Metabolomic analysis in Amycolatopsis keratiniphila disrupted the competing ECO0501 pathway for enhancing the accumulation of vancomycin.

Vancomycin is a clinically important glycopeptide antibiotic against Gram-positive pathogenic bacteria, especially methicillin-resistant Staphylococcus aureus. In the mutant strain of Amycolatopsis keratiniphila HCCB10007 Δeco-cds4-27, the production of ECO-0501 was disrupted, but enhanced vancomycin yield by 55% was observed compared with the original strain of A. keratiniphila HCCB10007. To gain insights into the mechanism of the enhanced production of vancomycin in the mutant strain, comparative metabolomics analyses were performed between the mutant strain and the original strain, A. keratiniphila HCCB10007 via GC-TOF-MS and UPLC-HRMS. The results of PCA and OPLS-DA revealed a significant distinction of the intracellular metabolites between the two strains during the fermentation process. 64 intracellular metabolites, which involved in amino acids, fatty acids and central carbon metabolism, were identified as differential metabolites. The high-yield mutant strain maintained high levels of glucose-1-phosphate and glucose-6-phosphate and they declined with the increases of vancomycin production. Particularly, a strong association of fatty acids accumulation as well as 3,5-dihydroxyphenylacetic acid and non-proteinogenic amino acid 3,5-dihydroxyphenylglycine (Dpg) with enhancement of vancomycin production was observed in the high-yield mutant strain, indicating that the consumption of fatty acid pools might be beneficial for giving rise to 3,5-dihydroxyphenylacetic acid and Dpg which further lead to improve vancomycin production. In addition, the lower levels of glyoxylic acid and lactic acid and the higher levels of sulfur amino acids might be beneficial for improving vancomycin production. These findings proposed more advanced elucidation of metabolomic characteristics in the high-yield strain for vancomycin production and could provide potential strategies to enhance the vancomycin production.

Relationship between moral resilience and secondary traumatic stress among ICU nurses: A cross-sectional study.

BACKGROUND: Since the outbreak of COVID-19, researchers worldwide have focused more on the issue of secondary traumatic stress (STS) experienced by nurses. This stress has an adverse effect on the health of nurses and the quality of nursing care, potentially undermining the stability of the nursing team and hindering the ability to meet the growing demand for nursing services. The impact of the COVID-19 pandemic, and the rise in global demand for ICU nursing, has placed a significant strain on ICU nurses, severely damaging their mental and physical health. Notably, ICU nurses also face high levels of moral distress, and moral resilience can effectively alleviate this distress and improve the quality of care. AIMS: This study aimed to examine the levels of moral resilience and STS among ICU nurses, to explore their relationship and identify the factors influencing STS. STUDY DESIGN: This cross-sectional study involved 229 ICU nurses from two tertiary hospitals in Xi'an, China, who participated between November and December 2023. The data were collected through email using anonymous electronic questionnaires, encompassing a self-designed demographic- and work-life-related characteristic questionnaire; the Rushton Moral Resilience Scale; and the Secondary Traumatic Stress Scale. Descriptive statistics, t-tests, analysis of variance and hierarchical regression analysis were performed to analyse the data. RESULTS: The findings of the study indicated that ICU nurses' moral resilience and STS scores were at an intermediate level. Hierarchical regression analysis indicated that STS was negatively correlated with the subscales of the Rushton Moral Resilience Scale, specifically moral adversity coping (ß, -0.156; 95% CI, -1.241 to -0.039) and relational integrity (ß, -0.245; 95% CI, -1.453 to -0.388), which are significant predictors of STS. Additionally, good sleep quality (ß, -.396; 95% CI, -14.948 to -7.117) and seeking psychological counselling because of work difficulties (ß, .107; 95% CI, 0.237-9.624) emerged as significant predictors of STS among ICU nurses, with the model's explanation of the variance in STS increasing to 45.5%, △R2 = .167, F = 16.482 (p < .001). CONCLUSION: This study found that ICU nurses have moderate levels of moral resilience and STS, which are negatively correlated. This suggests that improving the moral resilience of ICU nurses may help reduce their STS levels. RELEVANCE TO CLINICAL PRACTICE: The study revealed that ICU nurses' moral resilience and secondary traumatic stress levels were at a moderate level, indicative of the need to take measures to enhance their moral resilience and reduce their secondary traumatic stress, as their presence not only affects the health of ICU nurses but also diminishes the quality of care and increases turnover rates.

The biosafety incident response competence scale for clinical nursing staff: a development and validation study.

AIMS: This study was designed to develop a biosafety incident response competence scale and evaluate its validity and reliability among clinical nurses. DESIGN: This study employed a sequential approach, comprising four phases: (1) the establishment of a multidimensional conceptual model, (2) the preliminary selection of the items, (3) further exploration and psychometric testing of the items, (4) the application of the scale among clinical nurses. METHODS: The biosafety incident response competence conceptual model was developed through literature review and the Delphi method. A total of 1,712 clinical nurses participated in the preliminary items selection, while 1,027 clinical nurses were involved in the further psychometric testing from July 2023 to August 2023. The item analysis, exploratory factor analysis and confirmatory factor analysis were conducted to evaluate the construct validity. Reliability was measured using Cronbach's alpha, split-half reliability, and test-retest reliability, while validity analysis included content validity, structural validity, convergent validity, and discriminant validity. From September to November 2023, we conducted a survey using the established scale with a total of 4338 valid questionnaires collected. T-test and variance analysis was employed to determine potential variations in biosafety incident response competence based on participants characteristics. RESULTS: The final scale is composed of 4 factors and 29 items, including monitoring and warning abilities, nursing disposal abilities, biosafety knowledge preparedness, and infection protection abilities. The explanatory variance of the 4 factors was 75.100%. The Cronbach's alpha, split-half reliability and test-retest reliability were 0.974, 0.945 and 0.840 respectively. The Scale-level content validity index was 0.866. The Average Variance Extracted of the 4 factors was larger than 0.5, the Construct Reliability was larger than 0.7, and the Heterotrait-Monotrait ratio were less than 0.9. There were significant differences in the scores of response competence among nurses of different ages, working years, titles, positions, departments, marital status and participation in biosafety training (all P < 0.05). CONCLUSIONS: The biosafety incident response competence scale for nurses exhibits satisfactory reliability and validity, making it a valuable tool for assessing clinical nurses' abilities in responding to biosafety incidents.

The relationship between role ambiguity, emotional exhaustion and work alienation among chinese nurses two years after COVID-19 pandemic: a cross-sectional study.

BACKGROUND: work alienation is receiving increasing attention as a psychological risk at work, and little is known about the mechanisms of role ambiguity and work alienation in nurses in the context of the COVID-19 pandemic. This article aims to examine how role ambiguity affects work alienation among Chinese nurses during the two years after COVID-19 pandemic and verify emotional exhaustion as mediators. METHODS: A cross-sectional study design was used to recruit 281 Chinese nurses. Nurses completed online questionnaires containing demographic characteristics, role ambiguity, emotional exhaustion, and work alienation, and SPSS 26.0 and AMOS 24.0 were used for data analysis and structural equation modelling. RESULTS: work alienation scores were (34.64 ± 10.09), work alienation was correlated with role ambiguity and emotional exhaustion (r1 = 0.521, r2 = 0.755; p < .01), and role ambiguity was positively correlated with emotional exhaustion (r = 0.512; p < .01). A mediating effect of emotional exhaustion between role ambiguity and work alienation held (mediating effect of 0.288, 95% CI: 0.221-0.369, accounting for 74.8% of the total effect). CONCLUSION: Role ambiguity has a significant direct effect on nurses' feelings of alienation and exacerbates alienation through emotional exhaustion. Clarifying roles at work and being less emotionally drained are effective ways to reduce nurses' feelings of alienation.

Safety and efficacy of hydroxychloroquine as prophylactic against COVID-19 in healthcare workers: a meta-analysis of randomised clinical trials.

OBJECTIVE: We studied the safety and efficacy of hydroxychloroquine (HCQ) as pre-exposure prophylaxis for COVID-19 in healthcare workers (HCWs), using a meta-analysis of randomised controlled trials (RCTs). DATA SOURCES: PubMed and EMBASE databases were searched to identify randomised trials studying HCQ. STUDY SELECTION: Ten RCTs were identified (n=5079 participants). DATA EXTRACTION AND SYNTHESIS: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were used in this systematic review and meta-analysis between HCQ and placebo using a Bayesian random-effects model. A pre-hoc statistical analysis plan was written. MAIN OUTCOMES: The primary efficacy outcome was PCR-confirmed SARS-CoV-2 infection and the primary safety outcome was incidence of adverse events. The secondary outcome included clinically suspected SARS-CoV-2 infection. RESULTS: Compared with placebo, HCWs randomised to HCQ had no significant difference in PCR-confirmed SARS-CoV-2 infection (OR 0.92, 95% credible interval (CI): 0.58, 1.37) or clinically suspected SARS-CoV-2 infection (OR 0.78, 95% CI: 0.57, 1.10), but significant difference in adverse events (OR 1.35, 95% CI: 1.03, 1.73). CONCLUSIONS AND RELEVANCE: Our meta-analysis of 10 RCTs investigating the safety and efficacy of HCQ as pre-exposure prophylaxis in HCWs found that compared with placebo, HCQ does not significantly reduce the risk of confirmed or clinically suspected SARS-CoV-2 infection, while HCQ significantly increases adverse events. PROSPERO REGISTRATION NUMBER: CRD42021285093.

CRISPR/Cas9-mediated genome editing in vancomycin-producing strain Amycolatopsis keratiniphila.

Amycolatopsis is an important source of diverse valuable bioactive natural products. The CRISPR/Cas-mediated gene editing tool has been established in some Amycolatopsis species and has accomplished the deletion of single gene or two genes. The goal of this study was to develop a high-efficient CRISPR/Cas9-mediated genome editing system in vancomycin-producing strain A. keratiniphila HCCB10007 and enhance the production of vancomycin by deleting the large fragments of ECO-0501 BGC. By adopting the promoters of gapdhp and ermE*p which drove the expressions of scocas9 and sgRNA, respectively, the all-in-one editing plasmid by homology-directed repair (HDR) precisely deleted the single gene gtfD and inserted the gene eGFP with the efficiency of 100%. Furthermore, The CRISPR/Cas9-mediated editing system successfully deleted the large fragments of cds13-17 (7.7 kb), cds23 (12.7 kb) and cds22-23 (21.2 kb) in ECO-0501 biosynthetic gene cluster (BGC) with high efficiencies of 81%-97% by selecting the sgRNAs with a suitable PAM sequence. Finally, a larger fragment of cds4-27 (87.5 kb) in ECO-0501 BGC was deleted by a dual-sgRNA strategy. The deletion of the ECO-0501 BGCs revealed a noticeable improvement of vancomycin production, and the mutants, which were deleted the ECO-0501 BGCs of cds13-17, cds22-23 and cds4-27, all achieved a 30%-40% increase in vancomycin yield. Therefore, the successful construction of the CRISPR/Cas9-mediated genome editing system and its application in large fragment deletion in A. keratiniphila HCCB10007 might provide a powerful tool for other Amycolatopsis species.

Micro/Nanorobot: A Promising Targeted Drug Delivery System.

Micro/nanorobot, as a research field, has attracted interest in recent years. It has great potential in medical treatment, as it can be applied in targeted drug delivery, surgical operation, disease diagnosis, etc. Differently from traditional drug delivery, which relies on blood circulation to reach the target, the designed micro/nanorobots can move autonomously, which makes it possible to deliver drugs to the hard-to-reach areas. Micro/nanorobots were driven by exogenous power (magnetic fields, light energy, acoustic fields, electric fields, etc.) or endogenous power (chemical reaction energy). Cell-based micro/nanorobots and DNA origami without autonomous movement ability were also introduced in this article. Although micro/nanorobots have excellent prospects, the current research is mainly based on in vitro experiments; in vivo research is still in its infancy. Further biological experiments are required to verify in vivo drug delivery effects of micro/nanorobots. This paper mainly discusses the research status, challenges, and future development of micro/nanorobots.

Global Transcriptomic Analysis of Zebrafish Glucagon Receptor Mutant Reveals Its Regulated Metabolic Network.

The glucagon receptor (GCGR) is a G-protein-coupled receptor (GPCR) that mediates the activity of glucagon. Disruption of GCGR results in many metabolic alterations, including increased glucose tolerance, decreased adiposity, hypoglycemia, and pancreatic α-cell hyperplasia. To better understand the global transcriptomic changes resulting from GCGR deficiency, we performed whole-organism RNA sequencing analysis in wild type and gcgr-deficient zebrafish. We found that the expression of 1645 genes changes more than two-fold among mutants. Most of these genes are related to metabolism of carbohydrates, lipids, and amino acids. Genes related to fatty acid ß-oxidation, amino acid catabolism, and ureagenesis are often downregulated. Among gcrgr-deficient zebrafish, we experimentally confirmed increases in lipid accumulation in the liver and whole-body glucose uptake, as well as a modest decrease in total amino acid content. These results provide new information about the global metabolic network that GCGR signaling regulates in addition to a better understanding of the receptor's physiological functions.

Selection of Surrogate Bacteria for Use in Food Safety Challenge Studies: A Review.

Nonpathogenic surrogate bacteria are prevalently used in a variety of food challenge studies in place of foodborne pathogens such as Listeria monocytogenes, Salmonella, Escherichia coli O157:H7, and Clostridium botulinum because of safety and sanitary concerns. Surrogate bacteria should have growth characteristics and/or inactivation kinetics similar to those of target pathogens under given conditions in challenge studies. It is of great importance to carefully select and validate potential surrogate bacteria when verifying microbial inactivation processes. A validated surrogate responds similar to the targeted pathogen when tested for inactivation kinetics, growth parameters, or survivability under given conditions in agreement with appropriate statistical analyses. However, a considerable number of food studies involving putative surrogate bacteria lack convincing validation sources or adequate validation processes. Most of the validation information for surrogates in these studies is anecdotal and has been collected from previous publications but may not be sufficient for given conditions in the study at hand. This review is limited to an overview of select studies and discussion of the general criteria and approaches for selecting potential surrogate bacteria under given conditions. The review also includes a list of documented bacterial pathogen surrogates and their corresponding food products and treatments to provide guidance for future studies.