Risk of SARS-CoV-2 infection among contacts of individuals with COVID-19 in Hangzhou, China

Objectives

This study determined the rate of secondary infection among contacts of individuals with confirmed coronavirus disease 2019 (COVID-19) in Hangzhou according to the type of contacts, the intensity of contacts, and their relationship with the index patient.

Study design

This is a retrospective cohort study.

Methods

The analysis used the data of 2994 contacts of 144 individuals with confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The contacts were categorized according to the information source, type of contact, location, intensity of contact, and relationship with the index patient.

Results

The incidence of infection differed significantly according to contact type. Of the contacts, 186 (6.2%) developed symptoms, and 71 (2.4%) had confirmed SARS-CoV-2 infection. The main symptoms were cough and fever. Compared with those who had brief contact with the index case, those who had dined with the index case had 2.6 times higher risk of acquiring infection; those who had shared transport with, had visited, or had contact with the index case in a medical institution had 3.6 times higher risk of acquiring infection; and household contacts had 41.7 times higher risk of acquiring infection. Family members had 31.6 times higher risk of acquiring infection than healthcare providers or other patients exposed to an index case.

Conclusions

The form and frequency of contact are the main factors affecting the risk of infection among contacts of individuals with COVID-19. Centralized isolation and observation of close contacts of individuals with confirmed SARS-CoV-2 infection, in addition to population-based control measures, can reduce the risk of secondary infections and curb the spread of the infection.

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The incidence of infection differed significantly according to contact type.

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Contact form and frequency are important to the risk of COVID-19.

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Centralized isolation and observation of contacts curbed the spread of the infection.

Using IL-2R/lymphocytes for predicting the clinical progression of patients with COVID-19

Effective laboratory markers for the estimation of disease severity and predicting the clinical progression of coronavirus disease-2019 (COVID-19) is urgently needed. Laboratory tests, including blood routine, cytokine profiles and infection markers, were collected from 389 confirmed COVID-19 patients. The included patients were classified into mild (n = 168), severe (n = 169) and critical groups (n = 52). The leukocytes, neutrophils, infection biomarkers [such as C-reactive protein (CRP), procalcitonin (PCT) and ferritin] and the concentrations of cytokines [interleukin (IL)-2R, IL-6, IL-8, IL-10 and tumor necrosis factor (TNF)-α] were significantly increased, while lymphocytes were significantly decreased with increased severity of illness. The amount of IL-2R was positively correlated with the other cytokines and negatively correlated with lymphocyte number. The ratio of IL-2R to lymphocytes was found to be remarkably increased in severe and critical patients. IL-2R/lymphocytes were superior compared with other markers for the identification of COVID-19 with critical illness, not only from mild but also from severe illness. Moreover, the cytokine profiles and IL-2R/lymphocytes were significantly decreased in recovered patients, but further increased in disease-deteriorated patients, which might be correlated with the outcome of COVID-19. Lymphopenia and increased levels of cytokines were closely associated with disease severity. The IL-2R/lymphocyte was a prominent biomarker for early identification of severe COVID-19 and predicting the clinical progression of the disease.

Engineering CRISPR interference system to enhance the production of pyrroloquinoline quinone in Klebsiella pneumonia

Pyrroloquinoline quinone (PQQ) is a cofactor of glucose dehydrogenase (GDH) and thus participates in glucose utilization. In Klebsiella pneumoniae, glucose utilization involves PQQ-dependent direct oxidation pathway (DOP) and phosphoenolpyruvate-dependent transport system (PTS). It is challenging to overproduce PQQ, as its biosynthesis remains unclear. Here, we report that PQQ production can be enhanced by stimulating the metabolic demand for it. First, we developed CRISPR interference (CRISPRi) system to block PTS and thereby intensify DOP. In shake-flask cultivation, the strain with CRISPRi system (simultaneously inhibiting four PTS-related genes) produced 225·65 nmol l^-1 PQQ, which was 2·14 times that of wild type. In parallel, an exogenous soluble glucose dehydrogenase (sGDH) was overexpressed in K. pneumoniae. In the shake-flask cultivation, this sGDH-overexpressing strain accumulated 140·05 nmol l^-1 PQQ, which was 1·33 times that of wild type. To combine the above two strategies, we engineered a strain harbouring both CRISPRi vector and sGDH-overexpressing vector. In the shake-flask cultivation, this two-plasmid strain generated 287·01 nmol l^-1 PQQ, which was 2·72 times that of wild type. In bioreactor cultivation, this two-plasmid strain produced 2206·1 nmol l^-1 PQQ in 57 h, which was 7·69 times that in shake-flask cultivation. These results indicate that PQQ production can be enhanced by intensifying DOP, as the apo-enzyme GDH is intrinsically coupled with cofactor PQQ. This study provides a strategy for the production of cofactors whose biosynthesis mechanisms remain ambiguous. SIGNIFICANCE AND IMPACT OF THE STUDY: Pyrroloquinoline quinone (PQQ) is an economically important chemical, which typically serves as a cofactor of glucose dehydrogenase (GDH) and thus participates in glucose metabolism. Klebsiella pneumoniae can naturally synthesize PQQ, but current yield constrains its commercialization. In this study, the PQQ level was improved by stimulating metabolic demand for PQQ, instead of overexpressing PQQ synthetic genes, as the synthetic mechanism remains ambiguous.

[Genomic analysis of a 2019-novel coronavirus (2019-nCoV) strain in the first COVID-19 patient found in Hangzhou]

Objective: To understand the viral genomic characteristics of a 2019-novel coronavirus (2019-nCoV) strain in the first COVID-19 patient found in Hangzhou, China. Methods: Viral RNA was extracted in throat swab and sputum sample of the patient and was performed real-time reverse transcription PCR detection and obtained viral genome by high-throughput sequencing method. Phylogenetic analysis was conducted using 29 2019-nCoV genomes and 30 β-coronavirus genomes deposited in NCBI GenBank. Fifteen genomes from Wuhan were grouped by mutation sites and others were identified by Wuhan's or specific mutation sites. Results: A 29 833 bp length genome of the first 2019-nCoV strain in Hangzhou was obtained, covering full length of the coding regions of coronavirus. Phylogenetic analysis showed that the genome was closest to the genome of a bat SARS-like coronavirus strain RaTG13 with an identity of 96.11% (28 666/29 826). Among the genes between two genomes, E genes were highly conserved (99.56%), while S genes had lowest identity (92.87%). The genome sequence similarities among 29 strains from China (Hangzhou, Wuhan, and Shenzhen), Japan, USA, and Finland, were all more than 99.9%; however, some single nucleotide polymorphisms were identified in some strains. Conclusion: The genome of Hangzhou 2019-nCoV strain was very close to the genomes of strains from other cities in China and overseas collected at early epidemic phase. The 2019-nCoV genome sequencing method used in this paper provides an useful tool for monitoring variation of viral genes.

[The impact of carbapenem-resistance Pseudomonas aeruginosa infections on mortality of patients with hematological disorders]

Objective: To assess the risk factors for mortality and clinical outcome of carbapenem-resistant Pseudomonas aeruginosa (CRPA) infections in patients with hematological disorders. Methods: The data of in-patients with hematological disorders infected by CRPA or carbapenem-susceptible Pseudomonas aeruginosa (CSPA) were recorded in a seven-year retrospective cohort study. Risk factors for CRPA infections and impact of on mortality were identified. The primary end point was 30-day all-cause mortality. Results: A total of 81 patients with PA infections were included in the study, including 58 CSPA and 23 CRPA. Most of the primary diseases were acute leukemia or lymphoma (79.0%, 64/81). The median absolute neutrophil count at infection onset was 0.24×10(9)/L. Independent risk factors associated with carbapenem-resistance included longer duration of hospital stay (P=0.013, OR=1.045) and carbapenem exposure one month prior to infections (P=0.005, OR=8.132). The 30-day all-cause mortality of the whole cohort was 29.6%(24/81), and 30-day attributable mortality was 13.6%(11/81). Pulmonary infection was the leading cause of death, accounting for 41.7%(10/24). The adjusted 30-day mortality rate was significantly higher in patients with CRPA compared with CSPA [60.9%(14/23) vs. 17.2%(10/58), P<0.001, respectively]. CRPA infection was an independent prognostic factor for 30-day mortality(P=0.011, OR=5.427). Other factors included old age, longer duration of neutropenia and poor functional performance. Conclusions: Patients with hematological disorders have high mortality rate and poor prognosis caused by CRPA infections, which mainly develop in lungs.

X-ray operators' self-perceived competence, barriers and facilitators in general radiography practice in Western Australia

INTRODUCTION

Australian X-ray operators (XROs) are health workers qualified with a limited radiography licence to perform basic radiography examinations in rural areas of Australia. However, no previous study explored Western Australian (WA) XROs' radiography practice. The purpose of this study was to investigate WA XROs' self-perceived competence in the general radiography practice, and barriers and facilitators to their competence for determination of appropriate strategies to improve quality and safety of the radiographic service provided by them.

METHODS

Institutional review board approval and informed consent from participants were obtained. Interviews were conducted with the WA XROs to obtain demographic information and identify their self-perceived competence in the general radiography practice, and the barriers and facilitators to their competence. A thematic analysis was used to analyse the interview data.

RESULTS

A total of nine interviews were conducted (eight nurses and one paramedic). Participants indicated that they felt highly competent in patient care in radiography and adequately competent in the production of diagnostically acceptable images. The self-perceived barriers include overload of responsibilities, a lack of continuing professional development, and inadequacy of communication, support and XRO courses. The facilitators, post-qualification/course training, support in undertaking examinations, primary professional roles and a small population of the rural and remote areas were identified.

CONCLUSION

Based on interview data from nine WA XROs, the perception is that they have competence adequate for providing an acceptable quality radiographic service.

IMPLICATIONS FOR PRACTICE

A continuous XRO course review, and provision of a video conference support channel, an online XRO networking forum and additional XROs and/or radiographers working with XROs undertaking the radiography examinations were perceived as the appropriate strategies to improve the WA XROs' radiography practice. However, these require financial and/or managerial support from governments.

The effects of dietary sodium butyrate supplementation on the growth performance, carcass traits and intestinal microbiota of growing-finishing pigs

AIM

This study was carried out to investigate the effects of dietary sodium butyrate supplementation on growth performance, carcass traits and intestinal of growing-finishing pigs.

METHODS AND RESULTS

Thirty pigs (27·4 ± 0·4 kg) were randomly assigned to receive one of three diets: basal diet (negative control group), basal diet + 40 ppm zinc bacitracin (positive control group) and basal diet + 0·2% sodium butyrate (sodium butyrate group), respectively. The experiment lasted for 69 days, including 3 days for diet and housing condition adaptation. On day 70, five piglets from each diet group were slaughtered for collecting blood and tissue samples. When compared to the control group, final body weight, daily body weight gain and daily feed intake of pigs in the sodium butyrate group were increased (P < 0·05) and feed intake/body weight gain ratio was decreased (P < 0·05). Carcass weight of pigs in the sodium butyrate group was higher than that of pigs in the negative and positive groups (P < 0·05); backfat thickness of pigs in the positive group was higher than that of pigs in the negative group and sodium butyrate group (P < 0·001). When compared to the negative and positive groups, pigs fed diet supplemented with sodium butyrate showed a increased relative abundance of bacteroidetes in the caecum and a decreased relative abundance of fiemicutes and proteobacteria in the caecum (P < 0·05).

CONCLUSION

The results indicated that dietary sodium butyrate supplementation increased growth performance of growing-finishing pigs and improved the carcass traits and intestinal health.

SIGNIFICANCE AND IMPACT OF THE STUDY

Antibiotic-free feed has become an inevitable worldwide trend. This study showed that dietary sodium butyrate supplementation improved the growth performance and intestinal health of growing-finishing pigs. Thus, sodium butyrate can be applied in growing-finishing pig feed as an alternative of antibiotics.

A unified form of low-energy nodal electronic interactions in hole-doped cuprate superconductors

Using angle resolved photoemission spectroscopy measurements of Bi₂Sr₂CaCu₂O_8+δ over a wide range of doping levels, we present a universal form for the non-Fermi liquid electronic interactions in the nodal direction in the exotic normal state phase. It is described by a continuously varying power law exponent versus energy and temperature (hence named a Power Law Liquid or PLL), which with doping varies smoothly from a quadratic Fermi Liquid in the overdoped regime, to a linear Marginal Fermi Liquid at optimal doping, to a non-quasiparticle non-Fermi Liquid in the underdoped regime. The coupling strength is essentially constant across all regimes and is consistent with Planckian dissipation. Using the extracted PLL parameters we reproduce the experimental optics and resistivity over a wide range of doping and normal-state temperature values, including the T* pseudogap temperature scale observed in the resistivity curves. This breaks the direct link to the pseudogapping of antinodal spectral weight observed at similar temperature scales and gives an alternative direction for searches of the microscopic mechanism.

The normal state of hole-doped, high-temperature superconductors is a currently-unexplained "strange metal" with exotic electronic behaviour. Here, the authors show that a doping-dependent power law ansatz for the electronic scattering phenomenologically captures ARPES, transport and optics observations.

Paternal exposure to arsenic resulted in oxidative stress, autophagy, and mitochondrial impairments in the HPG axis of pubertal male offspring

Despite the knowledge of AS-induced reprotoxicity, the literature concerning arsenic trioxide (As₂O₃)-induced oxidative stress and consequent intracellular events, like autophagy process, in the hypothalamic-pituitary- gonadal (HPG) axis of F1- pubertal male mice is sparse to date. Hence, we made an attempt to study the reproductive toxicities and the underlying mechanisms induced by As₂O₃ in the HPG axis of pubertal F1- male mice in correlation with oxidative stress-induced autophagy. Parental mice were challenged with As₂O₃ (0, 0.2, 2, and 20 ppm) from five weeks before mating, and continued till puberty age for the male pups. It was recorded that higher As₂O₃ doses (2 and 20 ppm) were a potent inducer of oxidative stress and autophagy in the HPG axis. Concomitant with a decrease on mean body weight, total antioxidant capacity, and stereology indices, an increase in the number of MDC-labeled autophagic vacuoles, and MDA/GSH ratio in HPG axis of pubertal F1- male mice which were exposed to higher As₂O₃ doses was observed. Meanwhile, concomitant with a dose-dependent increment in the gene expression of ATG3, ATG5, Beclin, as well as protein expression of P62, ATG12, and Beclin in HPG axis tissues; a dose-dependent decrease in PI3K and mTOR gene expression was recorded in the HPG tissues of pubertal F₁-males. Altogether, our observations suggest that higher doses of As₂O₃ have detrimental effects on the functionality of HPG axis in pubertal male mice offspring by increasing MDA/GSH ratio and autophagic cell death-related genes and proteins, as well as by reducing total antioxidant capacity.

Effects of dietary calcium pyruvate on gastrointestinal tract development, intestinal health and growth performance of newly weaned piglets fed low-protein diets

AIM

This study was carried out to investigate the effects of dietary calcium pyruvate supplementation on growth performance and intestinal health of weaned piglets fed low-protein diets.

METHODS AND RESULTS

After a 7-day adaptation period, 60 individually housed piglets (Duroc × Yorkshire-Landrace) weaned at 28 days of age were randomly assigned to receive one of three treatments (20 pigs/treatment) for 28 days: control diet (20·0% crude protein [CP]), low-protein diet (15·5% CP), and experimental (15·5% CP + 1·8% calcium pyruvate). At the end of the experiment, six piglets from each diet group were slaughtered and blood and tissue samples were collected. Compared with the control group, feeding piglets with 15·5% CP decreased the daily body weight gain; lengths of the duodenum, jejunum and ileum; and weights of the stomach, duodenum, jejunum and ileum (P < 0·05), while 15·5% CP + 1·8% calcium pyruvate supplementation removed those differences (P > 0·05). Compared with the control group, the diarrhoea incidence and relative richness of Firmicutes in the colon contents of piglets in both the 15·5% CP and 15·5% CP + 1·8% calcium pyruvate groups was decreased. The relative richness of Bacteriodetes in the colon contents of piglets was higher in the 15·5% CP + 1·8% calcium pyruvate group than in the control and 15·5% CP groups (P < 0·05).

CONCLUSION

Calcium pyruvate supplementation for four weeks removed the negative effects of a low-protein diet on the gastrointestinal tract development and daily body weight gain of weaned piglets.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study showed that supplementing a low-protein diet with calcium pyruvate, an effective alternative metabolic fuel to amino acids, was beneficial in improving the intestinal health and maximizing the growth of newly weaned piglets.

Effects of Rhodotorula mucilaginosa fermentation product on the laying performance, egg quality, jejunal mucosal morphology and intestinal microbiota of hens

AIM

The aim of this study was to investigate the effects of dietary supplementation of Rhodotorula mucilaginosa solid-state fermentation product (RSFP) on the laying performance, egg quality and intestinal microbial flora of hens.

METHODS AND RESULTS

In this study, 40-week-old Roman laying hens (n = 216) were randomly assigned to one of the four groups: the control (CON) group, fed 87.5% basal diet +12.5% fermentation substrate; the 0.5% RSFP group, fed 87.5% basal diet +12.0% fermentation substrate +0.5% RSFP; the 2.5% RSFP group, fed 87.5% basal diet +10.0% fermentation substrate +2.5% RSFP; and the 12.5% RSFP group, fed 87.5% basal diet +12.5% RSFP. The effect of each treatment was analysed in six replicates of nine hens. The experimental period was 31 days, which included a 3-day adaptation period. After 31 days of feeding, one hen from each replicate was randomly selected and killed, and the jejunum and digesta in the cecum were collected for the determination of the intestinal morphology and microbial flora respectively. Daily egg mass in the 2.5 and 12.5% RSFP groups and egg production and feed conversion ratio in the 12.5% RSFP group were higher than those in control group (P < 0.05). The yolk colour was improved in hens fed RSFP-supplemented diets (P < 0.05). Hens fed RSFP-supplemented diet showed a decrease in the relative abundances of Proteobacteria, Bacteroides, Helicobacteraceae, Helicobacter and Lachnospiraceae UCG-002, but an increase in the relative abundance of Prevotellaceae UCG-001 in the cecum (P < 0.05).

CONCLUSION

Dietary RSFP supplementation improved the laying performance, egg quality and intestinal microflora of hens.

SIGNIFICANCE AND IMPACT OF THE STUDY

Dietary supplementing diet with Rhodotorula mucilaginosa solid-state fermentation product, which is rich in carotenoids, improved the yolk colour and increased the carotenoid content, thereby improving the intestinal health of hens.