Diagnostic status and epidemiological characteristics of community-acquired bacterial meningitis in children from 2019 to 2020: a multicenter retrospective study.

Community-acquired bacterial meningitis (CABM) is the main cause of morbidity and mortality in children. The epidemiology of CABM is regional and highly dynamic. To clarify the diagnostic status and epidemiological characteristics of children with CABM in this region, and pay attention to the disease burden, so as to provide evidence for the prevention and treatment of CABM. By retrospective case analysis, the clinical data of 918 CABM cases in children aged 0-14 years in Zhejiang Province from January, 2019 to December, 2020 were collected. The etiological diagnosis rate of CABM in children was 23.1%, the annual incidence rate 4.42-6.15/100,000, the annual mortality rate 0.06-0.09/100,000,the cure and improvement rate 94.4%, and the case fatality rate 1.4%. The total incidence of neuroimaging abnormalities was 20.6%. The median length of stay for CABM children was 20(16) days, with an average cost of 21,531(24,835) yuan. In addition, the incidence rate was decreased with age. Escherichia coli(E.coli) and group B Streptococcus agalactiae(GBS) were the principal pathogens in CABM infant<3 months(43.3%, 34.1%), and Streptococcus pneumoniae(S. pneumoniae) was the most common pathogen in children ≥ 3 months(33.9%). In conclusion, the annual incidence and mortality of CABM in children aged 0-14 years in Zhejiang Province are at intermediate and low level. The distribution of CABM incidence and pathogen spectrum are different in age; the incidence of abnormal neuroimaging is high; and the economic burden is heavy.

Study on the Effect of Precise Prevention of H-Type Hypertension, Cardiovascular, and Cerebrovascular Risks in Qingyuan District.

Objective: To explore the relationship between controlling the development of H-type hypertension and the effectiveness of precision prevention of cardiovascular risk. Methods: 518 patients with essential hypertension with hyperhomocysteinemia diagnosed in December 2019 to February 2020 in Qingyuan District Public Hospital were recruited as the experimental sample for prospective analysis and were equally divided into control and experimental groups according to their order of admission, i.e., 259 patients in each group. The control group was treated with antihypertensive drugs only, while the experimental group was given enalapril folic acid tablets (0.8 mg/d) and vitamin B once daily in addition to antihypertensive drugs, and then monitored for plasma Hcy levels, cardiovascular event rates, and survival at one year. Results: After treatment, the plasma Hcy levels of the experimental group were significantly lower than those of the control group (P < .001). During treatment, the total incidence of cardiovascular disease in the experimental group was less than that in the control group (P < .05). One year after the end of treatment, the mortality rate due to cardiovascular disease in the control group was higher than that in the experimental group (P < .05). Conclusion: It is worthwhile to promote the use of targeted management of patients with H-type hypertension to prevent the occurrence of cardiovascular diseases, improve Hcy levels, and stabilize blood pressure levels in patients.

Advances in preparation and application of antibacterial hydrogels.

Bacterial infections, especially those caused by drug-resistant bacteria, have seriously threatened human life and health. There is urgent to develop new antibacterial agents to reduce the problem of antibiotics. Biomedical materials with good antimicrobial properties have been widely used in antibacterial applications. Among them, hydrogels have become the focus of research in the field of biomedical materials due to their unique three-dimensional network structure, high hydrophilicity, and good biocompatibility. In this review, the latest research progresses about hydrogels in recent years were summarized, mainly including the preparation methods of hydrogels and their antibacterial applications. According to their different antibacterial mechanisms, several representative antibacterial hydrogels were introduced, such as antibiotics loaded hydrogels, antibiotic-free hydrogels including metal-based hydrogels, antibacterial peptide and antibacterial polymers, stimuli-responsive smart hydrogels, and light-mediated hydrogels. In addition, we also discussed the applications and challenges of antibacterial hydrogels in biomedicine, which are expected to provide new directions and ideas for the application of hydrogels in clinical antibacterial therapy.

Analysis of Serum Inflammatory Markers in Infants Under 6 Months of Age with Non-Syndromic Moderate and Severe Hearing Loss Associated with GJB2 Gene Mutations.

BACKGROUND The GJB2 gene is reported to be the main hereditary factor responsible for non-syndromic hearing impairment in infants. Several kinds of hearing loss have been linked to elevated inflammatory markers. This study aimed to evaluate serum levels of IL-2, IL-4, IL-6, IL-10, IL-17, alpha-TNF, and γ-IFN and the severity of hearing loss. MATERIAL AND METHODS Ninety newborns were divided into 3 groups: severe hearing impairment (31 infants), moderate hearing impairment (30 infants), and normal hearing (29 infants). Hearing screening was performed using otoacoustic emissions test. Mutations of the GJB2 gene were detected with Sanger sequencing. The patients had DNFB1 mutation. Seven blood inflammatory markers were tested using Cytometric Bead Array. We performed the t test to examine differences in expression of 7 inflammatory markers between sexes in the groups. The correlation between indicators within groups was studied using the Pearson correlation test. Correlation of different indicators among groups was studied using the Spearman correlation test. RESULTS When compared among the 3 groups (severe, moderate hearing impairment, and normal hearing group), we found that IL-10 had a positive correlation with the severity of GJB2-associated hearing loss, which was statistically significant (P<0.05). CONCLUSIONS This research aimed to assess the relationship of 7 serum inflammatory markers with GJB2-associated hearing loss in infants. Inflammatory marker IL-10 had a positive correlation with the severity of GJB2-associated infant hearing loss, and it might have the potential to become a future therapeutic target.

Factors associated with afebrile presentation and delayed defervescence of bacterial meningitis in children under 3 years of age: a multi-centre retrospective analysis.

BACKGROUND: This multi-center study aimed to identify factors affecting fever and delayed defervescence in bacterial meningitis (BM) patients under 3 years of age because of the variability of fever in this patient population. METHODS: Only BM patients under 3 years treated at 49 centers in China from November 2018 to end-April 2021 were included in the study. Univariate and multivariate logistic regression analyses were performed to determine factors associated with afebrile presentation and fever of delayed defervescence. RESULTS: A total of 863 BM patients under 3 years were included in the study. Coagulase negative staphylococcus was associated with afebrile presentation (OR = 1.176), while septicaemia and ear-nose-throat infections were associated with fever (P < 0.05). The patients with fever were assigned into early and delayed defervescence groups based on defervescence time (less than and more than or equal to one week). Furthermore, Streptococcus agalactiae meningitis (OR = 1.124), concomitant gastrointestinal infection (OR = 1.276), encephalomalacia (or = 1.339), and subdural effusion (OR = 1.454) were independently associated with delayed defervescence (all P < 0.05). CONCLUSIONS: The findings can aid in the efficient utilization of fever in auxiliary diagnosis and evaluating the condition of the disease.

Bispecific targeting of CD20 and CD19 increases polyfunctionality of chimeric antigen receptor T-cell products in B-cell malignancies.

BACKGROUND AIMS: Selective immune pressure contributes to relapse due to target antigen downregulation in patients treated with anti-CD19 chimeric antigen receptor (CAR) T cells. Bispecific lentiviral anti-CD20/anti-CD19 (LV20.19) CAR T cells may prevent progression/relapse due to antigen escape. Highly polyfunctional T cells within a CAR T-cell product have been associated with response in single-antigen-targeted anti-CD19 CAR T cells. METHODS: The authors performed a single-cell proteomic analysis to assess polyfunctional cells in our LV20.19 CAR T-cell product. Analysis was limited to those treated at a fixed dose of 2.5 × 106 cells/kg (n = 16). Unused pre-infusion CAR T cells were thawed, sorted into CD4/CD8 subsets and stimulated with K562 cells transduced to express CD19 or CD20. Single-cell production of 32 individual analytes was measured and polyfunctionality and polyfunctional strength index (PSI) were calculated. RESULTS: Fifteen patients had adequate leftover cells for analysis upon stimulation with CD19, and nine patients had adequate leftover cells for analysis upon stimulation with CD20. For LV20.19 CAR T cells, PSI was 866-1109 and polyfunctionality was 40-45%, which were higher than previously reported values for other CAR T-cell products. CONCLUSIONS: Stimulation with either CD19 or CD20 antigens resulted in similar levels of analyte activation, suggesting that this product may have efficacy in CD19- patient populations.

Alcohol consumption and smoking in relation to psoriasis: a Mendelian randomization study.

BACKGROUND: Alcohol consumption and smoking have been reported to be associated with psoriasis risk. However, a conclusion with high-quality evidence of causality could not be easily drawn from regular observational studies. OBJECTIVES: This study aims to assess the causal associations of alcohol consumption and smoking with psoriasis. METHODS: Genome-wide association study (GWAS) summary-level data for alcohol consumption (N = 941 280), smoking initiation (N = 1 232 091), cigarettes per day (N = 337 334) and smoking cessation (N = 547 219) was obtained from the GSCAN consortium (Sequencing Consortium of Alcohol and Nicotine use). The GWAS results for lifetime smoking (N = 462 690) were obtained from the UK Biobank samples. Summary statistics for psoriasis were obtained from a recent GWAS meta-analysis of eight cohorts comprising 19 032 cases and 286 769 controls and the FinnGen consortium, comprising 4510 cases and 212 242 controls. Linkage disequilibrium score regression was applied to compute the genetic correlation. Bidirectional Mendelian randomization (MR) analyses were conducted to determine casual direction using independent genetic variants that reached genome-wide significance (P < 5 × 10-8 ). RESULTS: There were genetic correlations between smoking and psoriasis. MR revealed a causal effect of smoking initiation [odds ratio (OR) 1·46, 95% confidence interval (CI) 1·32-1·60, P = 6·24E-14], cigarettes per day (OR 1·38, 95% CI 1·13-1·67, P = 0·001) and lifetime smoking (OR 1·96, 95% CI 1·41-2·73, P = 7·32E-05) on psoriasis. Additionally, a suggestive causal effect of smoking cessation on psoriasis was observed (OR 1·39, 95% CI 1·07-1·79, P = 0·012). We found no causal relationship between alcohol consumption and psoriasis (P = 0·379). The reverse associations were not statistically significant. CONCLUSIONS: Our findings provide causal evidence for the effects of smoking on psoriasis risk. What is already known about this topic? Alcohol consumption and smoking have been reported to be associated with psoriasis risk. Whether alcohol consumption and smoking have a causal effect on psoriasis risk remains unclear. What does this study add? This Mendelian randomization study shows a causal association between smoking, but not alcohol consumption, and the risk of developing psoriasis. Restricting smoking could be helpful in reducing the burden of psoriasis.

Long-term outcomes and predictors of early response, late relapse, and survival for patients treated with bispecific LV20.19 CAR T-cells.

We previously reported results of a first-in-human trial of bispecific LV20.19 chimeric antigen receptor T-cell (CAR-T) therapy, demonstrating high response rates in patients with relapsed, refractory (R/R) B-cell malignancies. We now report two-year survival outcomes and predictors of early response, late relapse, and survival. Patients from the previously reported phase 1 dose escalation and expansion trial of LV20.19 CAR-T therapy (NCT03019055) treated at target dose of 2.5 × 106 cells/kg (n = 16) were included in this updated analysis. Two-year progression-free survival (PFS) and overall survival (OS) were estimated using Kaplan-Meier method. The relationship of in-vivo CAR-T expansion, tumor burden, and effector: target ratio on early response (day 28) and late relapse (>180 days post-CAR-T) were assessed. Exact log-rank testing was performed to evaluate the impacts of clinical variables on survival outcomes. With a median of 31 months (range 27-40) of follow-up, two-year PFS and OS were 44% and 69%. Median PFS and OS were 15.6 months and not reached, respectively. For CAR-naïve large B-cell lymphoma patients (n = 8), two-year PFS and OS were 50% and 75%. No patient with progression experienced dual target antigen (CD19 or CD20) loss on post-relapse biopsy. Lower in vivo expansion was strongly associated with late relapse. Early treatment response was impeded by high metabolic tumor volume and low effector: target ratio. Bridging therapy and higher absolute lymphocyte count on day of CAR-T infusion were associated with inferior survival outcomes. In conclusion, this initial trial of LV20.19 CAR-T demonstrates a signal for favorable long-term outcomes for patients with R/R B-cell malignancies.

A CNN-Based Length-Aware Cascade Road Damage Detection Approach.

Accurate and robust detection of road damage is essential for public transportation safety. Currently, deep convolutional neural networks (CNNs)-based road damage detection algorithms to localize and classify damage with a bounding box have achieved remarkable progress. However, research in this field fails to take into account two key characteristics of road damage: weak semantic information and abnormal geometric properties, resulting in inappropriate feature representation and suboptimal detection results. To boost the performance, we propose a CNN-based cascaded damage detection network, called CrdNet. The proposed model has three parts: (1) We introduce a novel backbone network, named LrNet, that reuses low-level features and mixes suitable range dependency features to learn high-to-low level feature fusions for road damage weak semantic information representation. (2) We apply multi-scale and multiple aspect ratios anchor mechanism to generate high-quality positive samples regarding the damage with abnormal geometric properties for network training. (3) We designed an adaptive proposal assignment strategy and performed cascade predictions on corresponding branches that can establish different range dependencies. The experiments show that the proposed method achieves mean average precision (mAP) of 90.92% on a collected road damage dataset, demonstrating the good performance and robustness of the model.

Differential diagnosis between hepatic alveolar echinococcosis and intrahepatic cholangiocarcinoma with conventional ultrasound and contrast-enhanced ultrasound.

BACKGROUND: Misclassifications of hepatic alveolar echinococcosis (HAE) as intrahepatic cholangiocarcinoma (ICC) may lead to inappropriate treatment strategies. The aim of this study was to explore the differential diagnosis with conventional ultrasound and contrast-enhanced ultrasound (CEUS). METHODS: Sixty HAE lesions with 60 propensity score-matched ICC lesions were retrospectively collected. The 120 lesions were randomly divided into a training set (n = 80) and a testing set (n = 40). In the training set, the most useful independent conventional ultrasound and CEUS features was selected for differentiating between HAE and ICC. Then, a simplified US scoring system for diagnosing HAE was constructed based on selected features with weighted coefficients. The constructed US score for HAE was validated in both the training set and the testing set, and diagnostic performance was evaluated. RESULTS: Compared with ICC lesions, HAE lesions were mostly located in the right lobe and had mixed echogenicity, a pseudocystic appearance and foci calcifications on conventional ultrasound. On CEUS, HAE lesions showed more regular rim-like enhancement than ICC lesions and had late washout with a long enhancement duration. The simplified US score consisted of echogenicity, pseudocystic/calcification, bile duct dilatation, enhancement pattern, enhancement duration, and marked washout. In the testing set, the sensitivity, specificity, LR+, LR- and the area under the ROC curve for the score to differentiate HAE from ICC were 80.0, 81.3%, 4.27, 0.25 and 0.905, respectively. CONCLUSIONS: The US score based on typical features from both conventional ultrasound and CEUS could accurately differentiate HAE from ICC.

Closed-system manufacturing of CD19 and dual-targeted CD20/19 chimeric antigen receptor T cells using the CliniMACS Prodigy device at an academic medical center.

BACKGROUND AIMS: Multiple steps are required to produce chimeric antigen receptor (CAR)-T cells, involving subset enrichment or depletion, activation, gene transduction and expansion. Open processing steps that increase risk of contamination and production failure are required. This complex process requires skilled personnel and costly clean-room facilities and infrastructure. Simplified, reproducible CAR-T-cell manufacturing with reduced labor intensity within a closed-system is highly desirable for increased availability for patients. METHODS: The CliniMACS Prodigy with TCT process software and the TS520 tubing set that allows closed-system processing for cell enrichment, transduction, washing and expansion was used. We used MACS-CD4 and CD8-MicroBeads for enrichment, TransAct CD3/CD28 reagent for activation, lentiviral CD8 TM-41BB-CD3 ζ-cfrag vectors expressing scFv for CD19 or CD20/CD19 antigens for transduction, TexMACS medium-3%-HS-IL2 for culture and phosphate-buffered saline/ethylenediaminetetraacetic acid buffer for washing. Processing time was 13 days. RESULTS: Enrichment (N = 7) resulted in CD4/CD8 purity of 98 ± 4.0%, 55 ± 6% recovery and CD3+ T-cell purity of 89 ± 10%. Vectors at multiplicity of infection 5-10 resulted in transduction averaging 37%. An average 30-fold expansion of 108 CD4/CD8-enriched cells resulted in sufficient transduced T cells for clinical use. CAR-T cells were 82-100% CD3+ with a mix of CD4+ and CD8+ cells that primarily expressed an effector-memory or central-memory phenotype. Functional testing demonstrated recognition of B-cells and for the CAR-20/19 T cells, CD19 and CD20 single transfectants were recognized in cytotoxic T lymphocyte and interferon-γ production assays. DISCUSSION: The CliniMACS Prodigy device, tubing set TS520 and TCT software allow CAR-T cells to be manufactured in a closed system at the treatment site without need for clean-room facilities and related infrastructure.

[Clinical effect of pidotimod oral liquid as adjuvant therapy for infectious mononucleosis].

OBJECTIVE: To study the clinical effect of pidotimod oral liquid as adjuvant therapy for infectious mononucleosis and its effect on T lymphocyte subsets. METHODS: A total of 76 children with infectious mononucleosis, who were admitted to the hospital between July 2016 and June 2017, were enrolled and randomly divided into two groups: conventional treatment and pidotimod treatment (n=38 each). The children in the conventional treatment group were given antiviral therapy with ganciclovir for injection and symptomatic treatment. Those in the pidotimod treatment group were given pidotimod oral liquid in addition to the treatment in the conventional treatment group. The course of treatment was two weeks for both groups. The two groups were compared in terms of the recovery of clinical indices and the changes in peripheral blood T lymphocyte subsets. RESULTS: Compared with the conventional treatment group, the pidotimod treatment group had significantly shorter fever clearance time, time to the disappearance of isthmopyra, time to the relief of lymph node enlargement, time to the relief of hepatosplenomegaly, and length of hospital stay (P<0.05). After treatment, the pidotimod treatment group had significant reductions in the percentages of CD3+ and CD8+ T cells and had significantly lower percentages of CD3+ and CD8+ T cells than the conventional treatment group (P<0.001). The pidotimod treatment group had significant increases in the percentage of CD4+ T cells and CD4+/CD8+ ratio after treatment, which was significantly higher than those in the conventional treatment group (P<0.001). The conventional treatment group had no significant changes in T lymphocyte subsets after treatment (P>0.05). CONCLUSIONS: Pidotimod oral liquid has a good clinical effect as the adjuvant therapy for infectious mononucleosis and can improve cellular immune function, so it holds promise for clinical application.

[A Retrospective Analysis on 47 Children with Paragonimiasis in Ningbo City].

A retrospective analysis was performed on 47 children diagnosed with paragonimiasis in Ningbo Women and Children's Hospital from January 2004 to December 2014. The 47 children comprised 32 boys （68.1%） and 15 girls （48.9%）, and 24 cases（51.1%） in urban areas and 23 （48.9%） in rural areas （P>0.05）. There was a trend of increase in paragonimiasis occurrence in preschoolers since 2010. Forty-three cases had a history of eating raw or wine-preserved crabs and 4 cases had a history of drinking raw stream water． There were 2 cases of paragonimus encephalopathy and one case accompanied by subcutaneous nodules. Thirty-nine cases showed increases in eosinophil number and proportion in peripheral blood, and 29 cases showed increased serum IgE level. Forty-seven cases had negative results for detection of paragonimus eggs in sputum and stool. The dot immuno-gold filtration-assay and ELISA showed a 100% positive rate for paragonimus serum antibody. All the 47 cases were administered with praziquantel after diagnosis, and no adverse effect was reported during the treatment.

Transcriptome response of Lactobacillus sakei to meat protein environment.

Lactobacillus sakei is a heterofermentative species of lactic acid bacteria that is used in industrial meat fermentation. To investigate adaptation in a meat environment, whole-genome DNA microarrays were used to analyze the gene expression related to growth and survival of L. sakei strain La22 when grown in sarcoplasmic (S-) or myofibrillar (M-) protein-supplemented chemically defined medium (CDM). Differential expression was detected in 551 genes. Genes encoding enzymes involved in peptide hydrolysis were differentially upregulated in M-CDM or/and S-CDM, and only oppB and oppC, involved in the amino acid and peptide transport system, were upregulated. Most genes related to metabolism of peptides, amino acids and related molecules were over-expressed in M-CDM and S-CDM, except for glnA and metK. Expression of certain genes was according to the differential substrate environment. The expression of genes involved in the stress response was not induced by growth in M-CDM.

Effects of Transglutaminase-Induced ß-Conglycinin Gels on Intestinal Morphology and Intestinal Flora in Mice at Different High-Intensity Ultrasound Pretreatment Time.

TGase-7S gels prepared after different HIU pretreatment times were used to intervene in healthy mice to analyze their effects on growth characteristics and intestinal morphology, and 16S rRNA high-throughput sequencing was applied to fecal samples to investigate the effects of the gel on the structure and diversity of intestinal flora in mice. The results showed that the intestinal tissues of mice in different treatment groups showed better integrity, and the intake of gel increased the length of small intestinal villi in mice, among which the 30-gel group had the highest value of villi length (599.27 ± 44.28) µm (p < 0.05) and showed the neatest and tightest arrangement, indicating that the intake of gel did not have adverse effects on the intestinal tract. The effect of gel ingestion on the diversity of the intestinal microbial community structure was more significant, positively promoting the growth of beneficial bacteria such as Desferriobacterium, Synechococcus, and Bifidobacterium. In addition, the ingestion of the gel improved the intestinal health of mice by altering the physiological functions of the intestinal flora and modulating their participation in various metabolic pathways. The above findings provide some theoretical value for the safety of 7S gel in food applications.

A potential pathway for identifying hypertension among urban residents aged 60+ years in China: the role of health insurance.

Background: Identification is the first step for treatment of hypertension. However, the awareness rate of hypertension was not high globally. This study aimed to examine the potential role of health insurance for early-identifying hypertension among urban older residents in China. Methods: In this cross-sectional study, urban residents aged 60+ years were chosen from Nanjing municipality of China in 2018. The outcome measure was hypertension status ("no hypertension," "diagnosed hypertension" or "un-diagnosed hypertension"). Independent variable was health insurance ("Urban Employee Basic Medical Insurance scheme, UEBMI" or "Urban Resident Basic Medical Insurance scheme, URBMI"). Logistic regression models were introduced to estimate odds ratio (OR) and 95% confidence interval (CI) to examine the association between health insurance and hypertension. Results: Totally, 19,742 participants completed the study. Among overall, URBMI and UEBMI participants, 47.2% (95%CI = 46.5, 47.9%), 38.4% (95%CI = 37.3, 39.6%) and 52.1% (95%CI = 51.2, 53.0%), separately, were diagnosed with hypertension, while the prevalence of un-diagnosed hypertension was 12.7% (95%CI = 12.2, 13.2%), 18.5% (95%CI = 17.6, 19.4%) and 9.6% (95%CI = 9.1, 10.1%), respectively. For overall participants, those with UEBMI were more likely to have hypertension identified (OR = 1.20; 95%CI = 1.11, 1.29) and at lower odds to experience un-diagnosed hypertension (OR = 0.68; 95%CI = 0.61, 0.76) compared to their counterparts with URBMI after control for potential confounders. Moreover, such associations of health insurance with diagnosed and un-diagnosed hypertension were also observed among participants stratified by age and gender. Conclusion: Favorable health insurance may be a pathway for identifying hypertension among urban older residents in China. This study has important public health implications that hypertension may be identified early through favorable health insurance policies for older residents in China.

RfaH promotes the ability of the avian pathogenic Escherichia coli O2 strain E058 to cause avian colibacillosis.

Avian pathogenic Escherichia coli (APEC) infection causes avian colibacillosis, which refers to any localized or systemic infection, such as acute fatal septicemia or subacute pericarditis and airsacculitis. The RfaH transcriptional regulator in E. coli is known to regulate a number of phenotypic traits. The direct effect of RfaH on the virulence of APEC has not been investigated yet. Our results showed that the inactivation of rfaH significantly decreased the virulence of APEC E058. The attenuation was assessed by in vivo and in vitro assays, including chicken infection assays, an ingestion and intracellular survival assay, and a bactericidal assay with serum complement. The virulence phenotype was restored to resemble that of the wild type by complementation of the rfaH gene in trans. The results of the quantitative real-time reverse transcription-PCR (qRT-PCR) analysis and animal system infection experiments indicated that the deletion of rfaH correlated with decreased virulence of the APEC E058 strain.

The transfer-messenger RNA-small protein B system plays a role in avian pathogenic Escherichia coli pathogenicity.

Extraintestinal pathogenic Escherichia coli (ExPEC) is capable of colonizing outside of the intestinal tract and evolving into a systemic infection. Avian pathogenic E. coli (APEC) is a member of the ExPEC group and causes avian colibacillosis. Transfer-mRNA-small protein B (tmRNA-SmpB)-mediated trans-translation is a bacterial translational control system that directs the modification and degradation of proteins, the biosynthesis of which has stalled or has been interrupted, facilitating the rescue of ribosomes stalled at the 3' ends of defective mRNAs that lack a stop codon. We found that disruption of one, or both, of the smpB or ssrA genes significantly decreased the virulence of the APEC strain E058, as assessed by chicken infection assays. Furthermore, the mutants were obviously attenuated in colonization and persistence assays. The results of quantitative real-time reverse transcription-PCR analysis indicated that the transcription levels of the transcriptional regulation gene rfaH and the virulence genes kpsM, chuA, and iss were significantly decreased compared to those of the wild-type strain. Macrophage infection assays showed that the mutant strains reduced the replication and/or survival ability in the macrophage HD11 cell line compared to that of the parent strain, E058. However, no significant differences were observed in ingestion by macrophages and in chicken serum resistance between the mutant and the wild-type strains. These data indicate that the tmRNA-SmpB system is important in the pathogenesis of APEC O2 strain E058.

[Construction of aerobactin and sit operon mutant of avian pathogenic Escherichia coli E058 and evaluation of its pathogenicity].

OBJECTIVE: To elucidate the pathogenesis role of the vir region of APEC 02 strain E058. METHODS: The gene aerobactin/sitABC operon knockout mutants E058deltavir of APEC E058 strain was generated using Red recombination system. A series of pathogenicity tests including chick embryo inoculation, the competition experiment and the colonization and persistence in vivo were used to evaluate the pathogenicity of APEC E058deltavir and the wild-type strain E058. RESULTS: E058deltavir was similar to its parental strain E058 in the growth curves, invasion assays of HD-11 cell and in vitro competition assay. In the colonization and persistence test, the recovery colonies of E058deltavir were significantly decreased in all of the organs tested (P < 0.001). CONCLUSIONS: These results indicate that the virulence factors encoded by aerobactin/sit operon genes were important for the pathogenesis of APEC E058.

UHRF1-induced connexin26 methylation is involved in hearing damage triggered by intermittent hypoxia in neonatal rats.

Ubiquitin-like with plant homeodomain and ring finger domains 1 (UHRF1) promotes the maintenance of established patterns of DNA methylation in mammalian cells. Extensive methylation of connexin26 (COX26) during hearing impairment has been demonstrated. The present study aims to determine whether UHRF1 can induce the methylation of COX26 in cochlea damaged by intermittent hypoxia (IH). After the establishment of the cochlear injury model through IH treatment or isolation of the cochlea containing Corti's organ, pathological changes were observed via HE staining. Expressions of COX26 and UHRF1 were detected by quantitative reverse-transcription polymerase chain reaction and Western blot. The effect of COX26 methylation levels was analyzed by methylation-specific PCR (MSP). Phalloidin/immunofluorescence staining was used to observe structural changes. The binding relationship between UHRF1 and COX26 was verified by chromatin immunoprecipitation. IH caused cochlear damage, accompanied by increased methylation of COX26 and expression of UHRF1 in the cochlea of neonatal rats. CoCl2 treatment caused the loss of cochlear hair cells, downregulation and hypermethylation of COX26, abnormal upregulation of UHRF1, and disordered expressions of apoptosis-related proteins. UHRF1 in cochlear hair cells binds to COX26, and its knockdown upregulated COX26 level. Overexpressed COX26 partially alleviated the CoCl2-caused cell damage. UHRF1 induces COX26 methylation and aggravates the cochlear damage caused by IH.