Distinguishing coagulase-negative Staphylococcus bacteremia from contamination using blood-culture positive bottle detection pattern and time to positivity

AIM

Detection of coagulase-negative Staphylococcus in blood culture may be a result of either bacteremia or contamination. This often leads to diagnostic uncertainly. Our objective was to develop a method for differentiating whether a coagulase-negative Staphylococcus sp. positive blood culture represents bacteremia or contamination based on positive bottle detection pattern and time to positivity (TTP).

METHODS

This study included 155 and 51 adults with positive blood cultures for Staphylococcus epidermidis and Staphylococcus hominis, respectively, over a three-year period from 2016 to 2018. Positive blood culture cases were categorized as either bacteremia or contamination based on the clinically available information, and the detection pattern and TTP in each category were investigated.

RESULTS

A total of 57, 92, and 6 S. epidermidis positive blood cultures were categorized as bacteremia, contamination, and undetermined, respectively, whereas 15 and 36 S. hominis positive blood cultures were categorized as bacteremia and contamination, respectively. For positive blood cultures categorized as bacteremia, all four bottles in two sets of blood cultures were positive in 47/47 S. epidermidis and 14/14 S. hominis, respectively, whereas either one bottle in each of two sets or three bottles in two sets were positive in 10/19 S. epidermidis and 1/4 S. hominis, respectively; most of those TTPs were <48 h. Among them, the TTP in catheter-related blood stream infection was <24 h.

CONCLUSION

Although clinical assessment is crucial to differentiate between bacteremia and contamination, a combination of positive bottle detection pattern and TTP is a valuable diagnostic auxiliary tool.

Malnutrition at Admission Predicts In-Hospital Falls in Hospitalized Older Adults

Malnutrition leads to poor prognoses, including a predisposition to falls. Few studies have investigated the relationship between malnutrition and falls during hospitalization. This study aimed to determine malnutrition’s association with falls during hospitalization. A retrospective observational study was conducted. Patients aged ≥65 years that were admitted to and discharged from a university hospital between April 2018 and March 2019 were examined. Patients with independent basic activities of daily living were included. Diagnosis of malnutrition was based on the European Society for Clinical Nutrition and Metabolism (ESPEN) criteria at admission. Disease information such as the Charlson Comorbidity Index (CCI) and reasons for hospitalization were reviewed. Kaplan–Meier curve and multivariate Cox regression analyses were performed. Data from 6081 patients (mean age: 74.4 ± 6.1 years; males: 58.1%) were analyzed. The mean CCI was 2.3 ± 2.8 points. Malnutrition was detected in 668 (11.0%) and falls occurred in 55 (0.9%) patients. Malnourished patients experienced a higher fall rate than those without malnutrition (2.4% vs. 0.7%, log-rank test p < 0.001). In multivariate analysis, malnutrition had the highest hazard ratio for falls among covariates (hazard ratio 2.78, 95% confidence interval 1.51–5.00, p = 0.001). In conclusion, malnutrition at the time of admission to hospital predicts in-hospital falls.

SARC-F as a Screening Tool for Sarcopenia and Possible Sarcopenia Proposed by AWGS 2019 in Hospitalized Older Adults

OBJECT

The SARC-F questionnaire is a sarcopenia screening tool. However, the validity of the SARC-F score ≥4 (SARC-F≥4) for the evaluation of sarcopenia in the hospital setting has not been investigated. This study investigated the validity of SARC-F≥4 as a screening tool for sarcopenia among hospitalized older adults.

DESIGN

Cross-sectional retrospective study.

SETTING

A university hospital.

PARTICIPANTS

This study included older adult patients (age ≥65 years) who were hospitalized at, and subsequently discharged from, the hospital between April and September 2019 and underwent a nutritional assessment by the nutrition support team during their hospitalization.

MEASUREMENTS

SARC-F was recorded at the time of admission, and the criteria specified by the Asia Working Group for Sarcopenia in 2019 (AWGS 2019) were applied to diagnose sarcopenia and possible sarcopenia. Appendicular muscle mass was estimated through validated equations, and three different models were developed for sarcopenia diagnosis. The sensitivity, specificity, and positive/negative likelihood ratios were calculated to analyze the accuracy of the SARC-F≥4 for sarcopenia and possible sarcopenia. Receiver-operating characteristic analyses were conducted to calculate the area under the curve (AUC).

RESULTS

In total, 1,689 patients (mean age: 77.2±7.3 years; male: 54.4%) were analyzed, and 636 patients (37.7%) had SARC-F≥4. Patients with SARC-F≥4 had a statistically significant higher prevalence of AWGS 2019-defined sarcopenia than patients with SARC-F <4 in the models (65.4-78.9% vs 40.9-45.2%, p<0.001). The sensitivity, specificity, and positive/negative likelihood ratios of SARC-F≥4 for sarcopenia and possible sarcopenia were 49.1-51.3%, 73.9-81.2%, and 1.88-2.72/0.60-0.69 and 48.0%, 84.5%, and 3.11/0.62, respectively. The AUC for sarcopenia and possible sarcopenia were 0.644-0.695 and 0.708, respectively. The AUC of SARC-F for possible sarcopenia was equivalent to or larger than that for sarcopenia (DeLong test p=0.438, 0.088, and <0.001 vs the three models).

CONCLUSIONS

SARC-F≥4 is suitable as a screening tool for sarcopenia in hospitalized older adults. SARC-F assessment could facilitate the detection and exclusion of sarcopenia at hospitalization and may lead to early adoption of a therapeutic and preventive approach.

Development and Predictors of Sarcopenic Dysphagia during Hospitalization of Older Adults

The study aimed to investigate the impact of sarcopenia and sarcopenia-related conditions on the development of swallowing disorders during hospitalization. Older adult inpatients (n = 8768) without swallowing disorders in the premorbid period were studied. Sarcopenia-related conditions were evaluated in terms of nutritional status, physical status, and ambulatory conditions as well as hand-grip strength and muscle mass assessed by calf circumference. Development of swallowing disorders was defined based on food texture at discharge from the hospital. The patients’ mean age was 76.1 ± 6.9 years. A total of 374 (4.3%) patients developed swallowing disorders during hospitalization. They were older, with poorer nutritional status, and had more decline of physical performance than those without swallowing disorders. Performance Status score (odds ratio (OR) = 1.28 (1.12–1.46) p < 0.001), ambulatory dependency (OR = 1.72 (1.09–2.71), p = 0.020), malnutrition score (OR = 0.92 (0.87–0.97), p = 0.002), insufficient nutritional intake (OR = 2.33 (1.60–3.40), p < 0.001), and length of stay (OR = 1.01 (1.00–1.01), p = 0.001) were independent contributing factors for swallowing disorder development in the multivariate analysis. The presence of possible sarcopenia was also a contributor to swallowing disorder development. In conclusion, swallowing disorders could develop in patients with possible sarcopenia and sarcopenia-related conditions during hospitalization. Clinicians should be aware of this risk and provide appropriate interventions to prevent sarcopenic dysphagia.

Absence of Magnetic Thermal Conductivity in the Quantum Spin Liquid Candidate EtMe_{3}Sb[Pd(dmit)_{2}]_{2}

We present the ultralow-temperature specific heat and thermal conductivity measurements on single crystals of triangular-lattice compound EtMe_{3}Sb[Pd(dmit)_{2}]_{2}, which has long been considered as a gapless quantum spin liquid candidate. In specific heat measurements, a finite linear term is observed, consistent with the previous work [S. Yamashita et al., Nat. Commun. 2, 275 (2011)NCAOBW2041-172310.1038/ncomms1274]. However, we do not observe a finite residual linear term in the thermal conductivity measurements, and the thermal conductivity does not change in a magnetic field of 6 T. These results are in sharp contrast to previous thermal conductivity measurements on EtMe_{3}Sb[Pd(dmit)_{2}]_{2} [M. Yamashita et al., Science 328, 1246 (2010)SCIEAS0036-807510.1126/science.1188200], in which a huge residual linear term was observed and attributed to highly mobile gapless excitations, likely the spinons of a quantum spin liquid. In this context, the true ground state of EtMe_{3}Sb[Pd(dmit)_{2}]_{2} has to be reconsidered.

Topological charge transport by mobile dielectric-ferroelectric domain walls

The concept of topology has been widely applied in condensed matter physics, leading to the identification of peculiar electronic states on three-dimensional (3D) surfaces or 2D lines separating topologically distinctive regions. In the systems explored so far, the topological boundaries are built-in walls; thus, their motional degrees of freedom, which potentially bring about new paradigms, have been experimentally inaccessible. Here, working with a quasi-1D organic material with a charge-transfer instability, we show that mobile neutral-ionic (dielectric-ferroelectric) domain boundaries with topological charges carry strongly 1D-confined and anomalously large electrical conduction with an energy gap much smaller than the one-particle excitation gap. This consequence is further supported by nuclear magnetic resonance detection of spin solitons, which are required for steady current of topological charges. The present observation of topological charge transport may open a new channel for broad charge transport-related phenomena such as thermoelectric effects.

Lower grip strength and dynamic body balance in women with distal radial fractures

In this case-control study, we concluded that women with distal radial fractures who were surgically treated showed lower grip strength and dynamic body balancing than those of controls. These results suggest that measurements of grip strength and dynamic body balance may be useful screening tools to assess future fracture risk.

INTRODUCTION

Patients with distal radial fractures (DRFs) are at risk of future fragility fractures. However, their physical characteristics and tendencies for falls remain unclear. We aimed to compare the physical characteristics of women with and without distal radial fractures.

METHODS

We included 128 women with a DRF as their first fragility fracture (fracture group) who underwent surgical treatment. Concurrently, 128 age- and sex-matched participants without a history of fragility fractures were selected as controls (control group). The participants underwent assessments of grip strength and the body balancing ability test. Measurements were taken twice in the fracture group, at 2 weeks and 6 months postoperatively, and once in the control group. The body balancing ability test included the Functional Reach Test, Timed Up and Go test (TUG), 2-Step test (2ST), and Timed Uni-pedal Stance test. The participants also completed questionnaires about their health.

RESULTS

There were no significant differences (p > 0.05) in patient characteristics between the groups. The fracture group showed lower grip strength across all age groups. In the DRF group, prolonged TUG time was observed at 2 weeks postoperatively in all age groups and at 6 months in participants aged 55-74 years; the 2ST score was significantly lower in participants aged between 65 and 74 years.

CONCLUSIONS

Women with DRF demonstrated lower grip strength and dynamic body balancing ability. Lower grip strength and dynamic body balancing ability were identified as significant risk factors in women with DRF, suggesting that these may be useful screening tools to assess fracture risk.

Fragmented Electronic Spins with Quantum Fluctuations in Organic Mott Insulators Near a Quantum Spin Liquid

Magnetic structures of organic Mott insulators X[Pd(dmit)_{2}]_{2} (X=Me_{4}P, Me_{4}Sb), of which electronic states are located near a quantum spin liquid (X=EtMe_{3}Sb), are demonstrated by ^{13}C nuclear magnetic resonance. Antiferromagnetic spectra and nuclear relaxations show two distinct magnetic moments within each Pd(dmit)_{2} molecule, which cannot be described by single band dimer-Mott model and requires intramolecular electronic correlation. This unconventional fragmentation of S=1/2 electron spin with strong quantum fluctuation is presumably caused by nearly degenerated intramolecular multiple orbitals, and shares a notion of quantum liquids where electronic excitations are fractionalized and S=1/2 spin is no longer an elementary particle.

Correction to: Lower grip strength and dynamic body balance in women with distal radial fractures

The article Lower grip strength and dynamic body balance in women with distal radial fractures, written by. K. Fujita, H. Kaburagi, A. Nimura, T. Miyamoto, Y. Wakabayashi, Y. Seki, H. Aoyama, H. Shimura, R. Kato, A. Okawa was originally published electronically on the publisher's internet portal.

Burden of Premorbid Consumption of Texture Modified Diets in Daily Life on Nutritional Status and Outcomes of Hospitalization

OBJECTIVES

Due to the water-rich cooking process required to soften texture modified diets (TMDs), TMDs may have poorer nutrition. The aim of this study was to investigate the associations between daily premorbid TMD consumption and nutritional status at the time of hospitalization, and its burden on hospitalization outcomes.

DESIGN

Retrospective observational study.

SETTING

An academic hospital.

PARTICIPANTS

The cohort comprised 3,594 older adult patients aged ≥65 years admitted to the hospital.

MEASUREMENTS

Patients were interviewed on admission using a premorbid daily consumption meal form to determine whether the patient ate a TMD. Nutritional status was examined using nutritional screening tools (Mini-Nutritional Assessment Short Form [MNA-SF], Malnutrition Universal Screening Tool [MUST], Geriatric Nutritional Risk Index [GNRI]) and the European Society of Clinical Nutrition and Metabolism (ESPEN)-defined criteria of malnutrition at admission. Length of hospital stay (LOS) and in-hospital mortality were considered outcomes of hospitalization. Multivariate analyses were performed to detect associations between premorbid TMD consumption and nutritional status and outcomes.

RESULTS

The mean age of the subjects was 75.9±7.0 years, including 58% males. Overall, 110 (3.1%) patients consuming a premorbid TMD were identified. They were older (p<0.001), had poor nutritional status (lower MNA-SF score [p<0.001] and GNRI value [p<0.001], higher MUST score [p<0.001], and more prevalent ESPEN-defined malnutrition [61.8% vs. 14.0%, p<0.001] than did patients without a TMD. The mortality rate and LOS of patients with TMD was higher (7.3% vs. 2.9%, p=0.017) and longer (19 days vs. 8 days, p<0.001) than those without TMD. Multivariate analyses showed that TMD consumption was independently associated with poor nutritional status and prolonged LOS after adjusting confounders.

CONCLUSION

Daily consumption of a TMD during the premorbid period affects nutritional status at the time of hospitalization and outcomes. Further studies are necessary to investigate whether nutritional intervention can improve outcomes for people on a TMD.

Evidence for solitonic spin excitations from a charge-lattice-coupled ferroelectric order

Topological defects have been explored in different fields ranging from condensed matter physics and particle physics to cosmology. In condensed matter, strong coupling between charge, spin, and lattice degrees of freedom brings about emergent excitations with topological characteristics at low energies. One-dimensional (1D) systems with degenerate dimerization patterns are typical stages for the generation of topological defects, dubbed "solitons"; for instance, charged solitons are responsible for high electrical conductivity in doped trans-polyacetylene. Here, we provide evidence based on a nuclear magnetic resonance (NMR) study for mobile spin solitons deconfined from a strongly charge-lattice-coupled spin-singlet ferroelectric order in a quasi-1D organic charge-transfer complex. The NMR spectral shift and relaxation rate associated with static and dynamic spin susceptibilities indicate that the ferroelectric order is violated by dilute solitonic spin excitations, which were further demonstrated to move diffusively by the frequency dependence of the relaxation rate. The traveling solitons revealed here may promise the emergence of anomalous electrical and thermal transport.

Quantum spin liquids unveil the genuine Mott state

The localization of charge carriers by electronic repulsion was suggested by Mott in the 1930s to explain the insulating state observed in supposedly metallic NiO. The Mott metal-insulator transition has been subject of intense investigations ever since^1-3-not least for its relation to high-temperature superconductivity⁴. A detailed comparison to real materials, however, is lacking because the pristine Mott state is commonly obscured by antiferromagnetism and a complicated band structure. Here we study organic quantum spin liquids, prototype realizations of the single-band Hubbard model in the absence of magnetic order. Mapping the Hubbard bands by optical spectroscopy provides an absolute measure of the interaction strength and bandwidth-the crucial parameters that enter calculations. In this way, we advance beyond conventional temperature-pressure plots and quantitatively compose a generic phase diagram for all genuine Mott insulators based on the absolute strength of the electronic correlations. We also identify metallic quantum fluctuations as a precursor of the Mott insulator-metal transition, previously predicted but never observed. Our results suggest that all relevant phenomena in the phase diagram scale with the Coulomb repulsion U, which provides a direct link to unconventional superconductivity in cuprates and other strongly correlated materials.

Low-Energy Excitations in Quantum Spin Liquids Identified by Optical Spectroscopy

The electrodynamic response of organic spin liquids with highly frustrated triangular lattices has been measured in a wide energy range. While the overall optical spectra of these Mott insulators are governed by transitions between the Hubbard bands, distinct in-gap excitations can be identified at low temperatures and frequencies, which we attribute to the quantum-spin-liquid state. For the strongly correlated β^{'}-EtMe_{3}Sb[Pd(dmit)_{2}]_{2}, we discover enhanced conductivity below 175  cm^{-1}, comparable to the energy of the magnetic coupling J≈250  K. For ω→0, these low-frequency excitations vanish faster than the charge-carrier response subject to Mott-Hubbard correlations, resulting in a dome-shaped band peaked at 100  cm^{-1}. Possible relations to spinons, magnons, and disorder are discussed.

Mott transition by an impulsive dielectric breakdown

The transition of a Mott insulator to metal, the Mott transition, can occur via carrier doping by elemental substitution, and by photoirradiation, as observed in transition-metal compounds and in organic materials. Here, we show that the application of a strong electric field can induce a Mott transition by a new pathway, namely through impulsive dielectric breakdown. Irradiation of a terahertz electric-field pulse on an ET-based compound, κ-(ET) ₂Cu[N(CN) ₂]Br (ET:bis(ethylenedithio)tetrathiafulvalene), collapses the original Mott gap of ∼30 meV with a ∼0.1 ps time constant after doublon-holon pair productions by quantum tunnelling processes, as indicated by the nonlinear increase of Drude-like low-energy spectral weights. Additionally, we demonstrate metallization using this method is faster than that by a femtosecond laser-pulse irradiation and that the transition dynamics are more electronic and coherent. Thus, strong terahertz-pulse irradiation is an effective approach to achieve a purely electronic Mott transition, enhancing the understanding of its quantum nature.