To kill or to be killed: pangenome analysis of Escherichia coli strains reveals a tailocin specific for pandemic ST131.

BACKGROUND: Escherichia coli (E. coli) has been one of the most studied model organisms in the history of life sciences. Initially thought just to be commensal bacteria, E. coli has shown wide phenotypic diversity including pathogenic isolates with great relevance to public health. Though pangenome analysis has been attempted several times, there is no systematic functional characterization of the E. coli subgroups according to the gene profile. RESULTS: Systematically scanning for optimal parametrization, we have built the E. coli pangenome from 1324 complete genomes. The pangenome size is estimated to be ~25,000 gene families (GFs). Whereas the core genome diminishes as more genomes are added, the softcore genome (≥95% of strains) is stable with ~3000 GFs regardless of the total number of genomes. Apparently, the softcore genome (with a 92% or 95% generation threshold) can define the genome of a bacterial species listing the critically relevant, evolutionarily most conserved or important classes of GFs. Unsupervised clustering of common E. coli sequence types using the presence/absence GF matrix reveals distinct characteristics of E. coli phylogroups B1, B2, and E. We highlight the bi-lineage nature of B1, the variation of the secretion and of the iron acquisition systems in ST11 (E), and the incorporation of a highly conserved prophage into the genome of ST131 (B2). The tail structure of the prophage is evolutionarily related to R2-pyocin (a tailocin) from Pseudomonas aeruginosa PAO1. We hypothesize that this molecular machinery is highly likely to play an important role in protecting its own colonies; thus, contributing towards the rapid rise of pandemic E. coli ST131. CONCLUSIONS: This study has explored the optimized pangenome development in E. coli. We provide complete GF lists and the pangenome matrix as supplementary data for further studies. We identified biological characteristics of different E. coli subtypes, specifically for phylogroups B1, B2, and E. We found an operon-like genome region coding for a tailocin specific for ST131 strains. The latter is a potential killer weapon providing pandemic E. coli ST131 with an advantage in inter-bacterial competition and, suggestively, explains their dominance as human pathogen among E. coli strains.

Prevalence and associated factors of depression and anxiety symptoms among college students: a systematic review and meta-analysis.

BACKGROUND: To evaluate the global prevalence of depression and anxiety symptoms among college students and potential associated factors. METHODS: PubMed and Web of Science were searched from their inception to March 28, 2021. Random-effects models were used to calculate the pooled prevalence of depression and anxiety. Subgroup analyses were conducted to explore potential heterogeneity. Egger's and Begg's test were used to assess publication bias. RESULTS: A total of 64 studies with 100,187 individuals were included in the present meta-analysis. The pooled prevalence of depression and anxiety symptoms among college students was 33.6% (95% confidence interval [CI] 29.3%-37.8%) and 39.0% (95% CI, 34.6%-43.4%), respectively. The highest prevalence of depression symptoms was found in Africa region (40.1%, 95% CI 12.3-67.9%), lower middle-income countries (42.5%, 95% CI 28.6-56.3%), and medical college students (39.4%, 95% CI 29.3-49.6%). For the prevalence of anxiety symptoms, the highest was observed in North America (48.3%, 95% CI 37.4-59.2%), lower middle-income countries (54.2%, 95% CI 35.0-73.4%), medical college students (47.1%, 95% CI 35.1-59.1%) and identified by Beck Anxiety Inventory (BAI) (49.1%, 95% CI 31.0-43.0%). Besides, the prevalence of depression symptoms (35.9%, 95% CI 20.2-51.7%) and anxiety symptoms (40.7%, 95% CI 39.5-42.0%) was higher in studies conducted after the coronavirus disease 2019 (COVID-19) outbreak. CONCLUSIONS: Our study suggests that a lot of college students experience depression and anxiety symptoms and clarifies factors that are related to these mental disorders. Effective prevention and intervention strategies for mental disorders should be developed among college students.

The prevalence and global burden of hearing loss in 204 countries and territories, 1990-2019.

We aimed to describe the global prevalence and temporal trends of hearing loss. We collected detailed information of hearing loss from the Global Burden of Disease study between 1990 and 2019. Average annual percentage changes (AAPCs) in hearing loss age-standardized prevalence rate (ASPR), by sex, region, and category, were calculated to quantify the temporal prevalence trends. Globally, the prevalent cases of hearing loss increased from 7514.97×105 in 1990 to 14566.62×105 in 2019, and the ASPR increased from 173.33×102 per 100,000 in 1990 to 177.56×102 per 100,000 in 2019. The years lived with disability (YLDs) increased from 220080.97×102 in 1990 to 402353.05×102 in 2019. The AAPC was 83.27 (95% CI 70.66, 95.88) ×10-3 in prevalence and -72.87 (95% CI -92.18, -53.56) ×10-3 in YLDs. Significant correlations of AAPCs with ASPR (r=-0.60, p<0.001), and age-standardized YLD rate (r=-0.43, p=0.0012 for YLD<455, r=0.32, p<0.001 for YLD≥455) were detected. The YLDs of hearing loss owing to occupational noise (HLOON) increased from 39334.39 (95% UI 26881.04, 55999.67) ×102 in 1990 to 70014.49 (98% UI 47605.62, 100593.43) ×102 in 2019, and the increasing AAPC was observed for females and aged between 15 and 49 years old in global and most regions. The age effect was under zero in 7 age groups, the period effect of hearing loss prevalence was increasing and the birth cohort effect was decreasing with the time advance. The number of cases and ASPR of hearing loss in the world is still growing. Efforts to control hearing loss, especially HLOON, are imminent.

Association between locus of control and health risk behaviors among college students / 中国学校卫生

Objective@#To explore the prevalence of health risk behaviors and the association between locus of control and health risk behaviors among college students, and to provide reference for the formulation of health risk behavior intervention for college students.@*Methods@#A multi stage cluster random sampling method was used to select 2 provinces from the east, central and west regions of China, respectively. Two universities were then randomly selected from each selected province. A total of 3 951 college students from 12 universities completed the electronic and anonymous questionnaires, which included demographic characteristics, Multidimensional Health Locus of Control Questionnaire (MHLC) and Health Risk Behaviors Questionnaire. Chi square test and binary Logistic regression were applied to analyze data.@*Results@#Totally 2 287(57.88%) students reported having three or more kinds of health risk behaviors. The prevalence of excessive screen time, insufficient physical exercise, poor eating behaviors, drinking and smoking were 97.34%(3 846), 74.72%(2 952), 72.21%(2 853), 13.62%(538) and 5.57%(220). Internal locus of control was associated with lower risk of three or more kinds of health risk behavior ( OR =0.98) and inadequate physical activity ( OR =0.93) and associated with higher risk of smoking ( OR =1.07). The powerful others was associated with lower risk of three or more kinds of health risk behavior ( OR =0.98), drinking ( OR =0.95) and unhealthy eating behavior ( OR =0.97). And the chance was associated with higher risk of three or more kinds of health risk behavior ( OR = 1.04 ), drinking ( OR =1.04) and inadequate physical activity ( OR =1.03)( P <0.01).@*Conclusion@#College students have serious health risk behavior problems, the locus of control is associated with health risk behaviors among college students. Which might be helpful to prevent the occurrence of health risk behaviors, and improve overall health of college students.

Prevalence of hearing loss and influencing factors among workers in Wuhan, China.

We aimed to estimate the prevalence of hearing loss and influencing factors among workers in automobile manufacturing industry in Wuhan, China. We conducted cross-sectional analyses of 2017 through 2019 data from survey of the key occupational diseases on 17,176 workers in automobile manufacturing industry, Wuhan, China. Hearing loss was defined as a pure tone mean of 25 dB or higher in either ear at 0.5, 1, and 2 kHz for speech frequency and at 3, 4, and 6 kHz for high frequency. Among the 17,176 workers, more than a quarter of participants had high frequency hearing loss, and 6.41% had speech frequency hearing loss. The prevalence of hearing loss was higher among participants with diabetes mellitus and current smoking, temporary tinnitus, and sudden change in hearing. Compared with the controls, age (OR = 1.08, 95% CI = 1.08-1.09), male (OR = 1.40, 95% CI = 1.21-1.63), occupational noise exposure (OR = 1.19, 95% CI = 1.08-1.30), having temporary tinnitus (OR = 1.20, 95% CI = 1.08-1.33), and having sudden change in hearing (OR = 1.58, 95% CI = 1.20-2.08) were associated with higher prevalence of high frequency hearing loss; meanwhile, age (OR = 1.09, 95% CI = 1.08-1.09), male (OR = 1.38, 95% CI = 1.11-1.71), having family history of hearing loss (OR = 2.84, 95% CI = 1.35-5.97), and having sudden change in hearing (OR = 2.58, 95% CI = 1.80-3.70) were associated with higher prevalence of speech frequency hearing loss. No additive and multiplicative interaction was found between occupational noise and these factors for hearing loss. Hearing loss directly affects 25% of workers in automobile manufacturing industry in Wuhan. Measures should be implemented for the control of occupational noise and other factors simultaneously in the workplace.

Anxiety, Depression, and Satisfaction With Life Among College Students in China: Nine Months After Initiation of the Outbreak of COVID-19.

BACKGROUND/OBJECTIVE: Mental health problems are common among college students. This study sought to assess the prevalence and risk factors of depressive and anxiety symptoms and well-being among Chinese college students 9 months after initiation of the outbreak of COVID-19. METHOD: A cross-sectional study (N = 3,951, mean age = 19.58) was conducted from October to December 2020. An online survey was used to collect socio-demographic data, and the symptoms of depression and anxiety and satisfaction with life using Disorder 7-Item Scale (GAD-7), the Patient Health Questionnaire 9-Item Scale (PHQ-9), and the 5-items Satisfaction with Life Scale (SWLS). RESULTS: The prevalence of depressive and anxiety symptoms was 59.35 and 54.34%, respectively, and the score of satisfaction with life was 20.51 ± 6.42 among Chinese college students during the pandemic. After controlling for covariates, students in urban areas (AOR = 0.73, 95% CI = 0.61-0.87), with good family economic levels (AOR = 0.77, 95% CI = 0.66-0.91), and having psychological counseling (AOR = 0.55, 95% CI = 0.42-0.73) were positively associated with depression symptoms; meanwhile, higher anxiety symptoms were observed among medical students (AOR = 0.81, 95% CI = 0.69-0.95). Besides, healthy lifestyle such as regular physical activity and diet was associated with depression and anxiety symptoms. Multiple linear models revealed that medical students (ß = 0.479, P = 0.031), those with good family economic level by self-evaluation (ß = 1.283, P < 0.001 for good; ß = 3.013, P < 0.001 for general), good academic performance by self-evaluation (ß = 1.786, P < 0.001 for good; ß = 3.386, P < 0.001 for general), learning burden (ß = 1.607, P < 0.001 for general; ß = 2.117, P < 0.001 for light), regular physical activity (ß = 0.859, P < 0.001), daily routine (ß = 1.289, P < 0.001), diet (ß = 1.714, P < 0.001), and sufficient sleep (ß = 1.408, P < 0.001) had more score of SWLS (all ß > 0, P < 0.05), while senior students (ß = -1.053, P=0.009), students having psychological counseling (ß = -1.753, P < 0.001), and drinking (ß = -0.743, P = 0.012) had lower satisfaction with life. CONCLUSIONS: These findings suggest that more attention should be paid to psychological health among college students, especially during and after the COVID-19 outbreak. Policy makers and educators should help college students develop a healthy lifestyle with regular diet and exercise to promote the psychological health of college students.

[An immunofluorescence assay for the detection of SARS associated coronavirus antibody based on recombinant nucleocapsid antigen and its application].

OBJECTIVE: To establish a new technique for SARS-CoV antibody test to detect infection of severer acute respiratory syndrome (SARS). METHODS: Nucleocapsid gene was obtained by reverse transcription and polymerase chain reaction from a SARS patient and inserted into the vector pFastBacHTa expressing baculovirus. Insect Sf9 cells were transfected with the recombinant baculovirus expressing SARS nucleocapsid antigen and then cultured, fixed by acetone so as to make SARS-specific antigen. Immunofluorescence assay (IFA) technique and plaque reduction neutralization test (PRNT) were used to detect 7 samples of sera of 4 newly diagnosed SARS patients collected in different days, 48 samples of convalescent sera of SARS patients, 24 serum samples of healthy person undergoing physical examination, and 40 serum samples from non-SARS patients with fever by double blind test. RESULTS: The recombinant SARS-specific antigen reacted only with SARS positive sera but not with normal sera. Double blind test showed that 45 of the 46 PRNT positive sera were IFA positive with an accordance rate of 97.8%. 7 samples of sera from 4 SARS patients in acute progressive stage in Guangdong province were all IFA positive. SARS antibody could be detected since the sixth day after onset, and the titer increased from 1:40 to 1:600 on the ninth day. CONCLUSION: Immunofluorescence assay is highly specific and sensitive in detection of SARS. This reagent is safe and easy to prepare.

[Serological surveillance on vaccine against hemorrhagic fever with renal syndrome].

OBJECTIVE: To observe the serological and epidemiological efficacy of hemorrhagic fever renal syndrome (HFRS) vaccine in Zhejiang province. METHODS: Immunofluorescent antibody assay and Mcro-CPE method were used to test specific IgG antibody and the titer of neutralizing antibody. RESULTS: Two weeks after the injection of the third dose, the sero-conversion rates by both immunofluorescent antibody test (IgG) and neutralization test were 100.0% (67/67) (95% CI: 96.3 - 100.0) and 44.4% (8/18)(95% CI: 22.0 - 69.0) with geometric mean titers (GMTs) 72.1 and 4.6 respectively. The rates of seroconversion of immunofluorescent antibody by immunofluorescence antibody assay (IFA) were 28.6%, 83.3%, 75.0%, 53.1%, 22.6%, 10.0% and 55.0% before reinforcement, two weeks, one year, one year and a half years, two years, three years and five years after reinforcement. The rates of neutralizing antibody seroconversion by the Mcro-CPE method were found as 14.8%, 55.6%, 35.0%, 31.3%, 26.0%, 10.0% and 50.0% respectively. We found some antibody dependent immunization enhancement phenomenon among the inoculated population, but further observation was needed. CONCLUSION: HFRS vaccine was immunologically effective and the duration of serous antibody last long.