Uncovering the GacS-mediated role in evolutionary progression through trajectory reconstruction in Pseudomonas aeruginosa.

The genetic diversities of subpopulations drive the evolution of pathogens and affect their ability to infect hosts and cause diseases. However, most studies to date have focused on the identification and characterization of adaptive mutations in single colonies, which do not accurately reflect the phenotypes of an entire population. Here, to identify the composition of variant subpopulations within a pathogen population, we developed a streamlined approach that combines high-throughput sequencing of the entire population cells with genotyping of single colonies. Using this method, we reconstructed a detailed quorum-sensing (QS) evolutionary trajectory in Pseudomonas aeruginosa. Our results revealed a new adaptive mutation in the gacS gene, which codes for a histidine kinase sensor of a two-component system (TCS), during QS evolution. This mutation reduced QS activity, allowing the variant to sweep throughout the whole population, while still being vulnerable to invasion by the emerging QS master regulator LasR-null mutants. By tracking the evolutionary trajectory, we found that mutations in gacS facilitated QS-rewiring in the LasR-null mutant. This rapid QS revertant caused by inactive GacS was found to be associated with the promotion of ribosome biogenesis and accompanied by a trade-off of reduced bacterial virulence on host cells. In conclusion, our findings highlight the crucial role of the global regulator GacS in modulating the progression of QS evolution and the virulence of the pathogen population.

Uncovering a hidden functional role of the XRE-cupin protein PsdR as a novel quorum-sensing regulator in Pseudomonas aeruginosa.

XRE-cupin family proteins containing an DNA-binding domain and a cupin signal-sensing domain are widely distributed in bacteria. In Pseudomonas aeruginosa, XRE-cupin transcription factors have long been recognized as regulators exclusively controlling cellular metabolism pathways. However, their potential functional roles beyond metabolism regulation remain unknown. PsdR, a typical XRE-cupin transcriptional regulator, was previously characterized as a local repressor involved solely in dipeptide metabolism. Here, by measuring quorum-sensing (QS) activities and QS-controlled metabolites, we uncover that PsdR is a new QS regulator in P. aeruginosa. Our RNA-seq analysis showed that rather than a local regulator, PsdR controls a large regulon, including genes associated with both the QS circuit and non-QS pathways. To unveil the underlying mechanism of PsdR in modulating QS, we developed a comparative transcriptome approach named "transcriptome profile similarity analysis" (TPSA). Using this TPSA method, we revealed that PsdR expression causes a QS-null-like transcriptome profile, resulting in QS-inactive phenotypes. Based on the results of TPSA, we further demonstrate that PsdR directly binds to the promoter for the gene encoding the QS master transcription factor LasR, thereby negatively regulating its expression and influencing QS activation. Moreover, our results showed that PsdR functions as a negative virulence regulator, as inactivation of PsdR enhanced bacterial cytotoxicity on host cells. In conclusion, we report on a new QS regulation role for PsdR, providing insights into its role in manipulating QS-controlled virulence. Most importantly, our findings open the door for a further discovery of untapped functions for other XRE-Cupin family proteins.

Construction of a competency index system for shift nurses in China: A Delphi study.

AIM: This study developed a set of competency evaluation indicators for shift work nurses in China. BACKGROUND: Nurses on night shifts must deal with the treatment, nursing, and management work, which requires excellent competency of night shift nurses in their knowledge, skills, and ability. However, the competency evaluation index system for shift work nurses has not been established yet in China. METHODS: This study performed a literature review and semi-structured interviews to draft the preliminary competency evaluation indicators for nursing shift work. The Delphi technique was adopted to administer two rounds of questionnaires on 21 nursing experts. RESULTS: The positive coefficients of experts in the two rounds were 100% and 90.48%, respectively, whereas the authority coefficients were 0.974 and 0.971, respectively. The coefficients of variation were 0.00-0.26 and 0.00-0.16, respectively. The competency evaluation index system for shift work nurses consisted of 2 first-level indicators, 16 second-level indicators, and 67 third-level indicators. CONCLUSION: The competency index system of shift work nurses is scientific and applicable. IMPLICATIONS FOR NURSING MANAGEMENT: The competency evaluation index system of shift work nurses would provide an effective practical framework for shift nursing administration to evaluate, train, and assess the competency of shift work nurses.

Development of billing post competency evaluation index system for nurses in China: a Delphi study.

AIM: This study developed a set of competency evaluation indicators for billing nurses in China. BACKGROUND: In clinical practice, nurses often take up billing responsibilities that are accompanied by certain risks. However, the competency evaluation index system for billing nurses has not been established in China. METHODS: This study consisted of two main phases of research design: the first phase included a literature review and semi-structured interviews. Individual semi-structured interviews were conducted with 12 nurses in billing departments and 15 nurse managers in related departments. Concepts distilled from the literature review were linked to the results of the semi-structured interviews; this phase produced the first draft of indicators for assessing the professional competence of nurses in billing departments. In the second phase, two rounds of correspondence were conducted with 20 Chinese nursing experts using the Delphi method to test and evaluate the content of the index. The consensus was defined in advance as a mean score of 4.0 or above, with at least 75% agreement among participants. In this way, the final indicator framework was determined. RESULTS: Using the iceberg model as a theoretical foundation, the literature review identified four main dimensions and associated themes. The semi-structured interviews confirmed all of the themes from the literature review while generating new themes, both of which were incorporated into the first draft of the index. Then two rounds of the Delphi survey were conducted. The positive coefficients of experts in the two rounds were 100% and 95%, respectively, while the authority coefficients were 0.963 and 0.961, respectively. The coefficients of variation were 0.00-0.33 and 0.05-0.24, respectively. The competency evaluation index system for billing nurses consisted of 4 first-level indicators, 16 s-level indicators, and 53 third-level indicators. CONCLUSION: The competency evaluation index system for billing nurses, which was developed on the basis of the iceberg model, was scientific and applicable. IMPLICATIONS FOR NURSING MANAGEMENT: The competency assessment index system for billing nurses may provide an effective practical framework for nursing administration to evaluate, train, and assess the competency of billing nurses.

Efficacy and safety of early enteral and intravenous fluid resuscitation in severe acute pancreatitis: a systematic review and meta-analysis.

OBJECTIVE: To compare the efficacy and safety of enteral fluid resuscitation (via nasointestinal tube or colorectal tube) and intravenous fluid resuscitation (via intravenous route) in the early treatment of severe acute pancreatitis. METHODS: In this study, 8 electronic databases (PubMed, Web of Science, Embase, Cochrane Library, Scopus, China HowNet database, Wanfang database, and VIP database) were searched to collect clinical studies from inception to June 12, 2022. After the quality evaluation and data extraction of the included studies, the RevMan 5.3 software was used for analysis. RESULTS: A total of seven studies including 580 patients were studied in this meta-analysis, in which 291 cases were treated with enteral fluid resuscitation and 289 cases were treated with intravenous fluid resuscitation. Compared with the intravenous route group, the enteral route resuscitation group reduced the incidence of new organ failure (OR = 0.23, 95% CI: 0.12-0.43, P < 0.00001), the incidence of persistent organ failure (OR = 0.38, 95% CI: 0.22-0.64, P = 0.0003), the incidence of mechanical ventilation (OR = 0.15, 95% CI: 0.03-0.69, P = 0.01), the incidence of ICU care (OR = 0.49, 95% CI: 0.27-0.88, P = 0.02), and the incidence of pancreatic infection (OR = 0.38, 95% CI: 0.17-0.83, P = 0.02). There were no statistically significant differences in mortality (OR = 0.77, 95% CI: 0.35-1.66, P = 0.50), surgical intervention rate (OR = 0.47, 95% CI: 0.19-1.18, P = 0.11), and incidence of localized ascites (OR = 0.65, 95% CI: 0.25-1.73, P = 0.39). CONCLUSION: Early enteral fluid resuscitation is safe and effective for in severe pancreatitis. But this conclusion needs to be verified by more additional multi-centre randomized controlled trials with large samples.

Spontaneous quorum-sensing hierarchy reprogramming in Pseudomonas aeruginosa laboratory strain PAO1.

Pseudomonas aeruginosa strain PAO1 has been commonly used in the laboratory, with frequent genome variations reported. Quorum sensing (QS), a cell-cell communication system, plays important role in controlling a variety of virulence factors. However, the evolution and adaptability of QS in those laboratory strains are still poorly understood. Here we used the QS reporter and whole-genome sequencing (WGS) to systematically investigate the QS phenotypes and corresponding genetic basis in collected laboratory PAO1 strains. We found that the PAO1-z strain has an inactive LasR protein, while bearing an active Rhl QS system and exhibiting QS-controlled protease-positive activity. Our study revealed that an 18-bp insertion in mexT gene gave rise to the active QS system in the PAO1-z strain. This MexT inactivation restored the QS activity caused by the inactive LasR, showing elevated production of pyocyanin, cyanide and elastase. Our results implied the evolutionary trajectory for the PAO1-z strain, with the evulutionary order from the first Las QS inactivation to the final Rhl QS activation. Our findings point out that QS homeostasis occurs in the laboratory P. aeruginosa strain, offering a potential platform for the QS study in clinical isolates.

Codon-usage frequency mediated SNPs selection in lasR gene of cystic fibrosis Pseudomonas aeruginosa isolates.

Pseudomonas aeruginosa is an opportunistic pathogen with high clinical relevance for hospital infections of patients. Accumulating DNA sequencing results of clinical P. aeruginosa isolates have revealed frequent mutations in lasR gene, which encodes the highest arches component of quorum-sensing system (QS). We analyzed the sequencing data of lasR gene from a large collection of cystic fibrosis (CF) P. aeruginosa isolates. Our systematical analyses revealed that single nucleotide polymorphisms (SNPs) selection in lasR gene were largely constrained by codon-usage frequency. As a whole, SNP-substituted codons encoding unconserved amino acid resulted in unfavored codons with relatively low codon-usage frequency, while those associating with conserved amino acid were not strictly regulated in such way. These SNPs substitutions gives rise to diverse functional LasR isoforms and contributes to the relative growth fitness of recombinant lasR variant strains. Our survey reveals a novel pattern of SNPs selections in lasR gene of CF isolates. Our findings could be served as a powerful resource for understanding adaptive mechanism of clinical isolates under environmental constrains and developing anti-bacteria drugs for CF patients.

The clinical and etiological characteristics of influenza-like illness (ILI) in outpatients in Shanghai, China, 2011 to 2013.

INTRODUCTION: Clinical and etiological characteristics of influenza-like illness (ILI) in outpatients is poorly understood in the southern temperate region of China. We conducted laboratory-based surveillance of viral etiology for ILI outpatients in Shanghai from January 2011 to December 2013. MATERIALS AND METHODS: Clinical and epidemiological data from ILI outpatients, both children and adults, were collected. A total of 1970 nasopharyngeal swabs were collected and tested for 12 respiratory viruses using multiplex RT-PCR, and the data were analyzed anonymously. RESULTS: All 12 respiratory viruses were detected in the specimens. At least one virus was detected in 32.4% of 1970 specimens analyzed, with 1.1% showing co-infections. The most frequently detected agents were influenza A (11.7%), influenza B (9.6%), and rhinoviruses (3.1%).Other viruses were present at a frequency less than 3.0%. We observed a winter peak in the detection rate in ILI patients during 3 years of surveillance and a summer peak in 2012. HCoV, HADV, and HMPV were detected more frequently in children than in adults. Patients infected with influenza virus experienced higher temperatures, more coughs, running noses, headaches and fatigue than patients infected with other viruses and virus-free patients (p<0.001). CONCLUSIONS: The spectrum, seasonality, age distribution and clinical associations of respiratory virus infections in children and adults with influenza-like illness were analyzed in this study for the first time. To a certain extent, the findings can provide baseline data for evaluating the burden of respiratory virus infection in children and adults in Shanghai. It will also provide clinicians with helpful information about the etiological patterns of outpatients presenting with complaints of acute respiratory syndrome, but further studies should be conducted, and longer-term laboratory-based surveillance would give a better picture of the etiology of ILI.

Transition metal-mediated C═O and C═C bond-forming reactions: a regioselective strategy for the synthesis of imidazo[1,2-a]pyridines and imidazo[1,2-a]pyrazines.

A novel and convenient transformation for the regiospecific synthesis of functionalized imidazo[1,2-a]pyridine aldehydes/ketones and 3-vinyl imidazo[1,2-a]pyridines has been developed via copper(I)- and palladium(II)-catalyzed cyclization. The one-pot reaction proceeds smoothly with commercially available catalysts and affords the products in moderate to good yields. It represents an efficient approach for the formation of C-N, C═O, and C═C bonds under mild conditions.