Estimation of Incubation Period and Serial Interval for SARS-CoV-2 in Jiangxi, China, and an Updated Meta-Analysis.

INTRODUCTION: This paper aims to estimate the incubation period and serial intervals for SARS-CoV-2 based on confirmed cases in Jiangxi Province of China and meta-analysis method. METHODOLOGY: Distributions of incubation period and serial interval of Jiangxi epidemic data were fitted by "fitdistrplus" package of R software, and the meta-analysis was conducted by "meta" package of R software. RESULTS: Based on the epidemic data of Jiangxi, we found the median days of incubation period and serial interval were 5.9 days [IQR: 3.8 - 8.6] and 5.7 days [IQR: 3.6 - 8.3], respectively. The median days of the infectivity period at pre-symptomatic was 1.7 days [IQR: 1.1 - 2.4]. The meta-analysis based on 64 papers showed the pooled means of the incubation period and serial interval were 6.25 days (95% CrI: 5.75 - 6.75) and 5.15 days (95% CrI: 4.73 - 5.57), respectively. CONCLUSIONS: Our results contribute to a better understanding of COVID-19 and provide useful parameters for modelling the dynamics of disease transmission. The serial interval is shorter than the incubation period, which indicates that the patients are infectious at pre-symptomatic period, and isolation of detected cases alone is likely to be difficult to halt the spread of SARS-CoV-2.

Prevalence of suicide attempts among Chinese adolescents: A meta-analysis of cross-sectional studies.

OBJECTIVE: According to World Health Organization, for every committed suicide there were 20 suicide attempts at least. In the last decade, despite the increasing awareness on suicide attempts among adolescents in China, there has been no comprehensive system reporting vital statistics. Consequently, the prevalence of suicide attempts reported in some studies ranged variedly. Therefore, the purpose of this study was to provide the first meta-analysis of cross-sectional studies of suicide attempts to fill this gap. METHODS: Two reviewers independently screened potentially relevant cross-sectional studies of suicide attempts through PubMed-Medline, Embase, Wanfang Data, Chongqing VIP and Chinese National Knowledge Infrastructure databases using the core terms 'suicid*'/'suicide attempt*'/'attempted suicide' and 'adolescen*'/'youth'/'child*'/'student*' and 'China'/'Chinese' in the article titles, abstracts and keywords. Chi-square based Q test and I(2) statistic assessed the heterogeneity. Forest plot was used to display results graphically. Potential publication bias was assessed by the funnel plot, Begg's and Egger's test. RESULTS: In total, 43 studies with 200,124 participants met the eligibility criteria. The pooled prevalence of suicide attempts among Chinese adolescents was 2.94% (95% CI: 2.53%-3.41%). Substantial heterogeneity in prevalence estimates was revealed. Subgroup analyses showed that the prevalence for males was 2.50% (95% CI: 2.08%-3.01%), and for females was 3.17% (95% CI: 2.56%-3.91%). CONCLUSIONS: In sum, abstracting across the literatures, the prevalence of suicide attempts among Chinese adolescents was moderate compared with other countries around the world. Necessary measures should be set out prevent them in the future.

Clinical and molecular epidemiology of Escherichia coli sequence type 131 among hospitalized patients colonized intestinally with fluoroquinolone-resistant E. coli.

This study examined molecular and epidemiologic factors associated with Escherichia coli sequence type 131 (ST131) among hospitalized patients colonized intestinally with fluoroquinolone (FQ)-resistant E. coli between 2002 and 2004. Among 86 patients, 21 (24%) were colonized with ST131. The proportion of ST131 isolates among colonizing isolates increased significantly over time, from 8% in 2002 to 50% in 2004 (P = 0.003). Furthermore, all 19 clonally related isolates were ST131. Future studies should identify potential transmissibility differences between ST131 and non-ST131 strains.

The prevalence of suicidal ideation among the elderly in China: a meta-analysis of 11 cross-sectional studies.

OBJECTIVE: This study aimed to estimate the pooled prevalence of suicidal ideation among Chinese elderly aged ≥ 60 years. METHODS: Two reviewers independently searched the potentially relevant studies through electronic database (PubMed-Medline, Embase, Wanfang Data, Chinese National Knowledge Infrastructure and Chongqing VIP) using key terms 'suicid', 'suicidal ideation' combined with 'aged', 'elderly' and 'old people'. All selected studies should meet the eligibility criteria in this study. Chi-square based Q test and I(2) statistic assessed the heterogeneity. Forest plots were used to display results graphically. Potential publication bias was assessed by the funnel plot and Begg's test. Prevalence rate was meta-analysed. RESULTS: In total, 11 studies were included with 11,526 subjects. The prevalence of suicidal ideation among Chinese elderly ranged from 2.2% to 21.5%. The pooled prevalence of all 11 studies was 11.5% (95% CI: 8.3%-14.8%). Subgroup analyses showed the prevalence for males was 11.0%, and for the females was 15.6%. In three subgroups for age, 60-69, 70-79 and ≥ 80, the prevalence was 9.1%, 12.1% and 18.9% respectively. A slightly higher prevalence in rural areas was calculated than in urban (14.7% vs. 11.8%). In mainland China, the prevalence was 12.6%. And in Taiwan and Hongkong, the pooled prevalence was 9.2%. CONCLUSIONS: The prevalence of suicidal ideation was relatively high among elderly in China, and it should attract enough attention.

Impact of antibiotic use during hospitalization on the development of gastrointestinal colonization with Escherichia coli with reduced fluoroquinolone susceptibility.

OBJECTIVE: Infections due to fluoroquinolone-resistant Escherichia coli (FQREC) are associated with significant morbidity and mortality. Fluoroquinolone resistance likely arises at the level of gastrointestinal colonization. The objective of this study was to identify risk factors for the development of FQREC gastrointestinal tract colonization in hospitalized patients, including the impact of antibiotics prescribed during hospitalization. DESIGN: A prospective cohort study was conducted from 2002 to 2004 within a university health system. METHODS: Hospitalized patients initially colonized with fluoroquinolone-susceptible E. coli were followed up with serial fecal sampling for new FQREC colonization or until hospital discharge or death. A Cox proportional hazards regression model was developed to identify risk factors for new FQREC colonization, with antibiotic exposure modeled as time-varying covariates. RESULTS: Of 395 subjects, 73 (18.5%) became newly colonized with FQREC. Length of stay before sampling (hazard ratio [HR], 1.02 [95% confidence interval (CI), 1.1-1.03]; P = .003) and malignancy (HR, 0.37 [95% CI, 0.21-0.67]; P = .001) were significantly associated with the development of FQREC colonization. In addition, receipt of a first-generation cephalosporin (HR, 1.19 [95% CI, 1.10-1.29]; P < .001) or cefepime (HR, 1.05 [95% CI, 1.00-1.10]; P = .048) during hospitalization increased the risk of new FQREC colonization. CONCLUSIONS: The acquisition of FQREC in the hospital setting is complex, and antimicrobial stewardship programs should take into account patterns of antibiotic use in implementing strategies to reduce the development of new FQREC colonization. Future studies are needed to identify risk factors for infection in hospitalized patients newly colonized with FQREC.

Temporal changes in resistance mechanisms in colonizing Escherichia coli isolates with reduced susceptibility to fluoroquinolones.

The objective of this study was to characterize the temporal variability of fluoroquinolone resistance mechanisms among Escherichia coli colonizing the gastrointestinal tract of hospitalized patients. Patients with new fluoroquinolone-resistant E. coli (FQREC) colonization were followed with serial fecal sampling until discharge or death. Genetic mechanism(s) of resistance for all FQREC isolates was characterized, including mutations in gyrA and parC and efflux pump overexpression. Of 451 subjects, 73 (16.2%) became newly colonized with FQREC. There was significant variability in regard to temporal changes in resistance mechanisms and levofloxacin MICs among isolates from individual patients. Compared to patients with transient colonization, patients with persistent colonization were more likely to have a urinary catheter (P = 0.04), diarrhea (P = 0.04), and a longer duration of hospitalization (22 and 9.0 mean days, respectively; P = 0.01) prior to sampling. Our data demonstrate the significant variability of resistance mechanisms in colonizing E. coli isolates among hospitalized patients.

Risk factors for efflux pump overexpression in fluoroquinolone-resistant Escherichia coli.

BACKGROUND: We conducted a case-control study to identify risk factors for efflux overexpression, an important mechanism of fluoroquinolone resistance, among patients with fluoroquinolone-resistant Escherichia coli (FQREC) gastrointestinal tract colonization. METHODS: Three annual fecal surveillance surveys were performed hospital-wide, and all patients colonized with FQREC (levofloxacin minimum inhibitory concentration, ≥8 µg/mL) were included in the study. Cases and controls were defined on the basis of overexpression of the AcrAB efflux pump, as measured by the organic solvent tolerance (OST) assay. A multivariable logistic regression model was developed to identify risk factors for OST positivity among patients with FQREC colonization. RESULTS: Eighty-nine patients were colonized with FQREC: 44 (49.4%) and 45 (50.6%) patients had isolates that were OST-positive and OST-negative, respectively. On multivariable analyses, location on the surgical service was significantly associated with recovery of an OST-positive isolate (odds ratio, 7.36; 95% confidence interval, 1.82-29.7; P = .005). Furthermore, patients who had received a first-generation cephalosporin in the 30 days prior to sampling were less likely to have an OST-positive isolate (odds ratio, 0.20; 95% confidence interval, .04-.94; P = .04). CONCLUSIONS: Among phenotypically identical FQREC isolates, different factors may drive the emergence of different resistance mechanisms. Further studies are needed to elucidate the relationship between antimicrobial use and specific resistance mechanisms.

The prevalence of fluoroquinolone resistance mechanisms in colonizing Escherichia coli isolates recovered from hospitalized patients.

BACKGROUND: Fluoroquinolones are the most commonly prescribed antimicrobials. The epidemiology of fecal colonization with Escherichia coli demonstrating reduced susceptibility to fluoroquinolones remains unclear. METHODS: During a 3-year period (15 September 2004 through 19 October 2007), all patients hospitalized for >3 days were approached for fecal sampling. All E. coli isolates with reduced susceptibility to fluoroquinolones (minimum inhibitory concentration [MIC] of levofloxacin, 0.125 microg/mL) were identified. We characterized gyrA and parC mutations and organic solvent tolerance. Isolates were compared using pulsed-field gel electrophoresis. RESULTS: Of 353 patients colonized with E. coli demonstrating reduced fluoroquinolone susceptibility, 300 (85.0%) had 1 gyrA mutation, 161 (45.6%) had 1 parC mutation, and 171 (48.6%) demonstrated organic solvent tolerance. The mean numbers of total mutations (ie, gyrA and parC) for E. coli isolates with a levofloxacin MIC of 8 microg/mL versus <8.0 microg/mL were 2.70 and 0.82 (P < .001). Of the 136 E. coli isolates with a levofloxacin MIC of 8 microg/mL, 90 (66.2%) demonstrated a nalidixic acid MIC of 16 microg/mL. Significant differences were found over time in the proportion of E. coli isolates demonstrating gyrA mutation, parC mutation, and organic solvent tolerance. There was little evidence of clonal spread of isolates. Conclusions. Gastrointestinal tract colonization with E. coli demonstrating reduced susceptibility to levofloxacin is common. Although 40% of study isolates exhibited a levofloxacin MIC of <8 microg/mL (and would thus be missed by current Clinical and Laboratory Standards Institute breakpoints), nalidixic acid resistance may be a useful marker for detection of such isolates. Significant temporal changes occurred in the proportion of isolates exhibiting various resistance mechanisms.

Gastrointestinal tract colonization with fluoroquinolone-resistant Escherichia coli in hospitalized patients: changes over time in risk factors for resistance.

OBJECTIVE: The prevalence of fluoroquinolone (FQ) resistance in Escherichia coli has increased markedly in recent years. Despite the important role of gastrointestinal tract colonization with FQ-resistant E. coli (FQREC), the prevalence of and risk factors for FQREC colonization among the general hospitalized patient population have not been described, to our knowledge. The objective of this study was to identify the prevalence of and risk factors for FQREC colonization among hospitalized patients. DESIGN: Three-year case-control study. Case patients (ie, all subjects with FQREC colonization) were compared with control patients (ie, all subjects without FQREC colonization). SETTING: Two large medical centers within an academic health system. PARTICIPANTS: All patients hospitalized at the 2 study hospitals. MAIN OUTCOME MEASURE: Three annual fecal surveillance surveys were conducted. All patients colonized with FQREC (levofloxacin minimum inhibitory concentration, >or=8 microg/mL) were identified. RESULTS: Of the 774 subjects, 89 (11.5%) were colonized with FQREC. Although there was a significant association between prior FQ use and FQREC colonization on bivariable analysis (odds ratio [OR], 2.02 [95% confidence interval {CI}, 1.14-3.46]; P=.01), there was statistically significant effect modification by year of study (P=.005). In multivariable analyses, after controlling for the hospital and for the duration of hospitalization prior to sampling, the association between FQ use and FQREC colonization was as follows: adjusted OR (aOR), 0.97 (95% CI, 0.29-3.23) in 2002; aOR, 1.41 (95% CI, 0.57-3.50) in 2003; and aOR, 9.87 (95% CI, 3.67-26.55) in 2004. CONCLUSIONS: The association between prior FQ use and FQREC colonization varied significantly by study year, suggesting that the clinical epidemiology of resistant organisms may change over time. Furthermore, in the context of recent work showing significant changes in FQREC prevalence as well as changes in FQ resistance mechanisms (specifically, efflux overexpression) over the same time period, these results suggest a previously unrecognized complexity in the relationship between the clinical and molecular epidemiology of FQ resistance.

Duration of outpatient fecal colonization due to Escherichia coli Isolates with decreased susceptibility to fluoroquinolones: longitudinal study of patients recently discharged from the hospital.

Among 10 subjects colonized with Escherichia coli isolates with reduced susceptibility to fluoroquinolones, the median duration of colonization following hospital discharge was 80 days (range, 8 to 172 days). Colonization was longer for isolates demonstrating organic-solvent tolerance than for isolates that were not organic-solvent tolerant (151 versus 29 days, respectively; P = 0.07) but was not associated with other resistance mechanisms, demographics, or antibiotic use.

Phenotypic and genotypic characterization of fecal Escherichia coli isolates with decreased susceptibility to fluoroquinolones: results from a large hospital-based surveillance initiative.

BACKGROUND: The prevalence of fecal colonization with Escherichia coli that has reduced susceptibility to fluoroquinolones is unknown. A detailed characterization of such isolates is limited. METHODS: We conducted 3 annual fecal surveillance initiatives at 2 hospitals from 2002 to 2004. All E. coli isolates with reduced susceptibility to fluoroquinolones (minimum inhibitory concentration [MIC] to levofloxacin, > or = 0.125 microg/mL) were identified. We characterized gyrA and parC mutations and organic solvent tolerance (OST). Isolates were compared using pulsed-field gel electrophoresis. RESULTS: Of 789 fecal samples, 149 (18.9%) revealed E. coli with reduced susceptibility to fluoroquinolones. Of 149 isolates, 102 (68.5%) had a MIC > or = 8 microg/mL, 138 (92.6%) had > or = 1 gyrA mutation, 101 (67.8%) had > or = 1 parC mutation, and 59 (39.6%) demonstrated OST. Isolates with a MIC > or = 8 versus <8 microg/mL had more target mutations (median, 3 vs. 1; P<.001) and more often exhibited OST (51% vs. 15%; P<.001). Of 149 isolates, 144 (96.6%) demonstrated a MIC > or = 16 microg/mL to nalidixic acid. The prevalence of OST differed across study years (P = .01). There was no clonal spread of isolates. CONCLUSIONS: Colonization by E. coli with reduced fluoroquinolone susceptibility is common, and fluoroquinolone-resistance characteristics differ significantly over time. Resistance to nalidixic acid may be useful in the identification of E. coli with early resistance mutations.

Functional studies of the recombinant subunits of a cytolethal distending holotoxin.

Cytolethal distending toxin (CDT) is a multicomponent bacterial holotoxin that targets most eukarytotic cells causing distension and cell cycle arrest. A number of diverse pathogenic bacterial species associated with diarrhoea, chancroid, chronic hepatitis and periodontal disease produce a CDT. Synthesis of the holotoxin is directed by the expression of three genes, cdtA, cdtB and cdtC. Although the product of the CdtB gene was previously identified as a type I deoxyribonuclease, the functions of the cdtA and cdtC products have not been characterized. Using the periodontal pathogen, Actinobacillus actinomycetemcomitans, we demonstrate that the recombinant product of the CdtA gene binds to the surface of Chinese hamster ovary (CHO) cells. This protein did not induce distension or cytotoxicity when introduced into the cytosol using a lipid-based protein delivery system. Recombinant CdtB and CdtC proteins failed to bind to CHO cells. However, the delivery of either CdtB or CdtC into the cytosol resulted in the characteristic pattern of distension followed by cell death. Based on these results, it appears that the CdtA protein subunit alone is responsible for anchoring the holotoxin to the cell surface. The CdtC subunit, in concert with CdtB, contributes to the cytotoxic activities of the holotoxin. The specific mechanism of CdtC cytotoxicity is currently unknown.