Positive regulation of Type III secretion effectors and virulence by RyhB paralogs in Salmonella enterica serovar Enteritidis.

Small non-coding RNA RyhB is a key regulator of iron homeostasis in bacteria by sensing iron availability in the environment. Although RyhB is known to influence bacterial virulence by interacting with iron metabolism related regulators, its interaction with virulence genes, especially the Type III secretion system (T3SS), has not been reported. Here, we demonstrate that two RyhB paralogs of Salmonella enterica serovar Enteritidis upregulate Type III secretion system (T3SS) effectors, and consequently affect Salmonella invasion into intestinal epithelial cells. Specifically, we found that RyhB-1 modulate Salmonella response to stress condition of iron deficiency and hypoxia, and stress in simulated intestinal environment (SIE). Under SIE culture conditions, both RyhB-1 and RyhB-2 are drastically induced and directly upregulate the expression of T3SS effector gene sipA by interacting with its 5' untranslated region (5' UTR) via an incomplete base-pairing mechanism. In addition, the RyhB paralogs upregulate the expression of T3SS effector gene sopE. By regulating the invasion-related genes, RyhBs in turn affect the ability of S. Enteritidis to adhere to and invade into intestinal epithelial cells. Our findings provide evidence that RyhBs function as critical virulence factors by directly regulating virulence-related gene expression. Thus, inhibition of RyhBs may be a potential strategy to attenuate Salmonella.

Circulating Connective Tissue Growth Factor Is Associated with Diastolic Dysfunction in Patients with Diastolic Heart Failure.

BACKGROUND: Connective tissue growth factor (CTGF) and transforming growth factor ß1 (TGF-ß1) are emerging biomarkers for tissue fibrosis. The aim of this study was to investigate the association between circulating CTGF, TGF-ß1 levels and cardiac diastolic dysfunction in patients with diastolic heart failure (DHF). METHODS: Admitted subjects were screened for heart failure and those with left ventricular (LV) ejection fraction <45% were excluded. Diastolic dysfunction was defined as functional abnormalities that exist during LV relaxation and filling by echocardiographic criteria. Totally 114 patients with DHF and 72 controls were enrolled. Plasma levels of CTGF, TGF-ß1, and B-type natriuretic peptide (BNP) were determined. RESULTS: The plasma CTGF and TGF-ß1 levels increased significantly in patients with DHF. Circulating CTGF and TGF-ß1 levels were correlated with echocardiographic parameter E/e' and diastolic dysfunction grading in DHF patients. In multivariate logistic analysis, CTGF was significantly associated with diastolic dysfunction (odds ratio: 1.027, p < 0.001). Plasma CTGF (AUC: 0.770 ± 0.036, p < 0.001) and CTGF/BNP (AUC: 0.839 ± 0.036, p < 0.001) showed good predictive power to the diagnosis of DHF. CONCLUSIONS: This finding suggested CTGF could be involved in the pathophysiology of diastolic heart failure and CTGF/BNP might have auxiliary diagnostic value on diastolic heart failure.

Small non-coding RNA STnc640 regulates expression of fimA fimbrial gene and virulence of Salmonella enterica serovar Enteritidis.

BACKGROUND: Small non-coding RNAs (sRNAs) regulate bacterial gene expression at the post-transcriptional level. STnc640 is a type of sRNA that was identified in Salmonella Typhimurium. RESULTS: In this study, STnc640 in Salmonella Enteritidis was confirmed to be an Hfq-dependent sRNA. TargetRNA software analysis showed that fimbrial genes fimA and bcfA were likely to be the target genes of STnc640. To investigate the target mRNAs and function of STnc640 in pathogenicity, we constructed the deletion mutant strain 50336△stnc640 and the complemented strain 50336△stnc640/pstnc640 in Salmonella Enteritidis 50336. The RT-qPCR results showed that the mRNA level of fimA was decreased, while bcfA was unchanged in 50336△stnc640 compared with that in the wild type (WT) strain. The adhesion ability of 50336△stnc640 to Caco-2 cells was increased compared to the 50336 WT strain. The virulence of 50336△stnc640 was enhanced in a one-day-old chicken model of S. Enteritidis disease as determined by quantifying the 50% lethal dose (LD50) of the bacterial strains. CONCLUSIONS: The results demonstrate that STnc640 contributes to the virulence of Salmonella Enteritidis.

[Advances in new vaccines against human enterotoxigenic Escherichia coli--A review].

Enterotoxigenic Escherichia coli (ETEC) is the most common cause of diarrhea, which is a second leading cause of death for the children under five years old from all over the world. The key factors of ETEC contain both colonization factors (CFs) and enterotoxins including heat-labile enterotoxin (LT) and heat-stable enterotoxin (ST). CFs mediated the binding of bacteria to the host intestinal epithelial cells, whereas LT and ST stimulated the over-secretion of body fluids and electrolytes, resulting in the destruction of the host fluid balance and leading diarrhea. The vaccine against CFs and enterotoxins could stimulate the host immune response, blocking ETEC adhesion and neutralizing enterotoxins, which is effective in the prevention of ETEC diarrhea. For the moment, depending on the stimulated immune response against LT, a cholera vaccine called Dukoral has been approved for use in some countries for the short-term protection and prevention of travelers' diarrhea. ETEC candidate vaccines are still in progress, which is designed to provide a long and wide-spectrum protection for ETEC infections. This paper briefly summarizes the advanced findings and key problems of vaccine development, and discusses prospects for future research.

Molecular epidemiology of infectious bronchitis virus in eastern and southern China during 2021-2023.

As a highly infectious and contagious pathogen in chickens, infectious bronchitis virus (IBV) is currently grouped into nine genotypes (GI to GIX). However, the classification of serotypes of IBV is still not clear. In this study, 270 field strains of IBV were isolated from dead or diseased chicken flocks in eastern and southern China during January 2021 to April 2023. These isolated IBV strains could be classified into 2 genotypes, GI (including 5 lineages GI-1, GI-13, GI-19, GI-22, and GI-28) and GVI based on the complete S1 sequence. Further analysis showed that the GI-19, GI-13, GI-22, GI-28, and GVI were the dominant genotypes with the proportions of 61.48, 8.89, 8.89, 7.78, and 8.89% respectively, and the homology of S1 protein of these isolates ranged from 86.85 to 100% in GI-19, 92.22 to 100% in GI-13, 83.1 to 100% in GI-22, 94.81 to 100% in GI-28 and 90.0 to 99.8% in GVI, respectively. Moreover, cross-neutralization test with sera revealed that these isolates in GI-19 lineage could be classified into at least 3 serotypes according to the antigenic relationship. In addition, structure assay using PyMOL indicated that one mutation such as S120 in receptor binding site (RBD) of GI-19 might alter the antigenicity and conformation of S protein of IBV. Overall, our data demonstrate that not only multiple genotypes, but also multiple serotypes in a single genotype or lineage have been co-circulated in eastern and southern China, providing novel insights into the molecular evolution of the antigenicity of IBV and highlighting the significance of the selection of the dominant isolate for vaccine development in IBV endemic region.

A peptide-based ELISA for detection of antibodies against novel goose astrovirus type 1.

Goose gout disease is a high morbidity and mortality disease caused by novel serotype 1 goose astrovirus (GAstV-1), which has resulted in huge economic loss to the goose industry of China. However, few diagnostic methods have been developed for serological surveillance of GAstV-1. In our previous study, several novel B cell epitopes were identified in the ORF2 protein of GAstV-1. In this study, one novel peptide of 627-646 aa in the ORF2 recognized by monoclonal antibody (mAb) 6C6 was used as an antigen to develop an efficient peptide-based ELISA (pELISA) for detection of antibodies against GAstV-1. Specificity analysis showed that the pELISA only reacted with sera against GAstV-1, but not with sera against other pathogens tested. The sensitivity of the pELISA in detecting positive sera was higher than that of the IFA (Indirect immunofluorescence assay). The coefficients of variation (CV) of the intra-assay and inter-assay were both < 10%, indicating that the reproducibility of pELISA was good. For detection of clinical samples, the pELISA had 87.5% concordance with the IFA. Our data demonstrate that the pELISA generated here provides an accurate, rapid, and economical method for the detection antibodies against GAstV-1 for serological surveillance.

A novel S2-derived peptide-based ELISA for broad detection of antibody against infectious bronchitis virus.

Avian infectious bronchitis (IB) is a highly contagious disease caused by infectious bronchitis virus (IBV). Vaccination is an effective approach for controlling IBV. Therefore, reliable immune monitoring for IB is critical for poultry. In this study, a novel peptide derived from S2 protein was used to develop an enzyme-linked immunosorbent assay (ELISA) for the detection of broadly cross-reactive antibodies against IBV. The peptide-based ELISA (pELISA) showed good specificity and sensitivity in detecting IBV antibodies against different serotypes. A semilogarithmic regression method for determining IBV antibody titers was also established. Antibody titers detected by pELISA and calculated with this equation were statistically similar to those evaluated by indirect fluorescence assay (IFA). Moreover, the comparison analysis showed a 96.07% compatibility between the pELISA and IDEXX ELISA. All these data demonstrate that the pELISA generated here can be as a rapid and reliable serological surveillance tool for monitoring IBV infection or vaccination.

Predictive value of CTRP3 for the disease recurrence of atrial fibrillation patients after radiofrequency ablation.

OBJECTIVE: To explore the expression of plasma CTRP3 in patients with non-valvular paroxysmal atrial fibrillation after radiofrequency ablation and its predictive value for disease recurrence. METHODS: In this retrospective study, the patients in the Heart Center of Beijing Chaoyang Hospital from June 2016 to November 2017 were collected. According to the guidelines for diagnosis and treatment of atrial fibrillation 2016, patients diagnosed with paroxysmal atrial fibrillation were selected as the study subjects. All patients with successful radiofrequency ablation of atrial fibrillation were followed up by telephone or outpatient service at 1, 3, 6 and 12 months after radiofrequency ablation, respectively. Recurrence of atrial fibrillation was defined as a duration of rapid atrial arrhythmia ≥30 seconds confirmed by electrocardiogram or 24-hour ambulatory electrocardiogram 3 months after radiofrequency ablation. According to the follow-up results, the patients were divided into a recurrent group and non-recurrent group. The level of CTRP3 was detected by enzyme-linked immunosorbent assay (ELISA). RESULTS: Analysis of clinical baseline data showed significant differences between the recurrent group and the non-recurrent group in age, systolic blood pressure, diastolic blood pressure, EGFR, thyroid stimulating hormone level, platelet count, high-sensitivity C-reactive protein, NT proBNP, left atrial anterior posterior diameter, left atrial upper and lower diameter and CTRP3 (P < 0.05). The univariate logistic regression showed that older age (or = 1.08, P < 0.001), increased diastolic blood pressure (OR = 1.051, P = 0.002), cardiac dysfunction (OR = 2.594, P = 0.01), high-sensitivity C-reactive protein (OR = 1.134, P = 0.008) and NT proBNP (OR = 1.000, P = 0.005), increased anterior posterior diameter of left atrium (OR = 1.158, P < 0.001), increased upper and lower diameter of left atrium (OR = 1.133, P < 0.001), thrombocytopenia (OR = -0.008, P < 0.027) and CTRP3 (OR = 1.007, P = 0.006) were the risk factors for the recurrence of atrial fibrillation after radiofrequency ablation. Moreover, the multivariate logistic regression analysis demonstrated that CTRP3 (or = 1.032, P = 0.005) was an independent predictor of recurrence. CONCLUSION: The plasma concentration of CTRP3 increased significantly in patients with recurrent atrial fibrillation after radiofrequency ablation. Moreover, CTRP3 was a predictor of recurrence after radiofrequency ablation in patients with atrial fibrillation.

Fifteen-year mortality and prognostic factors in patients with dilated cardiomyopathy: persistent standardized application of drug therapy and strengthened management may bring about encouraging change in an aging society.

BACKGROUND: There is scarce data on the long-term mortality and associated prognostic factors in patients with dilated cardiomyopathy (DCM). The study aimed to investigate the all-cause mortality up to 15 years (mean 7.9 ± 5.7 years) in such patients, and the independent prognostic factors influencing their long-term mortality. METHODS: One hundred and sixty-six consecutive patients with DCM were prospectively enrolled from 2002 to 2003. The mean age of patients was 59.5 ± 10.4 years, and approximately 57% were male. They were followed up by telephone or outpatient visit at least every three months until 2019 or all-cause death occurred. Predictors of mortality were identified using multivariate logistic regression analysis. RESULTS: During the 15 years of follow-up, five patients were lost to follow-up, and the complete data records of 161 patients were included in the analysis. Patients were treated with angiotensin-converting-enzyme inhibitors (ACEI) or angiotensin-receptor blocker (ARB), ß-blockers, mineralocorticoid receptor antagonist (MRA), diuretics and digitalis from 2002 to 2004, and maintained at the maximum tolerated doses between 2004 and 2019. Our safety targets to maintain heart rate and blood pressure at 60-80 beats/min and 90-120/60-80 mmHg, respectively. All-cause mortality in the first five years was 55.9%. The independent risk factors for the 5-year mortality were age ≥ 70 years old (OR = 5.45, P = 0.006), systolic blood pressure (SBP) > 120 mmHg (OR = 3.63, P = 0.004), 6-minute walk distance (6MWD) < 450 m (OR = 3.84, P = 0.001). 15-year all-cause mortality was 65.8%. The independent risk factors for 15-year mortality were age ≥ 70 years old (OR = 16.07, P = 0.009), LVEF ≤ 35% (OR = 5.69, P = 0.003), and SBP > 120 mmHg (OR = 9.56, P < 0.001). CONCLUSIONS: This study was the first to demonstrate the 15-year survival rate of 34% in DCM patients. The DCM patients' first five-year all-cause mortality decreased significantly after continuous standardized treatment and intensive management. The mortality then plateaued in the following 10 years. Age ≥ 70 years, LVEF ≤ 35%, and SBP > 120 mmHg were independent predictors of 15-year all-cause mortality.

A non-coding small RNA MicC contributes to virulence in outer membrane proteins in Salmonella Enteritidis.

A non-coding small RNA (sRNA) is a new factor to regulate gene expression at the post-transcriptional level. A kind of sRNA MicC, known in Escherichia coli and Salmonella Typhimurium, could repress the expression of outer membrane proteins. To further investigate the regulation function of micC in Salmonella Enteritidis, we cloned the micC gene in the Salmonella Enteritidis strain 50336, and then constructed the mutant 50336ΔmicC by the λ Red-based recombination system and the complemented mutant 50336ΔmicC/pmicC carrying recombinant plasmid pBR322 expressing micC. qRT-PCR results demonstrated that transcription of ompD in 50336ΔmicC was 1.3-fold higher than that in the wild type strain, while the transcription of ompA and ompC in 50336ΔmicC were 2.2-fold and 3-fold higher than those in the wild type strain. These indicated that micC represses the expression of ompA and ompC. In the following study, the pathogenicity of 50336ΔmicC was detected by both infecting 6-week-old Balb/c mice and 1-day-old chickens. The result showed that the LD50 of the wild type strain 50336, the mutants 50336ΔmicC and 50336ΔmicC/pmicC for 6-week-old Balb/c mice were 12.59 CFU, 5.01 CFU, and 19.95 CFU, respectively. The LD50 of the strains for 1-day-old chickens were 1.13 x 109 CFU, 1.55 x 108 CFU, and 2.54 x 108 CFU, respectively. It indicated that deletion of micC enhanced virulence of S. Enteritidis in mice and chickens by regulating expression of outer membrane proteins.

The association between orthostatic blood pressure changes and subclinical target organ damage in subjects over 60 years old.

BACKGROUND: Although recent studies have indicated that both orthostatic hypotension and orthostatic hypertension independently predict cardiovascular events, the underlying mechanisms are still controversial. The aim of the study was to investigate the relationships between orthostatic changes and organ damage in subjects over 60 years old. METHODS: This is a prospective observational cohort study. One thousand nine hundred and ninety-seven subjects over 60 years old were enrolled. Participants were grouped according to whether they had a drop ≥ 20 mmHg in systolic or ≥ 10 mmHg in diastolic BP (orthostatic hypotension), an increase in mean orthostatic systolic blood pressure ≥ 20 mm Hg (orthostatic hypertension), or normal changes within 3 min of orthostatism. Multiple regression modeling was used to investigate the relationship between orthostatic hypotension, orthostatic hypertension and subclinical organ damage with adjustment for confounders. RESULTS: Orthostatic hypotension and orthostatic hypertension were found in 461 (23.1%) and 189 (9.5%) participants, respectively. Measurement of carotid intima-media thickness (IMT), brachial-ankle pulse wave velocity (baPWV), clearance of creatinine, and microalbuminuria were associated with orthostatic hypotension; measurement of IMT and baPWV were associated with orthostatic hypertension in a cruse model. After adjustment, IMT [odds ratio (OR), 95% confidence interval (CI) per one-SD increment: 1.385, 1.052-1.823; P = 0.02], baPWV (OR = 1.627, 95% CI: 1.041-2.544; P = 0.033) and microalbuminuria (OR = 1.401, 95% CI: 1.002-1.958; P = 0.049) were still associated with orthostatic hypotension, while orthostatic hypertension was only associated with IMT (OR = 1.730, 95% CI: 1.143-2.618; P = 0.009). CONCLUSIONS: Orthostatic hypotension seems to be independently correlated with increased carotid atherosclerosis, arterial stiffness and renal damage in subjects over 60 years old. Orthostatic hypertension correlates with carotid atherosclerosis only.

A severity index study of long-term prognosis in patients with chronic heart failure.

AIMS: The present study describes the derivation and validation of the Chronic Heart Failure Severity Index (CHFSI). MAIN METHODS: The CHFSI was derived using data obtained from a single-center prospective cohort study (2000-2014) that enrolled 756 patients. Logistic regression was used to identify independent predictors of mortality and quality of life over a 15-year follow-up period. KEY FINDINGS: The score was validated at the first 5-year (n = 644), second 5-year (n = 364), and third 5-year (n = 262). Independent predictors of mortality were older age (OR = 2.04, P < 0.001), etiology score (OR = 2.61, P < 0.001), faster heart rate (OR = 1.46, P = 0.027), higher systolic blood pressure (OR = 2.35, P < 0.001), and left ventricular ejection fraction ≤45% (OR = 1.97, P = 0.018). The derived CHFSI predicted the mortality, and the AUC for the logistic model was 0.78 (95% confidence interval = 0.74-0.81, P < 0.001). Based on the logistic model, an integer scoring system was derived. Patients were classified into three groups: low risk (0-7 points), intermediate risk (8-11 points) and high risk (≥12 points) groups. The cumulative mortality for 15 years was 45.5% (125/275), 84.0% (204/243), and 100% (99/99), respectively (P < 0.001). The 6-min walk test revealed a significant difference in quality of life among patients in the low, medium and high risk groups (all, P < 0.0001). SIGNIFICANCE: The CHFSI is a very useful clinical predictive tool that identifies patients at risk of future mortality and their quality of life across healthcare systems.

The RNA chaperone Hfq regulates expression of fimbrial-related genes and virulence of Salmonella enterica serovar Enteritidis.

Salmonella Enteritidis is an intracellular pathogen that causes enteritis and systemic disease in humans and other animals. The RNA chaperone protein Hfq mediates the binding of small noncoding RNAs to target mRNA and assists in post-transcriptional gene regulation in bacteria. In this study, we constructed an hfq deletion mutant in S. Enteritidis SE50336 and analyzed the expression of major fimbrial subunits sefA, bcfA, fimA, safA, stbA, sthA, csgA, csgD, and pegA using quantitative real-time PCR. The gene expression of sefA increased about 14-fold in the hfq mutant, as compared with its expression in the wild-type strain. The expression of fimA and pegA did not change significantly, while the expression of the other fimbrial genes was significantly down-regulated in the hfq mutant. The ability of SE50336Δhfq adhering to Caco-2 cells was also reduced as compared with wild-type adherence. The virulence of the hfq mutant was significantly reduced in a 1-day-old chicken model of S. Enteritidis disease, as determined by quantifying the lethal dose 50% of the bacterial strains. We conclude that Hfq critically contributes to S. Enteritidis virulence, likely partially affected by regulating fimbrial gene expression.