Yuejiao Dong

Serotypes, genotypes and antimicrobial resistance patterns of human diarrhoeagenic Escherichia coli isolates circulating in southeastern China

Diarrhoeagenic Escherichia coli (DEC) infection is a major health problem in developing countries. The prevalence and characteristics of DEC have not been thoroughly investigated in China. Consecutive faecal specimens from outpatients with acute diarrhoea in nine sentinel hospitals in southeastern China were collected from July 2009 to June 2011. Bacterial and viral pathogens were detected by culture and RT-PCR, respectively. DEC isolates were further classified into five pathotypes using multiplex PCR. The O/H serotypes, sequence types (STs) and antimicrobial susceptibility profiles of the DEC isolates were determined. A total of 2466 faecal specimens were collected, from which 347 (14.1%) DEC isolates were isolated. DEC was the dominant bacterial pathogen detected. The DEC isolates included 217 EAEC, 62 ETEC, 52 EPEC, 14 STEC, one EIEC and one EAEC/ETEC. O45 (6.6%) was the predominant serotype. Genotypic analysis revealed that the major genotype was ST complex 10 (87, 25.6%). Isolates belonging to the serogroups or genotypes of O6, O25, O159, ST48, ST218, ST94 and ST1491 were highly susceptible to the majority of antimicrobials. In contrast, isolates belonging to O45, O15, O1, O169, ST38, ST226, ST69, ST31, ST93, ST394 and ST648 were highly resistant to the majority of antimicrobials. DEC accounted for the majority of bacterial pathogens causing acute diarrhoea in southeastern China, and it is therefore necessary to test for all DEC, not only the EHEC O157:H7. Some serogroups or genotypes of DEC were highly resistant to the majority of antimicrobials. DEC surveillance should be emphasized.

Detection of a novel avian influenza A (H7N9) virus in humans by multiplex one-step real-time RT-PCR assay

BackgroundA novel avian influenza A (H7N9) virus emerged in eastern China in February 2013. 413 confirmed human cases, including 157 deaths, have been recorded as of July 31, 2014.MethodsClinical specimens, including throat swabs, sputum or tracheal aspirates, etc., were obtained from patients exhibiting influenza-like illness (ILIs), especially from those having pneumonia and a history of occupational exposure to poultry and wild birds. RNA was extracted from these samples and a multiplex one-step real-time RT-PCR assay was developed to specifically detect the influenza A virus (FluA). PCR primers targeted the conserved M and Rnase P (RP) genes, as well as the hemagglutinin and neuraminidase genes of the H7N9 virus.ResultsThe multiplex assay specifically detected the avian H7N9 virus, and no cross-reaction with other common respiratory pathogens was observed. The detection limit of the assay was approximately 0.05 50% tissue culture infective doses (TCID50), or 100 copies per reaction. Positive detection of the H7N9 virus in sputum/tracheal aspirates was higher than in throat swabs during the surveillance of patients with ILIs. Additionally, detection of the matrix (M) and Rnase P genes aided in the determination of the novel avian H7N9 virus and ensured the quality of the clinical samples.ConclusionsThese results demonstrate that the multiplex assay detected the novel avian H7N9 virus with high specificity and sensitivity, which is essential for the early diagnosis and treatment of infected patients.

Changes of Costimulatory Molecule CD28 on Circulating CD8+ T Cells Correlate with Disease Pathogenesis of Chronic Hepatitis B

Costimulatory signals are critical for antiviral immunity. The aim of this study was to evaluate the change of costimulatory molecule CD28 on circulating CD8+ T cells in chronic hepatitis B patients (CHB). Seventy CHB patients and fifty-six healthy controls were included, and forty-eight CHB patients were recruited for 52 weeks of longitudinal investigation. The proportions of circulating CD8+CD28+ and CD8+CD28− subpopulations were determined by flow cytometry, and the CD8+CD28+/CD8+CD28− T cells ratio was calculated. Compared with the subpopulation in healthy controls, high proportions of CD8+CD28− subpopulation were observed in CHB patients. Similarly, the CD8+CD28+/CD8+CD28− T cells ratio was significantly decreased in CHB patients compared with healthy controls and correlated significantly with hepatitis B virus (HBV) loads. High proportions of CD8+CD28− subpopulation and low CD8+CD28+/CD8+CD28− T cells ratio were observed in hepatitis B e antigen- (HBeAg-) positive individuals as compared with that in HBeAg-negative subjects. A significant decrease in CD8+CD28− subpopulation, increase in CD8+CD28+ subpopulation, and CD8+CD28+/CD8+CD28− T cells ratio were seen in those patients who received efficient antiviral therapy. Thus, aberrant CD28 expression on circulating CD8+ T cells and the CD8+CD28+/CD8+CD28− T cells ratio reflect the dysregulation of T cell activation and are related to the pathogenesis of chronic HBV infection.

Correlation of hepatitis B surface antigen level with response to telbivudine in naive patients with chronic hepatitis B

Hepatitis B surface antigen (HBsAg) has become a marker to judge immunological response to hepatitis B therapy. Quantified serum HBsAg levels can predict the response to pegylated interferon and entecavir. In this study, we aimed to explore the correlation of serum HBsAg levels with response to telbivudine (LdT) treatment in patients with chronic hepatitis B (CHB).

Increasing LAG-3 expression suppresses T-cell function in chronic hepatitis B: A balance between immunity strength and liver injury extent

Abstract Weak or absent virus-specific CD8+ T-cell responses to hepatitis B virus (HBV) infection are thought to be responsible for persistent HBV infection. Previous studies have indicated that multiple inhibitory receptors, including lymphocyte activation gene-3 (LAG-3), can suppress the CD8+ T-cell response in chronic viral infection. This study aimed to detect LAG-3 expression and to investigate the manner in which the immune response is regulated to balance the strength of the response with the extent of liver injury in chronic HBV infection. The results showed that LAG-3 expression levels were significantly higher in CD8+ T cells from chronic hepatitis B patients in the immune-active phase compared with chronic asymptomatic HBV carriers and healthy controls. CD8+ T-cell function was suppressed in cells with high LAG-3 expression, and these cells exhibited reduced interferon-&ggr; (IFN-&ggr;) secretion. Furthermore, IFN-&ggr; secretion was restored in CD8+ T cells that were treated with a specific antibody to LAG-3. Taken together, liver injury was prominent in the immune-active phase, but suppressing T-cell function could mitigate this damage. Importantly, the inhibitory function of LAG-3 can be blocked using a LAG-3-specific antibody, and this can restore the activity of non-functional T cells.

Differences between the metabolic profiles of decompensated and compensated cirrhosis patients with Hepatitis B virus infections under high-performance liquid chromatography-mass spectrometry

To improve the grading and staging of liver cirrhosis among patients with HBV infection noninvasively, a high-performance liquid chromatography with mass spectrometry metabolomics method was used to investigate the potential metabolic biomarkers in the serum of patients with different degrees of hepatic cirrhosis. The results demonstrate that lysophosphatidyl choline (LPC) from positive electrospray ionization (ESI) mode, and fatty acids and bile acids from negative ESI mode play important roles in distinguishing decompensated from compensated cirrhosis. A total of 21 differential metabolites were found from the two groups of patients. LPCs, fatty acids, and taurocholic acid (TCA) 3-sulfate decreased in patients with decompensated cirrhosis, whereas other bile acids increased significantly. The levels of TCA 3-sulfate, LPC 16:0, and LPC 18:0 were significantly correlated with the stages of the decompensated cirrhosis, and they may serve as potential biomarkers for the stage assessment of liver cirrhosis in patients with HBV infections.

Inhibition of SATB1 expression in regulatory T cells contributes to hepatitis B virus-related chronic liver inflammation

Regulatory T cells (Tregs) contribute to the pathogenesis of chronic hepatitis B (CHB). Special AT-rich sequence-binding protein 1 (SATB1) may be a key component of this process. In the present study, Tregs and conventional T cells (Tconvs) were isolated by magnetic cell sorting of peripheral blood from CHB patients (n=57), individuals with resolved hepatitis B virus (HBV) infections (n=15), and healthy controls (n=29). SATB1 expression was studied by reverse transcription-quantitative PCR, flow cytometry and immunofluorescence microscopy, and the correlation of SATB1 expression to the expression of liver inflammation serum markers and the HBV DNA load was assessed. CHB patients showed significantly reduced SATB1 expression in Tregs than healthy controls and individuals with resolved HBV infections. Moreover, SATB1 expression in Tregs was significantly lower than in Tconvs of patients with chronic HBV infection. Serum HBV DNA and liver inflammation markers were inversely correlated to the SATB1 mRNA level in Tregs. Antiviral treatment was accompanied by increased expression of the SATB1 gene in Tregs. Thus, Tregs from CHB patients have reduced levels of SATB1, which is resolved with antiviral therapy. Inhibition of SATB1 expression may impair the hepatic inflammatory response and contribute to HBV persistence.

Monitoring the efficacy of infant hepatitis B vaccination and revaccination in 0- to 8-year-old children: Protective anti-HBs levels and cellular immune responses

Vaccination against hepatitis B virus (HBV) is recommended worldwide. The aim of this study was to assess the efficacy of infant hepatitis B vaccination and revaccination in 0- to 8-year-old children in the context of protective anti-HBs levels and cellular immune responses. Using a random questionnaire survey, 1695 pre-school children were recruited as research subjects during January 2015 to June 2017. Blood samples were obtained to measure HBV serological markers as well as peripheral immunocytes. The children were divided into non-, low- and hyper- responsive groups (NR, LR, and HR) based on the vaccination efficacy. Additionally, the effect of revaccination on the NR group was evaluated at 1 month after completion of the vaccination course. Among a total of 1695 children, 1591 (93.86%) were infants who were followed while undergoing their primary course of hepatitis B vaccination at the 0-1-6 month schedule, and 1249 (79.30%) of them developed antibodies against HBsAg (anti-HBs) titers greater than 10 IU/L. The results of immunocyte studies indicated that the CD8+ T cells, CD4+CD45RO+ T cells, CD8+CD45RA+ T cells, and T follicular helper (Tfh) cells increased significantly in NR compared with HR. However, lymphocytes, CD4+ T cells, and CD4+CD45RA+ T cells in NR were lower than that in HR. 96 of the non-response cases showed seroprotection after revaccination among 103 cases. Therefore, most of the preschool children who received hepatitis B vaccine in infancy achieved significant seroprotection. Seroconversion rates of individuals revaccinated after initial vaccination failure were significantly higher than those after primary vaccination. Different vaccination efficacy groups showed significant changes in circulating immunocytes, which might be a factor affecting the recombinant HBV vaccines immune effectiveness.