, the hMSC were able to migrate into the interior of the scaffolds, producing a multilamellar hybrid construct. The present morphology constitutes a useful pattern onto which hMSC cells attach and proliferate for guided formation of a highly oriented extracellular matrix.
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Regeneración Tisular Dirigida/métodos , Seda/química , Ingeniería de Tejidos/métodos , Absorción , Fosfatasa Alcalina/metabolismo , Amidas/química , Animales , Forma de la Célula , Células Cultivadas , Cristalización , ADN/metabolismo , Fibroínas/química , Fibroínas/ultraestructura , Liofilización , Humanos , Células Madre Mesenquimatosas/citología , Células Madre Mesenquimatosas/enzimología , Células Madre Mesenquimatosas/ultraestructura , Microscopía Confocal , Microscopía Electrónica de Rastreo , Seda/ultraestructura , Espectroscopía Infrarroja por Transformada de Fourier , Andamios del Tejido , Vibración , Agua/químicaRESUMEN
Despite its potential importance, the role of the timing of mating(s) as a source of variation in female lifetime reproductive success has been largely overlooked. Here, using a laboratory-adapted population of the model species Drosophila melanogaster, we explore how temporal variation in the patterns of single and multiple matings influences female fecundity. We find that the boost to fecundity known to occur after a virgin female's initial mating also extends to subsequent matings as nonvirgins, but only for a short duration. This fecundity boost at least partially offsets the direct costs of multiple matings to females in this population of D. melanogaster. The implications of these results for our understanding of the evolution and maintenance of polyandry in this species are discussed in the context of sexual conflict.
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Evolución Biológica , Drosophila melanogaster/fisiología , Aptitud Genética/fisiología , Conducta Sexual Animal/fisiología , Animales , Tamaño Corporal , Femenino , Fertilidad/fisiología , Masculino , Análisis de Regresión , Factores de TiempoRESUMEN
The heritability of genome-wide fitness that is expected in finite populations is poorly understood, both theoretically and empirically, despite its relevance to many fundamental concepts in evolutionary biology. In this study, we used two independent methods of estimating the heritability of lifetime female fecundity (the predominant female fitness component in this population) in a large, outbred population of Drosophila melanogaster that had adapted to the laboratory environment for over 400 generations. Despite strong directional selection on adult female fecundity, we uncovered high heritability for this trait that cannot be explained by antagonistic pleiotropy with juvenile fitness. The evolutionary significance of this high heritability of lifetime fecundity is discussed.
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Drosophila melanogaster/fisiología , Adaptación Fisiológica/fisiología , Animales , Drosophila melanogaster/genética , Femenino , Fertilidad/fisiología , Herencia , Masculino , FenotipoRESUMEN
AIMS: To develop methods to differentiate Escherichia coli O157:H7 and related serotypes by the use of amplicon length polymorphism (ALP) analysis based on identifying DNA sequence deletions within highly homologous regions of three sequenced E. coli strains. METHODS AND RESULTS: Potential primer locations along the ancestral genomic backbone were identified and evaluated against three sequenced genomes and then applied to a reference set of pathogenic E. coli strains. All 16 primer combinations generated the expected diagnostic fragments as predicted for the E. coli K12 MG1655, O157:H7 EDL933, and O157:H7B Sakai genomes. CONCLUSIONS: This study defines a collection of primers distributed along the length of the E. coli genome that were applied to ALP analysis methods to successfully differentiate between serotypes of E. coli O157:H7 and other E. coli serotypes. SIGNIFICANCE AND IMPACT OF THE STUDY: ALP-PCR analysis method was validated as an independent method of classification when compared with that of rep-PCR. The principles underlying ALP analysis can be readily applied for the detection and differentiation of other closely related microbial species because of the abundance of complete DNA sequence data for a large number of microbial genomes.
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Cartilla de ADN , Escherichia coli O157/aislamiento & purificación , Genoma Bacteriano , Reacción en Cadena de la Polimerasa/métodos , Secuencia de Bases , Escherichia coli O157/clasificación , Escherichia coli O157/genética , Datos de Secuencia Molecular , SerotipificaciónRESUMEN
Magnetic anisotropy, magnetization reversal and the magnetooptic Kerr effect in Co(x)Mn(y)Ge(z) have been studied over a range of compositions between 0 and 50 at.% of Ge and between 1 and 3 in the Co to Mn atomic ratio, including the Heusler alloy Co(2)MnGe. A strong quadratic magnetooptic Kerr effect has been observed within a narrow region of composition centered around the Co to Mn atomic ratio of 2, which has been used to probe and quantify the magnetic anisotropy and magnetization reversal of the system. The anisotropy is sixfold with a weak uniaxial component, and it exhibits sensitive dependence on composition, especially on the atomic ratio between Co and Mn. The magnetization reversal process is consistent with the single-domain Stoner-Wohlfarth model.
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The presence of young massive stars orbiting on eccentric rings within a few tenths of a parsec of the supermassive black hole in the galactic center is challenging for theories of star formation. The high tidal shear from the black hole should tear apart the molecular clouds that form stars elsewhere in the Galaxy, and transport of stars to the galactic center also appears unlikely during their lifetimes. We conducted numerical simulations of the infall of a giant molecular cloud that interacts with the black hole. The transfer of energy during closest approach allows part of the cloud to become bound to the black hole, forming an eccentric disk that quickly fragments to form stars. Compressional heating due to the black hole raises the temperature of the gas up to several hundred to several thousand kelvin, ensuring that the fragmentation produces relatively high stellar masses. These stars retain the eccentricity of the disk and, for a sufficiently massive initial cloud, produce an extremely top-heavy distribution of stellar masses. This potentially repetitive process may explain the presence of multiple eccentric rings of young stars in the presence of a supermassive black hole.
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Sexual conflict theory is based on the observation that females of many species are harmed through their interactions with males. Direct harm to females, however, can potentially be counterbalanced by indirect genetic benefits, where females make up for a reduction in offspring quantity by an increase in offspring quality through a generic increase in offspring fitness (good genes) and/or one restricted to the context of sexual selection (sexy sons). Here, we quantify the magnitude of the good genes mechanism of indirect benefits in a laboratory-adapted population of Drosophila melanogaster. We find that despite high-standing genetic variance for fitness, females gain at most only a modest benefit through the good genes form of indirect benefits--far too little to counterbalance the direct cost of male-induced harm.
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Conflicto Psicológico , Drosophila melanogaster/genética , Conducta Sexual Animal/fisiología , Animales , Cruzamientos Genéticos , Femenino , Fertilidad/fisiología , MasculinoRESUMEN
Intralocus sexual conflict, which occurs when a trait is selected in opposite directions in the two sexes, is a taxonomically widespread phenomenon. The strongest genetic evidence for a gender load due to intralocus sexual conflict comes from the Drosophila melanogaster laboratory model system, in which a negative genetic correlation between male and female lifetime fitness has been observed. Here, using a D. melanogaster model system, we utilize a novel modification of the 'middle class neighbourhood' design to relax selection in one sex, while maintaining selection in the other. After 26 generations of asymmetrical selection, we observed the expected drop in fitness of the non-selected sex compared to that of the selected sex, consistent with previous studies of intralocus sexual conflict in this species. However, the fitness of the selected sex also dropped compared to the base population. The overall decline in fitness of both the selected and the unselected sex indicates that most new mutations are harmful to both sexes, causing recurrent mutation to build a positive genetic correlation for fitness between the sexes. However, the steeper decay in the fitness of the unselected sex indicates that a substantial number of mutations are gender-limited in expression or sexually antagonistic. Our experiment cannot definitively resolve these two possibilities, but we use recent genomic data and results from previous studies to argue that sexually antagonistic alleles are the more likely explanation.
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Drosophila melanogaster/genética , Genoma de los Insectos/genética , Selección Genética , Caracteres Sexuales , Animales , Evolución Biológica , Femenino , MasculinoRESUMEN
AIMS: The intent of this study is to exploit both the genetic diversity and conservation demonstrated between the Salmonella enterica ssp. enterica serovar Typhi CT18 and Salm. enterica ssp. enterica serovar Typhimurium LT2 genomes by utilizing amplicon length polymorphism (ALP) to detect and differentiate various Salmonella strains. METHODS AND RESULTS: Methods of ALP-PCR analysis were developed based on identifying DNA sequence deletions within highly homologous regions of the Salm. Typhi CT18 and Salm. Typhimurium LT2 genomes. This study describes the application of genome-based ALP-PCR using primer pairs designed to detect genomic differences present within both Salmonella genomes and evaluated against a reference set of Salmonella strains. CONCLUSIONS: This study defines a collection of primer sequences broadly distributed along the Salmonella genome that can differentiate various Salmonella strains. SIGNIFICANCE AND IMPACT OF THE STUDY: Genome-based ALP-PCR provides a useful and powerful analytical method to evaluate variability within a group of Salmonella strains independent of serological, phenotypic or other molecular approaches.